Factors Causing Post-Anesthetic High Respiratory Resistance in Patients Undergoing Transurethral Resection of Bladder Tumors

BACKGROUND: In this study, we investigated the causes of high respiratory resistance that is observed after general anesthesia. We focused on respiratory resistance at 5 Hz (R5), which were measured preoperatively and postoperatively. METHODS: Our prospective observational study enrolled 68 patients who underwent transurethral resection of bladder tumors from April to October 2015. Respiratory impedance was measured the day before surgery and immediately after general anesthesia. Participants were divided into 2 groups: Group L (postoperative R5 values < 4.0 cmH(2)O/L/sec; n = 33) and Group H (postoperative R5 values ≥ 4.0 cmH(2)O/L/sec; n = 35). Patient background, preoperative R5 values, endotracheal tube or subglottic devices, anaesthetic period, desflurane or sevoflurane, and endotracheal suctioning were compared. RESULTS: Significant parameters were height, inhalation of desflurane, endotracheal suctioning, and preoperative R5 value. Logistic regression showed that endotracheal suctioning and a higher preoperative R5 level increased postoperative respiratory resistance (> 4 cmH(2)O/L/sec). CONCLUSIONS: The endotracheal suctioning at the end of anesthesia influenced respiratory resistance more than use of the endotracheal tube and desflurane.