Effect of propofol and isoflurane on gas exchange parameters following one-lung ventilation in thoracic surgery: a double-blinded randomized controlled clinical trial

The use of anesthetic drugs with minimal inhibitory effects on the hypoxic pulmonary vasoconstriction (HPV) could have a decisive role in preventing the hypoxemia during one-lung ventilation (OLV). The aim of this study was to compare the effects of propofol and isoflurane on the changes in gas exchange parameters following OLV in thoracic surgery. This double-blinded randomized controlled clinical trial was conducted on patients who were candidates for elective right thoracotomy referred to the central operating room of Ghaem Hospital in Mashhad, Iran, during February 2016-2017. Patients with age range of 18 to 75 years, class I and II American Society of Anesthesiologists (ASA) and thoracotomy with OLV for pulmonary resection or cyst drainage were included. The patients were randomly allocated (1:1 ratio) into two groups of propofol (P, 50-100μg/kg/min) and isoflurane (I, 1 minimum alveolar concentration (MAC) 1.1%). Partial pressure of carbon dioxide (PaCO2), partial pressure of oxygen (PaO2), end-tidal carbon dioxide (ETCO2) and arterial oxygen saturation (SPO2) were recorded before and 15 minutes after OLV and compared between the two groups. The comparison of the mean gas exchange parameters before and 15 minutes after OLV was performed using Mann-Whitney test in SPSS version 19 software. P