Effect Of Parecoxib Pretreatment On Intrapulmonary Shunt And Oxygenation During One-lung Ventilation In Patients Undergoing Esophageal Cancer Resection

Objective Pulmonary shunt is inevitably increased during one-lung ventilation （OLV）,which is also one of the most causes of hypoxemia. Alveolar collapse, mechanicalstretch, surgical operations cause ventilation/perfusion ratio dysequilibrium andpulmonary hypoxic-ischemic injury. At the same time, pulmonary inflammatoryresponse can be triggered by the release of various inflammatory factors, making thethings get much worse. Waterfalls cascade of cytokine and excessive activation of whiteblood cells lead to ventilation-induced lung injury and the changes of systemicimmune function, and then result in lung surfactant be damaged. At last, the occurrenceof postoperative atelectasis increased. Inflammatory response affect lung function,therefore reducing the inflammatory response is one of the effective methods to reducepulmonary shunt. Parecoxib sodium is a new kind of Cyclooxygenase2（COX-2）inhibitors, which suppress excessive inflammatory reaction through different ways. Inpresent study, we just observe and confirm whether preoperative intravenous parecoxibsodium could help to improve arterial oxygenation and protect pulmonary functionduring OLV.Methods Forty ASA â…  or â…¡ patients of both sexes, aged25-64yr, weighing45-70kg,with body height156-178cm, undergoing elective esophageal surgery, were randomlydivided into2groups （n=20each）: normal saline group （NS） and parecoxib group （P）. Parecoxib40mg （in normal saline10ml） was injected intravenously30min beforeanesthesia in group P, while the equal volume of normal saline was given instead ofparecoxib in group NS. Anesthesia was induced with iv injection of propofol, fentanyland rocuronium. Bronchial blocker was inserted after tracheal intubation and the correctposition was confirmed by bronchoscopy. Anesthesia was maintained with iv infusionof propofol and remifentanil and intermittent iv boluses of atracurium. HR, MAP, SpO₂and mean airway pressure (P_mean) were determined at5min of two-lung ventilation, at40min of one-lung ventilation, and at30min after re-expansion of the collapsed lung(T_0-2). Blood samples were taken simultaneously from jugular vein and radial artery forblood gas analysis. Intrapulmonary shunt （Q_s/Q_t） was calculated.Results There were no significant differences in hemodynamic parameters and P_meanbetween the two groups （P>0.05）. PaO₂was significantly lower, while Q_s/Q_t wassignificantly higher at T_1,2than at T₀in groups NS and P （P<0.05）. PaO₂wassignificantly higher, while Q_s/Q_t was significantly lower at T₂than at T₁in groups NSand P （P<0.05）. Q_s/Q_t was significantly lower at T_1,2and PaO₂was significantlyhigher at T₂in group P than in group NS （P<0.05）.Conclusion This research showed that preoperative intravenous parecoxib sodium cansignificantly reduce the intrapulmonary shunt and improve oxygenation in patientsduring one-lung ventilation.