Stuart Roop

The Prevalence and Impact of Respiratory Symptoms in Asthmatics and Nonasthmatics during Deployment

OBJECTIVE The purpose of this study was to compare the prevalence, severity, and impact of respiratory symptoms in asthmatics and nonasthmatics during Operation Enduring Freedom and Operation Iraqi Freedom. METHODS A survey was given to 1,250 active duty soldiers and Department of Defense contractors returning from Operation Enduring Freedom/Operation Iraqi Freedom. Subjects were asked about demographics, smoking habits, respiratory symptoms, and impact on job performance before and during deployment. Patients with a history of asthma were asked method of diagnosis, current symptoms, and asthma therapy. RESULTS A total of 1,193 subjects returned the completed questionnaire (95% response rate). Mean age of respondents was 38 +/- 11 years, 83% (n = 977) were male, and 31% (n = 375) were past or present smokers. Sixty-one subjects (5%) reported a previous diagnosis of asthma. Both asthmatics and nonasthmatics had increased respiratory symptoms of wheezing, cough, sputum production, chest pain/tightness, and allergy symptoms during deployment compared to predeployment (p < 0.05 for all). When compared to nonasthmatics, asthmatic subjects reported more wheezing, sputum production, and chest pain/tightness during deployment (p < 0.0001, 0.05, 0.05 respectively), had more difficulty with military duties (p < 0.05), and were more likely to seek medical attention and receive duty restrictions (p < 0.0001). Twenty-six percent (n = 16) of asthmatics reported poor baseline symptom control, and this group had significantly increased symptoms, functional limitations, and health care utilization when compared to asthmatics who were symptom-controlled at baseline. CONCLUSIONS Respiratory symptoms were common among both asthmatics and nonasthmatics during deployment. Differences in symptoms and health care utilization in this group of asthmatics were primarily due to subjects with poor baseline control.

Inhalational exposure to nerve agents.

The respiratory system plays a major role in the pathogenesis of nerve agent toxicity. It is the major route of entry and absorption of nerve agent vapor, and respiratory failure is the most common cause of death follow-ing exposure. Respiratory symptoms are mediated by chemical irritation,muscarinic and nicotinic receptor overstimulation, and central nervous system effects. Recent attacks have demonstrated that most patients with an isolated vapor exposure developed respiratory symptoms almost immediately. Most patients had only mild and transient respiratory effects, and those that did develop significant respiratory compromise did so rapidly. These observations have significant ramifications on triage of patients in a mass-casualty situation, because patients with mild-to-moderate exposure to nerve agent vapor alone do not require decontamination and are less likely to develop progressive symptoms following initial antidote therapy. Limited data do not demonstrate significant long-term respiratory effects following nerve agent exposure and treatment. Provisions for effective respiratory protection against nerve agents is a vital consideration in any emergency preparedness or health care response plan against a chemical attack.

Racial discordance in spirometry comparing four commonly used reference equations to the National Health and Nutrition Examination Study III

Diagnosing lung function abnormalities requires application of the appropriate reference equation for a given patient population. Current guidelines recommend the National Health and Examination Study III data set for evaluating patients in the United States. In Caucasian patients, relying on older reference equations, as opposed to those derived from the NHANES III data set, will often result in a different interpretation of a patients spirometry. The present study assessed whether similar discordance would occur in African-American patients. A cross-sectional analysis of African-American patients undergoing spirometry testing at our hospital was performed. Patients were classified as normal, restricted, obstructed or mixed based upon the ATS/ERS guidelines, using Crapo, Knudson, Morris, Glindmeyer, and NHANES III prediction equations. Differences in classification were evaluated. 4463 subjects were identified, with a mean age of 49.6. Discordance in interpretation was most common when results from prediction equations by Morris, Knudson, and Glindmeyer were compared to NHANES III (24.6%, 26.4%, and 20.1%, respectively). Discordance was less common when comparing Crapo to NHANES III (12.8%). There was a tendency for Knudson, Morris and Glindmeyer to under classify restriction, and for Crapo, Morris, and Glindmeyer to over classify obstruction. There is significant discordance in interpretation when spirometry for African-American patients is referenced to equations published by Crapo, Morris, Knudson, and Glindmeyer, compared to NHANES III.