injuries poisoning
Gas Toxicity During Diving
High pressure neurologic syndrome
A poorly understood syndrome of neuromuscular and cerebral abnormalities can develop at≥180 m (≥600 ft), particularly when divers are compressed rapidly while breathing helium/oxygen mixtures. Symptoms include nausea, vomiting, fine tremors, incoordination, dizziness, fatigue, somnolence, myoclonic jerking, stomach cramps, and decrements in intellectual and psychomotor performance. Diagnosis is clinical. Prevention is usually accomplished by slowing the rate of compression and/or adding a small amount of a narcotic gas (eg, 5% nitrogen) to the breathing mix. 