Abnormal glucose levels found in transportation accidents.

BACKGROUND: The Federal Aviation Administration's Office of Aerospace Medicine is responsible for the certification of pilots with diabetic conditions. The present study evaluated the use of postmortem vitreous humor and urine glucose levels in transportation accident fatalities as indicators of potentially incapacitating medical conditions or performance impairment. METHODS: Vitreous humor and/or urine from 192 accident fatalities were analyzed for glucose using a hexokinase method. Cases with values below the lower limit of detection (10 mg x dl(-1)) and above 3 standard deviations (SD) from the mean were not included in the final statistics. All cases more than 5 SD above the mean were deemed abnormal and a full case history was evaluated based on the available medical history. RESULTS: The mean vitreous humor glucose concentration was 30+/-21 mg x dl(-1) (N=98), while it was 27+/-16 mg x dl(-1) in urine (N=127). Of the 192 cases, 9 were identified as having abnormal glucose levels. Abnormal glucose levels were found in 5 of the 8 cases with a known diabetic condition. Glycosuria or low renal threshold was reported in 2 fatal pilots; 1 of these pilots had an abnormal glucose level. CONCLUSIONS: Hyperglycemia can be established from the vitreous humor and urine glucose levels. All of the abnormal glucose cases detected were previously identified during the medical certification process or had a medical reason for the abnormal level. Elevated vitreous humor and urine glucose levels have proven useful in identifying individuals with a pre-existing diabetic condition that might have been a factor in the accident.

Herbal preparations: a primer for the aeromedical physician.

PURPOSE: This study was an effort to identify the botanical preparations of potential risk to the aviator and aviation safety, and to ascertain whether aviators are using dietary supplements despite extensive educational efforts discouraging over-the-counter medication use. Herbal preparations may be used by nearly 20% of the adult population. Although the aviator population may be presumed to use them as well, the actual degree of use among aviators is unknown. Use of such substances as health promotion or therapeutic agents may provide health benefits, but may also carry risk. Military and civilian aviators are not currently required to disclose such use, nor are examiners obligated to inquire or counsel aviators about them. This paper examines the trends in post-mortem toxicological samples suggesting botanical preparation use, and develops a rational method for determining suitability for use by the aviator. METHOD: The toxicological test results from 3177 mishap pilots performed at the Civil Aeromedical Institute from 1989-1997 were examined for the presence of substances suggesting botanical preparation use. The prevalence of positive test results for ephedrine among mishap pilots was compared with the prevalence of tests positive for chemically and biologically similar non-botanical substances among mishap pilots. A review of existing literature was also performed to identify substances posing possible risk to the aviator health or aviation safety. RESULTS: Ephedrine was found to be the only substance routinely screened on toxicological specimens that was suitable for association with botanical substance utilization. The percent of specimens positive for ephedrine increased three- to four-fold while the percent of specimens positive for similar non-botanical substances decreased overall. The literature revealed sufficient evidence that a number of open market botanical agents are capable of causing incapacitation by cardiovascular or neuropsychiatric mechanisms, yet are legally permitted for use by aviators. CONCLUSION: Aviators are using botanical products with increasing frequency, and many of those substances may pose significant risk of incapacitation, altered sensorium, or adverse health effects. The flight surgeon must be diligent in eliciting a history of use and assisting aviators to minimize personal risk and risks to flight safety. A rational approach to assessing risk is presented.

Monovision contact lens use in the aviation environment: a report of a contact lens-related aircraft accident.

BACKGROUND: The use of contact lenses to satisfy the distance visual acuity requirements for obtaining a civil airman medical certificate has been permitted since 1976. According to the Federal Aviation Administrations Guide for Aviation Medical Examiners, the use of monovision contact lenses is not considered acceptable for aviation duties. METHODS: A report is presented using information from a National Transportation Safety Board (NTSB) aircraft report (NTSB/AAR-97/03) of a nonfatal accident on a scheduled airline flight. Past studies on the use of contact lenses in the aviation environment are reviewed. RESULTS: On October 19, 1996, a McDonnell Douglas MD-88 aircraft, Delta Airlines Flight 554, was substantially damaged in an undershoot approach while landing at LaGuardia Airport, Flushing, New York. The approach, with less than favorable weather conditions, was over water to Runway 13 and the flight crew transitioned to visual references just above the decision height. During continued descent, the plane struck an approach light structure and the end of the runway deck, shearing off the main landing gear and sliding 2,700 feet down the runway. CONCLUSIONS: The NTSB determined that the probable cause of this accident was the inability of the pilot to overcome his misperception of the airplane's position relative to the runway, due to the use of monovision contact lenses. The adverse effects of wearing contact lenses in the aviation environment are discussed.

Survival at high altitudes: wheel-well passengers.

There have been 10 specific "wheel-well" passenger stowaway flights (the wheel-well area was entered just before take-off) documented in the N.Y. Times between 1947-1993. Five stowaways survived flights encompassing altitudes as high as 39,000 feet, with six dying in the process (one flight had two stowaways, one fatal, one surviving). Three Douglas DC-8 and four Boeing 707 aircraft, plus a Caravelle, an unknown jet, and a piston airliner were involved. Several of the wheel-well flight stowaways were reportedly politically motivated to attempt these international flights. This paper describes the unpressurized flight environment and the physiology that enabled human survival under conditions of extreme hypoxia and cold, inducing a virtual "hibernative" state. It is likely that similar attempts will continue, and alert airport security preventive measures are indicated.