Deployment-related pulmonary symptoms and cardiopulmonary exercise testing in military personnel

Background: The objective of this study was to investigate differences in Cardiopulmonary Exercise Testing (CPET) between deployed and non-deployed military personnel undergoing a clinical evaluation for dyspnea. Methods: A retrospective electronic medical record review was conducted on active military personnel who underwent CPET at Brooke Army Medical Center during a clinical evaluation for dyspnea from 2007 through 2011. Studies were performed on a cycle ergometer to the point of maximum exercise tolerance. Review of CPET records identified values from expired gas analysis related to cardiac and respiratory exercise limitations and review of medical records identified pre-CPET diagnostic testing and medical and deployment history. Results: A total of 268 patients were identified. The cohort was predominantly male (78%) and had deployed to Southwest Asia (62%). Demographic comparison of deployed and non-deployed groups showed age (32.2 vs. 30.5 years) and body mass index (28.1 vs. 26.6 kg•m-2) were higher in deployed personnel. Diffusing capacity for carbon monoxide was low in deployed and non-deployed personnel (71.1 vs. 75.0% predicted) and was significantly lower in deployed personnel with onset of dyspnea during or post-deployment (70.0% predicted). Anaerobic threshold was lower in deployed personnel (49.8 vs. 55.8% predicted) but there were no significant differences in maximum work rate, maximum oxygen consumption, maximum heart rate, heart rate response, maximum respiratory rate or other respiratory parameters. Conclusions: Deployed males in this study were heavier and older than non-deployed males. There were small significant differences between the two groups in some CPET results (all within normal ranges); however, no specific CPET parameters were identified within this study that clearly defined an underlying pulmonary process related to deployment. Correspondence to: Paul D. Hiles, M.D, Capt. USAF, MC, Pulmonary/Critical Care Service, Department of Medicine, San Antonio Military Medical Center, JBSA Fort Sam Houston, TX 78234, USA, Tel: 703-470-5685; E-mail: paul.d.hiles. [email protected]