Objective: To test the hypothesis that in surgical patients ≥70 years, preoperative cognitive impairment is independently associated with postoperative delirium. Background: Postoperative delirium is common among elderly surgical patients and is associated with longer hospitalization and significant morbidity. Some evidence suggest that baseline cognitive impairment is an important risk factor. Routine screening for both preoperative cognitive impairment and postoperative delirium is recommended for older surgical patients. As of 2019, we implemented such routine perioperative screening in all elective surgical patients ≥70 years. Methods: Retrospective single-center analysis of prospectively collected data between January and December 2020. All elective noncardiac surgical patients ≥70 years without pre-existing dementia were included. Postoperative delirium, defined as 4A’s test score ≥4, was evaluated in the postanesthesia care unit and during the initial 2 postoperative days. Patients’ electronic records were also reviewed for delirium symptoms and other adverse outcomes. Results: Of 1518 eligible patients, 1338 (88%) were screened preoperatively [mean (SD) age 77 (6) years], of whom 21% (n=279) had cognitive impairment (Mini-Cog score ≤2). Postoperative delirium occurred in 15% (199/1338). Patients with cognitive impairment had more postoperative delirium [30% vs. 11%, adjusted odds ratio (95% confidence interval) 3.3 (2.3–4.7)]. They also had a higher incidence of a composite of postoperative complications [20% vs. 12%, adjusted odds ratio: 1.8 (1.2–2.5)], and median 1-day longer hospital stay [median (interquartile range): 6 (3,12) vs. 5 (3,9) days]. Conclusions: One-fifth of elective surgical patients ≥70 years present to surgery with preoperative cognitive impairment. These patients are at increased risk of postoperative delirium and major adverse outcomes.

Postoperative pulmonary complications (PPCs) increase the morbidity and mortality of surgery in obese patients. High levels of positive end-expiratory pressure (PEEP) with lung recruitment maneuvers may improve intraoperative respiratory function, but they can also compromise hemodynamics, and the effects on PPCs are uncertain. We hypothesized that intraoperative mechanical ventilation using high PEEP with periodic recruitment maneuvers, as compared with low PEEP without recruitment maneuvers, prevents PPCs in obese patients. The PRotective Ventilation with Higher versus Lower PEEP during General Anesthesia for Surgery in OBESE Patients (PROBESE) study is a multicenter, two-arm, international randomized controlled trial. In total, 2013 obese patients with body mass index ≥35 kg/m2 scheduled for at least 2 h of surgery under general anesthesia and at intermediate to high risk for PPCs will be included. Patients are ventilated intraoperatively with a low tidal volume of 7 ml/kg (predicted body weight) and randomly assigned to PEEP of 12 cmH2O with lung recruitment maneuvers (high PEEP) or PEEP of 4 cmH2O without recruitment maneuvers (low PEEP). The occurrence of PPCs will be recorded as collapsed composite of single adverse pulmonary events and represents the primary endpoint. To our knowledge, the PROBESE trial is the first multicenter, international randomized controlled trial to compare the effects of two different levels of intraoperative PEEP during protective low tidal volume ventilation on PPCs in obese patients. The results of the PROBESE trial will support anesthesiologists in their decision to choose a certain PEEP level during general anesthesia for surgery in obese patients in an attempt to prevent PPCs. ClinicalTrials.gov identifier: NCT02148692. Registered on 23 May 2014; last updated 7 June 2016.