Junior doctors' shifts and sleep deprivation

The European working time directive may put doctors' and patients' lives at risk

The European working time directive was implemented for doctors in training in the UK NHS and elsewhere in Europe in August 2004. Junior doctors' working hours are now limited to a shift of no more than 13 hours followed by a break of at least 11 hours.1 As a result, the work pattern out of hours for most junior doctors at the front line of acute medicine has changed completely from providing on-call cover to working in shifts.2 The directive aims to reduce working hours in order to improve workers' health and safety, but the current NHS shift system could threaten doctors' and, moreover, patients' safety.

More than three quarters of medical senior house officers and nearly half of specialist registrars in NHS trusts were working seven consecutive night shifts when surveyed in December 2004 by the Royal College of Physicians.2 Some 40% of acute hospitals had introduced rotas with shorter, more frequent blocks of three to five night shifts for their medical specialist registrars, but only 11% had devised rotas with one to two serial night shifts. Thus, many of these doctors were forced to work up to 91 hours during the night in one week, as well as travelling to and from home each day. These doctors are exhausted: 70% of specialist registrars in one hospital, working the seven consecutive night shifts, slept for an average of two hours per night while contracted to work, and most had problems with sleep in the daytime.3 In the United States, interns working a traditional schedule of 77-81 hours per week caused 36% more serious medical errors than when working an average 65 hours per week.4 Furthermore, interns had fewer than half the number of failures of attention at night when working a shorter week.5 A third study reported that extended work shifts pose safety hazards for interns: the risk of any motor vehicle crash increased by 9% while working those shifts, and the risk of a crash during commuting increased by 16%.6 All these adverse effects owing to exhaustion can be expected among British junior doctors forced to work a 91 hour week as a series of night shifts.

Views are conflicting on the optimum number of consecutive night shifts needed to retain acceptable levels of performance. However, it is clear that a long stretch of night shifts results in an accumulation of daily sleep deficits and does not encourage adjustment of circadian rhythms.7 A week of night shifts is the pattern most associated with poor performance and accidents.8 Risk increases exponentially over the course of the night and increases further still over consecutive nights.9

Any shift system should have as few successive night shifts as possible, with a maximum of three consecutive nights: a single night shift, with a day off before and after, is reported to show the least distortion of circadian rhythms.7

The aviation industry has taken note of research on short periods of sleep, and pilots and cabin crew are now rostered to sleep during night flights. A NASA field study evaluated the benefit of short sleeps in cockpits and found that after a 40 minute nap, performance increased by 34% and physiologic alertness by 54% compared with no nap.10

The NHS must reassess the practice of shift work to maximise doctors' safety and efficiency, and to safeguard the interests of patients. We propose that most doctors should be rostered for single nights, with one or two night shifts over a weekend. This arrangement is flexible enough to cope with unexpected staffing changes and reduces sleep deprivation, and any additional loss of daytime specialist experience is relatively slight. In every NHS night shift, certain health and safety measures could be implemented. A scheduled two hour rest period during the course of the night (with the bleep or pager taken by a medical shift partner) should not only reduce fatigue, but would also mean that, for the other 11 hours of the shift, doctors could reasonably be expected to be full and active members of the Hospital at Night team.3

It is inevitable that some doctors must work night shifts. But they should be taught how to cope with night work. And they must have adequate, high quality, restorative sleep during the day, aided if necessary at home by using heavy curtains, eye masks, ear plugs, silenced telephone answering machines and mobile phones, and wearing dark glasses when returning from work.11