Technical feasibility of hyperbaric oxygen therapy for gas embolism with ECMO support: a brief report

Gas embolism (GE) occurs when gas enters into the circulation. Whilst small quantities of gas may be harmless, massive, or systemic GE may be life-threatening, when associated with coma, cardiogenic shock, or cardiac arrest. GE is a known complication of Extracorporeal Membrane Oxygenation (ECMO). Hyperbaric Oxygen Therapy (HBOT) is a corner-stone of GE management. Delivery of HBOT in patients supported by ECMO is an emerging area of interest. We aimed to assess the feasibility of using the Rotaflow I® (Maquet, Germany) ECMO device during HBOT, configured with mock circulatory loops (MCL) such that the pump head unit and oxygenator were located inside and the console external to the hyperbaric chamber. A control MCL was positioned outside the hyperbaric chamber with similar characteristics and parameters. Both oxygenators were alimented with oxygen sweep gas. Outflow stability was measured before, during and after a pressurization profile. Laboratory markers for hemolysis were assessed. Measurements were performed simultaneously on both MCL. ECMO outflow displayed on the console remained stable during hyperbaric pressurization profile. [maximum variation (delta max) of 0.16 L/min (3.1%) during HBOT versus 0.19 L/min (3.8%) at atmospheric pressure]. No significant variation was found between pre- and post-oxygenator pressure in the H-ECMO device (delta max 1 mmHg in pre- and post-oxygenator). Hemoglobin, haptoglobin and schistocytes concentrations remained stable. Conversely, measured plasma-free hemoglobin and LDH were increased temporarily during run in the device exposed to HBOT, then decreased when back at atmospheric pressure. These changes are likely related to technical issues. No relevant changes were observed in the control. Delivery of HBOT to patients with GE supported by ECMO seems technically feasible using a Rotaflow I® device with externalization of the console outside the hyperbaric chamber. No significant effect on performance or sustained effect on hemolysis were observed.