Ergonomics and Health Care

Ergonomics and Health Care

Wednesday, 02 March 2011 15:16

Hospital Ergonomics: A Review

Author: Madeleine R. Estryn-Béhar

Ergonomics is an applied science that deals with the adaptation of work and the workplace to the characteristics and capabilities of the worker so that he or she may perform the duties of the job effectively and safely. It addresses the worker’s physical capacities in relation to the physical requirements of the job (e.g., strength, endurance, dexterity, flexibility, ability to tolerate positions and postures, visual and auditory acuity) as well as his or her mental and emotional status in relation to the way the work is organized (e.g., work schedules, workload and work-related stress). Ideally, adaptations are made to the furniture, equipment and tools used by the worker and to the work environment to enable the worker to perform adequately without risk to himself/herself, co-workers and the public. Occasionally, it is necessary to improve the worker’s adaptation to the job through, for example, special training and the use of personal protective equipment.

Since the mid 1970s, the application of ergonomics to hospital workers has broadened. It is directed now at those involved in direct patient care (e.g., physicians and nurses), those involved in ancillary services (e.g., technicians, laboratory staff, pharmacists and social workers) and those providing support services (e.g., administrative and clerical personnel, food service staff, housekeeping staff, maintenance workers and security staff).

Extensive research has been conducted into the ergonomics of hospitalization, with most studies attempting to identify the extent to which hospital administrators should allow hospital personnel latitude in developing strategies to reconcile an acceptable workload with good quality of care. Participatory ergonomics has become increasingly widespread in hospitals in recent years. More specifically, wards have been reorganized on the basis of ergonomic analyses of activity undertaken in collaboration with medical and paramedical personnel, and participatory ergonomics has been used as the basis for the adaptation of equipment for use in health care.

In studies of hospital ergonomics, workstation analysis must extend at least to the departmental level—the distance between rooms and the amount and location of equipment are all crucial considerations.

Physical strain is one of the primary determinants of the health of HCWs and the quality of care that they dispense. This being said, the frequent interruptions that hinder care-giving and the effect of psychological factors associated with confrontations with serious illness, ageing and death must also be addressed. Accounting for all these factors is a difficult task, but approaches focusing only on single factors will fail to improve either working conditions or the quality of care. Similarly, patients’ perception of the quality of their hospital stay is determined by the effectiveness of the care they receive, their relationship with physicians and other personnel, the food and the architectural environment.

Basic to hospital ergonomics is study of the sum and interaction of personal factors (e.g., fatigue, fitness, age and training) and circumstantial factors (e.g., work organization, schedule, floor layout, furniture, equipment, communication and psychological support within the work team), which combine to affect the performance of work. Precise identification of the actual work performed by health care workers depends on ergonomic observation of entire workdays and collection of valid and objective information on the movements, postures, cognitive performance and emotional control called upon to satisfy work requirements. This helps to detect factors that may interfere with effective, safe, comfortable and healthy work. This approach also sheds light on the potential for workers’ suffering or taking pleasure in their work. Final recommendations must take the interdependence of the various professional and ancillary personnel attending the same patient into account.

These considerations lay the groundwork for further, specific research. Analysis of strain related to the use of basic equipment (e.g., beds, meal carts and mobile x-ray equipment) may help clarify the conditions of acceptable use. Measurements of lighting levels may be complemented by information on the size and contrast of medication labels, for example. Where alarms emitted by different intensive-care-unit equipment can be confused, analysis of their acoustic spectrum may prove useful. Computerization of patient charts should not be undertaken unless the formal and informal information-support structures have been analysed. The interdependence of the various elements of the work environment of any given caregiver should therefore always be borne in mind when analysing isolated factors.

Analysis of the interaction of different factors influencing care—physical strain, cognitive strain, affective strain, scheduling, ambience, architecture and hygiene protocols—is essential. It is important to adapt schedules and common work areas to the needs of the work team when attempting to improve overall patient management. Participatory ergonomics is a way of using specific information to bring about wide-ranging and relevant improvements to the quality of care and to working life. Involving all categories of personnel in key stages of the search for solution helps ensure that the modifications finally adopted will have their full support.

Working Postures

Epidemiological studies of joint and musculoskeletal disorders. Several epidemiological studies have indicated that inappropriate postures and handling techniques are associated with a doubling of the number of back, joint and muscle problems requiring treatment and time off the job. This phenomenon, discussed in greater detail elsewhere in this chapter and Encyclopaedia, is related to physical and cognitive strain.

Working conditions differ from country to country. Siegel et al. (1993) compared conditions in Germany and Norway and found that 51% of German nurses, but only 24% of Norwegian nurses, suffered lower-back pain on any given day. Working conditions in the two countries differed; however, in German hospitals, the patient-nurse ratio was twice as high and the number of adjustable-height beds half that in Norwegian hospitals, and fewer nurses had patient handling equipment (78% versus 87% in Norwegian hospitals).

Epidemiological studies of pregnancy and its outcome. Because the hospital workforce is usually predominantly female, the influence of work on pregnancy often becomes an important issue (see articles on pregnancy and work elsewhere in this Encyclopaedia). Saurel-Cubizolles et al. (1985) in France, for example, studied 621 women who returned to hospital work after giving birth and found that a higher rate of premature births were associated with heavy housekeeping chores (e.g., cleaning windows and floors), carrying heavy loads and long periods of standing. When these tasks were combined, the rate of premature births was increased: 6% when only one of these factors was involved and up to 21% when two or three were involved. These differences remained significant after adjustment for seniority, social and demographic characteristics and professional level. These factors were also associated with a higher frequency of contractions, more hospital admissions during pregnancy and, on average, longer sick leave.

In Sri Lanka, Senevirane and Fernando (1994) compared 130 pregnancies borne by 100 nursing officers and 126 by clerical workers whose jobs presumably were more sedentary; socio-economic backgrounds and use of prenatal care were similar for both groups. Odds-ratios for complications of pregnancy (2.18) and preterm delivery (5.64) were high among nursing officers.

Ergonomic Observation of Workdays

The effect of physical strain on health care workers has been demonstrated through continuous observation of workdays. Research in Belgium (Malchaire 1992), France (Estryn-Béhar and Fouillot 1990a) and Czechoslovakia (Hubacova, Borsky and Strelka 1992) has shown that health care workers spend 60 to 80% of their workday standing (see table 1). Belgian nurses were observed to spend approximately 10% of their workday bent over; Czechoslovakian nurses spent 11% of their workday positioning patients; and French nurses spent 16 to 24% of their workday in uncomfortable positions, such as stooping or squatting, or with their arms raised or loaded.

Table 1. Distribution of nurses’ time in three studies

	Czechoslovakia	Belgium	France
Authors	Hubacova, Borsky and Strelka 1992^*	Malchaire 1992^**	Estryn-Béhar and Fouillot 1990a^***
Departments	5 medical and surgical departments	Cardiovascular surgery	10 medical and surgical departments
Average time for the main postures and total distance walked by nurses:
Per cent working hours standing and walking	76%	Morning 61% Afternoon 77% Night 58%	Morning 74% Afternoon 82% Night 66%
Including stooping, squatting, arms raised, loaded	11%		Morning 16% Afternoon 30% Night 24%
Standing flexed		Morning 11% Afternoon 9% Night 8%
Distance walked		Morning 4 km Afternoon 4 km Night 7 km	Morning 7 km Afternoon 6 km Night 5 km
Per cent working hours with patients	Three shifts: 47%	Morning 38% Afternoon 31% Night 26%	Morning 24% Afternoon 30% Night 27%

Number of observations per shift:* 74 observations on 3 shifts. ** Morning: 10 observations (8 h); afternoon: 10 observations (8 h); night: 10 observations (11 h). *** Morning: 8 observations (8 h); afternoon: 10 observations (8 h); night: 9 observations (10-12 h).

In France, night-shift nurses spent somewhat more time sitting, but they end their shift by making beds and dispensing care, both of which involve work in uncomfortable positions. They are assisted in this by a nurses’ aide, but this should be contrasted with the situation during the morning shift, where these tasks are usually performed by two nurses’ aides. In general, nurses working day shifts spend less time in uncomfortable positions. Nurses’ aides were on their feet constantly, and uncomfortable positions, due largely to inadequate equipment, accounted for 31% (afternoon shift) to 46% (morning shift) of their time. Patient facilities in these French and Belgian teaching hospitals were spread out over large areas and consisted of rooms containing one to three beds. Nurses in these wards walked an average of 4 to 7 km per day.

Detailed ergonomic observation of entire workdays (Estryn-Béhar and Hakim-Serfaty 1990) is useful in revealing the interaction of the factors that determine quality of care and the manner in which work is performed. Consider the very different situations in a paediatric intensive care unit and a rheumatology ward. In paediatric resuscitation units, the nurse spends 71% of her time in patients’ rooms, and each patient’s equipment is kept on individual carts stocked by nurses’ aides. The nurses in this ward change location only 32 times per shift, walking a total of 2.5 km. They are able to communicate with physicians and other nurses in the adjoining lounge or nurses’ station through intercoms which have been installed in all the patients’ rooms.

By contrast, the nursing station in the rheumatology ward is very far from patients’ rooms, and care preparation is lengthy (38% of shift time). As a result, the nurses spend only 21% of their time in patients’ rooms and change location 128 times per shift, walking a total of 17 km. This clearly illustrates the interrelationship between physical strain, back problems and organizational and psychological factors. Because they need to move rapidly and get equipment and information, nurses only have time for hallway consultations—there is no time to sit while dispensing care, listen to patients and give patients personalized and integrated responses.

Continuous observation of 18 Dutch nurses in long-term-stay wards revealed that they spent 60% of their time performing physically demanding work with no direct contact with their patients (Engels, Senden and Hertog 1993). Housekeeping and preparation account for most of the 20% of the time described as spent in “slightly hazardous” activities. In all, 0.2% of shift time was spent in postures requiring immediate modification and 1.5% of shift time in postures requiring rapid modification. Contact with patients was the type of activity most frequently associated with these hazardous postures. The authors recommend modifying patient-handling practices and other less hazardous but more frequent tasks.

Given the physiological strain of the work of nurses’ aides, continuous measurement of heart rate is a useful complement to observation. Raffray (1994) used this technique to identify arduous housekeeping tasks and recommended not restricting personnel to this type of task for the whole day.

Electro-myographical (EMG) fatigue analysis is also interesting when body posture must remain more or less static—for example, during operations using an endoscope (Luttman et al. 1996).

Influence of architecture, equipment and organization

The inadequacy of nursing equipment, particularly beds, in 40 Japanese hospitals was demonstrated by Shindo (1992). In addition, patients’ rooms, both those lodging six to eight patients and single rooms reserved for the very ill, were poorly laid out and extremely small. Matsuda (1992) reported that these observations should lead to improvements in the comfort, safety and efficiency of nursing work.

In a French study (Saurel 1993), the size of patient rooms was problematic in 45 of 75 medium- and long-term-stay wards. The most common problems were:

lack of space (30 wards)

difficulty in manoeuvring patient-transfer gurneys (17)

inadequate space for furniture (13)

the need to take beds out of the room to transfer patients (12)

difficult access and poor furniture layout (10)

doors that were too small (8)

difficulty moving between beds (8).

The mean available area per bed for patients and nurses is at the root of these problems and decreases as the number of beds per room increases: 12.98 m², 9.84 m², 9.60 m², 8.49 m² and 7.25 m² for rooms with one, two, three, four and more than four beds. A more accurate index of the useful area available to personnel is obtained by subtracting the area occupied by the beds themselves (1.8 to 2.0 m²) and by other equipment. The French Department of Health prescribes a useful surface area of 16 m² for single rooms and 22 m² for double rooms. The Quebec Department of Health recommends 17.8 m² and 36 m², respectively.

Turning to factors favouring the development of back problems, variable-height mechanisms were present on 55.1% of the 7,237 beds examined; of these, only 10.3% had electric controls. Patient-transfer systems, which reduce lifting, were rare. These systems were systematically used by 18.2% of the 55 responding wards, with over half the wards reporting using them “rarely” or “never”. “Poor” or “rather poor” manoeuvrability of meal carts was reported by 58.5% of 65 responding wards. There was no periodic maintenance of mobile equipment in 73.3% of 72 responding wards.

In almost half the responding wards, there were no rooms with seats that nurses could use. In many cases, this appears to have been due to the small size of the patient rooms. Sitting was usually possible only in the lounges—in 10 units, the nursing station itself had no seats. However, 13 units reported having no lounge and 4 units used the pantry for this purpose. In 30 wards, there were no seats in this room.

According to statistics for 1992 provided by the Confederation of Employees of the Health Services Employees of the United Kingdom (COHSE), 68.2% of nurses felt that there were not enough mechanical patient lifts and handling aides and 74.5% felt that they were expected to accept back problems as a normal part of their work.

In Quebec, the Joint Sectoral Association, Social Affairs Sector (Association pour la santé et la sécurité du travail, secteur afffaires sociales, ASSTAS) initiated its “Prevention-Planning-Renovation-Construction” project in 1993 (Villeneuve 1994). Over 18 months, funding for almost 100 bipartite projects, some costing several million dollars, was requested. This programme’s goal is to maximize investments in prevention by addressing health and safety concerns early in the design stage of planning, renovation and design projects.

The association completed the modification of the design specifications for patient rooms in long-term-care units in 1995. After noting that three-quarters of occupational accidents involving nurses occur in patient rooms, the association proposed new dimensions for patients’ rooms, and new rooms must now provide a minimum amount of free space around beds and accommodate patient lifts. Measuring 4.05 by 4.95 m, the rooms are more square than the older, rectangular rooms. To improve performance, ceiling-mounted patient lifts were installed, in collaboration with the manufacturer.

The association is also working on the modification of construction standards for washrooms, where many occupational accidents also occur, although to a lesser extent than in the rooms themselves. Finally, the feasibility of applying anti-skid coatings (with a coefficient of friction above the minimum standard of 0.50) on floors is being studied, since patient autonomy is best promoted by providing a non-skid surface on which neither they nor nurses can slip.

Evaluation of equipment that reduces physical strain

Proposals for improving beds (Teyssier-Cotte, Rocher and Mereau 1987) and meal carts (Bouhnik et al. 1989) have been formulated, but their impact is too limited. Tintori et al. (1994) studied adjustable-height beds with electric trunk-lifts and mechanical mattress-lifts. The trunk-lifts were judged satisfactory by the staff and patients, but the mattress-lifts were very unsatisfactory, since adjusting the beds required more than eight pedal strokes, each of which exceeded standards for foot force. Pushing a button located close to the patient’s head while talking to her or him is clearly preferable to pumping a pedal eight times from the foot of the bed (see figure 1). Because of time constraints, the mattress lift was often simply not used.

Figure 1. Electronically-operated trunk-lifts on beds effectively reduce lifting accidents

B. Floret

Van der Star and Voogd (1992) studied health care workers caring for 30 patients in a new prototype of bed over a period of six weeks. Observations of the workers’ positions, the height of work surfaces, physical interaction between nurses and patients and the size of the work space were compared to data collected on the same ward over a seven-week period prior to the introduction of the prototype. Use of the prototypes reduced the total time spent in uncomfortable positions while washing patients from 40% to 20%; for bed-making the figures were 35% and 5%. Patients also enjoyed greater autonomy and often changed positions on their own, raising their trunks or legs by means of electric control buttons.

In Swedish hospitals, each double room is equipped with ceiling-mounted patient lifts (Ljungberg, Kilbom and Goran 1989). Rigorous programmes such as the April Project evaluate the interrelation of working conditions, work organization, the establishment of a back school and the improvement of physical fitness (Öhling and Estlund 1995).

In Quebec, ASSTAS developed a global approach to the analysis of working conditions causing back problems in hospitals (Villeneuve 1992). Between 1988 and 1991, this approach led to modifications of the work environment and equipment used in 120 wards and a 30% reduction in the frequency and severity of occupational injuries. In 1994, a cost-benefit analysis performed by the association demonstrated that the systematic implementation of ceiling-mounted patient lifts would reduce occupational accidents and increase productivity, compared to the continued use of mobile, ground-based lifts (see figure 2).

Figure 2. Using ceiling-mounted patient lifts to reduce lifting accidents

Accounting for individual variation and facilitating activity

The female population in France is generally not very physically active. Of 1,505 nurses studied by Estryn-Béhar et al. (1992), 68% participated in no athletic activity, with inactivity more pronounced among mothers and unskilled personnel. In Sweden, fitness programmes for hospital personnel have been reported to be useful (Wigaeus Hjelm, Hagberg and Hellstrom 1993), but are feasible only if potential participants do not end their work day too tired to participate.

The adoption of better work postures is also conditioned by the possibility of wearing appropriate clothing (Lempereur 1992). The quality of shoes is particularly important. Hard soles are to be avoided. Anti-skid soles prevent occupational accidents caused by slips and falls, which in many countries are the second-leading cause of accidents leading to work absence. Ill-fitting overshoes or boots worn by operating room personnel to minimize the build-up of static electricity may be a hazard for falls.

Slips on level floors can be prevented by using low-slip floor surfaces that require no waxing. The risk of slips, particularly at doorways, can also be reduced by using techniques that do not leave the floor wet for long. The use of one mop per room, recommended by hygiene departments, is one such technique and has the additional advantage of reducing the handling of buckets of water.

In Vasteras County (Sweden), the implementation of several practical measures reduced painful syndromes and absenteeism by at least 25% (Modig 1992). In the archives (e.g., record or file rooms), ground- and ceiling-level shelves were eliminated, and an adjustable sliding board on which personnel can take notes while consulting the archives was installed. A reception office equipped with movable filing units, a computer and a telephone was also constructed. The height of the filing units is adjustable, allowing employees to adjust them to their own needs and facilitating the transition from sitting to standing during work.

Importance of “anti-lifting”

Manual patient-handling techniques designed to prevent back injuries have been proposed in many countries. Given the poor results of these techniques that have been reported to date (Dehlin et al. 1981; Stubbs, Buckle and Hudson 1983), more work in this area is needed.

The department of kinesiology of the University of Groningen (Netherlands) has developed an integrated patient-handling programme (Landewe and Schröer 1993) consisting of:

recognition of the relationship between patient-handling and back strain

demonstration of the value of the “anti-lifting” approach

sensitization of nursing students throughout their studies to the importance of avoiding back strain

the use of problem-resolution techniques

attention to implementation and evaluation.

In the “anti-lifting” approach, the resolution of problems associated with patient transfers is based on the systematic analysis of all aspects of transfers, especially those related to patients, nurses, transfer equipment, teamwork, general working conditions and environmental and psychological barriers to the use of patient lifts (Friele and Knibbe 1993).

The application of European standard EN 90/269 of 29 May 1990 on back problems is an example of an excellent starting point for this approach. Besides requiring employers to implement appropriate work organization structures or other appropriate means, particularly mechanical equipment, to avoid manual handling of loads by workers, it also emphasizes the importance of “no-risk” handling policies that incorporate training. In practice, the adoption of appropriate postures and handling practices depends on the amount of functional space, presence of appropriate furniture and equipment, good collaboration on work organization and quality of care, good physical fitness and comfortable work clothing. The net effect of these factors is improved prevention of back problems.

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madeleine r estrynbehar

Strain in Health Care Work

Cognitive Strain

Continuous observation has revealed that nurses’ workdays are characterized by continual reorganization of their work schedules and frequent interruptions.

Belgian (Malchaire 1992) and French (Gadbois et al. 1992; Estryn-Béhar and Fouillot 1990b) studies have revealed that nurses perform 120 to 323 separate tasks during their workday (see table 1). Work interruptions are very frequent throughout the day, ranging from 28 to 78 per workday. Many of the units studied were large, short-term-stay units in which the nurses’ work consisted of a long series of spatially dispersed, short-duration tasks. Planning of work schedules was complicated by the presence of incessant technical innovation, close interdependence of the work of the various staff members and a generally haphazard approach to work organization.

Table 1. Number of separate tasks undertaken by nurses, and interruptions during each shift

	Belgium	France	France
Authors	Malchaire 1992^*	Gadbois et al. 1992^**	Estryn-Béhar and Fouillot 1990b^***
Departments	Cardiovascular surgery	Surgery (S) and medicine (M)	Ten medical and surgical departments
Number of separate tasks	Morning 120/8 h Afternoon 213/8 h Night 306/8 h	S (day) 276/12 h M (day) 300/12 h	Morning 323/8 h Afternoon 282/8 h Night 250/10–12 h
Number of interruptions		S (day) 36/12 h M (day) 60/12 h	Morning 78/8 h Afternoon 47/8 h Night 28/10–12 h

Number of hours of observation: * Morning: 80 h; afternoon: 80 h; night: 110 h. ** Surgery: 238 h; medicine: 220 h. *** Morning : 64 h; afternoon: 80 h; night: 90 h.

Gadbois et al. (1992) observed an average of 40 interruptions per workday, of which 5% were caused by patients, 40% by inadequate transmission of information, 15% by telephone calls and 25% by equipment. Ollagnier and Lamarche (1993) systematically observed nurses in a Swiss hospital and observed 8 to 32 interruptions per day, depending on the ward. On average, these interruptions represented 7.8% of the workday.

Work interruptions such as these, caused by inappropriate information supply and transmission structures, prevent workers from completing all their tasks and lead to worker dissatisfaction. The most serious consequence of this organizational deficiency is the reduction of time spent with patients (see table 2). In the first three studies cited above, nurses spent at most 30% of their time with patients on average. In Czechoslovakia, where multiple-bed rooms were common, nurses needed to change rooms less frequently, and spent 47% of their shift time with patients (Hubacova, Borsky and Strelka 1992). This clearly demonstrates how architecture, staffing levels and mental strain are all interrelated.

Table 2. Distribution of nurses’ time in three studies

	Czechoslovakia	Belgium	France
Authors	Hubacova, Borsky and Strelka 1992^*	Malchaire 1992^**	Estryn-Béhar and Fouillot 1990a^***
Departments	5 medical and surgical departments	Cardiovascular surgery	10 medical and surgical departments
Average time for the main postures and total distance walked by nurses:
Per cent working hours standing and walking	76%	Morning 61% Afternoon 77% Night 58%	Morning 74% Afternoon 82% Night 66%
Including stooping, squatting, arms raised, loaded	11%		Morning 16% Afternoon 30% Night 24%
Standing flexed		Morning 11% Afternoon 9% Night 8%
Distance walked		Morning 4 km Afternoon 4 km Night 7 km	Morning 7 km Afternoon 6 km Night 5 km
Per cent working hours with patients	Three shifts: 47%	Morning 38% Afternoon 31% Night 26%	Morning 24% Afternoon 30% Night 27%

Number of observations per shift: * 74 observations on 3 shifts. ** Morning: 10 observations (8 h); afternoon: 10 observations (8 h); night: 10 observations (11 h). *** Morning: 8 observations (8 h); afternoon: 10 observations (8 h); night: 9 observations (10-12 h).

Estryn-Béhar et al. (1994) observed seven occupations and schedules in two specialized medical wards with similar spatial organization and located in the same high-rise building. While work in one ward was highly sectorized, with two teams of a nurse and a nurses’ aide attending half of the patients, there were no sectors in the other ward, and basic care for all patients was dispensed by two nurses’ aides. There were no differences in the frequency of patient-related interruptions in the two wards, but team-related interruptions were clearly more frequent in the ward without sectors (35 to 55 interruptions compared to 23 to 36 interruptions). Nurses’ aides, morning-shift nurses and afternoon-shift nurses in the non-sectorized ward suffered 50, 70 and 30% more interruptions than did their colleagues in the sectorized one.

Sectorization thus appears to reduce the number of interruptions and the fracturing of work shifts. These results were used to plan the reorganization of the ward, in collaboration with the medical and paramedical staff, so as to facilitate sectorization of the office and the preparation area. The new office space is modular and easily divided into three offices (one for physicians and one for each of the two nursing teams), each separated by sliding glass partitions and furnished with at least six seats. Installation of two counters facing each other in the common preparation area means that nurses who are interrupted during preparation can return and find their materials in the same position and state, unaffected by their colleagues’ activities.

Reorganization of work schedules and technical services

Professional activity in technical departments is much more than the mere sum of tasks associated with each test. A study conducted in several nuclear medicine departments (Favrot-Laurens 1992) revealed that nuclear medicine technicians spend very little of their time performing technical tasks. In fact, a significant part of technicians’ time was spent coordinating activity and workload at the various workstations, transmitting information and making unavoidable adjustments. These responsibilities stem from technicians’ obligation to be knowledgeable about each test and to possess essential technical and administrative information in addition to test-specific information such as time and injection site.

Information processing necessary for the delivery of care

Roquelaure, Pottier and Pottier (1992) were asked by a manufacturer of electroencephalography (EEG) equipment to simplify the use of the equipment. They responded by facilitating the reading of visual information on controls which were excessively complicated or simply unclear. As they point out, “third-generation” machines present unique difficulties, due in part to the use of visual display units packed with barely legible information. Deciphering these screens requires complex work strategies.

On the whole, however, little attention has been paid to the need to present information in a manner that facilitates rapid decision-making in health care departments. For example, the legibility of information on medicine labels still leaves much to be desired, according to one study of 240 dry oral and 364 injectable medications (Ott et al. 1991). Ideally, labels for dry oral medication administered by nurses, who are frequently interrupted and attend several patients, should have a matte surface, characters at least 2.5 mm high and comprehensive information on the medication in question. Only 36% of the 240 medications examined satisfied the first two criteria, and only 6% all three. Similarly, print smaller than 2.5 mm was used in 63% of labels on the 364 injectable medications.

In many countries where English is not spoken, machine control panels are still labelled in English. Patient-chart software is being developed in many countries. In France, this type of software development is often motivated by a desire to improve hospital management and undertaken without adequate study of the software’s compatibility with actual working procedures (Estryn-Béhar 1991). As a result, the software may actually increase the complexity of nursing, rather than reduce cognitive strain. Requiring nurses to page through multiple screens of information to obtain the information they need to fill a prescription may increase the number of errors they make and memory lapses they suffer.

While Scandinavian and North American countries have computerized much of their patient records, it must be borne in mind that hospitals in these countries benefit from a high staff-to-patient ratio, and work interruptions and constant reshuffling of priorities are therefore less problematic there. In contrast, patient-chart software designed for use in countries with lower staff-to-patient ratios must be able to easily produce summaries and facilitate reorganization of priorities.

Human error in anaesthesia

Cooper, Newbower and Kitz (1984), in their study of the factors underlying errors during anaesthesia in the United States, found equipment design to be crucial. The 538 errors studied, largely drug administration and equipment problems, were related to the distribution of activities and the systems involved. According to Cooper, better design of equipment and monitoring apparatus would lead to a 22% reduction in errors, while complementary training of anaesthesiologists, using new technologies such as anaesthesia simulators, would lead to a 25% reduction. Other recommended strategies focus on work organization, supervision and communications.

Acoustic alarms in operating theatres and intensive-care units

Several studies have shown that too many types of alarms are used in operating theatres and intensive-care units. In one study, anaesthetists identified only 33% of alarms correctly, and only two monitors had recognition rates exceeding 50% (Finley and Cohen 1991). In another study, anaesthetists and anaesthesia nurses correctly identified alarms in only 34% of cases (Loeb et al. 1990). Retrospective analysis showed that 26% of nurses’ errors were due to similarities in alarm sounds and 20% to similarities in alarm functions. Momtahan and Tansley (1989) reported that recovery-room nurses and anaesthetists correctly identified alarms in only 35% and 22% of cases respectively. In another study by Momtahan, Hétu and Tansley (1993), 18 physicians and technicians were able to identify only 10 to 15 of 26 operating-theatre alarms, while 15 intensive-care nurses were able to identify only 8 to 14 of 23 alarms used in their unit.

De Chambost (1994) studied the acoustic alarms of 22 types of machines used in an intensive-care unit in the Paris region. Only the cardiogram alarms and those of one of the two types of automated-plunger syringes were readily identified. The others were not immediately recognized and required personnel first to investigate the source of the alarm in the patient’s room and then return with the appropriate equipment. Spectral analysis of the sound emitted by eight machines revealed significant similarities and suggests the existence of a masking effect between alarms.

The unacceptably high number of unjustifiable alarms has been the object of particular criticism. O’Carroll (1986) characterized the origin and frequency of alarms in a general intensive-care unit over three weeks. Only eight of 1,455 alarms were related to a potentially fatal situation. There were many false alarms from monitors and perfusion pumps. There was little difference between the frequency of alarms during the day and night.

Similar results have been reported for alarms used in anaesthesiology. Kestin, Miller and Lockhart (1988), in a study of 50 patients and five commonly used anaesthesia monitors, reported that only 3% indicated a real risk for the patient and that 75% of alarms were unfounded (caused by patient movement, interference and mechanical problems). On average, ten alarms were triggered per patient, equivalent to one alarm every 4.5 minutes.

A common response to false alarms is simply to disable them. McIntyre (1985) reported that 57% of Canadian anaesthetists admitted deliberately inactivating an alarm. Obviously, this could lead to serious accidents.

These studies underscore the poor design of hospital alarms and the need for alarm standardization based on cognitive ergonomics. Both Kestin, Miller and Lockhart (1988) and Kerr (1985) have proposed alarm modifications that take into account risk and the expected corrective responses of hospital personnel. As de Keyser and Nyssen (1993) have shown, the prevention of human error in anaesthesia integrates different measures—technological, ergonomic, social, organizational and training.

Technology, human error, patient safety and perceived psychological strain

Rigorous analysis of the error process is very useful. Sundström-Frisk and Hellström (1995) reported that equipment deficiencies and/or human error were responsible for 57 deaths and 284 injuries in Sweden between 1977 and 1986. The authors interviewed 63 intensive-care-unit teams involved in 155 incidents (“near-accidents”) involving advanced medical equipment; most of these incidents had not been reported to authorities. Seventy typical “near-accident” scenarios were developed. Causal factors identified included inadequate technical equipment and documentation, the physical environment, procedures, staffing levels and stress. The introduction of new equipment may lead to accidents if the equipment is poorly adapted to users’ needs and is introduced in the absence of basic changes in training and work organization.

In order to cope with forgetfulness, nurses develop several strategies for remembering, anticipating and avoiding incidents. They do still occur and even when patients are unaware of errors, near-accidents cause personnel to feel guilty. The article "Case Study: Human Error and Critical Taks" deals with some aspects of the problem.

Emotional or Affective Strain

Nursing work, especially if it forces nurses to confront serious illness and death, can be a significant source of affective strain, and may lead to burn-out, which is discussed more fully elsewhere in this Encyclopaedia. Nurses’ ability to cope with this stress depends on the extent of their support network and their possibility to discuss and improve patients’ quality of life. The following section summarizes the principal findings of Leppanen and Olkinuora’s (1987) review of Finnish and Swedish studies on stress.

In Sweden, the main motivations reported by health professionals for entering their profession were the “moral calling” of the work, its usefulness and the opportunity to exercise competence. However, almost half of nurses’ aides rated their knowledge as inadequate for their work, and one-quarter of nurses, one-fifth of registered nurses, one-seventh of physicians and one-tenth of head nurses considered themselves incompetent at managing some types of patients. Incompetence in managing psychological problems was the most commonly cited problem and was particularly prevalent among nurses’ aides, although also cited by nurses and head nurses. Physicians, on the other hand, consider themselves competent in this area. The authors focus on the difficult situation of nurses’ aides, who spend more time with patients than the others but are, paradoxically, unable to inform patients about their illness or treatment.

Several studies reveal the lack of clarity in delineating responsibilities. Pöyhönen and Jokinen (1980) reported that only 20% of Helsinki nurses were always informed of their tasks and the goals of their work. In a study conducted in a paediatric ward and an institute for disabled persons, Leppanen showed that the distribution of tasks did not allow nurses enough time to plan and prepare their work, perform office work and collaborate with team members.

Responsibility in the absence of decision-making power appears to be a stress factor. Thus, 57% of operating-room nurses felt that ambiguities concerning their responsibilities aggravated their cognitive strain; 47% of surgical nurses reported being unfamiliar with some of their tasks and felt that patients’ and nurses’ conflicting expectations were a source of stress. Further, 47% reported increased stress when problems occurred and physicians were not present.

According to three European epidemiological studies, burn-out affects approximately 25% of nurses (Landau 1992; Saint-Arnaud et al. 1992; Estryn-Béhar et al. 1990) (see table 3 ). Estryn-Béhar et al. studied 1,505 female health care workers, using a cognitive strain index that integrates information on work interruptions and reorganization and an affective strain index that integrates information on work ambience, teamwork, congruity of qualification and work, time spent talking to patients and the frequency of hesitant or uncertain responses to patients. Burn-out was observed in 12% of nurses with low, 25% of those with moderate and 39% of those with high cognitive strain. The relationship between burn-out and affective strain increases was even stronger: burn-out was observed in 16% of nurses with low, 25% of those with moderate and 64% of those with high affective strain. After adjustment by logistic multivariate regression analysis for social and demographic factors, women with a high affective strain index had an odds ratio for burn-out of 6.88 compared to those with a low index.

Table 3. Cognitive and affective strain and burn-out among health workers

	Germany^*	Canada^**	France^***
Number of subjects	24	868	1,505
Method	Maslach Burn-out Inventory	Ilfeld Psychiatric Symptoms Index	Goldberg General Health Questionnaire
High emotional exhaustion	33%	20%	26%
Degree of burn-out, by shift	Morning 2.0; afternoon 2.3; split shift 3.4; night 3.3		Morning 25%; afternoon 25%; night 29%
Percentage suffering high emotional exhaustion, by strain level		Cognitive and affective strain: low 16.5%; high 36.6%	Cognitive strain: low 12%, middle 25%, high 39% Affective strain: low 16%, middle 35%, high 64%

* Landau 1992. ** Saint Arnand et. al. 1992. *** Estryn-Béhar et al. 1990.

Saint-Arnaud et al. reported a correlation between the frequency of burn-out and the score on their composite cognitive and affective strain index. Landau’s results support these findings.

Finally, 25% of 520 nurses working in a cancer treatment centre and a general hospital in France were reported to exhibit high burn-out scores (Rodary and Gauvain-Piquard 1993). High scores were most closely associated with a lack of support. Feelings that their department did not regard them highly, take their knowledge of the patients into account or put the highest value on their patients’ quality of life were reported more frequently by nurses with high scores. Reports of being physically afraid of their patients and unable to organize their work schedule as they wished were also more frequent among these nurses. In light of these results, it is interesting to note that Katz (1983) observed a high suicide rate among nurses.

Impact of workload, autonomy and support networks

A study of 900 Canadian nurses revealed an association between workload and five indices of cognitive strain measured by the Ilfeld questionnaire: the global score, aggression, anxiety, cognitive problems and depression (Boulard 1993). Four groups were identified. Nurses with a high workload, high autonomy and good social support (11.76%) exhibited several stress-related symptoms. Nurses with a low workload, high autonomy and good social support (35.75%) exhibited the lowest stress. Nurses with high workload, little autonomy and little social support (42.09%) had a high prevalence of stress-related symptoms, while nurses with a low workload, little autonomy and little social support (10.40%) had low stress, but the authors suggest that these nurses may experience some frustration.

These results also demonstrate that autonomy and support, rather than moderating the relationship between workload and mental health, act directly on workload.

Role of head nurses

Classically, employee satisfaction with supervision has been considered to depend on the clear definition of responsibilities and on good communication and feedback. Kivimäki and Lindström (1995) administered a questionnaire to nurses in 12 wards of four medical departments and interviewed the wards’ head nurses. Wards were classified into two groups on the basis of the reported level of satisfaction with supervision (six satisfied wards and six dissatisfied wards). Scores for communication, feedback, participation in decision-making and the presence of a work climate that favours innovation were higher in “satisfied” wards. With one exception, head nurses of “satisfied” wards reported conducting at least one confidential conversation lasting one to two hours with each employee annually. In contrast, only one of the head nurses of the “dissatisfied” wards reported this behaviour.

Head nurses of the “satisfied” wards reported encouraging team members to express their opinions and ideas, discouraging team members from censuring or ridiculing nurses who made suggestions, and consistently attempting to give positive feedback to nurses expressing different or new opinions. Finally, all the head nurses in “satisfied” wards, but none of the ones in “dissatisfied” ones, emphasized their own role in creating a climate favourable to constructive criticism.

Psychological roles, relationships and organization

The structure of nurses’ affective relationships varies from team to team. A study of 1,387 nurses working regular night shifts and 1,252 nurses working regular morning or afternoon shifts revealed that shifts were extended more frequently during night shifts (Estryn-Béhar et al. 1989a). Early shift starts and late shift ends were more prevalent among night-shift nurses. Reports of a “good” or “very good” work ambience were more prevalent at night, but a “good relationship with physicians” was less prevalent. Finally, night-shift nurses reported having more time to talk to patients, although that meant that worries and uncertainties about the appropriate response to give patients, also more frequent at night, were harder to bear.

Büssing (1993) revealed that depersonalization was greater for nurses working abnormal hours.

Stress in physicians

Denial and suppression of stress are common defence mechanisms. Physicians may attempt to repress their problems by working harder, distancing themselves from their emotions or adopting the role of a martyr (Rhoads 1977; Gardner and Hall 1981; Vaillant, Sorbowale and McArthur 1972). As these barriers become more fragile and adaptive strategies break down, bouts of anguish and frustration become more and more frequent.

Valko and Clayton (1975) found that one-third of interns suffered severe and frequent episodes of emotional distress or depression, and that one-quarter of them entertained suicidal thoughts. McCue (1982) believed that a better understanding of both stress and reactions to stress would facilitate physician training and personal development and modify societal expectations. The net effect of these changes would be an improvement in care.

Avoidance behaviours may develop, often accompanied by a deterioration of interpersonal and professional relationships. At some point, the physician finally crosses the line into a frank deterioration of mental health, with symptoms which may include substance abuse, mental illness or suicide. In yet other cases, patient care may be compromised, resulting in inappropriate examinations and treatment, sexual abuse or pathological behaviour (Shapiro, Pinsker and Shale 1975).

A study of 530 physician suicides identified by the American Medical Association over a five-year period found that 40% of suicides by female physicians and less than 20% of suicides by male physicians occurred in individuals younger than 40 years (Steppacher and Mausner 1974). A Swedish study of suicide rates from 1976 to 1979 found the highest rates among some of the health professions, compared to the overall active population (Toomingas 1993). The standardized mortality ratio (SMR) for female physicians was 3.41, the highest value observed, while that for nurses was 2.13.

Unfortunately, health professionals with impaired mental health are often ignored and may even be rejected by their colleagues, who attempt to deny these tendencies in themselves (Bissel and Jones 1975). In fact, slight or moderate stress is much more prevalent among health professionals than are frank psychiatric disorders (McCue 1982). A good prognosis in these cases depends on early diagnosis and peer support (Bitker 1976).

Discussion groups

Studies on the effect of discussion groups on burn-out have been undertaken in the United States. Although positive results have been demonstrated (Jacobson and MacGrath 1983), it should be noted that these have been in institutions where there was sufficient time for regular discussions in quiet and appropriate settings (i.e., hospitals with high staff-patient ratios).

A literature review of the success of discussion groups has shown these groups to be valuable tools in wards where a high proportion of patients are left with permanent sequelae and must learn to accept modifications in their lifestyle (Estryn-Béhar 1990).

Kempe, Sauter and Lindner (1992) evaluated the merits of two support techniques for nurses near burn-out in geriatrics wards: a six-month course of 13 professional counselling sessions and a 12-month course of 35 “Balint group” sessions. The clarification and reassurance provided by the Balint group sessions were effective only if there was also significant institutional change. In the absence of such change, conflicts may even intensify and dissatisfaction increase. Despite their impending burn-out, these nurses remained very professional and sought ways of carrying on with their work. These compensatory strategies had to take into account extremely high workloads: 30% of nurses worked more than 20 hours of overtime per month, 42% had to cope with understaffing during more than two-thirds of their working hours and 83% were often left alone with unqualified personnel.

The experience of these geriatrics nurses was compared to that of nurses in oncology wards. Burnout score was high in young oncology nurses, and decreased with seniority. In contrast, burnout score among geriatrics nurses increased with seniority, attaining levels much higher than those observed in oncology nurses. This lack of decrease with seniority is due to the characteristics of the workload in geriatrics wards.

The need to act on multiple determinants

Some authors have extended their study of effective stress management to organizational factors related to affective strain.

For example, analysis of psychological and sociological factors was part of Theorell’s attempt to implement case-specific improvements in emergency, paediatric and juvenile psychiatry wards (Theorell 1993). Affective strain before and after the implementation of changes was measured through the use of questionnaires and the measurement of plasma prolactin levels, shown to mirror feelings of powerlessness in crisis situations.

Emergency-ward personnel experienced high levels of affective strain and frequently enjoyed little decisional latitude. This was attributed to their frequent confrontation with life-and-death situations, the intense concentration demanded by their work, the high number of patients they frequently attended and the impossibility of controlling the type and number of patients. On the other hand, because their contact with patients was usually short and superficial, they were exposed to less suffering.

The situation was more amenable to control in paediatric and juvenile psychiatry wards, where schedules for diagnostic procedures and therapeutic procedures were established in advance. This was reflected by a lower risk of overwork compared to emergency wards. However, personnel in these wards were confronted with children suffering from serious physical and mental disease.

Desirable organizational changes were identified through discussion groups in each ward. In emergency wards, personnel were very interested in organizational changes and recommendations concerning training and routine procedures—such as how to treat rape victims and elderly patients with no relations, how to evaluate work and what to do if a called physician doesn’t arrive—were formulated. This was followed by the implementation of concrete changes, including the creation of the position of head physician and the ensuring of the constant availability of an internist.

The personnel in juvenile psychiatry were primarily interested in personal growth. Reorganization of resources by the head physician and the county allowed one-third of the personnel to undergo psychotherapy.

In paediatrics, meetings were organized for all the personnel every 15 days. After six months, social support networks, decisional latitude and work content all had improved.

The factors identified by these detailed ergonomic, psychological and epidemiological studies are valuable indices of work organization. Studies which focus on them are quite different from in-depth studies of multi-factor interactions and instead revolve around the pragmatic characterization of specific factors.

Tintori and Estryn-Béhar (1994) identified some of these factors in 57 wards of a large hospital in the Paris region in 1993. Shift overlap of more than 10 minutes was present in 46 wards, although there was no official overlap between the night and morning shifts in 41 wards. In half the cases, these information communication sessions included nurses’ aides in all three shifts. In 12 wards, physicians participated in the morning-afternoon sessions. In the three months preceding the study, only 35 wards had held meetings to discuss patients’ prognoses, discharges and patients’ understanding of and reaction to their illnesses. In the year preceding the study, day-shift workers in 18 wards had received no training and only 16 wards had dispensed training to their night-shift workers.

Some new lounges were not used, since they were 50 to 85 metres from some of the patients’ rooms. Instead, the personnel preferred holding their informal discussions around a cup of coffee in a smaller but closer room. Physicians participated in coffee breaks in 45 day-shift wards. Nurses’ complaints of frequent work interruptions and feelings of being overwhelmed by their work are no doubt attributable in part to the dearth of seats (less than four in 42 of the 57 wards) and cramped quarters of the nursing stations, where more than nine people must spend a good part of their day.

The interaction of stress, work organization and support networks is clear in studies of the home-care unit of the hospital in Motala, Sweden (Beck-Friis, Strang and Sjöden 1991; Hasselhorn and Seidler 1993). The risk of burn-out, generally considered high in palliative care units, was not significant in these studies, which in fact revealed more occupational satisfaction than occupational stress. Turnover and work stoppages in these units were low, and personnel had a positive self-image. This was attributed to selection criteria for personnel, good teamwork, positive feedback and continuing education. Personnel and equipment costs for terminal-stage cancer hospital care are typically 167 to 350% higher than for hospital-based home care. There were more than 20 units of this type in Sweden in 1993.

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Published in Ergonomics and Health Care

Work Schedules and Night Work in Health Care

For a long time, nurses and nursing assistants were among the only women working at night in many countries (Gadbois 1981; Estryn-Béhar and Poinsignon 1989). In addition to the problems already documented among men, these women suffer additional problems related to their family responsibilities. Sleep deprivation has been convincingly demonstrated among these women, and there is concern about the quality of care they are able to dispense in the absence of appropriate rest.

Organization of Schedules and Family Obligations

It appears that personal feelings about social and family life are at least partially responsible for the decision to accept or refuse night work. These feelings, in turn, lead workers to minimize or exaggerate their health problems (Lert, Marne and Gueguen 1993; Ramaciotti et al. 1990). Among non-professional personnel, financial compensation is the main determinant of the acceptance or refusal of night work.

Other work schedules may also pose problems. Morning-shift workers sometimes must rise before 05:00 and so lose some of the sleep that is essential for their recovery. Afternoon shifts finish between 21:00 and 23:00, limiting social and family life. Thus, often only 20% of women working in large university hospitals have work schedules in synchrony with the rest of society (Cristofari et al. 1989).

Complaints related to work schedules are more frequent among health care workers than among other employees (62% versus 39%) and indeed are among the complaints most frequently voiced by nurses (Lahaye et al. 1993).

One study demonstrated the interaction of work satisfaction with social factors, even in the presence of sleep deprivation (Verhaegen et al. 1987). In this study, nurses working only night shifts were more satisfied with their work than nurses working rotating shifts. These differences were attributed to the fact that all the night-shift nurses chose to work at night and organized their family life accordingly, while rotating-shift nurses found even rare night-shift work a disturbance of their personal and family lives. However, Estryn-Béhar et al. (1989b) reported that mothers working only night shifts were more tired and went out less frequently compared with male night-shift nurses.

In the Netherlands, the prevalence of work complaints was higher among nurses working rotating shifts than among those working only day shifts (Van Deursen et al. 1993) (see table 1).

Table 1. Prevalence of work complaints according to shift

	Rotating shifts (%)	Day shifts (%)
Arduous physical work	55.5	31.3
Arduous mental work	80.2	61.9
Work often too tiring	46.8	24.8
Under-staffing	74.8	43.8
Insufficient time for breaks	78.4	56.6
Interference of work with private life	52.8	31.0
Dissatisfaction with schedules	36.9	2.7
Frequent lack of sleep	34.9	19.5
Frequent fatigue on rising	31.3	17.3

Source: Van Deursen et al. 1993.

Sleep disturbances

On workdays, night-shift nurses sleep an average of two hours less than other nurses (Escribà Agüir et al. 1992; Estryn-Béhar et al. 1978; Estryn-Béhar et al. 1990; Nyman and Knutsson 1995). According to several studies, their quality of sleep is also poor (Schroër et al. 1993; Lee 1992; Gold et al. 1992; Estryn-Béhar and Fonchain 1986).

In their interview study of 635 Massachusetts nurses, Gold et al. (1992) found that 92.2% of nurses working alternating morning and afternoon shifts were able to maintain a nocturnal “anchor” sleep of four hours at the same schedule throughout the month, compared to only 6.3% of night-shift nurses and none of the nurses working alternating day and night shifts. The age- and seniority-adjusted odds ratio for “poor sleep” was 1.8 for night-shift nurses and 2.8 for rotating-shift nurses with night work, compared to morning- and afternoon-shift nurses. The odds ratio for taking sleep medication was 2.0 for night- and rotating-shift nurses, compared to morning- and afternoon-shift nurses.

Affective Problems and Fatigue

The prevalence of stress-related symptoms and reports of having stopped enjoying their work was higher among Finnish nurses working rotating shifts than among other nurses (Kandolin 1993). Estryn-Béhar et al. (1990) showed that night-shift nurses’ scores on the General Health Questionnaire used to evaluate mental health, compared to day-shift nurses (odds ratio of 1.6) showed poorer general health.

In another study, Estryn-Béhar et al. (1989b), interviewed a representative sample of one-quarter of night-shift employees (1,496 individuals) in 39 Paris-area hospitals. Differences appear according to sex and qualification (“qualified”=head nurses and nurses; “unqualified”=nurses’ aides and orderlies). Excessive fatigue was reported by 40% of qualified women, 37% of unqualified women, 29% of qualified men and 20% of unqualified men. Fatigue on rising was reported by 42% of qualified women, 35% of unqualified women, 28% of qualified men and 24% of unqualified men. Frequent irritability was reported by one-third of night-shift workers and by a significantly greater proportion of women. Women with no children were twice as likely to report excessive fatigue, fatigue on rising and frequent irritability than were comparable men. The increase compared to single men with no children was even more marked for women with one or two children, and greater still (a four-fold increase) for women with at least three children.

Fatigue on rising was reported by 58% of night-shift hospital workers and 42% of day-shift workers in a Swedish study using a stratified sample of 310 hospital workers (Nyman and Knutsson 1995). Intense fatigue at work was reported by 15% of day-shift workers and 30% of night-shift workers. Almost one-quarter of night-shift workers reported falling asleep at work. Memory problems were reported by 20% of night-shift workers and 9% of day-shift workers.

In Japan, the health and safety association publishes the results of medical examinations of all the country’s salaried employees. This report includes the results of 600,000 employees in the health and hygiene sector. Nurses generally work rotating shifts. Complaints concerning fatigue are highest in night-shift nurses, followed in order by evening- and morning-shift nurses (Makino 1995). Symptoms reported by night-shift nurses include sleepiness, sadness and difficulty concentrating, with numerous complaints about accumulated fatigue and disturbed social life (Akinori and Hiroshi 1985).

Sleep and Affective Disorders among Physicians

The effect of work content and duration on young physicians’ private lives, and the attendant risk of depression, has been noted. Valko and Clayton (1975) found that 30% of young residents suffered a bout of depression lasting an average of five months during their first year of residency. Of the 53 residents studied, four had suicidal thoughts and three made concrete suicide plans. Similar rates of depression have been reported by Reuben (1985) and Clark et al. (1984).

In a questionnaire study, Friedman, Kornfeld and Bigger (1971) showed that interns suffering from sleep deprivation reported more sadness, selfishness and modification of their social life than did more-rested interns. During interviews following the tests, interns suffering from sleep deprivation reported symptoms such as difficulty reasoning, depression, irritability, depersonalization, inappropriate reactions and short-term memory deficits.

In a one-year longitudinal study, Ford and Wentz (1984) evaluated 27 interns four times during their internship. During this period, four interns suffered at least one major bout of depression meeting standard criteria and 11 others reported clinical depression. Anger, fatigue and mood swings increased throughout the year and were inversely correlated with the amount of sleep the preceding week.

A literature review has identified six studies in which interns having spent one sleepless night exhibited deteriorations of mood, motivation and reasoning ability and increased fatigue and anxiety (Samkoff and Jacques 1991).

Devienne et al. (1995) interviewed a stratified sample of 220 general practitioners in the Paris area. Of these, 70 were on call at night. Most of the on-call physicians reported having had their sleep disturbed while on call and finding it particularly difficult to get back to sleep after having been awakened (men: 65%; women: 88%). Waking up in the middle of the night for reasons unrelated to service calls was reported by 22% of men and 44% of women. Having or almost having a car accident due to sleepiness related to being on call was reported by 15% of men and 19% of women. This risk was greater among physicians who were on call more than four times per month (30%) than in those on call three or four times per month (22%) or one to three times per month (10%). The day after being on call, 69% of women and 46% of men reported having difficulty concentrating and feeling less effective, while 37% of men and 31% of women reported experiencing mood swings. Accumulated sleep deficits were not recovered the day following on-call work.

Family and Social Life

A survey of 848 night-shift nurses found that over the previous month one-quarter had not gone out and had entertained no guests, and half had participated in such activities only once (Gadbois 1981). One-third reported refusing an invitation because of fatigue, and two-thirds reported going out only once, with this proportion rising to 80% among mothers.

Kurumatani et al. (1994) reviewed the time sheets of 239 Japanese nurses working rotating shifts over a total of 1,016 days and found that nurses with young children slept less and spent less time on leisure activities than did nurses without young children.

Estryn-Béhar et al. (1989b) observed that women were significantly less likely than men to spend at least one hour per week participating in team or individual sports (48% of qualified women, 29% of unqualified women, 65% of qualified men and 61% of unqualified men). Women were also less likely to frequently (at least four times per month) attend shows (13% of qualified women, 6% of unqualified women, 20% of qualified men and 13% of unqualified men). On the other hand, similar proportions of women and men practised home-based activities such as watching television and reading. Multivariate analysis showed that men with no children were twice as likely to spend at least one hour per week on athletic activities than were comparable women. This gap increases with the number of children. Child care, and not gender, influences reading habits. A significant proportion of the subjects in this study were single parents. This was very rare among qualified men (1%), less rare among unqualified men (4.5%), common in qualified women (9%) and extremely frequent in unqualified women (24.5%).

In Escribà Agüir’s (1992) study of Spanish hospital workers, incompatibility of rotating shifts with social and family life was the leading source of dissatisfaction. In addition, night-shift work (either permanent or rotating) disturbed the synchronization of their schedules with those of their spouses.

Lack of free time interferes severely with the private life of interns and residents. Landau et al. (1986) found that 40% of residents reported major conjugal problems. Of these residents, 72% attributed the problems to their work. McCall (1988) noted that residents have little time to spend on their personal relationships; this problem is particularly serious for women nearing the end of their low-risk-pregnancy years.

Irregular Shift Work and Pregnancy

Axelsson, Rylander and Molin (1989) distributed a questionnaire to 807 women employed at the hospital in Mölna, Sweden. The birth weights of children born to non-smoking women working irregular shifts were significantly lower than that of children born to non-smoking women who only worked day shifts. The difference was greatest for infants of at least grade 2 (3,489 g versus 3,793 g). Similar differences were also found for infants of at least grade 2 born to women working afternoon shifts (3,073 g) and shifts alternating every 24 hours (3,481 g).

Vigilance and Quality of Work among Night-Shift Nurses

Englade, Badet and Becque (1994) performed Holter EEGs on two groups of nine nurses. It showed that the group not allowed to sleep had attention deficits characterized by sleepiness, and in some cases even sleep of which they were unaware. An experimental group practised polyphasic sleep in an attempt to recover a little sleep during work hours, while the control group was not allowed any sleep recovery.

These results are similar to those reported by a survey of 760 California nurses (Lee 1992), in which 4.0% of night-shift nurses and 4.3% of nurses working rotating shifts reported suffering frequent attention deficits; no nurses from the other shifts mentioned lack of vigilance as a problem. Occasional attention deficits were reported by 48.9% of night-shift nurses, 39.2% of rotating-shift nurses, 18.5% of day-shift nurses and 17.5% of evening-shift nurses. Struggling to stay awake while dispensing care during the month preceding the survey was reported by 19.3% of night-shift and rotating-shift nurses, compared to 3.8% of day- and evening-shift nurses. Similarly, 44% of nurses reported having had to struggle to stay awake while driving during the preceding month, compared to 19% of day-shift nurses and 25% of evening-shift nurses.

Smith et al. (1979) studied 1,228 nurses in 12 American hospitals. The incidence of occupational accidents was 23.3 for nurses working rotating shifts, 18.0 for night-shift nurses, 16.8 for day-shift nurses and 15.7 for afternoon-shift nurses.

In an attempt to better characterize problems related to attention deficits among night-shift nurses, Blanchard et al. (1992) observed activity and incidents throughout a series of night shifts. Six wards, ranging from intensive care to chronic care, were studied. In each ward, one continuous observation of a nurse was performed on the second night (of night work) and two observations on the third or fourth nights (depending on the wards’ schedule). Incidents were not associated with serious outcomes. On the second night, the number of incidents rose from 8 in the first half of the night to 18 in the second half. On the third or fourth night, the increase was from 13 to 33 in one case and from 11 to 35 in another. The authors emphasized the role of sleep breaks in limiting risks.

Gold et al. (1992) collected information from 635 Massachusetts nurses on the frequency and consequences of attention deficits. Experiencing at least one episode of sleepiness at work per week was reported by 35.5% of rotating-shift nurses with night work, 32.4% of night-shift nurses and 20.7% of morning-shift and afternoon-shift nurses working exceptionally at night. Less than 3% of nurses working the morning and afternoon shifts reported such incidents.

The odds ratio for sleepiness while driving to and from work was 3.9 for rotating-shift nurses with night work and 3.6 for night-shift nurses, compared to morning- and afternoon-shift nurses. The odds ratio for total accidents and errors over the past year (car accidents driving to and from work, errors in medication or work procedures, occupational accidents related to sleepiness) was almost 2.00 for rotating-shift nurses with night work compared to morning- and afternoon-shift nurses.

Effect of Fatigue and Sleepiness on the Performance of Physicians

Several studies have shown that the fatigue and sleeplessness induced by night-shift and on-call work leads to deteriorations of physician performance.

Wilkinson, Tyler and Varey (1975) conducted a postal questionnaire survey of 6,500 British hospital physicians. Of the 2,452 who responded, 37% reported suffering a degradation of their effectiveness due to excessively long work hours. In response to open-ended questions, 141 residents reported committing errors due to overwork and lack of sleep. In a study performed in Ontario, Canada, 70% of 1,806 hospital physicians reported often worrying about the effect of the quantity of their work had on its quality (Lewittes and Marshall 1989). More specifically, 6% of the sample—and 10% of interns—reported often worrying about fatigue affecting the quality of care they dispensed.

Given the difficulty in performing real-time evaluations of clinical performance, several studies on the effects of sleep deprivation on physicians have relied upon neuropsychological tests.

In the majority of studies reviewed by Samkoff and Jacques (1991), residents deprived of sleep for one night exhibited little deterioration in their performance of rapid tests of manual dexterity, reaction time and memory. Fourteen of these studies used extensive test batteries. According to five tests, the effect on performance was ambiguous; according to six, a performance deficit was observed; but according to eight other tests, no deficit was observed.

Rubin et al. (1991) tested 63 medical-ward residents before and after an on-call period of 36 hours and a subsequent full day of work, using a battery of self-administered computerized behavioural tests. Physicians tested after being on call exhibited significant performance deficits in tests of visual attention, coding speed and accuracy and short-term memory. The duration of sleep enjoyed by the residents while on call was as follows: two hours at most in 27 subjects, four hours at most in 29 subjects, six hours at most in four subjects and seven hours in three subjects. Lurie et al. (1989) reported similarly brief sleep durations.

Virtually no difference has been observed in the performance of actual or simulated short-duration clinical tasks—including filling out a laboratory requisition (Poulton et al. 1978; Reznick and Folse 1987), simulated suturing (Reznick and Folse 1987), endotracheal intubation (Storer et al. 1989) and venous and arterial catheterization (Storer et al. 1989)—by sleep-deprived and control groups. The only difference observed was a slight lengthening of the time required by sleep-deprived residents to perform arterial catheterization.

On the other hand, several studies have demonstrated significant differences for tasks requiring continuous vigilance or intense concentration. For example, sleep-deprived interns committed twice as many errors when reading 20-minute ECGs as did rested interns (Friedman et al. 1971). Two studies, one relying on 50-minute VDU-based simulations (Beatty, Ahern and Katz 1977), the other on 30-minute video simulations (Denisco, Drummond and Gravenstein 1987), have reported poorer performance by anaesthesiologists deprived of sleep for one night. Another study has reported significantly poorer performance by sleep-deprived residents on a four-hour test exam (Jacques, Lynch and Samkoff 1990). Goldman, McDonough and Rosemond (1972) used closed-circuit filming to study 33 surgical procedures. Surgeons with less than two hours of sleep were reported to perform “worse” than more-rested surgeons. The duration of surgical inefficiency or indecision (i.e., of poorly planned manoeuvres) was over 30% of the total duration of the operation.

Bertram (1988) examined the charts of emergency admissions by second-year residents over a one-month period. For a given diagnosis, less information on medical histories and the results of clinical examinations was gathered as the number of hours worked and patients seen increased.

Smith-Coggins et al. (1994) analysed the EEG, mood, cognitive performance and motor performance of six emergency-ward physicians over two 24-hour periods, one with diurnal work and nocturnal sleep, the other with nocturnal work and diurnal sleep.

Physicians working at night slept significantly less (328.5 versus 496.6 minutes) and performed significantly less well. This poorer motor performance was reflected in the increased time required to perform a simulated intubation (42.2 versus 31.56 seconds) and an increased number of protocol errors.

Their cognitive performance was evaluated at five test periods throughout their shift. For each test, physicians were required to review four charts drawn from a pool of 40, rank them and list the initial procedures, the treatments and the appropriate laboratory tests. Performance deteriorated as the shift progressed for both night-shift and day-shift physicians. Night-shift physicians were less successful at providing correct responses than day-shift physicians.

Physicians working during the day rated themselves as less sleepy, more satisfied and more lucid than did night-shift physicians.

Recommendations in English-speaking countries concerning the work schedules of physicians-in-training have tended to take these results into account and now call for work-weeks of at most 70 hours and the provision of recovery periods following on-call work. In the US, following the death of a patient attributed to errors by an overworked, poorly supervised resident physician which received much media attention, New York State enacted legislation limiting work hours for hospital staff physicians and defining the role of attending physicians in supervising their activities.

Content of Night Work in Hospitals

Night work has long been undervalued. In France, nurses used to be seen as guardians, a term rooted in a vision of nurses’ work as the mere monitoring of sleeping patients, with no delivery of care. The inaccuracy of this vision became increasingly obvious as the length of hospitalization decreased and patients’ uncertainty about their hospitalization increased. Hospital stays require frequent technical interventions during the night, precisely when the nurse:patient ratio is lowest.

The importance of the amount of time spent by nurses in patients’ rooms is demonstrated by the results of a study based on continuous observation of the ergonomics of nurses’ work in each of three shifts in ten wards (Estryn-Béhar and Bonnet 1992). The time spent in rooms accounted for an average of 27% of the day and night shifts and 30% of the afternoon shift. In four of the ten wards, nurses spent more time in the rooms during the night than during the day. Blood samples were of course taken less frequently during the night, but other technical interventions such as monitoring vital signs and medication, and administering, adjusting and monitoring intravenous drips and transfusions were more frequent during the night in six of seven wards where detailed analysis was performed. The total number of technical and non-technical direct-care interventions was higher during the night in six of seven wards.

Nurses’ work postures varied from shift to shift. The percentage of time spent seated (preparation, writing, consultations, time spent with patients, breaks) was higher at night in seven of ten wards, and exceeded 40% of shift time in six wards. However, the time spent in painful postures (bent over, crouched, arms extended, carrying loads) exceeded 10% of shift time in all wards and 20% of shift time in six wards at night; in five wards the percentage of time spent in painful positions was higher at night. In fact, night-shift nurses also make beds and perform tasks related to hygiene, comfort and voiding, tasks which are all normally performed by nurses’ aides during the day.

Night-shift nurses may be obliged to change location very frequently. Night-shift nurses in all the wards changed location over 100 times per shift; in six wards, the number of changes of location was higher at night. However, because rounds were scheduled at 00:00, 02:00, 04:00 and 06:00, nurses did not travel greater distances, except in juvenile intensive-care wards. Nonetheless, nurses walked over six kilometres in three of the seven wards where podometry was performed.

Conversations with patients were frequent at night, exceeding 30 per shift in all wards; in five wards these conversations were more frequent at night. Conversations with physicians were much rarer and almost always brief.

Leslie et al. (1990) conducted continuous observation of 12 of 16 interns in the medical ward of a 340-bed Edinburgh (Scotland) hospital over 15 consecutive winter days. Each ward cared for approximately 60 patients. In all, 22 day shifts (08:00 to 18:00) and 18 on-call shifts (18:00 to 08:00), equivalent to 472 hours of work, were observed. The nominal duration of the interns’ work week was 83 to 101 hours, depending on whether or not they were on call during the weekends. However, in addition to the official work schedule, each intern also spent an average of 7.3 hours each week on miscellaneous hospital activities. Information on the time spent performing each of 17 activities, on a minute-by-minute basis, was collected by trained observers assigned to each intern.

The longest continuous work period observed was 58 hours (08:00 Saturday to 06:00 Monday) and the longest work period was 60.5 hours. Calculations showed that a one-week sickness leave of one intern would require the other two interns in the ward to increase their workload by 20 hours.

In practice, in wards admitting patients during on-call shifts, interns working consecutive day, on-call and night shifts worked all but 4.6 of the 34 elapsed hours. These 4.6 hours were devoted to meals and rest, but interns remained on call and available during this time. In wards that did not admit new patients during on-call shifts, interns’ workload abated only after midnight.

Due to the on-call schedules in other wards, interns spent approximately 25 minutes outside their home ward each shift. On average, they walked 3 kilometres and spent 85 minutes (32 to 171 minutes) in other wards each night shift.

Time spent filling out requests for examinations and charts, in addition, is often performed outside of their normal work hours. Non-systematic observation of this additional work over several days revealed that it accounts for approximately 40 minutes of additional work at the end of each shift (18:00).

During the day, 51 to 71% of interns’ time was spent on patient-oriented duties, compared to 20 to 50% at night. Another study, conducted in the United States, reported that 15 to 26% of work time was spent on patient-oriented duties (Lurie et al. 1989).

The study concluded that more interns were needed and that interns should no longer be required to attend other wards while on call. Three additional interns were hired. This reduced interns’ work week to an average of 72 hours, with no work, excepting on-call shifts, after 18:00. Interns also obtained a free half-day following an on-call shift and preceding a weekend when they were to be on call. Two secretaries were hired on a trial basis by two wards. Working 10 hours per week, the secretaries were able to fill out 700 to 750 documents per ward. In the opinion of both senior physicians and nurses, this resulted in more efficient rounds, since all the information had been entered correctly.

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Yassi, A, D Gaborieau, I Gi

Hospital Ergonomics: A Review

Strain in Health Care Work

Work Schedules and Night Work in Health Care

Contents

Health Care Facilities and Services References