Work Physiology Clearance for Return to Work in a Level A Hazmat Suit
A 34-year-old man (physically active, mostly resistance training) working in the military (wears a level A hazmat suit) presents for second opinion of a newly diagnosed cardiomyopathy. In February 2014, on routine physical exam, baseline 12-lead ECG demonstrated a complete left bundle branch block. At that time, patient recalled an episode of severe chest pain one month prior that started while exercising and lasted 8-12 hours. In April 2014, complete 2-D echocardiography showed a moderate-severe decrease in LV systolic function with an ejection fraction (EF) of 30% and abnormal septal motion. He was diagnosed with idiopathic nonischemic dilated cardiomyopathy and initiated on carvedilol 25 mg twice daily. Subsequent echocardiography revealed some improvement in EF. He had several cardiac MRIs in May 2014 exhibiting a mildly dilated left ventricle with an EF of 46% without evidence of fibrosis. He also underwent CT coronary angiogram which was normal. EF improved to 51% by March 2015, however, he had not been cleared to return to work.
An oxygen consumption study was performed.
- Exercised 12.7 minutes (12.7 METS)
- Limited by general fatigue
- Peak respiratory exchange ratio (RER) = 1.06
- HR 45 → 162 bpm (87% predicted)
- PVC < 5/min
- BP 120/90 → 176/82 mmHg
- Peak VO2 = 38.5 mL/kg/min (90% predicted for age, sex, exercise mode)
- VE/VCO2 nadir = 25
Is there sufficient evidence to demonstrate the patient can safely perform the physical demands of working in a level A hazmat suit?