Analysis of factors related to failure in the pressure test: a six-year experience in Taiwan.

INTRODUCTION: The Republic of China Navy instituted the pressure test as one of the selection tools for diving troops and submarine crews. We analyzed factors associated with failure in the pressure test.
METHODS: This was a retrospective cohort study designed to investigate pressure test failure in Navy recruits between January 2010 and August 2015. The recruits received pressurization in a hyperbaric chamber to a simulated depth of 112 feet of seawater (fsw) at a rate of 25 fsw/minute. Data describing trainee demographics, disease history, causes and depth of failure, as well as type of injury, were extracted from case notes and facility databases for statistical analysis.
RESULTS: Of 3,608 trial cohorts, there were 435 failures, with an overall failure rate of 12.06%. About 95% of these failure trials were within a simulated depth of 60 fsw. Fifty-seven (57) failures did not record causes of failure. Among the other 378 failures, the most commonly identified causes were ear barotrauma (365 trials, 96.56%) and sinus barotrauma (10 trials, 2.65%). Statistical analysis revealed that recent upper respiratory tract infection, allergic rhinitis, and cigarette smoking were all significantly associated with higher incidence of middle ear barotrauma.
CONCLUSIONS: Our results suggest that pressure testing to a depth of 60 fsw is effective in disqualifying personnel entering diving and submarine service. Recent infection of the upper respiratory tract, allergic rhinitis and cigarette smoking are risk factors for middle ear barotrauma, resulting in failure of the pressure test. Copyright© Undersea and Hyperbaric Medical Society.