Editor’s Perspective: What We Already Know about This Topic: What This Article Tells Us That Is New: Background: Airway closure causes lack of communication between proximal airways and alveoli, making tidal inflation start only after a critical airway opening pressure is overcome. The authors conducted a matched cohort study to report the existence of this phenomenon among obese patients undergoing general anesthesia. Methods: Within the procedures of a clinical trial during gynecological surgery, obese patients underwent respiratory/lung mechanics and lung volume assessment both before and after pneumoperitoneum, in the supine and Trendelenburg positions, respectively. Among patients included in this study, those exhibiting airway closure were compared to a control group of subjects enrolled in the same trial and matched in 1:1 ratio according to body mass index. Results: Eleven of 50 patients (22%) showed airway closure after intubation, with a median (interquartile range) airway opening pressure of 9 cm H₂O (6 to 12). With pneumoperitoneum, airway opening pressure increased up to 21 cm H₂O (19 to 28) and end-expiratory lung volume remained unchanged (1,294 ml [1,154 to 1,363] vs. 1,160 ml [1,118 to 1,256], P = 0.155), because end-expiratory alveolar pressure increased consistently with airway opening pressure and counterbalanced pneumoperitoneum-induced increases in end-expiratory esophageal pressure (16 cm H₂O [15 to 19] vs. 27 cm H₂O [23 to 30], P = 0.005). Conversely, matched control subjects experienced a statistically significant greater reduction in end-expiratory lung volume due to pneumoperitoneum (1,113 ml [1,040 to 1,577] vs. 1,000 ml [821 to 1,061], P = 0.006). With airway closure, static/dynamic mechanics failed to measure actual lung/respiratory mechanics. When patients with airway closure underwent pressure-controlled ventilation, no tidal volume was inflated until inspiratory pressure overcame airway opening pressure. Conclusions: In obese patients, complete airway closure is frequent during anesthesia and is worsened by Trendelenburg pneumoperitoneum, which increases airway opening pressure and alveolar pressure: besides preventing alveolar derecruitment, this yields misinterpretation of respiratory mechanics and generates a pressure threshold to inflate the lung that can reach high values, spreading concerns on the safety of pressure-controlled modes in this setting.

Catheter-related bladder discomfort (CRBD), affecting surgical patients requiring large catheters, is often intolerable. In this prospective controlled study, we compared the efficacy of three analgesic approaches in the management of CRBD. Here, 33 patients undergoing robot-assisted laparoscopic prostatectomy (RALP) were allocated to the following three groups: intrathecal morphine (IM), transversus abdominis plane block (TAP), and tramadol intravenous infusion (TI). The primary outcome was CRBD assessed at admission in the recovery room (RR) (T0), and 1 h (T1), 12 h (T2), and 24 h (T3) after surgery. The secondary outcomes included the following: Aldrete score; postoperative pain, measured with a numerical rate scale (NRS) at T0, T1, T2, and T3; postoperative opioid consumption; and flatus. The patients of the IM group showed significantly lower CRBD values over time compared to the patients of the TI group (p = 0.006). Similarly, NRS values decreased significantly over time in patients receiving IM compared to patients treated with TI (p < 0.0001). Postoperative nausea and vomiting did not differ among the three groups. Postoperative opioid consumption was significantly lower in the IM group compared to the other two groups. Most patients of the IM group (9 of 11) had flatus on the first postoperative day. In conclusion, IM may prevent CRBD and reduce pain perception and postoperative opioid consumption and expedite bowel function recovery.