Background: Because minimally invasive surgery can improve postoperative recovery, it became the preferred technique for patients with significant comorbidities. However, steep Trendelenburg position and abdominal CO2-insufflation can lead to a significant increase in upper airway resistance and an alteration of overall lung function. In particular, patients who already suffer from an obstructive airway disease like obstructive sleep apnea syndrome (OSAS) might be at risk for postoperative airway complications. Therefore, we perioperatively performed spirometric tests in patients with OSAS undergoing robotic surgery in steep Trendelenburg position.
Methods: Twenty patients with OSAS were enrolled in the study. A day before surgery lung function measurements were performed and repeated preoperatively, 40, 120, and 240 minutes and 1 and 5 days postoperatively. We measured vital capacity (VC), forced expiratory volume in 1 second (FEV1), maximal mid expiratory and inspiratory flow (MEF50, MIF50), arterial oxygen saturation, and nasal flow.
Results: The ratio of MEF50 to MIF50, as an indicator of upper airway resistance, was increased significantly postoperatively and normalized within 24 hours (p < 0.0001), while FEV1 and VC were significantly reduced and recovered only partially as much as the fifth postoperative day (p < 0.0001).
Conclusion: Airway resistance increased following robotic radical prostatectomy in Trendelenburg position in patients with OSAS. Two separate major effects can be observed. A significant increase of the upper airway resistance, which improved to preoperative conditions within 24 hours, and a reduction in FEV1 and VC, which recovered only partially as much as the fifth postoperative day.
Keywords: airway assessment; obstructive sleep apnea; robotic prostatectomy.