Hypoxemia of the lower limbs during robot-assisted radical prostatectomy in Trendelenburg position

Objectives The objective of this study is to assess frequency and risk factors for intraoperative hypoxemia of the lower limbs during robot-assisted radical prostatectomy (RARP). Trendelenburg position during RARP may contribute to hypoxemia and compartment syndrome (CS) of the lower limbs as a major but rare complication.Patients and methods This prospective study included patients undergoing RARP for prostate cancer. Preoperative calculation of the ankle-brachial-index (ABI) was performed. Peripheral oxygen saturation (SpO2) at the toes was routinely measured. Occurrence of SpO2 levels of <90% was defined as hypoxemic events and treated immediately. Blood pressure, intraabdominal pressure, SpO2 of the upper limb and surgery time were monitored in case of hypoxemia. A multivariable logistic regression model was performed with age, BMI, nicotine abuse, MAP, comorbidities as covariates and hypoxemia of the lower limbs as the outcome.Results A total of 207 patients were included. Among these, 126 patients had ABI measurements with 10.6% having an abnormal ABI value. One, two or at least three events of lower limb hypoxemia occurred intraoperatively in 19.7%, 14.8% and 16.9%, respectively. In 20 events, surgical instruments were affecting vascular perfusion by compression. None of the covariates were statistically significant associated with lower limb hypoxemia. No patient developed a compartment syndrome.Conclusion Decrease in oxygen saturation of the lower extremities was observed frequently during RARP, without revealing any risk factors for its occurrence. Routine oximetry leads to an early detection of hypoxemia of the lower extremities, giving the anaesthesiologist and surgeon the opportunity to make adequate adjustments (increasing blood pressure and ending iliac vessel compression).