Journal Of Clinical and Diagnostic Research

Influence of Repeated Daily Diving on Decompression StressDecompression sickness, also known as diver's disease, occurs when bubbles form from inert gases within the blood stream during depressurization.This phenomenon can cause extreme discomfort for divers, such as joint pain, neurologic changes, headache, generalized fatigue, and shortness of breath.Venous gas emboli (VGE) after diving can be monitored with transthoracic ultrasonography showing bubble flow through the heart.Although prior studies have shown that more extreme dives increase the rate and severity of decompression sickness, it is unknown whether repeated diving results in acclimatization to the diving process.The purpose of this study was to determine whether 4 consecutive days of diving results in acclimatization, as assessed by changes in bubble flow through the heart on ultrasonography.Sixteen healthy male volunteers performed 1 daily 18-m dive with a 47-minute bottom time for 4 consecutive days.In addition to standard hemodynamic monitoring, transthoracic echocardiography was performed at set 20-minute intervals for 2 hours after surfacing.Based on a prior study, bubble flow was graded from 1 to 5, with 5 being the most and representing substantial VGE.The investigators found that the odds ratio of having a higher bubble grade was 0.85 on day 2 (vs day 1) and 0.52 on day 4 (vs day 1).In other words, there was half the chance of having a higher bubble grade on day 4 vs day 1.The researchers concluded that repeated consecutive diving days significantly lower the risk of having higher-grade bubbles on transthoracic echocardiography.Although VGE is an indicator of decompression stress, it does not automatically represent decompression sickness; the researchers carefully note that the reduction in VGE represents an acclimatization process to diving, but cannot be directly extrapolated to patient signs and symptoms.Further research is needed to correlate VGE to patient symptoms and outcomes.Limitations of the study include a relatively short diving period and a limited ability to correlate with true decompression sickness.