Effect of positive end-expiratory pressure ventilation on plasma nitric oxide, endothelin-1 and vascular celladhesion molecule-1 levels in patients undergoing uvulopalatopharyngoplasty

Abstract

BACKGROUND: During uvulopalatopharyngoplasty (UPPP), cardiovascular adverse events may occur which can be harmful to patients. OBJECTIVE: To evaluate the effect of the protective ventilation strategy on the function of vascular endothelial cells. METHODS: Forty obstructive apnea syndrome (OSA) patients who underwent uvulopalatopharyngoplasty (UPPP) were enrolled. Patients were randomly divided into the control group (group C, PEEP = 0 cm H2O) and PEEP group (group P, PEEP = 5 cm H2O). Each group (n= 20) received intermittent volume controlled ventilation (VCV) with tidal volume 6 ml/kg of the predicted body weight, I:E 1:2, rate titrated for ETCO2 35–45, FiO2 0.7. Blood from the radial artery was sampled for blood gas analysis at four time points: the fifth minute of inhaling pure oxygen (T0), after tracheal intubation (T1), at the end of the operation (T2), and 20 minutes after extubation (T3). Three ml of arterial blood was retained, preserved at -20∘C after serum isolation, and plasma nitric oxide (NO), endothelin-1 (ET-1) and vascular celladhesion molecule-1 (VCAM-1) levels were determined by enzyme linked immunosorbent assay (ELISA). RESULTS: Compared with group C, plasma ET-1 at T3 decreased in group P, and plasma NO levels at T2 and T3 increased (P< 0.05). Compared with samples collected at T0, plasma VCAM-1 levels at T1, T2 and T3 increased in group C, while plasma VCAM-1 levels at T2 and T3 decreased in group P (P< 0.05). Compared with group C, plasma VCAM-1 levels T2 and T3 decreased in group P (P< 0.05). CONCLUSIONS: Positive end-expiratory pressure (PEEP) ventilation has a protective effect on vascular endothelial cell function in patients during UPPP.