ABSTRACT
Background@#Existing literature lacks high-quality evidence regarding the ideal intraoperative positive end-expiratory pressure (PEEP) to minimize postoperative pulmonary complications (PPCs). We hypothesized that applying individualized PEEP derived from electrical impedance tomography would reduce the severity of postoperative lung aeration loss, deterioration in oxygenation, and PPC incidence. @*Methods@#A pilot feasibility study was conducted on 36 patients who underwent open abdominal oncologic surgery. The patients were randomized to receive individualized PEEP or conventional PEEP at 4 cmH2O. The primary outcome was the impact of individualized PEEP on changes in the modified lung ultrasound score (MLUS) derived from preoperative and postoperative lung ultrasonography. A higher MLUS indicated greater lung aeration loss. The secondary outcomes were the PaO2/FiO2 ratio and PPC incidence. @*Results@#A significant increase in the postoperative MLUS (12.0 ± 3.6 vs 7.9 ± 2.1, P < 0.001) and a significant difference between the postoperative and preoperative MLUS values (7.0 ± 3.3 vs 3.0 ± 1.6, P < 0.001) were found in the conventional PEEP group, indicating increased lung aeration loss. In the conventional PEEP group, the intraoperative PaO2/FiO2 ratios were significantly lower but not the postoperative ratios. The PPC incidence was not significantly different between the groups. Post-hoc analysis showed the increase in lung aeration loss and deterioration of intraoperative oxygenation correlated with the deviation from the individualized PEEP. @*Conclusions@#Individualized PEEP appears to protect against lung aeration loss and intraoperative oxygenation deterioration. The advantage was greater in patients whose individualized PEEP deviated more from the conventional PEEP.
ABSTRACT
General anesthesia causes inhibition of thermoregulatory mechanisms. Propofol has been reported to cause more temperature fall, but in case of deliberate mild hypothermia, both sevoflurane and propofol were comparable. Thermoregulation is found to be disturbed in cases of pituitary tumors. We aimed to investigate which of the two agents, sevoflurane or propofol, results in better preservation of thermoregulation in patients undergoing transsphenoidal excision of pituitary tumors. Twenty-six patients scheduled to undergo transsphenoidal removal of pituitary adenomas were randomly allocated to receive propofol or sevoflurane anesthesia. Baseline esophageal temperature was noted. Times for temperature to fall by 1[degree sign] C or 35[degree sign] C and to return to baseline were also comparable [P>0.05]. After that warmer was started at 43[degree sign] C and time to rise to baseline was noted. Duration of surgery, total blood loss, and total fluid intake were also noted. If any, side effects such as delayed arousal and recovery from muscle relaxant were noted. The demographics of the patients were comparable. Duration of surgery and total blood loss were comparable in the two groups. The time for temperature to fall by 1[degree sign] C or 35[degree sign] C and time to return to baseline was also comparable [P>0.05]. No side effects related to body temperature were noted. Both propofol and sevoflurane show similar effects in maintaining thermal homeostasis in patients undergoing transsphenoidal pituitary surgery