Context Surgical site infection (SSI) in the general surgical population is a significant public health issue. The use of a high fractional inspired concentration of oxygen (FIO 2 ) during the perioperative period has been reported to be of benefit in selected patients, but its role as a routine intervention has not been investigated.Objective To determine whether the routine use of high FIO 2 during the perioperative period alters the incidence of SSI in a general surgical population.Design, Setting, and Patients Double-blind, randomized controlled trial conducted between September 2001 and May 2003 at a large university hospital in metropolitan New York City of 165 patients undergoing major intra-abdominal surgical procedures under general anesthesia.Interventions Patients were randomly assigned to receive either 80% oxygen (FIO 2 of 0.80) or 35% oxygen (FIO 2 of 0.35) during surgery and for the first 2 hours after surgery.Main Outcome Measures Presence of clinically significant SSI in the first 14 days after surgery, as determined by clinical assessment, a management change, and at least 3 prospectively defined objective criteria. ResultsThe study groups were closely matched in a large number of clinical variables. The overall incidence of SSI was 18.1%. In an intention-to-treat analysis, the incidence of infection was significantly higher in the group receiving FIO 2 of 0.80 than in the group with FIO 2 of 0.35 (25.0% vs 11.3%; P=.02). FIO 2 remained a significant predictor of SSI (P=.03) in multivariate regression analysis. Patients who developed SSI had a significantly longer length of hospitalization after surgery (mean [SD], 13.3 [9.9] vs 6.0 [4.2] days; PϽ.001). ConclusionsThe routine use of high perioperative FIO 2 in a general surgical population does not reduce the overall incidence of SSI and may have predominantly deleterious effects. General surgical patients should continue to receive oxygen with cardiorespiratory physiology as the principal determinant.

Background Delirium and pain are common and serious postoperative complications. Subanaesthetic ketamine is often administered intraoperatively for postoperative analgesia and to spare postoperative opioids. Some evidence also suggests that ketamine prevents delirium. The primary purpose of this trial was to evaluate the effectiveness of ketamine in preventing postoperative delirium in older adults after major surgery. Secondary outcomes, viewed as strongly related to delirium, were postoperative pain and opioid consumption. Methods This was a multicentre, international, randomised trial that enrolled adults older than 60 undergoing major cardiac and noncardiac surgery under general anaesthesia. Participants were enrolled prior to surgery and gave written informed consent. We used a computer-generated randomisation sequence. Patients at study sites were randomised to one of three study groups in blocks of 15 to receive intraoperative administration of (i) placebo (intravenous normal saline), (ii) low dose ketamine (0.5 mg/kg) or (iii) high dose ketamine (1 mg/kg). Study drug was administered following induction of anaesthesia, prior to surgical incision. Participants, clinicians, and investigators were all masked to group assignment. Delirium and pain were assessed twice daily in the first three postoperative days using the Confusion Assessment Method and Visual Analog Scale, respectively. Postoperative opioid use was recorded, and hallucinations and nightmares were assessed. Analyses were performed by intention-to-treat and adverse events were evaluated. The Prevention of Delirium and Complications Associated with Surgical Treatments [PODCAST] trial is registered in clinicaltrials.gov; NCT01690988 Findings Between February 6, 2014 and June 26, 2016, 1360 patients assessed and 672 were randomised, with 222 in the placebo group, 227 in the low dose ketamine group, and 223 in the high dose ketamine group. There was no difference in postoperative delirium incidence between those in the combined ketamine groups and those who received placebo (19.45% vs. 19.82%, respectively; absolute difference, 0.36%; 95% CI, −6.07% to 7.38%; p=0.92). There were no significant differences among the three groups in maximum pain scores (p=0.88) or median opioid consumption (p=0.47) over time. There were more postoperative hallucinations (p=0.01) and nightmares (p=0.03) with escalating doses of ketamine. Adverse events (cardiovascular, renal, infectious, gastrointestinal, bleeding), whether viewed individually (P value for each >0.40) or collectively (82/222 [36.9%] in placebo group, 90/227 [39.6%] in low dose ketamine group, 91/223 in high dose ketamine group [40.8%]; P=0.69), did not differ significantly across the three groups. Interpretation The administration of a single subanaesthetic dose of ketamine to older adults during major surgery did not show evidence of reducing postoperative delirium, pain, or opioid consumption, and might cause harm by inducing negative experiences. Given current evidence and guidelines related...

Background: Postoperative delirium is a serious complication of surgery associated with prolonged hospitalisation, longterm cognitive decline, and mortality. This study aimed to determine whether targeting bispectral index (BIS) readings of 50 (light anaesthesia) was associated with a lower incidence of POD than targeting BIS readings of 35 (deep anaesthesia). Methods: This multicentre randomised clinical trial of 655 at-risk patients undergoing major surgery from eight centres in three countries assessed delirium for 5 days postoperatively using the 3 min confusion assessment method (3D-CAM) or CAM-ICU, and cognitive screening using the Mini-Mental State Examination at baseline and discharge and the Abbreviated Mental Test score (AMTS) at 30 days and 1 yr. Patients were assigned to light or deep anaesthesia. The primary outcome was the presence of postoperative delirium on any of the first 5 postoperative days. Secondary outcomes included mortality at 1 yr, cognitive decline at discharge, cognitive impairment at 30 days and 1 yr, unplanned ICU admission, length of stay, and time in electroencephalographic burst suppression. Results: The incidence of postoperative delirium in the BIS 50 group was 19% and in the BIS 35 group was 28% (odds ratio 0.58 [95% confidence interval: 0.38e0.88]; P¼0.010). At 1 yr, those in the BIS 50 group demonstrated significantly better cognitive function than those in the BIS 35 group (9% with AMTS 6 vs 20%; P<0.001).

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* In some instances, the sample size for BMI calculation is less than the number of patients as either height or weight was not recorded in the medical record. y CVD, cardiovascular disease, including diagnoses of: hyperlipidaemia, coronary artery disease, myocardial infarction, electrical arrhythmias. z Malignancy, including diagnosis of both solid organ and haematologic malignancies. OSA, obstructive sleep apnoea. ¶ Pulmonary disease, including diagnoses of: asthma, chronic obstructive pulmonary disease, interstitial fibrosis.