An algorithm for pulmonary screening of military pilots in Israel

Rare pulmonary barotrauma after explosive decompression: a case report

Background

Pneumothorax as a consequence of pulmonary barotrauma during explosive decompression military crew training in a hypobaric chamber is an extremely rare and sparsely diagnosed complication. Extensive bilateral tissue damage is even more unexpected.

Case presentation

A 26-year-old active duty Air Force pilot was performing an explosive decompression simulation from 8000 ft. (2438.4 m) to 25,000 ft. (7620 m) in a 1.5 s interval. The training was interrupted due to the pilot’s apparent health complications. After transfer to the emergency department, a CT scan showed bilateral lung barotrauma with emphysema.

Conclusions

The case report shows extensive emphysema and pneumothorax after a rapid decompression done for training purposes. It is a possible but rare complication. The cause remains unclear, with suspicion of a predisposed lung disease.

Correlation between eosinophil count and methacholine challenge test in asymptomatic subjects

BACKGROUND

Methacholine challenge test is used to identify airway hyperresponsiveness (AHR). Total eosinophil counts in peripheral blood reflect asthmatic activity and are useful for early detection of exacerbations. Correlation between the two is poorly defined, particularly in asymptomatic subjects.

OBJECTIVE

The aim is to define correlation between methacholine challenge test and peripheral blood eosinophilia.

METHODS

All flight academy candidates evaluated in the Israeli Air Force Aero Medical Center between the years 2010 and 2011 were included. Candidates were referred to methacholine challenge test based on a personal history of asthma or wheezing in childhood, a first-degree relative with the diagnosis of asthma, or an abnormal spirometry. All methacholine tests were analyzed retrospectively.

RESULTS

Asymptomatic subjects with a positive methacholine challenge test demonstrated significantly (p < .002) higher levels of absolute eosinophil count compared with the group with a negative methacholine test (0.46 ± 0.21 vs. 0.21 ± 0.01 K/μL). Total white blood cell and neutrophil counts were higher in the group with a positive methacholine test compared with the group with a negative methacholine test, but to a lesser extent (7.1 ± 0.25 vs. 6.6 ± 0.09 K/μL, p = .04 and 3.9 ± 0.24 vs. 3.5 ± 0.07 K/μL, p = .04, respectively). No association was demonstrated between eosinophil count and severity of AHR expressed by the methacholine concentration evoking a response.

CONCLUSION

There is a strong association between eosinophil count and AHR in asymptomatic subjects.

Pulmonary function testing and extreme environments

Millions of people worldwide engage in leisure or occupational activities in extreme environments. These environments entail health risks even for normal subjects. The presence of lung disease, or other conditions, further predisposes to illness or injury. Patients who have lung conditions should, but often do not, consult with their pulmonary clinicians before traveling. Normal subjects, including elderly or deconditioned adults, may be referred to pulmonologists for evaluation of risk prior to exposure. Other patients may present for consultations after complications occur. Pulmonary function testing before or after exposure can assist physicians counseling patients about the likelihood of complications.

The use of pulmonary function testing in piloting, air travel, mountain climbing, and diving

Millions of people engage in occupational or leisure activities at high altitude or at variable depths below sea level. This article presents an overview of the utility of pulmonary function testing in evaluating complications and other consequences of exposure to high and low pressure environments. The authors review recent literature concerning expected changes in pulmonary function with hyperbaric and hypobaric exposures. The article provides guidance for clinicians evaluating mountain climbers, pilots, aircrew members, airline passengers and deep sea divers.