Yeo Poh Teck PHD, FRACP
Sleep Disorders Centre, Gleneagles Hospital, Singapore

* The contents of this article were presented at the "Seminar on Sleep Medicine" organised by the Singapore Sleep Society on 15 August 2004 at the Singapore General Hospital

ABSTRACT

Sleep apnoea has now been recognised to have major adverse effects on driving: drivers suffering from this condition are more likely to have motor vehicle accidents with a crash rate ranging from 2 to 3.6 times that of the general population. Because driving is common in most communities for social and commercial purposes, the relationship between sleep apnoea and driving has a major economic and health impact. The ramifications are medico-legal and relate to the responsibility of the affected individual, the employer of an affected employee, the health practitioner who treats such a patient, and the legal and medical regulatory bodies determining public policies. These issues have important relevance in the globalised city state of Singapore where there is particular prevalence of this condition.

Keywords: driving, medicolegal implications, sleep apnoea

Introduction

It has long been conventional wisdom that sleepiness is a cause of industrial accidents but it took the catastrophic accidents of Chernobyl, Exxon Valdez and Bhopal to put a spotlight on this relationship.¹ In the relatively mundane domain of day-to-day living, the relationship between sleepiness and driving does not usually reach advertence, yet its prevalence and commonality must surely confer a big impact on society and thereby argue the cogency for public policy in dealing with this problem.

Medical Effects

In modern society, driving is an integral activity for most people in both personal enjoyment and business activity. MacLean et al in a clinical review on "the hazards and prevention of driving whilst sleepy", stated that 29 to 55% of drivers reported feeling drowsy whilst driving; 11 to 31% had fallen asleep at the wheel and 4 to 12% had a crash due to sleepiness.² They further stated "sleepiness is the second most important factor, after alcohol, in the occurrence of single and multiple vehicle accidents and yields a significant human and financial cost".

Physiological and psychological studies have demonstrated many deleterious effects of sleepiness on driving. These include the occurrence of lapses (blocks and microsleeps); progressive unevenness and gradual decline in performance; decline in optimum levels of responding; cognitive slowing; memory problems and the well-known "time on task decrement". Acutely sleep-deprived individuals adopt a higher risk strategy, thereby increasing the danger to the driver and other road users.²

Social Impact

Pack et al made a retrospective analysis of crash reports in which the driver had been judged to be sleepy and identified certain common features of such crashes.³ These include primarily "drive off the road"; higher speed; a fatality rate similar to alcohol-related crashes; occurrence primarily in younger males and occurrence in 2 major time bands: between 3 to 5am and between 2 to 4pm.⁴ Akerstedt et al have shown that night time accidents could not be explained simply by darkness.⁴ It was further noted that early morning driving was several times more dangerous than driving during the forenoon and the effects seemed related to sleepiness but not to darkness. In particular, the combination of sleepiness and alcohol intake, even moderate, substantially increases the risk of accidents.⁵

In 1989, Broughton described the impact of medical sleep disorders on the lives of patients.⁶ It was noted that patients with sleep apnoea syndrome were more likely to have motor vehicle accidents with a crash rate ranging from 2 to 3.6 times that of the general population.^7-13 This is true for both non-commercial and commercial drivers. The studies by George and Smiley suggest that increased automobile accidents in obstructive sleep apnoea (OSA) "maybe restricted to the cases of more severe apnoea with apnoea-hypopnea index (AH1) greater than 40" (AHI refers to the number of events per hour).¹⁴ A year later, Horstmann et al confirmed that in sleep apnoea patients, 12.4% of all drivers had motor vehicle accidents as compared to 2.9% in the control group.¹⁵ The motor vehicle accident rate was 13 per million kilometres in patients with severe sleep apnoea (AH1 > 34) as compared to 1.1 in patients with milder sleep apnoea syndrome (AH1 10-34) and 0.78 in the control group. More importantly, they also found that during treatment with nasal continuous positive airway pressure (ncpap), the motor vehicle accident rate dropped from 10.6 to 2.7 per million kilometres.

Economic Burden

The nexus between economic burden of sleep apnoea and driving is the topic of a major discussion by Wittmann and Rodenstein.¹⁶ Their discussion looked at the indirect and direct, non-medical and medical costs. Indirect medical costs covered vehicle repairs or replacement, hospital stay, and days lost for work it was calculated in the USA for 1998, the figure was about USD50 billion. Based on George’s finding that treatment with CPAP could reduce the number of motor vehicle accidents, Findley and Suratt have estimated that treating 500 patients for 3 years could save USD369,000 in direct property damage and medical expenses and USD648,000 in legal and administrative cost.^13,17

With regard to direct medical expenditure, Kapur et al concluded that patients incurred significantly higher median and mean health care costs than controls during the year, preceding the diagnosis of sleep apnoea.¹⁸ In addition the health-related cost burden for undiagnosed sleep apnoea in USA was about USD3.4 billion per year.

These figures must be viewed against other less easily quantifiable health parameters. These are mainly subjective complaints and symptoms. In the Sleep Heart Health Study, mild to moderate sleep apnoea was associated with reduced vitality whilst severe sleep apnoea was broadly associated with poorer quality of life (QoL).¹⁹ Subjective sleep symptoms were comprehensively associated with poorer QoL when the QoL was assessed using the Medical outcome Survey (Mos) SF – 36, a health-related QoL measure, it was found that patients with sleep apnoea had symptoms equivalent to other chronic diseases in the US general population. A reduced QoL, though not easily measurable, nevertheless carries a major burden.

Clearly, sleep apnoea has a wide-ranging and significant impact both medical and non-medical on the individual.

Given these implications on societal function, it is surprising that the medico legal aspects of sleep apnoea and driving have not been adequately addressed in many countries.

These issues can be examined from the following points of view:

1. legal and regulatory issues and public policy

2. responsibility of the individual

3. responsibility of the employer who has an affected employee

4. responsibility of the health practitioner treating such a patient

Legal and Regulatory Issues and Public Policy

Because driving is such a prevalent activity, regulatory bodies have found it impossible to balance the requirements of competing interests. These include the protection of public safety whilst ensuring no adverse impact on economic imperatives from regulating the driving of sleep apnoea patients. Indeed, Maclean has reported that 13 to 75% of drivers failed compliance with regulations regarding permitted driving time.² In a study by Hakkanen et al on sleepiness at work amongst commercial drivers, it was found that non-compliance with driving hour regulations was not unusual in the trucking industry because of the often tight delivery schedules.²⁰

The results of this study indicated that about 13% of long haul drivers had violated driving time regulations despite the fact that the majority of drivers occasionally experienced difficulty in staying alert while driving and nearly all of them believed that driving whilst sleepy impaired their driving performance. There was association between being a violator and frequency of self reported dozing off while driving. This behaviour was intensified by economic circumstances of low remuneration, employment for a for-hire carrier and criticisms for late delivery. The study further confirmed the findings of other studies that sleepiness was perceived subjectively long before manifestation of actual behaviour problems in relation to sleepiness. Also, the majority of long haul drivers reported coping with sleepiness by taking a break, but this corrective action did not have any lasting effect on the drivers’ sleepiness.

Due to the complexity of perception, behaviour changes and the economic impact of sleepiness and driving, it appears likely that any regulatory measures instituted by appropriate legal bodies would be fraught with great difficulties and possible repercussions.

Responsibility of the Driver

Ellis and Grunstein have stated that "every driver of the motor vehicle whether or not they suffer from sleep disorder, has responsibility both under statutory obligation and as a civil duty of care".²¹ The standard of care is an objective one. The duty of care, as defined by Justice Mason, consists of 2 parts: 1) whether there is sufficient relationship of proximity between the parties; 2) whether a reasonable person in the defendant’s position would foresee that carelessness on his part may be likely to cause damage to the plantiff.^L1

However, with regard to falling asleep at the wheel, legal opinion has been divided and a subsequent view of the High Court of Australia is at odds with medical evidence. In a 1992 Australian case, a driver had set out at 11pm to drive a distance of about 1,000km.^L2 Prior to that, he had an afternoon nap and had subsequently stayed awake. The driver claimed that he had fallen asleep without warning after 2½ hours of driving time. In finding for the driver, the judge established, "driving dangerously by falling asleep at the wheel" was a strict liability offence but also felt the defendant could plead common law defence of an honest and reasonable mistake. The High Court further made a distinction between driving whilst being sleepy and driving in a manner dangerous to the public because of sleepiness. The argument is technical in the legal definition of "automatism". If a person is in an involuntary state of "automatism"’ legally he could not be said to have voluntary control of the vehicle and therefore, could not have the intent to perform a criminal act. However, the argument regarding liability would more likely hinge on whether during the period prior to falling asleep, the same driver should have behaved reasonably either by not driving or by taking appropriate measures to obviate or minimise the risk. There is more particular pertinence in the light of recent medical evidence that healthy people do not fall asleep without significant prior warning symptoms of sleepiness. Reyner et al believe that usually the driver has forewarning of sleepiness on average, 45.5 minutes before the major accident.²²

The question therefore arises whether a person who knowingly has sleep apnoea has the right to plead "automatism". The situation could be addressed by referring to some English judgment involving similar medical conditions. In a 1983 case, the defendant, a diabetic, was charged with wounding with intent and with an alternative count of unlawful wounding.^L3 His defence was automatism caused by hypoglycaemia due to his failure to take sufficient food after taking insulin. He claimed accordingly that he lacked the specific intent and the basic intent required but the judge directed the jury that as the appellant’s incapacity was self-induced; he could not plead automatism. In a 1994 case, the defendant, who had paedophiliac tendency, was convicted of indecent assault on a 15-year-old boy.^L4 He raised the defence that he had been drugged by his co-defendant who had intended to blackmail him and that he would not otherwise have committed the offence. The judge took the view that the act charged was voluntary, notwithstanding that it might not be ordinarily considered so, by reason of condition of the perpetrator, because his condition still proceeded from a voluntary choice made by him. The "Kingston" case is particularly significant in the concept of intrinsic fault.

The Australian judge’s opinion that the driver was not necessarily dangerous just because he or she was not aware of being sleepy, is remarkably similar to the beliefs held a hundred years ago regarding the dangers of alcohol intake and driving.^L2 Yet current legal opinion on alcohol related "crimes" is not consonant with this view having been extinguished in a 1976 judgement.^L5 The defendant had appealed against a conviction of assault on the grounds that he was too intoxicated through a combination of drugs and alcohol to be aware of his actions. In the judgement of the House of Lords, a distinction was to made between 1) intention as applied to acts considered in relation to the purposes and 2) intention as applied to acts apart from their purposes. A general intent attending the commission of an act is, in some cases, the only intent required to constitute the crime while in others, there must be, in addition to general intent, a specific intent attending the purpose for the commission of the act.

Responsibility of the Employer

In many countries, there are statutory regulations governing responsibility of an employer to ensure that his/her employees or contractors are not exposed to unacceptable risk and vice versa, that their conduct would not cause risks to the public. Ian Callinan QC in Australia stated that the liability of the employer employing a sleep apnoea patient is covered not only under statutory provision but also under principles of vicarious liability in the civil court.²³ He specifically stated that "employers will owe a duty of care in respect of the sleep apnea of any employee if that condition poses, or realizes a threat, not only to the safety and health of other employees, but also to the employee himself suffering the condition". He further states "the potential consequences of resulting motor vehicle accidents are so horrendous, that a responsible employer would be entitled to insist upon, and an employee/driver not entitled to decline, participating in appropriate screening". In an employment setting, it raises the issue of whether the employer, who has a recalcitrant employee who refuses to "cooperate", then has the right to terminate his employment. So far, it appears the scenario has not been tested in a court of law.

Responsibility of Health Practitioners

The medical practitioner is often in an unenviable position. In a conventional Western medical jurisdiction, the health practitioner is often caught between a need to preserve confidentially and at the same time, to fulfil his responsibility to society and to the regulatory body of the land.

Primarily, the health practitioner owes a duty of care to the patient to make a clinical diagnosis; to inform him of his medical condition; to choose appropriate diagnostic procedures to confirm the clinical diagnosis and to provide appropriate management based on evidence. Sleep medicine has now developed into a distinct speciality in its own right. It is generally accepted that the family physician is not expected to diagnose or manage cases of sleep disorder at the outset. This is left to the sleep medicine specialist who is expected not only to treat the sleep disorder but also ensure that the treatment programmes do not interfere or exacerbate the patient’s other conditions.

In the complexity of current day society, whether one welcomes it or otherwise, the responsibility of the health practitioner extends beyond that of his immediate care of the patient. Western medicine is founded on the principles of Hippocrates and the axis of confidentiality. These overarching principles are crafted on the preservation of information about the patient, in particular the prohibition on divulging any information without the patient’s permission, unless a court of law so demands. This may no longer apply when there is multifarious interaction of competing interests and imperatives. Driving is a prevalent and has a widespread impact on society. The court in most modern jurisdiction insists and in fact demands, that when there is significant public interest, the time-honoured preservation of trust between practitioner and patient may well be over ridden. The current situation in Australia would suggest that where sleep disorders are concerned, the health practitioner may be compelled to reach outside the code of ethics by warning members of the public if 1) the person has refused to notify those people at risk; 2) a real risk of injury exists; 3) appropriate counselling has failed; 4) advice from colleagues or an institutional ethics committee has been sought; 5) the person has been warned that notification will occur after reasonable time and 6) the parties notified are obliged to keep confidential the information so revealed.

Whether the practitioner has a further duty to warn a specified third party who is not in the direct care of the practitioner is debatable.

An extension of the duty to warn necessarily includes statutory and legislative authorities. The requirements in various jurisdictions differ, ranging from permissive to mandatory requirements. Category reporting refers to a requirement upon diagnosis of a condition; it may not be mandatory. Functional reporting occurs when a person has a diagnosis and a functional impairment. For instance, in sleep disordered breathing, the American Thoracic Society recommends reporting when the patient with sleep apnoea has excessive daytime sleepiness and history of motor vehicle accidents; when the patient’s condition is untreatable or not immediately amendable to treatment or if the patient is recalcitrant in accepting treatment and not refraining from driving.

Conclusion

The medico legal issues discussed have a wide-ranging impact on the diverse parties of employer, health practitioner, the legal fraternity, patient, society and the prevailing jurisdiction.

Firstly, because driving is so widely prevalent, if not universal in some countries, unnecessary restriction of driving would have a very severe impact on the functions of society. Since most people with sleep apnoea can be considered to drive safely and indeed, most can be expected to behave responsibly, it will certainly be very difficult to impose restrictions at any level on the fitness of all affected patients to drive. Indeed, the impact on the country’s economy of such a proscription could be profound. Secondly, one must bear in mind that even if sleep apnoea can be considered a major factor in motor vehicle accidents, there are also compounding factors including shift work, time of day, seasons, traffic density, condition of roads and other coexistent medical disorders. Each of these, jointly and severally, could have possible adverse effects on sleep. Which then should be considered fundamentally of prime importance?

This discussion on the responsibility on the employers and health practitioners to the public and to statutory bodies would appear to impose an unusual watchdog burden. From an employer’s viewpoint, there will certainly be a need for alterations in labour laws to demarcate areas of responsibility and to confer protection from charges of unfair discrimination by employees. The health practitioner is undoubtedly in an unenviable position. The argument for public safety and public policy as the grounds for intervening in the time-honoured patient-doctor relationship would certainly erode trust, which is fundamental to open communication and faith, so crucial in the effective management of the patient’s clinical disorder. However, if this relationship were to be strained by aspersions, there is a danger that an affected patient may conceal information and thus destroy the primary objective of ensuring the public’s good.

The Implication for Singapore

These issues have particular application in the globalised city-state of Singapore. Puvanendran and Goh reported in 1999 that the prevalence of snoring and syndrome in Singapore was around 77% and 15%, respectively.²⁴ In 2004, Seneviratne and Puvanendran published their findings on 195 patients with OSA, of whom 89.4% were male and 10.6% were female.²⁵ Excessive daytime sleepiness was demonstrated in 87.2%. Sleep onset rapid eye movement (REM) periods were detected in 28.2% of patients when multiple sleep latency tests were carried out. These results are particularly significant in 1) documenting a higher incidence of sleep apnoea syndrome in Singapore; 2) providing further confirmation of male preponderance and 3) documenting the high prevalence of excessive daytime sleepiness and importantly, sleep onset REM. It means, in effect, a very significant segment of the economically productive population may be "medically impaired".

It is now an opportune time to put this medical disorder under scrutiny and raise the issue of its impact on our society for discussion.

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Case Law References

L1. Council of the Shire of Wyong vs Shirt (1980) 146 Commonwealth Law Report 40

L2. Jiminez vs. the Queen (1992) 173, Commonwealth Law Reports 572

L3. R vs. Bailey (1983) 1: Weekly Law Report 760, Court of Appeal

L4. R vs. Kingston, (1994) 3 Weekly Law Report 519, House of Lords

L5. DPP vs. Majewski (1976) 2 Weekly Law Reports 623, House of Lords