Morbidity rates on Vanguard Class submarines during nuclear deterrent patrol: a retrospective review over 13 years.

The submarines responsible for the United Kingdom's nuclear deterrent have carried a junior doctor as their medical officer since the program's inception. The Vanguard Class of submarine carries approximately 150 men and deploys for about 3 months at a time. One of the central tenets of submarine operations is to remain undetected and as such the submarine will only surface in an emergency, which may include the evacuation of casualties. The prime reason for carriage of a medical officer is to mitigate against the need to evacuate personnel for medical reasons. We examined the medical section of the patrol reports submitted upon completion of each patrol over a 13 year period to determine both the rates of medical and dental attendance onboard and also the occurrence of potential medical threats to patrol integrity. The most common reasons for attendance were dermatological and musculoskeletal, consistent with previous studies of this population and working environment. There were few dental cases due to the high rates of dental fitness in the pre-sailing crews. Patrol threatening cases occurred at a rate of approximately 1 per 3 patrols, with acute appendicitis being the most common presentation. This progressed to evacuation at a rate of 1 per 15 patrols, with the successful onboard management in 79% of cases. The junior doctor onboard has limited monitoring equipment and formulary, no diagnostic equipment, basic surgical equipment and no opportunity to seek senior advice, and is therefore reliant on clinical judgement. Despite the limitations placed on the doctor on board these submarines they have proven to be effective in reducing the rate of medical evacuation.