Dioxygen consumption after deep hypothermic circulatory arrest pulmonary endarterectomy

Cardiac surgery is associated with an increased dioxygen (O₂) consumption (VO₂) following cardiopulmonary bypass (CPB). But data on intraoperative VO₂ variation during pulmonary endarterectomy (PEA) are scarce. We aimed to assess the variation of VO₂ and O₂ delivery (DO₂) between the induction of general anesthesia and the weaning off CPB in patients undergoing PEA.

A prospective single center observational study was conducted from May to November 2023 in patients that underwent PEA. Hemodynamic and biological data were collected from arterial and venous blood gas after the induction of general anesthesia and after CPB weaning.

Forty-nine patients were included in the final analysis. The mean age was 57 ( $\pm$ 14.3) years, and 30 (61%) patients were male. There was no significant change in VO₂ and DO₂ (O₂ delivery) after CPB weaning (VO₂=104.5 ( $\pm$ 45.9) vs 110.5 ( $\pm$ 30.4) ml of O₂/min/m²; p=0.33; DO₂=426.1 ( $\pm$ 166.3) vs 398.1 ( $\pm$ 109.4) ml of O₂/min/m²; p=0.18 respectively). There was a weak correlation between CPB duration and VO₂ following CPB weaning (R=0.41; p=0.008). No correlation between the duration of aortic cross clamp time, the duration of circulatory arrest, and post CPB VO₂ were found (R=0.22; p=0.14 and R=0.22; p=0.10, respectively).

There was no significant increase in VO₂ and DO₂ after deep hypothermic circulatory arrest PEA surgery.