Decompression sickness and arterial gas embolism are treated with recompression using hyperbaric oxygen (HBO) in a specially designed chamber. Nitrogen narcosis occurs at depths of 100 feet seawater or greater and improves upon ascent. Pulmonary barotrauma (e.g., pneumothorax) should be treated with tube thoracostomy drainage but does not require recompression with HBO unless there is an associated arterial gas embolism. Sinus barotraumas is best treated symptomatically with decongestants, whereas inner ear barotrauma may require otologic intervention.