Christer Carenfelt

Clinical symptoms of sleep apnea syndrome and automobile accidents

Patients with clinical features of sleep apnea syndrome (SAS) and self-reported sleep spells at the wheel do poorly in simulated monotonous driving. To evaluate whether drivers with defined symptoms of SAS (heavy snoring, sleep disturbances and daytime sleepiness) compensate in real traffic by careful driving or not, the rate of car accidents over a 5-year period was investigated. A questionnaire was addressed to 140 patients with and 142 controls without symptoms associated to SAS. Seventy-three of the patients had a complete triad of SAS-associated symptoms. Fifty-two percent of these patients reported habitual sleep spells at the wheel, as opposed to less than one percent by the controls. The ratio of drivers being involved in one or more combined-car accident was similar for patients and control drivers, but for single-car accidents the ratio was about 7 times higher for patients with a complete triad of symptoms of SAS compared to controls (p less than 0.001). When corrected for mileage driven, the total number of single-car accidents was almost 12 times higher among patients with sleep spells whilst driving, compared to controls (p less than 0.001). It is concluded that drivers with the clinical features of SAS are at increased risk especially for single-car accidents and that the risk seems to vary with the severity of symptoms.

Does uvulopalatopharyngoplasty inhibit automobile accidents

Patients with rhonchopathy, which includes obstructive sleep apnea syndrome (OSAS), who report sleepy spells at the wheel do poorly on simulated monotonous driving tests and have a twofold to threefold increase in traffic accidents. To assess whether drivers with rhonchopathy (heavy snoring, sleep disturbances, and daytime sleepiness) cause fewer automobile accidents after uvulopalatopharyngoplasty (UPPP), the car accident rate for the first 5 years after surgery was compared to the rate of the 5 years immediately before the operation. Data were collected by means of a self‐report questionnaire. Fifty‐six patients with rhonchopathy were compared to 142 controls without rhonchopathy who had been subjected to nasal surgery. The response rates were 96% and 94%, respectively. The reported habitual sleepiness while driving had disappeared in 87% (P<.001) of drivers who had the problem preoperative. The accident risk reduction (corrected for mileage) in patients was almost four times greater than the reduction in controls (P<.001) after surgery. The relative rate of patients involved in any single‐car accident fell by 77% (P<.05), and the relative rate of single‐car accidents fell by 83% (P<.001). It is concluded that drivers with rhonchopathy have an increased risk for car accidents, especially single‐car accidents, but that this risk returns to normal after UPPP.

Driving Vigilance Simulator Test

Drivers suffering from sleepiness at the wheel run the risk of being involved in car accidents. To evaluate whether objective data of driving performance can be assessed in patients with excessive tendency of falling asleep at the wheel, two test versions of a computerized driving program were created to fit an advanced driving simulator. For the evaluation 15 male drivers with habitual sleep spells whilst driving were selected among patients with the clinical features of the sleep apnoea syndrome. The brake reaction time and the deviations from straight road-line were significantly increased when compared to the performance of 10 matched controls. Irrespective of test version, the driving simulator with the program used was found to be a sensitive method to ascertain driving vigilance impairment in quantitative terms. It would also be a valuable method to evaluate the efficiency of treatment in selected patients.

SLEEP APNEA SYNDROME SYMPTOMS AND AUTOMOBILE DRIVING IN A GENERAL POPULATION

Automobile accidents are reported as being overrepresented in those suffering from the obstructive sleep apnea syndrome (SAS), evident by snoring, sleep disturbances and diurnal hypersomnia. An estimation of the prevalence of these symptoms amongst an adult population, predominantly automobile drivers, was assessed by using a one-stage questionnaire procedure. From a national random sample of 1214 persons a weighted reply rate of 76% was achieved. Snoring, breath cessations, mid-sleep awakenings, and diurnal hypersomnia were reported in 24, 3.8, 27 and 9.1%, respectively. The maximum prevalence of SAS was estimated as 2.8-5.5% among men, aged 30-69 years, depending on definition used. Driving frequency in potential sleep apneics was similar to that of the entire population studied. Diurnal hypersomnia, considered a consequence of SAS, was reported as an overall 2.2%, corresponding to 100,000 automobile drivers in Sweden.

Simulated Long-Term Driving Performance before and after Uvulopalatopharyngoplasty

To investigate whether automobile drivers with the clinical features of sleep apnea syndrome (SAS) perform worse than controls in a simulated long-term test drive, and to see if their driving improves after uvulopalatopharyngoplasty (UPPP), 15 male drivers with SAS, suffering from sleep spells whilst driving, and 10 matched controls without a history of SAS or hypersomnia at the wheel were tested in an advanced driving simulator. Brake reaction time, lateral position deviation and off-road episodes were measured during a 90-min rural drive at twilight conditions. The clinical evaluation was made by a questionnaire scoring symptoms of snoring, sleep disturbances and diurnal sleepiness before and after surgery. Before UPPP the patient group showed impaired performance in all three effect measures compared to controls. UPPP resulted in improved reaction time performance (average mean improvement: 0.5 s, average 90th percentile improvement 0.8 s). Furthermore, 12 of the 15 patients reported a marked improvement regarding sleepiness whilst driving. For these clinically successful cases the number of off-road episodes decreased substantially. We conclude that most patients improve their long-term driving performance as a result of UPPP.

Incidence, Aetiology, and Prognosis of Acute Epiglottitis in Children and Adults in Sweden

A retrospective study of the incidence, aetiology and case fatality rate of acute epiglottitis in children and adults was performed. The study covered the whole of Sweden (population 8.4 million) during the years 1987-89, before general vaccination against Haemophilus influenzae (Hi) type b was started. Patients were included if it was documented that they fulfilled all 3 of the following criteria: (a) red and swollen epiglottis visualized by indirect laryngoscopy, (b) inspiratory stridor or difficulties in swallowing, and (c) a temperature > or = 38 degrees C. A total of 306 children and adolescents (0-19 years) and 502 adults (> or = 20 years) were found. The age-specific incidence was highest in children aged 0-4 years, (14.7/100,000 per year). The total incidence was 3.2/100,000 per year. In the age group 0-19 years, blood cultures had been obtained from 195 (64%) and Hi was isolated from 154 (79%). In adults (> or = 20 years), 114 of 298 blood cultures yielded Hi, while pneumococci were isolated from 5 and group A streptococci from 3 patients. A total of 220 children (72%) and 114 adults (23%) needed an artificial airway. Five children and 12 adults died. In conclusion, the incidence of acute epiglottis in Sweden is very high. Compared to a previous country-wide study covering the years 1981-83 that used the same methods for case finding and case definition, the incidence in children had decreased while the incidence in adults had increased.

Treatment of Sinus Empyema in Adults: A Coordinated Nordic Multicenter Trial of Cefixime vs. Cefaclor

In sinus empyema, H. influenzae is the most prevalent pathogen in some subpopulations and in case of therapeutic failure. Cefixime, the first oral cephalosporin of the 3rd generation, is highly potent in vitro against H. influenzae. To study the efficacy and safety of cefixime in adults with acute sinusitis, a coordinated, double-blind multicenter trial was designed for purulent cases, as confirmed by antral aspiration. A total of 364 patients were enrolled in the study with 125 cases randomized to the reference group, assigned to treatment with cefaclor. Evaluation was based on clinical outcome and on antral reaspiration (86% of the cases). No significant differences between the treatment groups were found, as regards short-term or long-term clinical outcome. However, the clinical examination overestimated the therapeutic results. Only 4% of the patients were considered as failures, but the re-aspiration demonstrated remaining suppuration in 14% of all cases (p less than 0.001). Based on re-aspiration, the failure rate among patients with initial growth of pathogens was lower for cefixime (8%) than for cefaclor (20%) (p less than 0.05). Such a difference was not found among patients with growth of H. influenzae. No serious adverse reactions were recorded, but loose stools and diarrhoea were significantly more frequent in the cefixime treatment group. Five patients (2%) in the cefixime treatment group discontinued their treatment due to adverse events.