The objective of this study is to determine the effect of mechanical ventilation (MV) on endothelial biomarkers associated with ventilator-induced vascular injury (VIVI), and determine the correlation of these biomarkers with non-invasive microvascular perfusion monitoring data and semaphorin 3E levels.~Blood samples will be collected immediately pre-operatively and post-operatively.~Biomarkers will be expressed as an absolute value and as a relative percentage change from baseline to account for inter-individual variability. Hemodynamic and surgical variables will be extracted from the OR data: blood pressure, oxygen saturation, blood loss, fluid administration, length of surgery, and MV parameters such as tidal volume, inspired oxygen, respiratory rate, and positive end-expiratory pressure.~During surgery, patients will be monitored using a non-invasive near-infrared spectroscopy technique to quantify skeletal muscle microvascular perfusion. These devices will be applied immediately prior to induction of anesthetic and data collected until immediately prior to transfer to the post-anesthesia care unit.
Investigation of the effect of mechanical ventilation on biomarkers of microvascular damage