Sleep disorders and impaired alertness are a major public health concern.1 To our knowledge, their prevalence has not been evaluated among French anaesthesiologists and intensivists. These professions are associated with on-call duties and, therefore, atypical working hours. An atypical working schedule is one of the major risk factors related to these disorders.2–5 Sleep disorders are a group of syndromes associated with disturbance in the duration of sleep, quality or timing of sleep, and performance or physiological conditions associated with sleep.6 Impaired alertness represents daytime sleepiness defined as difficulty to maintain the required state of vigilance required. Sleep disorders and impaired alertness can affect a physician's health. They also lead to an increased number of medical errors.7–9
These disorders are associated with neuropsychological illness (depression, anxiety), metabolic syndrome (obesity) and cardiovascular diseases.10–16 In addition, they are responsible for traffic accidents.17 Furthermore, human errors are identified in 80% of incidents and they can be related to fatigue syndrome.18–21 Literature analysis highlights the negative impact of atypical work patterns and sleep disorders on health and professional skills.22–24
Our study was aimed to assess the level of self-perceived sleep disorders and impaired alertness among French anaesthesiologists and intensivists. The first objective was to determine the prevalence of these disorders. The secondary objective was to identify independent factors related to these disorders.
Materials and methods
A survey was carried out from November 2012 to December 2012. The participants were anaesthesiologists and intensivists working in French public hospitals. The Ethics Committee (Comité de Protection des Personnes Sud Est 6, Clermont Ferrand, France) waived the need for approval and our study was registered by the French Data Control Regulation ‘Commission Nationale de l’Informatique et des Libertés’ (1613842 v 0). We sent an electronic anonymous questionnaire to all public institution departments representing 5891 senior physicians and 1618 residents. During the study period, we sent two reminders to the entire mailing list. The responses were automatically recorded.
The anonymous questionnaire included 39 items. The first set of items defined the features of the surveyed population related to personal data (age, sex, marital status, parenting status), consumption behaviour (tea, coffee, carbonated drinks, alcohol, tobacco, anxiolytics, antidepressants, psychotropic agents and sport) and professional activity (status, activity, type of institution, number of extended work shifts per month, number of weekends worked per month, number of on-call duties and safety rests). Several items explored the level of stress. The WHO defines stress as ‘the reaction people may have when presented with demands and pressures that are not matched to their knowledge and abilities and which challenge their ability to cope’.25 Other items were related to sleep patterns (self-perceived sleep disturbances, specific medical consultations for sleep disorders, number of sleeping hours during holidays).
The second set of items was related to the Pittsburg Sleep Quality Index (PSQI).26 This scale measures sleep quality during the month before the assessment, consisting of a self-administered questionnaire. We used a version that was previously validated in French.27 A cut-off at 5 differentiates the ‘good’ and ‘poor’ quality sleepers. Responders with a PSQI greater than 5 were considered as ‘poor quality sleepers’ [sensitivity 89.6% and specificity 86.5%; P < 0.001)].26
The third set of questions assessed excessive daytime sleepiness during professional activities and vacations, using the Epworth Sleepiness Scale.28,29 This scale was designed to assess the efficiency of sleep apnoea treatments. It is also used for the subjective sleepiness assessment based on the likelihood of falling asleep in different everyday life situations. This results in an overall score [the Epworth Sleepiness Scale (ESS)] ranging from 0 to 24. A score greater than 10 represents moderate excessive daytime sleepiness (ESS, 11 to 15), and a score above 15 represents severe excessive daytime sleepiness (ESS, 16 to 24).
Data processing was performed using the R-project version 2.14 for Gnu Linux Ubuntu. Quantitative data are presented as median and interquartile range; qualitative data are presented as absolute numbers and proportions. The comparisons of average durations were performed by the Mann–Whitney test and a Chi-square test was used to compare proportions. Univariate analysis was performed to assess the criteria related to PSQI greater than 5 and an ESS greater than 10. A P value of 0.05 was chosen as statistically significant. In a second step, multivariate analysis (stepwise logistic regression) was performed. The variables were selected according to their statistical significance (P < 0.1). Of note, age was not included given inconsistent results with literature data (likely reporting bias). In addition, data on the duration of sleep and excessive daytime sleepiness in the working period and during holiday periods were compared.
We received 1517 responses. Thirteen responses were excluded from analysis because of incomplete data. Hence, 1504 responses were analysed, representing 20% of French anaesthesiologists and intensivists working in public hospitals. Personal, professional, type of consumption and sleep data are summarised in Table 1.
During professional activity, the average sleep duration was 6.5 [6.0 to 7.0] h. Sleep disorders were reported by 642 (43%) responders. However, only 75 (5%) responders had consulted a sleep specialist. Six hundred and seventy-four (45%) responders had a PSQI greater than 5. During their work time, 662 (44%) of responders had an ESS greater than 10, including 99 (15%) with an ESS greater than 15. The features of physicians with sleep disorders are summarised in Table 1.
In order to assess the impact of work duties on sleep disorders, the responders were invited to compare the phases of professional activities and vacations. A significant improvement was perceived during vacations. Sleep duration below 7 h was found in 785 (52%) of responders during their professional activities, whereas only 195 (13%) of responders declared this sleep duration during vacations (P < 0.05). Of note, 662 (44%) of responders had an ESS greater than 10 during their professional activity versus 146 (29%) of responders during vacations (P < 0.05) (Figures 1 and 2). Independent factors significantly associated with sleep disorders are summarised in Table 2. Duration of sleep below 7 h and self-reported sleep disorders were the major independent risk factors associated with a PSQI greater than 5. Independent factors significantly associated with excessive daytime sleepiness are summarised in Table 3.
The prevalence of sleep disorders among anaesthesiologists and intensivists in France has been evaluated. We identified that the prevalence of sleep disorder was 45% in our responders. Excessive daytime sleepiness was twice as severe in our cohort of anaesthesiologists as in the general population.
Our findings would allow occupational health physicians to use a simple interview and the PSQI to investigate high-risk populations such as professionals working with atypical work schedules. This detection could be important, as only 5% of the respondents had undergone a sleep consultation. This rate is lower than that reported in the general population (11%).30 This difference could be due to the ability of physicians to handle their own symptoms, thus limiting the assistance sought from a colleague.
The average sleep duration was lower than in the general population (6.5 vs. 7.1 h in 2012).31,32 For 50 years, there has been a trend towards a reduction of sleep duration. This was attributed to the use of television and internet. The organisation of work with night ‘on-calls’ and atypical work schedules can also affect sleep duration.33 We noted a significant increase in sleep duration during vacations. A sleep duration less than 7 h is an independent risk factor for sleep disorders.2 Sleep restriction and fragmentation cause cumulative sleep deficit.34 In addition, sleep deprivation interferes with personal motivation, learning abilities, personal life and increases in conflict situations.22,23 This can be critical at an individual level, with a large study showing a relationship between sleep duration and mortality.35
We found that use of anxiolytics and psychotropic agents were independent factors related to sleep disorders. They can reflect adaptive responses to insomnia and anxiety. Anxiety is a displeasing feeling of fear and concern. A previous study reported anxiety as an independent risk factor associated with sleep disorders.30 Sleepiness is associated with a decrease in reaction time, memory capacity, psychomotor coordination, information acquisition and effective decision-taking.2,34 These dysfunctions also generate symptoms of anxiety.30 Our results show that excessive daytime sleepiness is an independent factor for sleep disorders. To our knowledge, this finding was not been reported elsewhere. Sleepiness may be the cause or the consequence of sleep disorders and future studies need to investigate this relation.
In agreement with other reports,36,37 stress at work and stress at home were independent risk factors for sleep disorders. Sleep disorders may be due to abnormal activation of the sympathetic nervous system. Self-perception of a stressful event activates the sympathetic nervous system and the hypothalamus-pituitary-adrenal axis. This stimulation generates the release of hormones promoting a state of hypervigilance. High cortisol and norepinephrine blood concentrations are found in those with a short sleep duration.38,39
Our study shows that the number of extended work shifts was associated with daytime sleepiness. The cut-off was four nights a month. This highlights the impact of atypical work schedules on sleep disorders. As excessive daytime sleepiness is associated with decreased cognitive and motor abilities,34 this probably leads to an enhanced risk of medical errors.40 A parallel can be drawn between the occurrence of excessive daytime sleepiness and the burn-out syndrome.41 Thus, in terms of work organisation, whenever possible, the number of on-duty night calls should be limited for each individual. In our model, the aim should be to have no more than five on-duty night calls a month. However, at this stage, it is difficult to combine reported medical errors with work overload and sleep disorders.
Tea consumption and regular practice of naps were independently associated with excessive daytime sleepiness. Tea and coffee block adenosine receptors and thus serve to keep the individual awake. The wake-up period corresponds to high consumption of ATP in the brain with an increase of its degradation product represented by ADP. Beyond a certain concentration, ADP triggers the activation of sleep-promoting neurons and inhibits those related to awakening. A short nap has been associated with improved performance, alertness and reduced risk of accident.42
Our study has several limitations. First, the number of responders represented 20% of French professionals working in public hospitals. This response rate could have affected our findings. Indeed, the features of our responders may not be representative of French anaesthesiologists and intensivists. As it is a national survey, our results cannot be generalised, but it might reflect the situation in other European countries. Second, it was a self-administered questionnaire. Thus, the responses were subjective, reflecting the self-perception of responders rather than an objective assessment. Face-to-face interviews using specific psychological tools should be used in a next study. Third, we cannot control a time-effect on the quality of responses. However, the responders were invited to avoid filling the questionnaire during the 2 days after an on-call night duty. We focused our investigation on professionals working at public hospitals. Thus, our results cannot be extrapolated to private practice. The organisation of work differs according to the healthcare system of each country and this investigation should be replicated in different healthcare systems.
In conclusion, sleep disorders were similar to those reported in the general population, but daytime sleepiness twice as severe as in the general population was observed. The present study shows that a simple interview facilitates the detection of professionals with sleep disorders. The organisation of work affects the occurrence of sleep disorders. The relationship between sleep disorders and patient safety remains to explore.
Acknowledgements relating to this article
Assistance with the survey: none.
Financial support and sponsorship: none.
Conflicts of interest: none.
Presentation: This study was presented as a poster at the annual congress of the Société Française d’Anesthésie Réanimation, September 2013, Paris.
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