A nightmare for drivers
Sleep apnoea is an ever-increasing problem for professional drivers, thus deserving great exposure. Dr Betty Maguire highlights the condition.
Sleep apnoea is a serious condition, in which airflow from the nose and mouth is restricted during sleep, resulting in pauses in breathing, which can last ten seconds or more. It can occur up to 400 times a night.
As they don’t sleep properly lying down at night, people who are affected by sleep apnoea (or obstructive sleep apnoea), suffer from various symptoms, including: excessive daytime sleepiness, heavy snoring at night, falling asleep at inappropriate times, impaired concentration, irritability, personality change and memory impairment.
For professional drivers, these symptoms are potentially deadly. Driving is a skill which incorporates many simultaneous activities by the brain, thus requiring full concentration. It is thought that up to 20 percent of fatigue-related accidents are related to nocturnal sleep deprivation.
Of course, daytime sleepiness may occur in people without a sleep disorder, for instance those who take certain medications – some anti-allergic medications, antidepressants, or sleeping pills – but obstructive sleep apnoea has been found to be the most common reason for habitually drowsy driving.
These drivers are as dangerous as those with high blood-alcohol levels and the condition cannot be picked up in a breathalyser test, so the drivers themselves have to be aware of their sleepiness.
During investigations, it has been found that drivers, who were involved in major incidents, had stated that they had been fighting sleep when these incidents occurred and had noticed themselves to be sleepy before the incident, but had failed to appreciate that extreme sleepiness is accompanied by a high likelihood of actually nodding off.
In these cases there is a “micro sleep” of a few seconds or so where the driver will have driven up to 100 m while sound asleep.
Obstructive sleep apnoea occurs most often in moderately or severely obese persons who attempt to sleep on their backs – four percent of men and two percent of women are affected. Obstruction of their breathing passages causes a repeating cycle of sleep, snoring heavily, sudden obstructive choking and then awakening with gasping. Daytime drowsiness follows.
This problem is one of the sleep disorders and can be diagnosed fairly quickly and dealt with equally rapidly.
If a driver suspects he or she might have sleep apnoea, an assessment should be arranged as a matter of urgency, preferably by a specialist, as there are immediate measures that can be taken. For example, there is a nasal mask that can be applied immediately and may eliminate the apnoea and improve daytime alertness. This is known as the Continuous Positive Airway Pressure (CPAP) mask.
There are surgical treatments, which involve widening the airways, and nasal surgery is also an option. There is the fairly drastic means of surgical weight loss. This has been found to have a most dramatic effect on sleep apnoea. However, some minor behavioural changes, such as sleeping on the side rather than the back, also help.
As the body mass index (BMI) correlates closely with obstructive sleep apnoea (and the professional driver has a tendency to be overweight), a Canadian Insurance company – that had details of drivers’ weights – found that there was two to three times the risk of accidents with sleep apnoea in the overweight driver.
It is important to assess the professional driver carefully, as their livelihood is at stake. There is no good objective test to foretell sleepiness. We must, therefore, rely on the driver’s own report of sleepiness, their spouse’s assessment and any previous accidents due to sleepiness. An assessment of their own attitude to the problem, (including their stated intention to avoid driving while drowsy) as well as a medical examination, is also important.
As part of a study of the mechanism of accidents, a steering simulator was used, which demonstrated impaired steering ability with increased wandering around the road and delayed responses to distracting events. This was found in persons with sleep apnoea, and was a result of a combination of increased sleepiness and poor hand/eye coordination. All these factors were found to have improved in the drivers who wore the CPAP mask.
In fact, in professional drivers, who require a higher standard of fitness than those who only drive for short distance, there is evidence that, even though there is some sleep apnoea in these drivers, their accident rate is generally low. Bearing that in mind, fear of losing their licences should not inhibit drivers from reporting episodes of sleepiness, as the problem might then go underground.
Finally, it is the driver who has to decide whether or not to drive if he or she is sleepy. Some responsibility also falls on the driver’s medical doctor, and also those who are involved in granting driving licences. Greater awareness, rapid diagnosis and immediate treatment, where appropriate, would seem to be the answer to this problem.
As regular readers of FOCUS know, this magazine has been appointed an associate member of the International Truck of the Year (IToY)! FOCUS is the sole South African magazine to have joined this prestigious body. One of the advantages of this association is access to exclusive articles, specially written for FOCUS by ITOY jury members. This is one such article.