Recognising sleep apnoea

Most people spend a third of their lives sleeping, and thus, sleep has a major impact on all of us. As sleep is a function and not a structure, it is challenging to treat and prevent its complications. Sleep apnoea is one such complication, with serious and potentially life-threatening consequences. Local studies estimate that about 15% of Singapore’s population is afflicted with sleep apnoea. The resulting sleep fragmentation may result in poor quality of sleep, leading to daytime sleepiness. Sleep apnoea may also be the underlying cause of high blood pressure, memory loss, poor concentration and work performance, motor vehicle accidents, and marital problems. Evaluation involves a sleep study, followed by patient education, and an individualised step-wise management approach should be explored. Many patients will require follow-up for a long period of time, as management options may not offer a permanent cure; other contributory causes may arise at different phases of their lives, compounded by genetic and hormonal issues, ethnicity and the modern hazards of a fast-paced society.     

Sleep-disordered breathing and cardiovascular disease

Sleep-disordered breathing (SDB) describes a group of disorders characterised by abnormalities in the frequency and/or depth of breathing while asleep. The most common type is the obstructive sleep apnoea/hypopnoea syndrome (OSAHS); it affects 2-4% of the adult population and is an independent risk factor for hypertension. Another type is central sleep apnoea (CSA), which includes Cheyne-Stokes respiration; it is most commonly seen in patients with congestive heart failure and other critical illnesses including cerebrovascular accidents. There is accumulating evidence that both these types of SDB are associated with cardiac failure, arrhythmias and coronary artery disease. Treatment of OSAHS with continuous positive airway pressure (CPAP) has lowered blood pressure, reduced the frequency and severity of some arrhythmias, and improved markers of endovascular inflammation. CPAP has had a mild positive effect on left ventricular function in chronic heart failure by treating co-existent SDB, but it has not improved mortality, possibly because it does not fully treat associated CSA. Clinicians need to be aware of the increasing associations of SDB, especially OSAHS, with cardiovascular dysfunction, as treatment of co-existent SDB will not only improve sleepiness, quality of life, and driving risk, but there is growing evidence that it may also improve cardiovascular risk itself, even in non-sleepy subjects.     

Sleep apnoea presenting as severe hypertension and silent occipital haemorrhage

A 39-year old Chinese man presented with an acute onset of severe headache, accelerated hypertension and subsequently an unexpected extensive right occipital haemorrhage. These were found to be related to a sleep apnoea syndrome which had been unrecognized for many years despite its typical symptoms of loud snoring and excessive daytime sleepiness. Weight reduction led to significant clinical but not polysomnographic improvement of the sleep apnoea syndrome.     

Determining medical fitness to drive: physicians'' responsibilities in Canada.

Current legislation indicates that physicians in Canada have a legal responsibility to know which medical conditions may impede driving ability, to detect these conditions in their patients and to discuss with their patients the implications of these conditions. The requirements to report unfit drivers vary among the provinces, and the interpretations of the law vary among the courts; therefore, physicians' risks of liability are unclear. Physicians may be sued by their patients if they fail to counsel the patients on the dangers of driving associated with certain medications or medical conditions. Physicians may also face legal action by victims of motor vehicle accidents caused by their patients if the court decides that the physicians could have foreseen the danger of their patients' continuing to drive. Physicians' legal responsibilities to report patients with certain medical conditions override their ethical responsibilities to keep patients' medical histories confidential.     

Multiple level pharyngeal surgery for obstructive sleep apnoea

The aim of the study is to evaluate the results of multiple level pharyngeal surgery in patients with moderate to severe obstructive sleep apnoea in Changi General Hospital, Singapore. 13 patients who failed non-surgical treatment underwent surgery which includes uvulopharyngopalatoplasty, genioglossal advancement and modified hyoid myotomy and suspension. Epworth sleepiness scale, Cephalometric analysis and Sleep study were performed pre- and post-operatively to evaluate the results. 76.9% of the patients achieved more than 50% reduction in AHI with post-operative AHI of less than 20. Cephalometric analysis showed an average of 5.2 mm increase in posterior airway space. All patients achieved improvement in Epworth sleepiness scale with an average improvement of 11.8 points. The mean follow-up period of the 13 patients is 12.6 months. Our preliminary results suggest that multiple level pharyngeal surgery is an effective option in the treatment of moderate to severe obstructive sleep apnoea.     

Impaired driving from medical conditions: a 70-year-old man trying to decide if he should continue driving

Some medical disorders can impair performance, increasing the risk of driving safety errors that can lead to vehicle crashes. The causal pathway often involves a concatenation of factors or events, some of which can be prevented or controlled. Effective interventions can operate before, during, or after a crash occurs at the levels of driver capacity, vehicle and road design, and public policy. A variety of systemic, neurological, psychiatric, and developmental disorders put drivers at potential increased risk of a car crash in the short or long term. Medical diagnosis and age alone are usually insufficient criteria for determining fitness to drive. Strategies are needed for determining what types and levels of reduced function provide a threshold for disqualification in drivers with medical disorders. Evidence of decreased mileage, self-restriction to driving in certain situations, collisions, moving violations, aggressive driving, sleepiness, alcohol abuse, metabolic disorders, and multiple medications may trigger considerations of driver safety. A general framework for evaluating driver fitness relies on a functional evaluation of multiple domains (cognitive, motor, perceptual, and psychiatric) that are important for safe driving and can be applied across many disorders, including conditions that have rarely been studied with respect to driving, and in patients with multiple conditions and medications. Neurocognitive tests, driving simulation, and road tests provide complementary sources of evidence to evaluate driver safety. No single test is sufficient to determine who should drive and who should not.     

Road traffic accidents in patients with obstructive sleep apnoea

Three patients involved in road traffic accidents were suspected to have obstructive sleep apnoea (OSA). Two of them fell asleep while riding motorcycles and one patient fell asleep behind the wheel of a truck causing it to overturn. The diagnosis of OSA in each case was suspected based on a history of loud snoring, restless sleep, and excessive daytime somnolence and was confirmed by sleep studies.     

Driver casualties in Victoria (1978-1980). Predominant influences of driver inexperience and alcohol

The driving experience and blood alcohol profiles of motor vehicle driver casualties in Victoria for the period 1978-1980 were examined. Drivers with less than five years' experience were markedly over-represented among the casualties. There was a progressive and marked decline in the number of driver casualties between each of the first five years of driving experience. First-year probationary drivers had three times the casualty involvement of drivers with five years' experience. Probationary licensed drivers, who hold approximately 13% of licenses, accounted for 28% of driver casualties. Blood alcohol levels in excess of the legal limit of 11 mmol/L (0.05 g/100 mL) were more frequent in probationary drivers than in fully licensed drivers (30.4%, compared with 24.4% in fully licensed drivers). These findings, in conjunction with the known impairment of driving skills caused even by blood alcohol levels lower than the legal limit, lead us to recommend that legislation should be enacted making it an offence for probationary license holders to drive a motor vehicle after the ingestion of alcohol. In addition, educational programmes about high-risk accident situations and the alcohol problem on the road should be instituted as an integral part of training before a driving license is issued.     

四川省道路交通事故死亡分析

对四川省１９９４年１月至１９９４年１２月之间发生的４３４７例道路交通事故死亡情况进行分析。结果表明：每百万公里行驶死亡率、每十万车辆死亡率和每十万人口死亡率分别为４．３５、４２．４１和３．９２，同其他国家相比，每百万公里行驶死亡率及每十万车辆死亡率较发达国家高，而每十万人口死亡率则较低；死亡者主要以２１～４０岁男性为主，其死因顺位居各种事故首位，且估计道路交通事故死亡的经济损失，达近６千万元人民币。对此提出了预防对策和措施     

四川省道路交通事故死亡分析

对四川省１９９４年１月至１９９４年１２月之间发生的４３４７例道路交通事故死亡情况进行了分析。结果表明：每百万公里行驶死亡率，每十万国辆死亡率和每十万人口死亡率分别为４．３５，４２．４１和３．９２，同其他国家相比，每百万公里行驶死亡率及每十万车辆死亡率较发达国家高，而每十万人口死亡率则较低；死亡者主要以２１－４０岁男性为主，其死因顺位居各种事故首位，且估计道路交通事故死亡的经济损失，在近６千万元人民     

汽车安全气囊所致的眼外伤

目的：报告了因汽车安全气囊造成的眼外伤及化学性烧伤。希望引起眼科同仁的高度重视．方法：４例病人均是进口高档小卧车，在发生碰撞时因汽车安全气囊高速膨胀打开及气囊破裂所致的眼损伤及化学烧伤．分析了汽车型号及种类，事故发生时的速度，眼损伤的类型和视力情况．结果：第一例病人为碱性化学性角膜炎伴虹膜根部离断及瞳孔括约肌破裂而造成瞳孔扩大；第二例病人为近视镜片致角巩膜板层撕裂伤；第三例病人为广泛角膜擦伤伴前房出血；第四例病人为视网膜水肿出血伴后极部脉络膜裂伤．结论：安全气囊能保护生命降低致伤率，但因气囊的冲击力量引起的机械损伤和气囊中强碱性气体导致的化学烧伤更要引起国内眼科医生的注意．     

Role of respiratory sleep disorders in the pathogenesis of nocturnal angina and arrhythmias.

This report documents how respiratory sleep disorders can adversely effect ischaemic heart disease. Three male patients (aged 60-67 years) with proven ischaemic heart disease are described. They illustrate a spectrum of nocturnal cardiac dysfunction, two with nocturnal angina and one with nocturnal arrhythmias. Full sleep studies were performed in a dedicated sleep laboratory on all patients, and one patient had 48 hours of continuous Holter monitoring. Two patients were found to have obstructive sleep apnoea with apnoea/hypopnoea indices of 57 and 36 per hour, respectively, the former with nocturnal arrhythmias and the latter with nocturnal angina. In both cases, nasal continuous positive airways pressure successfully treated the sleep apnoea, with an associated improvement in nocturnal arrhythmias and angina. The third patient who presented with nocturnal angina, did not demonstrate obstructive sleep apnoea (apnoea/hypopnoea index = 7.2) but had significant oxygen desaturation during rapid eye movement (REM) sleep. This patient responded to a combination of nocturnal oxygen and protriptyline, an agent known to suppress REM sleep, and had no further nocturnal angina. All patients were considered to be an optimum cardiac medication and successful symptom resolution only occurred with the addition of specific therapy aimed at their sleep-related respiratory problem. We conclude that all patients with nocturnal angina or arrhythmias should have respiratory sleep abnormalities considered in their assessment.     

Sleep apnoea syndrome--a report of 14 cases

Patients with sleep apnoea syndrome suffer considerable morbidity and an increased mortality. We reviewed the characteristics of 14 patients with sleep apnoea syndrome (11 males and 3 females) who were studied since 1986. All were less than or equal to 60 years of age with the majority in their 4th and 5th decade. Obesity was present in 8 patients (57%) and hypertension in 6 (43%). Overnight sleep studies showed that 11 patients had obstructive sleep apnoea, 2 had central and one had predominantly mixed sleep apnoea. Ten patients (71%) had some form of nose and/or throat pathology. Tonsillectomy seemed an effective therapeutic procedure in those with upper airway obstruction due to enlarged tonsils. Four out of 5 patients had significant symptomatic improvement post-tonsillectomy. Nasal continuous positive airway pressure was also effective in alleviating apnoeas and relieving symptoms in 4 other patients who had no obvious upper airway obstruction. A high proportion of our patients had obstructive sleep apnoea due to enlarged tonsils. Tonsillectomy offered a simple and effective therapy for such patients. Nasal continuous positive airway pressure was also effective in the treatment of obstructive sleep apnoea.     

昆明市出租车司机疲劳与相关健康和安全危险因素

［摘要］目的　确定昆明市出租车司机群体的疲劳发生率，了解出租车司机的一般工作和健康状况，并确定与疲劳驾驶相关的危险因素．方法　随机选取昆明市400名出租车司机为研究对象．采用自填式问卷调查方式，调查个人资料、社会习惯、工作模式和睡眠模式，同时测量身高和体重．采Epworth嗜睡量表评价疲劳和嗜睡水平．多元逻辑回归分析调整后的比值比，95%置信区间和出租车司机疲劳的危险因素的关系．结果　出租车司机群体患肥胖、高血压、糖尿病和高胆固醇的比例很高；疲劳驾驶与睡眠不足或睡眠质量差、额外兼职工作和每天驾车时间>10 h有关．结论　针对出租车司机的工作和健康状况，可为下一步干预提供参考，提高生产力和道路安全．     

Driver Sleepiness and Risk of Car Crashes in Shenyang, a Chinese Northeastern City： Population-based Case-control Study

Objective To estimate the association of driver sleepiness with the risk of car crashes. Methods A population-based case-control study was conducted in Shenyang, a northeastern city in China, between November 2001 and July 2002. The case group comprised 406 car drivers involved in crashes, and 438 car drivers recruited at randomly selected sites, and on the day of week, and the time of day when they were driving on highways in the study region during the study period were used as control groups. Face-to-face interviews with drivers were conducted according to a well-structured questionnaire covering the circumstances of their current trip and their background information. Stanford sleepiness scale and Epworth sleepiness scale were used to quantify acute sleepiness and chronic sleepiness respectively. Results There was a strong association between chronic sleepiness and the risk of car crash. Significantly increased risk of crash was associated with drivers who identified themselves as sleepy (Epworth sl     

Accidents involving off-road motor vehicles in a northern community.

The increasing number of accidents associated with off-road motor vehicles used for recreational purposes prompted this prospective study. During 1985 the records of victims of all motor vehicle accidents who were seen at the Hudson Bay Union Hospital, Hudson Bay, Sask., were studied; patients involved in on-road vehicle accidents were included for comparison. Emphasis was placed on age, vehicle type, mechanism of accident, injury severity and the use of safety features. Almost half of the victims of off-road vehicle accidents were under 16 years of age. The poor adherence to government legislation and manufacturer recommendations was evident in the number of people who did not wear helmets or use headlights.     

Drinking and driving: choosing the legal limits

The legal limit for drinking and driving in Britain is 80 mg/dl (17.4 mmol/l) of alcohol in the blood. This was chosen 20 years ago on the basis of studies that have recently been reanalysed. Changes in public opinion, the results of recent research, and the evaluation of other countermeasures, such as random breath testing, show that there are good grounds for revising the legal limit downwards. It is suggested that the legal limit should be reduced from 80 mg/dl to 50 mg/dl (10.9 mmol/l) and random breath testing introduced as in most Nordic countries. A zero limit is proposed for learner and first year drivers, who are likely to have accidents even with low concentrations of alcohol in their blood.     

Apnoeic episodes induced by smothering: two cases identified by covert video surveillance

Recurrent cyanotic episodes associated on some occasions with loss of consciousness due to cerebral hypoxia were investigated by long term tape recordings of breathing activity, oxygen saturation, air flow, electrocardiographic activity, and in some cases electroencephalographic activity. In 51 infants and children the mechanisms for the cyanotic episodes were identified (prolonged expiratory apnoea in 45, sleep related airway obstruction in three, seizure induced apnoea in one, behaviour induced apnoea in one). In one child apnoea was suspected as being caused by suffocation (smothering) by the mother. This was confirmed after enlisting the help of the police, who undertook covert video surveillance during cyanotic episodes. Each cyanotic episode was associated with a pattern of disturbance on the multichannel tape recordings which may be pathognomonic of this type of apnoea. A second infant with cyanotic episodes in whom smothering was suspected was referred for similar investigation after the availability of video recordings became established. Maternal smothering was again supported by specific patterns on multichannel tape recordings and confirmed by video surveillance. Diagnosis by video surveillance produces unequivocal evidence in these cases and avoids the need for medical and nursing staff to confront the mother with a possibly incorrect suspicion or in a court of law.     

Obstructive sleep apnoea: a new disease for Papua New Guinea?

Obstructive sleep apnoea is a common disorder in western societies and has a strong association with obesity and alcohol use. The condition has not previously been recorded in Papua New Guinea. The clinical details of 2 patients from Papua New Guinea with obstructive sleep apnoea are described, and the principles of treatment of this condition are outlined. Sleep apnoea is likely to become an increasing problem in Papua New Guinea.     

Bicycle accidents in childhood

The results of a 10 year study of bicycle fatalities and an eight year study of serious non-fatalities are reported for urban Brisbane (population 1,000,000). There were 845 serious non-fatal bicycle accidents and 46 fatalities during the study. Boys were involved in 86% of accidents. Boys have an accident rate of 134.21 per 100,000 population at risk and a fatality rate of 5.06 per 100,000 at risk. Serious bicycle accidents have increased by 50% in this decade; but considering fatal cases alone, no secular trend was evident over the 10 year period of the study. This suggests that an increase in the overall rate of bicycle accidents has been in part compensated by less serious injuries. In 70% of fatalities children had head injuries, and 87% of fatalities followed a collision between a cyclist and a motor vehicle or a train. Bicycle accidents on the roads most commonly occur to boys aged between 12 and 14 years on a straight road at "mid-block" between 3 and 5 pm in clear weather conditions and in daylight. It is concluded that injuries and fatalities after bicycle accidents can be reduced by protecting children's heads, separating child cyclists from other road traffic, or educating and training both cyclists and other road users in safe behaviour. The compulsory use of helmets and the restriction of access to the roads by child cyclists to reduce injuries are, however, still controversial in many areas.