Portuguese Version

Year:  2002  Vol. 68   Ed. 3 - (18º)

Artigo de Revisão

Pages: 412 to 415

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Sleep apnea and automobile accidents: review of regulations for drivers

Author(s): Silke Anna Theresa Weber(1),
Jair Cortez Montovani(2)

Keywords: sleep apnea syndrome, road accidents, regulamentation for driver license

Abstract:
Several studies show a crescent association between sleep-disordered breathing, excessive sleepiness and automobile accidents. Many countries already discussed a regulamentation dealing with fitness to drive of persons with these conditions, including questionnaire and/or investigation by a qualified specialist. In Brazil, these discussions are only at the beginning. This way, we suggest some items to be included in our traffic law.

INTRODUCTION

Sleep obstructive apnea (SOA) is a breathing disorder during sleep characterized by partial prolonged airway obstruction or intermittent complete obstruction (per time stages) that interrupts the ventilation during sleep and normal sleeping patterns.

Partial and complete airway obstruction leads to hypercapnia, hypoxemia, cor pulmonale, behavioral and developmental disorders, along with other signs and symptoms.

A number of risk factors are related or associated to sleep obstructive apnea: obesity, endocrinology and neuromuscular diseases, cardiovascular diseases and drug abuse, such as alcohol use.

Although in other countries many studies have shown that subjects with ventilation disorders and sleep obstructive apnea are more likely to get involved or cause traffic accidents, there is absolute no information about it in the Brazilian literature. We did not find any information concerning specific traffic norms and regulations for drivers who have sleep disorders. Once SOA is detected and diagnosed, what kind of counseling does the patient receive? Should they be banned from driving? For how long? We wondered how much these questions and answers could help preventing accidents.

The purpose of the present study was to show the specific legislation for drivers with sleep disorders and, based on these data, make proposals to regulate the Brazilian traffic legislation.

REVIEW OF LITERATURE

Traffic accidents are among the most severe and important problems of the contemporary society and in general they are neglected, especially in Brazil, where traffic is a real chaos. To give a general overview, traffic accidents in Brazil are ranked as the 9th cause of death in the world, the 5th among developed countries and the 10th among developing countries.

According to the Brazilian Ministry of Health, these traumas increase annually, and only in 1998, there were over 300,000 car accidents and about 27,000 deaths, which was the main cause of death in the age range of 15 to 44 years. External causes (accidents and violence) are the main causes of death in children and adolescents aged 5 to 19 years. They amount to 57% of the total mortality in the age range of 0 to 19 years, and traffic accidents total 30% of them1.

As of the 80s', many studies showed that car accidents are associated with factors such as fatigue after long driving hours, obesity, sleep-disordered breathing and drug use, especially alcohol2-9.

In Brazil, there is only one study published by Rizzo10, related to the factors above-mentioned and traffic accidents. The study described interviews with 1,000 drivers (out of which, 33.3% were truck drivers), about the following parameters: sleep habits, snoring, diurnal sleepiness, sleepiness during driving and obesity. They observed that: 1) 254 drivers had had one or more accidents, out of which 20.1% were probably caused for excessive sleepiness; 2) 58.2% of the respondents were occasionally sleepy while driving and 16% were frequently sleepy; 3) 41.7% of the truck drivers reported they occasionally dozed off while driving; 4) 58.4% took stimulants to be awaken; and 5) only 7.2% of the drivers had the habit of stopping the car to rest if they felt tired.

Differently from the Brazilian literature, there are innumerous foreign articles addressing these aspects: Stoohs et al.11 studied the incidence of sleep-disordered breathing in 159 truck drivers by monitoring respiratory patterns during sleep and observing that 46% of them presented ventilation disorders.

Ricardo et al. (1994)12 studied 90 truck drivers assessing the following parameters: sleep habits, snoring, excessive diurnal sleepiness, obesity and involvement in accidents. They observed that people with ventilation disorders, diurnal sleepiness and obesity were twice more frequently involved in accidents than drivers who did not present the studied abnormalities.

Han et al. (1996)13, studied 253 patients with complaints of sleep disorders, snoring and diurnal sleepiness using polysomnography and they demonstrated that 68% of them had Sleep Apnea Syndrome and 31% had already been involved in a car accident before. The drivers reported their tendency to sleep in inappropriate situations and many had passed through their trip destination without noticing it. As a conclusion, they suggested that the initial step to identify drivers with sleep-disordered breathing problems was to introduce a questionnaire to be filled out upon the driver's license process.

Young et al. (1997)14 conducted prospective studies in 913 patients during 5 years and compared SOA and polysomnography (PSG) versus car accidents. People with diagnosis of sleep-disordered breathings were three time more likely to get involved in an accident than those without the pathology. This ratio was even higher when patients with SOA were considered. Mild and moderate cases of SOA showed 4.6 more likelihood to have an accident and the patients with severe SOA (Apnea/Hypopnea index above 15), had seven times higher likelihood14.

Krieger et al. (1997)15 followed 547 patients with diagnosis of SOA and use of Continuous Positive Airway Pressure (CPAP), related to sleepiness and number of traffic accidents one year before treatment and six and twelve months after treatment and they observed that there was a significant reduction in number of accidents. They observed that narcolepsy, SOA and other forms of excessive sleepiness, such as Pickwick syndrome, are currently considered risk factors for driving.

Based on the observations by Findley et al. (1989)17, the Federal Highway Administration in the United States, in 1990, published that: "subjects with sleep apnea syndrome (symptoms of snoring and excessive sleepiness), not treated and/or suspected, should be considered not qualified to drive a commercial vehicle up to diagnosis is ruled out or the disorder is treated, and drivers with no SOA treatment should be submitted to Multiple Sleep Latency Test (MSLT) annually". The North-American Chest Society has also proposed to its members that they should be stricter when assessing and counseling sleep apnea and sleep-disordered breathing patients. Drivers should be warned in writing about the possibilities of getting involved in a car accident and referred to medical treatment. After two months of treatment, clinical conditions should be reassessed and if necessary, they would receive further guidance and treatment. In case of therapeutic failure, traffic authorities should be notified.

In order to comply with such guidelines, a number of American states developed their own traffic legislation to prevent narcolepsy and SOA people to drive. In Texas, Utah and North Carolina, these two conditions prevent patients from driving commercial cars, but they can still get a license to drive automobiles, provided that they have been under treatment for at least 6 months and are symptom-free. The state of Maine proposed that Multiple Sleep Latency Test (MSLT) or PSG be performed annually to assess people who have sleep disorders and are driving candidates. The indexes they use are Epworth's scale: a) MSLT from 10 to 15 minutes and/or Apnea and Hypopnea Index (AHI) greater than 10 - minimal restriction; b) MSLT from 5 to 10 min and AHI equal or greater than 10 - mild disease; c) MSLT below 5 minutes and AHI equal or greater than 10 - moderate disease, and above these values, the disease is considered severe. In the first three conditions, the driver needs annual medical assessment to renew bus and truck driver's license and in the latter, they are not allowed to drive commercial vehicles. Other states, such as California, Maryland and Oregon adopted the same regulation, but they extended driving prohibition to all types of vehicles.

Countries such as Canada and United Kingdom have unspecific legislation about such cases but they refer to the fact that subjects with narcolepsy, cataplexy or other sleep disorders that cause excessive diurnal sleepiness should be prevented from getting a driver's license for commercial purposes. The application or renewal of the driver's license requires appropriate control of symptoms and periodical medical examinations after 1, 2 and 3 years, depending on the diagnosis and the severity of symptoms.

In the Netherlands, consciousness abnormalities (somnolence, confusion) caused by diseases, illegal drugs and medications lead to temporary restriction of driving. If the condition persists or is recurrent, it should be considered a definite restriction to driving.

In Sweden, subjects with diagnosis of SOA are forbidden to drive commercial vehicles. Currently, there is a proposal in discussion that extends this restriction to subjects with severe snoring and excessive diurnal sleepiness.

In Australia, subjects with narcolepsy are forbidden to drive. After treatment and minimal observation period of 3 months, they can drive cars. They are also currently debating the extension of the legislation to people with SOA.

DISCUSSION

Sleep obstructive apnea, associated or not to metabolic disorders (obesity), cardiovascular diseases and use of drugs (alcohol) is currently considered a risk factor for automotive accidents. However, studies have shown that there is great variation in interpretation and definition of rules concerning driving and these subjects.

Owing to this information, some countries such as the USA, developed specific legislation for drivers with SOA and other sleep disorders. To identify the drivers with the disorders, candidates have to undergo polysomnography, among other tests. However, even among specialists, these standardization is not unanimous, because Aldrich (1989)3 observed that the results of groups of drivers with and without SOA involved in accidents was not differentiable.

Other countries, such as Canada and England, developed their own norms to drivers with SOA, recommending that the drivers be treated during period of 2, 3 and up to 12 months. Unfortunately, physiological grounding for such recommendations are not very clear, because if we consider the different severity of SOA (mild, moderate and severe), treatment periods may range from very short to long.

It seems that instead of standardizing or regulating these issues, the identity of SOA is what should be considered. However, the review of the literature showed us that there are few studies demonstrating the correlation between SOA and accidents. Pakola et al. (1995)18 observed that only drivers with severe apnea (apnea/hypopnea index greater than 50) are involved in higher number of accidents. Findley et al. (1988), studied 46 drivers (16 mild SOA, 17 moderate and 13 severe affection), and they noticed that only those with severe SOA had higher likelihood of getting involved in accidents.

As we can see, despite this information, SOA/accident correlations are controversial, especially if of mild or moderate nature. Therefore, what can be said is that there is a increased risk of drivers with SOA having accidents, which has significant medical and legal implications. Owing to this aspect, the debate is not limited to the medical arena and involves other areas, such as legal and traffic safety public policies.

It seems that in Brazil alike, despite the only published study (Rizzo)10 whose results showed that sleepiness, excessive speed, alcohol and aggressive driving contribute to or are risk factors to car accidents, this discussion is still under course. This discussion will certainly emphasize the need for further data about these correlations, and it will show the importance of performing studies not only with drivers who have SOA, but also with healthy people who are temporarily deprived of sleep because of their life style or working hours.

CLOSING REMARKS

In Brazil, there is no specific legislation concerning drivers with sleep-disordered breathing or narcolepsy. This discussion has just begun, which is past time in our opinion. A number of scientific societies have shown the need to introduce a specific legislation oriented to such cases in our traffic code, requiring mandatory tests at the application for driver's license: 1) screening questionnaires to identify the diseases; 2) specialized medical tests for obese candidates or those who take central nervous system depressing drugs; 3) in case of abnormal responses to the questionnaire and if there were diagnostic suspicions, diagnostic tests would be mandatory (MSLT and PSG); 4) clinical follow-up of drivers who failed these tests; 5) awareness and outreach campaigns through the media.

It is important to emphasize that the adoption of these norms and others based on other countries' legislation should be as brief as possible, because we know that prevention, more than repression, is the alternative to reduce the alarming rates of traffic violence. This challenge is undoubtedly encouraging and motivating to physicians who are key players in the discussion about these painful and costly evils that traffic accidents represent to our societies.

REFERENCES

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17. Findley CJ, Fabrizio MJ, Knight H et al. Driving simulator performance in patients with sleep apnea. Am Rev Respir Dis 1989;140:529-30.
18. Pakola Stephen Diuges D, Pach A. Driving and sleepiness: review of regulations and guidelines for Commercial and non Commercial Drivers with sleep apnea and narcolepsy. Sleep 1995;18(9):787-796.

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[1] Teaching Assistant, Discipline of Otorhinolaryngology, Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Medical School, Botucatu - UNESP.
[2] Full Professor, Discipline of Otorhinolaryngology, Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Medical School, Botucatu - UNESP.

Address correspondence to: Silke Anna Theresa Weber - Dep. Oft/Orl/Ccp

Faculdade de Medicina de Botucatu - UNESP - Botucatu - São Paulo - 18618-000 - Brazil

Tel/Fax: (55 14) 6802.6256 - E-mail: montovan@fmb.unesp.br

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