Aim: 

It is widely accepted that gas bubbles forming during decompression are generated by the micronuclei in all tissues and may manifest as a spectrum of symptoms (decompression sickness, DCS). Therefore, the reduction or elimination of micronuclei may be beneficial in reducing the formation of gas bubbles during decompression and consequently the risk of DCS.

Objective: 

The aim of the present study is to test the hypothesis that oxygen pre-treatment (normobaric NBO/hyperbaric HBO) immediately before an open water scuba dive might reduce bubble formation, platelets activation, and adaptations in order to decrease risk of DCS in humans.

Methods: 

6 healthy volunteer subjects participated in this study with a three day protocol: 1. Compression at 4 ATA for 20'; 2. Compression at 1.6 ATA for 20' with 100% oxygen (HBO), immediately after recompression at 4 ATA for 20'; 3. Normobaric treatment for 20' with 100% oxygen (NBO), immediately after recompression at 4 ATA for 20'. Once the surface was reached, they were monitored with precordial ultrasonic doppler (2 Mhz probe) after 20 min and 50 min. Venous blood samples were obtained immediately before and after pressure exposure to study flow cytometric analysis of platelet activation as marker of decompression stress.

Results: 

Pre-treatment with HBO significantly reduced decompression induced air bubbles at 20 min and platelet activation (p < 0.01). Pre-treatment with NBO significantly reduced platelet activation (p < 0.05), without affecting bubble formation.

Conclusion: 

Our study suggests that pre-treatment with both HBO and NBO may be effective in preventing DCS but in different way matter of speculation.