Effect of hyperbaric air exposure with prolonged oxygen inhalation during decompression on the cardiovascular function in divers.

Objective: This study aimed to evaluate the effect of prolonged oxygen inhalation during decompression on the cardiovascular function in divers with hyperbaric air exposure.

Methods: Eight divers were pressurized to 400 kPa and then depressurized 30 minutes later. During the decompression, the time of oxygen breathing was prolonged at different depths. The cardiac, carotid, and brachial arterial functions were evaluated by ultrasonography immediately before and after exposure and then compared.

Results: After hyperbaric exposure, diastolic blood pressure increased significantly, heart rate reduced markedly, but systolic blood pressure tended to reduce. The peak systolic velocity and end diastolic velocity of the common carotid artery reduced markedly, but its resistance index slightly increased, and the diameter of the brachial artery tended to increase. In addition, the end-diastolic volume, cardiac output, E wave, and A wave of the heart reduced markedly, but the flow velocity of the pulmonary artery tended to reduce.

Conclusion: Hyperbaric air exposure at 400 kPa with prolonged oxygen inhalation during decompression mildly affects divers' cardiovascular function.