According to a team of French researchers, medical staff who drive home after a night shift are more likely to have an accident.

The researchers examined the driving skills of 30 anesthesia trainees in a sleep-deprived condition (SDC) and after a night of normal sleep. Study participants were asked to complete simulated driving tests at 8am.

The trainees drove for 15 minutes in urban conditions and then for 60 minutes under monotonous driving conditions, such as motorways or highways.

The researchers found that it was harder for participants to hold a straight line while driving when they were sleep deprived than after a normal night of sleep. Furthermore, they found it harder to control their speed when driving in monotonous conditions.

Dr. Ségolène Arzalier-Daret, from the Department of Anaesthesiology and Intensive Care, Caen Teaching Hospital, Caen, France, hopes that results from this study increase awareness among medical staff about the dangers of driving when sleep deprived.

Dr. Arzalier-Daret will present her findings at the annual conference of the European Society of Anesthesiology, Sunday June 10.

“Sleepiness at the wheel is a public health problem in France, the first cause of death on the autoroute network in 2009, and responsible for many crashes in towns the same year. There have been a number of campaigns to promote knowledge of this problem, but these statistics show us that there is a long way to go,” said Dr. Arzalier-Daret

The team also examined how fast participants reacted, number of crashes in urban conditions, average speed, variations in speed in autoroute conditions, as well as the deviation of lateral position (failure to keep a straight line).

Dr. Arzalier-Daret, explained: “We found that there were differences between those who had had a normal sleep and those who were sleep-deprived because of working overnight.

In urban conditions, sleep-deprived drivers drove at an average of 2km per hour slower than those who had had a normal night’s sleep, perhaps because they were aware that their driving skills might have been affected.

Lateral deviation and speed variations were more significant in sleep-deprived drivers under monotonous conditions that in those who had slept normally. We know from official statistics that road accidents peak between 8 and 9 am, so it is particularly worrying that the trainees normally finish their shift around this time.”

According to the researchers, medical staff who are regularly on call at night often experience chronic sleep deprivation. They state that medical staff should be allowed to sleep in the hospital before they drive home, especially if they live over 20 minutes away.

Dr. Arzalier-Daret said:

“The differences in driving skills between those who were sleep deprived and those who were not appeared after 20 minutes (lateral deviation) and 30 minutes (speed), and we believe that staff who live further than 20 minutes’ drive from their place of work should have the opportunity to rest before taking the wheel after a shift of night duty.”

Although coffee can help avoid drowsiness, it would be safer for these staff if their employers provided a taxi home, as some hospitals do in the United States. In addition, reducing the number of hours worked consecutively would also help, but this could result in staffing shortages. Canada has cut night duty hours from 24 to 16.

Dr. Arzalier-Daret explained:

“Car manufacturers and road authorities can also play their part, by making electronic systems to alert the driver to sideways movement of their vehicle more widely available, changing road markings and installing bands that give off audible warnings when a driver accidentally enters the hard shoulder.”

Even though participants simulated driving in the study, the team believe that these results would be similar in real life.

The researchers also found that:

  • 13% of participants reported falling asleep at the wheel after night duty
  • 11% had a accident after their night shift
  • 6% of participants said their accident was due to falling asleep

The researchers highlight that drivers are not always conscious of falling asleep at the wheel, if the sleep episode is very brief.

Dr. Arzalier-Daret said:

“Personally, I don’t like driving home after work after a night shift, though I only live five minutes away. Even though our study didn’t show any definitive proof that driving conduct was altered in town, as opposed to on the autoroute, I know that I have driven on autopilot and haven’t remembered anything about the journey when I arrived home. And epidemiological studies show that fatal accidents due to somnolence mainly happen in town and on short journeys.

I hope that our work will help to raise awareness of the dangers of driving when tired, and that employers of those who have to work night shifts will take measures to protect their staff from these dangers.”

Written By Grace Rattue