How long should symptoms stabilize or improve with 100% oxygen before considering in-water recompression?

The choice of 30 minutes for symptoms to stabilize or improve with 100% oxygen is based on established medical protocols for treating decompression sickness (DCS). When a diver shows signs of DCS, administering 100% oxygen can help speed up the elimination of nitrogen bubbles in the bloodstream by increasing the partial pressure of oxygen, which enhances the efficiency of nitrogen washout.

Research and clinical guidelines indicate that divers should receive this oxygen therapy for a duration that allows sufficient time for significant physiological changes to occur. Typically, 30 minutes is considered an appropriate timeframe for assessing whether oxygen therapy is effective in alleviating symptoms. If there is no significant improvement in symptoms within this period, the diver may require in-water recompression as a next step, indicating that the condition may not be responding adequately to the oxygen treatment alone.

In contrast, shorter times like 15 minutes might not provide enough time for the body to respond to the oxygen therapy, while longer times such as 60 minutes or 90 minutes can delay necessary interventions if symptoms do not improve. Thus, the time frame of 30 minutes strikes a balance between allowing for a response while not delaying potentially critical treatment.