Effects of lithotomy and prone positions on hemodynamic parameters, respiratory mechanics, and arterial oxygenation in percutaneous nephrolithotomy performed under general anesthesia

Abstract

Aim: The position of the body during surgery may affect the patient’s body functions, especially the hemodynamic parameters. We aimed to comparatively analyze the effects of lithotomy and prone position on respiratory mechanics, arterial oxygenation, and hemodynamic parameters in patients who underwent percutaneous nephrolithotomy (PNL). Materials and methods: The study included 40 patients aged 16-63 years who underwent kidney stone surgery. The patients had no history of diabetes or cardiopulmonary disease and had an American Society of Anesthesiology (ASA) score of I–II. The pH, partial arterial oxygen pressure, partial arterial carbon dioxide pressure, HCO3, arterial oxygen saturation, end-tidal carbon dioxide (EtCO2), alveolar oxygen partial pressure, dead space volume/tidal volume ratio, P(A-a)O2, peak inspiratory pressure (PIP), inspiratory plateau airway pressure (PPlt), systolic arterial pressure, diastolic arterial pressure, mean arterial pressure, and heart rate (HR) values were assessed simultaneously throughout the surgery and comparatively analyzed both for lithotomy and prone positions. Results: There was a significant difference between lithotomy and prone positions with regard to pH and HCO3 values, which are among the arterial blood gas parameters measured at 20 minutes (p<0.05 and p<0.001, respectively). There was a significant difference between lithotomy and prone positions with regard to EtCO2, PIP, PPlt, and HR measured at 20 minutes (p<0.05, p<0.001, p<0.001, and p<0.05, respectively). Conclusions: The prone position decreased dynamic and static compliance and increased the PIP and PPlt values in patients undergoing PNL. However, these changes do not have a negative effect on the hemodynamic parameters in low-risk patients.