Morbidity among airline pilots: the AMAS experience. Aviation Medicine Advisory Service.

BACKGROUND: Various cohort studies, military databases, and Federal Aviation Administration databases have characterized morbidity and disability in pilots. However, an overriding limitation of these studies is acquiring complete and accurate medical information from pilots with a profession, hobby, or aircraft investment to protect (6). The unique role of Aviation Medicine Advisory Service (AMAS) as pure pilot advocate with guaranteed patient confidentiality eliminates the aviator's need to conceal medical problems. Therefore, analyses of cases reported to AMAS might provide additional insight regarding the true prevalence of morbidity in airline pilots. METHODS: All AMAS cases of airline pilots and flight engineers from January 1996 through November 1999 were reviewed (n = 20,522). During that time, AMAS provided consultation to approximately 51 U.S. and Canadian airlines. Diagnoses were stratified by decades ranging from 20 to 69 yr of age. RESULTS: Notably, the five conditions most frequently inquired about at AMAS were similar to the major causes of long term disability found in a cohort of Air Canada pilots (5). Cardiovascular conditions accounted for almost 25% of the inquiries. However, the relative percentage especially in the older population was less than that reported previously. Interestingly, orthopedic and musculoskeletal cases (10-11%) rated second only to cardiovascular cases. CONCLUSIONS: These findings are limited by the inability to draw an exact reference population at risk, the use of proportional measures for description and the inherent difficulty in attempting to utilize an administrative index as an epidemiological tool. Further study addressing the impact of aviator nondisclosure of medical problems on the reported prevalence of disease among U.S. airline pilots may help target preventive efforts in the future.

Results of Holter monitoring U.S. Air Force aircrew with ectopy on 12-lead electrocardiograms.

PURPOSE: To evaluate the results of 24-h Holter monitoring performed on healthy U.S. Air Force aircrew with asymptomatic ectopy on resting electrocardiograms (ECG). METHODS: A historical review of the USAF Central ECG Library database was conducted on all Holter studies completed for evaluation of ECG ectopy between 1 Jan 86 and 31 Dec 97. Univariate and multivariate statistical analyses were performed to determine the association between ectopy and the aeromedical dispositions of aircrew evaluated for incidental ECG ectopy. RESULTS: During this period, 147,571 resting ECGs were submitted to the Aeromedical Consultation Service (ACS) for interpretation. The mean age of the subjects was 35 yr (range 19 to 57 yr). There were 480 24-h Holter studies performed for ECG ectopy. Of these, 49% had normal or normal variant findings; another 11% were found acceptable for flying after normal treadmill testing and echocardiography. ACS evaluation was required for the remaining 40% of subjects. Overall, 4% were permanently disqualified, and 17% were lost to follow-up. Excluding subjects lost to follow-up, 95% of aircrew were returned to flying status (with or without a waiver). CONCLUSIONS: When controlled for age, no significant difference of aeromedical outcome was seen when comparing supraventricular and ventricular ectopy. Of the subjects, 51% had abnormal Holter studies, but the vast majority were returned to flying. Results of this study provide information useful in further defining aircrew medical evaluation protocols for evaluation of asymptomatic ECG ectopy with Holter monitoring.

Altitude-induced migraine headache secondary to pravastatin: case report.

A 46-yr-old airline captain with many exposures to altitude chamber, fighter, and airliner flight developed migraine-type headaches after exposure to cabin altitudes above 6,000 feet. He had no prior history of chronic headaches or migraine. Symptoms began within days of starting pravastatin for hypercholesterolemia, but had not occurred during 4 yr of treatment with lovastatin. Headache intensity related directly to increasing pressure altitudes above 6,000 ft for periods of time greater than 45 min. Descent below 5,000 ft cabin altitudes relieved headaches. Exposure to barometric pressure changes has been associated with migraine headache. Vascular headaches are also a prominent feature of acute mountain sickness. Although the HMG-CoA reductase inhibitors are reported to be associated with increased occurrence of headache, the mechanism is poorly understood. Migraine headaches may be triggered in previously asymptomatic individuals by unique combinations of trigger factors. However, there have been no prior reports of migraine headaches triggered by the combined exposure to pravastatin and reduced barometric pressure.

Prospective assessment of stereoscopic visual status and USAF pilot training attrition.

The role of stereopsis (i.e., the use of binocular cues for depth perception) in military aviation is undetermined. Pilots possessing adequate near stereopsis but having deficient distant stereopsis are thought to have microtropias. Historical reviews of microtropia and research concerning the role of depth perception in military aviation are described. A historical prospective study of student pilots entering U.S. Air Force Undergraduate Pilot Training (UPT) from Oct 1990 through Sep 1991 (FY 90-91) compares UPT attrition rates according to their preselection stereoscopic status (microtropia vs. normal). Univariate and multiple logistic regression analyses do not show significant differences in attrition rates between the two groups, implying that distant stereopsis is not critical to successful completion of UPT. The U.S. Air Force decided in Oct 91 to eliminate near stereoscopic vision screening while retaining distant stereoacuity testing as a criterion for candidates to qualify medically for UPT. Valid rationale for this decision includes simplified and uniform administration of stereoacuity testing, minimizing spurious results, the continued validity of stereopsis testing as a cross-check of other areas of visual function, the uncertain role of stereopsis in critical areas of flight operations, and the large applicant pool competing for a limited number of pilot training positions.