Hypoxic Syncope in a Competitive Breath-Hold Diver with Elevation of the Brain Damage Marker S100B

LINER MH, ANDERSSON JPA. Hypoxic syncope in a competitive breath-hold diver with elevation of the brain damage marker S100B. Aviat Space Environ Med 2009; 80:1066-8. Introduction: Competitive breath-hold divers can accomplish previously unbelievable performances; e.g., the current world record for apnea during rest (static apnea) is 11 min 35 s. However, whether such performances are associated with a risk for hypoxic brain damage has not been established. Case Report: A breath-hold diver's competitive performance resulted in a loss of consciousness, after which he was subjected to a medical examination by the event physician. Blood samples were collected for analysis of the brain damage marker S100B in serum. The SI 0013 in serum was 0.100 mu g . L(-1) in the blood sample collected 15 min after the loss of consciousness. At I and 5 d after the incident it was 0.097 mu g . L(-1) and 0.045 mu g . L(-1), respectively. Discussion: The elevated level of SI 0013, close to the upper reference limit (0.105 mu g . L(-1)) indicates that the incident affected the integrity of the central nervous system. Even though this case does not establish that hypoxic brain damage is an inherent risk with loss of consciousness in competitive breath-hold diving, the observation raises concerns. We suggest that it should be considered that repetitive exposures to prolonged apneas leading to severe hypoxia may be associated with negative long-term effects.