Published: 30/06/2005, Volume II5, No. 5962 Page 34 35

The importance of rest for clinical staff is well documented and, with the advent of the European working-time directive, it is now more important than ever. National Patient Safety Agency risk adviser Mark Boult signposts the potential pitfalls

The relationship between impaired human performance, fatigue and poor shift patterns is well established. The European working-time directive lays down minimum safety and health requirements. To meet these, the NHS is changing the way staff work.

As we change, it is important to ensure that shift patterns do not expose staff to a high risk of fatigue. In this way we will achieve not only improved safety and health for our staff, but also for patients.

The National Patient Safety Agency's risk and human factors team has been studying the impact of change on patient safety for the Modernisation Agency's Hospital at Night project, which seeks to redefine how out-of-hours medical cover is provided in hospitals.

Unsurprisingly, one potential risk is staff fatigue contributing to patient safety incidents. To manage this, shift planners need to be aware of the causes and effects of fatigue and how to manage it.

Research tells us that during night shifts lack of sleep can reduce a person's ability to communicate by 30 per cent, make judgements by 50 per cent, remember facts and figures by 30 per cent and remain attentive by 75 per cent. It also tells us that 17 hours of sustained wakefulness affects cognitive performance as much as a blood alcohol concentration of 0.05 per cent - a level that would make driving a car illegal in most industrialised countries.

Factors related to early, late or night shift work that impact on the quality and quantity of sleep include working long shifts (more than nine hours) and having only short periods of time off between shifts (less than 13 hours). Working for long periods without breaks also has an impact, as do working successive (three days) early, late or night shifts and working a rotating shift pattern that does not include rest days.

It is generally accepted that performance improves with more sleep.

After working three or more consecutive night shifts, one day of recovery is never sufficient. At least two full days' rest with two good nights' sleep are required to remove fatigue caused by 'sleep debt'.

This means we need to design and implement shift patterns that avoid or minimise fatigue. To help this, the Health and Safety Executive has a fatigue index model that predicts fatigue associated with different shift patterns.

In designing effective shift patterns we should learn from other safety-critical industries. For example, best practices identified in a survey of a wide range of industries for Railtrack in 2000 include:

keeping night shifts as short as possible;

limiting the number of consecutive night shifts to three;

incorporating frequent breaks into work schedules during normal operations;

scheduling at least 14 hours' rest before the start of a shift;

providing 51 hours for recovery after more than two consecutive night shifts;

including the time taken to travel to and from home when calculating the fatigue effects of shift working.

Managers should also look to introduce other measures that mitigate the effects of fatigue and improve alertness. A review for Railtrack in 2000 suggested a number of strategies, including:

moderate exercise (enhanced fitness levels improve sleep quality);

exposure to bright light;

taking a nap of about one hour during the early morning hours of a night shift;

some noise - for example, music (temporary benefit);

caffeinated drink (temporary benefit);

including interesting and active tasks.

Poorly designed shift patterns result in staff fatigue that could contribute to patient safety incidents. Careful planning of shift working will help minimise risks.

www. npsa. nhs. uk -www. hse. gov. uk