Indirect Measurement of Respiratory Quotient in Unipulmonary Ventilation.

The measurement of VO2 and VCO2 makes it possible to calculate the respiratory quotient (RQ) (VCO2 / VO2) which is a reflection of human energy metabolism and therefore of anaerobiosis. A study has been conducted in our department to demonstrate the ability of the indirectly measured respiratory quotient (RQ) from the inspired and exhaled breath analysis of the anesthetic respirator to predict the onset of anaerobic metabolism and postoperative complications in the operating room. Unipulmonary ventilation is the rule in thoracic surgery: it improves surgical exposure and protects the operated lung. However, no study has examined the impact of these mechanisms on the indirect measurement of RQ in unipulmonary ventilation. The main objective of our work is to validate indirect RQ measurement during unipulmonary ventilation. The secondary objective was to assess the predictability of postoperative complications of indirect QR.