Optimization of diver recompression methods after emergency ascent to prevent decompression sickness: experimental study

Abstract

OBJECTIVE: Based on the analysis of national normative documents and a series of animal experiments to evaluate the effectiveness of a not common method of a diver’s recompression after emergency ascent, skipping all the mandatory decompression stops in order to prevent the development of decompression sickness. MATERIALS AND METHODS: In the study Wister rats (n = 30) were used. The animals were placed in the chamber and there was air compression up to 9 АТА with exposure under pressure within 15 min. Decompression was carried out by pressure release with imitation of emergency ascent. After 5 minutes there was recompression by air up to АТА, isopressure within 10 minutes and elongated decompression. During recompression, further decompression and 2 hours after its completion the animals experienced behavioral response and signs of compression disorder development. RESULTS: The study showed that the test group where the animals’ exposure under 9 ATA completed with the planned decompression on the regime did not experience any behavioral disorder and reflexes of posture during and after decompression. There were also no registered gas bubbles in the brain. Similar results were obtained in the test group with emergency ascent, recompression and further elongated decompression, but not in the group with emergency ascent without recompression. DISCUSSION: The application of the proposed recompression method after imitation of emergency ascent leads to neither visual nor morphologically registered signs of decompression disorders. Along with a shorter period of recompression and decompression as compared with the ones, described in regulatory documents, it allows to adopt the proposed method for reducing the loss of time and resources while maintaining diver’s health and performance after emergency ascent.