Article start

Original ResearchCauses and Management of Sleepiness Among Pilotsin a Norwegian and an Austrian Air AmbulanceServiceA Comparative StudyErik Zakariassen,1,2*, Siri Waage,1,3, Anette Harris,4, Pia Gatterbauer-Trischler,5,Bernd Lang,5, Wolfgang Voelckel,6, Stale Pallesen,3,4, Bjùrn Bjorvatn,1,31Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway2The Norwegian Air Ambulance Foundation, Drùbak, Norway3Norwegian Competence Center for Sleep Disorders, Haukeland University Hospital, Bergen, Norway4Department of Psychosocial Science, Faculty of Psychology, University of Bergen, Bergen, Norway5Air Rescue College, Christophorus Flugrettungsverein, Vienna, Austria6Medical Department, Christophorus Flugrettungsverein, Vienna, AustriaABSTRACTObjective:We compared subjectively reported sleepiness and fatigue as well as causes and managementstrategies for combating sleepiness among pilots working in 2 different helicopter emergency medical serv-ices operating with different shift systems.Methods:Pilots from the Norwegian Air Ambulance (NAA) and Christophorus Flugrettungsverein (CFV) inAustria participated. NAA performsflight missions 24/7, whereas at the time of the study the participatingCFV bases did notfly after sunset. The pilots are on duty for 1 week in both services. NAA and CFV used anidentical research protocol, including questionnaires about sleep, sleepiness (Epworth Sleepiness Scale andKarolinska Sleepiness Scale), coping strategies, and work-related causes of fatigue.Results:CFV pilots kept busy, whereas NAA pilots slept and did physical exercise as strategies to preventsleepiness. The majority in both groups used napping and coffee consumption as strategies. CFV pilotsreported more frequently than NAA pilots that administrative duties and environmental factors were reasonspreventing napping.Conclusion:Some differences existed between the 2 pilot groups regarding strategies for managing sleepinessand causes that prevented pilots from napping. Pilots in both groups were healthy, physically active, and hadnormal Epworth Sleepiness Scale and Karolinska Sleepiness Scale scores.© 2018 The Authors. Published by Elsevier Inc. on behalf of Air Medical Journal Associates. This is an openaccess article under the CC BY-NC-ND license. ( working hours that overlap with usual sleeping time andextended working hours influence biological rhythms and social life.Shift work, and especially night work, usually involve activity whenthe circadian rhythm promotes sleep and sleep when the circadianrhythm promotes wakefulness. This causes misalignment betweenthe endogenous circadian timing system and the external 24-hourtiming system. Accordingly, shift work has consistently been shownto be associated with health problems. Most common are sleepdisturbances such as prolonged sleep onset, reduced sleep duration,and excessive sleepiness.1,2Sleepiness is not equivalent to fatigue. Sleepiness refers to a stateof increased sleep propensity3and is distinguished from fatigue,which is frequently differentiated into muscular and mental fatigue.Muscular fatigue refers to an exercise-induced reduction in maximalvoluntary muscle force,4whereas mental fatigue comprises a psycho-biological state caused by prolonged periods of demanding cognitiveactivity and is characterized by subjective feelings oftirednessandlack of energy.5In aviation, fatigue and sleepiness have long beenidentified as occupational hazards.6,7However, relevant research onemergency medical service providers, air ambulance, helicopteremergency medical service (HEMS), and shift work is scarce.8-11Anette Harris received salary for 6 months from The Norwegian Air AmbulanceFoundation.* Address for correspondence: Erik Zakariassen, Department of Global Public Healthand Primary Care, PO Box 7810, 5020 Bergen, Norway,E-mail Zakariassen).1067-991X/$36.00© 2018 The Authors. Published by Elsevier Inc. on behalf of Air Medical Journal Associates. This is an open access article under the CC BY-NC-ND license.( Medical Journal 38 (2019) 2529Contents lists available atScienceDirectAir Medical Journaljournal homepage:
Different shift systems and different methods used in research renderit difficult to compare data between different systems across coun-tries and services. Research on how pilots in HEMS manage sleepinessand what they consider as work-related causes of sleepiness is verylimited. Nevertheless, the International Civil Aviation Organizationmanual has suggested some personal fatigue mitigation strategies,such as what to do when sleep at home is disturbed by a new baby orin the case of extended commuting before duty period.12To addressthe aforementioned limited research and knowledge, the main aim ofthis study was to compare the pilotsgeneral/overall perception ofsubjectively reported sleepiness, causes of sleepiness, and manage-ment strategies for combating sleepiness in a Norwegian and anAustrian HEMS service.Material and MethodsIn 2014, the Norwegian Air Ambulance (NAA) established a fatiguerisk management system (FRMS). Therefore, to meet the need forbaseline data, a larger research project was initiated. At that time, theNAA operated 8 bases in Norway, with 9 helicopters.The NAA pilots are on duty 7 days and off duty 14 days followedby 7 days on duty and 21 days off duty. They perform helicopter mis-sions 24/7 while on duty throughout the year. During the duty week,they live together with the other crewmembers at the base in singlebedrooms. As part of the safety policy, there are duty time limitationsand rest requirements. For the Norwegian pilots, the maximumallowableflight time (measured from takeoff and landing on base onreturn + 1 hour) for crewmembers amounts to 7 hours within a con-secutive 24-hour period, 12 hours in a consecutive 48-hour period,and maximum of 30 hours during a consecutive 7-day period. During6 summer weeks, 30 NAA pilots performed 483 missions, 10% of themissions between midnight and 6AM. The mean time spent on mis-sions per duty week was 1,424 minutes with a 95 % confidence inter-val between 1,207 and 1,642 minutes.To be able to compare causes and management strategies forsleepiness and fatigue between Austrian and Norwegian pilots, theNorwegian research group invited the Austrian air ambulance Chris-tophorus Flugrettungsverein (CFV) to participate and to perform asimilar study using the same research protocol. The normal schedulefor the CFV pilots included 7 days on duty followed by 7 days offduty. At that time, the crews in Austria only performed missions thatstarted at daylight. During the work period, the crews mainly livetogether at the base in single bedrooms. However, if the pilots liveclose to the base (eg,<a 30-minute drive), they may spend the nightat home.The maximum hours on duty and the respective maximum timefor HEMS operations for the Austrian pilots is 16 hours on duty with7 hours as the maximum allowableflight time (measured from take-off at the base to landing on base on after return) and 112 hours onduty within 7 successive days. The minimum rest period for HEMSoperations is 8 hours between 2 HEMS duty days, and 36 hours ofrest time between 2 HEMS duty periods (7 successive days on duty).During 7 summer weeks, 21 CFV pilots performed 576 missions. Themean time spent on missions per duty week was 1,539 minutes witha 95% confidence interval between 1,331 and 1,793 minutes.An identical research protocol was used in both Norway and Aus-tria. All pilots in NAA (n = 30) and half of the pilots in CFV (n = 24)were invited to participate. In order to obtain a balance betweenurban and busier bases and rural and less busy bases, the pilots inAustria were selected based on geographic differences and numbersof missions per year on the different HEMS bases. The pilots com-pleted a questionnaire about sleep and sleepiness while at work. Thequestionnaire included items about demographic and backgroundvariables like sex, age, marital status, children, years in present work,health and different questions about sleep, work-related sleepiness,and management of sleepiness. Management of sleepiness wasdivided into 15 different strategies, and the pilots could tick off asmany as applicable. Response options to a question about what pre-vented pilots from napping were divided into 10 different causes,and the pilots could tick off as many as applicable. Work-relatedcauses of fatigue were divided into 8 different potential fatigue-trig-gering situations. For each situation, the pilot could choose betweendoes not cause fatigue, low fatigue, moderate fatigue, high fatigue,and not applicable.Epworth Sleepiness ScaleThe Epworth Sleepiness Scale (ESS) is considered a trait measureof subjective sleepiness and was completed once. ESS assesses thesubject's general tendency to fall asleep or doze off in 8 different sit-uations. Each item is scored from 0 (no probability) to 3 (high proba-bility), yielding a total score between 0 and 24. The scale has shownhigh validity and reliability. ESS>10 indicates excessive daytimesleepiness.13,14Cronbach alpha based on categorical principal analy-sis in the CFV pilot group was 0.89, and in the NAA pilot group, it was0.87.Karolinska Sleepiness ScaleThe Karolinska Sleepiness Scale (KSS) comprises a 1-item 9-pointscale measuring subjective sleepiness rated from 1 = very alert,3 = alert, 5 = either alert or sleepy, 7 = sleepy but no problems stayingawake to 9 = very sleepy,fighting sleep, effort to stay awake.15,16When awake, the pilots were instructed to complete the KSS everysecond hour during the workweek.StatisticsStatistical analyses were conducted with SPSS, Version 20 (IBMCorp, Armonk, NY). Standard descriptive data analyses were used tocharacterize the sample. The response options in work-related causesof fatigue were merged before statistical analyses. Does not causefatigue and low fatigue were merged into no fatigue, and moderatefatigue and high fatigue were merged into fatigue. The response alter-native not applicable was excluded from statistical analyses. Thescores on the ESS and KSS are presented in terms of mean, standarddeviation (SD), and range (minimum-maximum). The distribution ofdata concerning age, number of years in same occupational position,and sleep need (hours) were skewed and were thus presented as amedian with interquartile range;t-tests to compare statistical differ-ences between means and the Mann-WhitneyUtest to compare sta-tistical differences between median values were used to evaluatedifferences between the 2 pilot groups. For other comparisons, thePearson chi-square was used, and the Fisher exact test was usedwhen tables had cells with a frequency of less than 5. APvalue of .05or below was considered statistically significant.EthicsThe Regional Committee for Medical and Health Research Ethics,Health Region West (no. 2014/593) approved the Norwegian part ofthe study. In Austria, Ethikkommission, Land Salzburg informed CFVthat ethical approval was not needed (415-EP/73/671-2016).ResultsEighty-eight percent of the CFV pilots (n = 21) and 80% (n = 24) ofthe NAA pilots responded to the questionnaire. There were no statis-tical differences between the pilots from the CFV compared with theNAA pilots in regard to background variables like marriage/cohabita-tion, children at home, age, and hours of sleep needed (Table 1). Thepilots from CFV had been in the same position as a pilot longer thanNAA pilots (P= .04). Regarding physical health, the majority in bothgroups reported this to bevery goodorgood.The majority of allpilots in both groups reported that they got sufficient sleep both onand off duty.26E. Zakariassen et al. / Air Medical Journal 38 (2019) 2529