Aim: 

Platelet and lymphocytes could modulate bubble formation and decompression sickness (DCS) manifestations. The present study investigates the hypothesis that normo (NBO) and hyperbaric (HBO) oxygen pre-breathing immediately before an open water scuba dive might reduce the risk of DCS.

Methods: 

Six healthy volunteers participated in this study with an exposure to a standard compressed air dive to 4 ATA for 20', repeated for four different days: 1. Control, without pre-breathing; 2. NBO prebreathing for 20'; 3. HBO prebreathing at 1.6 ATA for 20'; 4. HBO prebreathing at 2.2 ATA for 15'. After dive, they were monitored with precordial ultrasonic doppler. Venous blood samples were obtained before and after pressure exposures to study flow cytometric patterns of platelet activation. In lymphocytes, ROS accumulation and antioxidant enzyme assays were executed by spectrophotometric determinations; SOD1, CAT and GPX1 mRNA expression, by real time-PCR; [Ca2+]i by Fura2-AM.

Results: 

Pre-treatment with HBO significantly reduced decompression induced air bubbles and platelet activation. NBO prebreathing significantly decreased platelet activation, without affecting bubble formation. Compared with basal condition lymphocytes, intracellular H2O2 production was reduced in all types of scuba diving while catalase activity was increased in HBO at 1,6 and 2,2 ATA. The gene expression analysis revealed no variation of CAT, up-regulation of SOD1 and GPX1 in HBO at 1,6 ATA. Basal [Ca2+]i was increased compared to untreated control and it is significantly reduced only in HBO at 1.6 ATA.

Conclusion: 

This study indicate that HBO pre-breathing may form the basis for a new way of preventing serious decompression sickness.