Guidelines to promote the early recovery of patients undergoing major surgery recommend a restrictive intravenous-fluid strategy for abdominal surgery. However, the supporting evidence is limited, and there is concern about impaired organ perfusion.

Tranexamic acid reduces the risk of bleeding among patients undergoing cardiac surgery, but it is unclear whether this leads to improved outcomes. Furthermore, there are concerns that tranexamic acid may have prothrombotic and proconvulsant effects. In a trial with a 2-by-2 factorial design, we randomly assigned patients who were scheduled to undergo coronary-artery surgery and were at risk for perioperative complications to receive aspirin or placebo and tranexamic acid or placebo. The results of the tranexamic acid comparison are reported here. The primary outcome was a composite of death and thrombotic complications (nonfatal myocardial infarction, stroke, pulmonary embolism, renal failure, or bowel infarction) within 30 days after surgery. Of the 4662 patients who were enrolled and provided consent, 4631 underwent surgery and had available outcomes data; 2311 were assigned to the tranexamic acid group and 2320 to the placebo group. A primary outcome event occurred in 386 patients (16.7%) in the tranexamic acid group and in 420 patients (18.1%) in the placebo group (relative risk, 0.92; 95% confidence interval, 0.81 to 1.05; P=0.22). The total number of units of blood products that were transfused during hospitalization was 4331 in the tranexamic acid group and 7994 in the placebo group (P<0.001). Major hemorrhage or cardiac tamponade leading to reoperation occurred in 1.4% of the patients in the tranexamic acid group and in 2.8% of the patients in the placebo group (P=0.001), and seizures occurred in 0.7% and 0.1%, respectively (P=0.002 by Fisher’s exact test). Among patients undergoing coronary-artery surgery, tranexamic acid was associated with a lower risk of bleeding than was placebo, without a higher risk of death or thrombotic complications within 30 days after surgery. Tranexamic acid was associated with a higher risk of postoperative seizures. (Funded by the Australian National Health and Medical Research Council and others; ATACAS Australia New Zealand Clinical Trials Registry number, ACTRN12605000557639.)

This report presents the Consolidated Standards of Reporting Trials (CONSORT) extension for the stepped wedge cluster randomised trial (SW-CRT). The SW-CRT involves randomisation of clusters to different sequences that dictate the order (or timing) at which each cluster will switch to the intervention condition. The statement was developed to allow for the unique characteristics of this increasingly used study design. The guideline was developed using a Delphi survey and consensus meeting; and is informed by the CONSORT statements for individual and cluster randomised trials. Reporting items along with explanations and examples are provided. We include a glossary of terms, and explore the key properties of the SW-CRT which require special consideration in their reporting.

Several rating scales have been developed to measure quality of recovery after surgery and anaesthesia, but the most extensively used is the QoR-40, a 40-item questionnaire that provides a global score and subscores across five dimensions: patient support, comfort, emotions, physical independence, and pain. It has been evaluated in a variety of settings, but its overall psychometric properties (validity, reliability, ease of use, and interpretation) and clinical utility are uncertain. We undertook a quantitative systematic review of studies evaluating psychometric properties of the QoR-40. Data were combined in meta-analyses using random effects models. This resulted in a total sample of 3459 patients from 17 studies originating in nine countries. We confirmed content, construct, and convergent [pooled r=0.58, 95% confidence interval (CI): 0.51-0.65] validity. Reliability was confirmed by excellent intraclass correlation (pooled α=0.91, 95% CI: 0.88-0.93), test-retest reliability (pooled r=0.90, 95% CI: 0.86-0.92), and inter-rater reliability (intraclass correlation=0.86). The clinical utility of the QoR-40 instrument was supported by high patient recruitment into evaluation studies (97%), and an excellent completion and return rate (97%). The mean time to complete the QoR-40 was 5.1 (95% CI: 4.4-5.7) min. The QoR-40 is a widely used and extensively validated measure of quality of recovery. The QoR-40 is a suitable measure of postoperative quality of recovery in a range of clinical and research situations.

Background: Nitrous oxide is widely used in anesthesia, often administered at an inspired concentration around 70%. Although nitrous oxide interferes with vitamin B12, folate metabolism, and deoxyribonucleic acid synthesis and prevents the use of high inspired oxygen concentrations, the consequences of these effects are unclear. Methods: Patients having major surgery expected to last at least 2 h were randomly assigned to nitrous oxide-free (80% oxygen, 20% nitrogen) or nitrous oxide-based (70% N2O, 30% oxygen) anesthesia. Patients and observers were blind to group identity. The primary endpoint was duration of hospital stay. Secondary endpoints included duration of intensive care stay and postoperative complications; the latter included severe nausea and vomiting, and the following major complications: pneumonia, pneumothorax, pulmonary embolism, wound infection, myocardial infarction, venous thromboembolism, stroke, awareness, and death within 30 days of surgery. Results: Of 3,187 eligible patients, 2,050 consenting patients were recruited. Patients in the nitrous oxide-free group had significantly lower rates of major complications (odds ratio, 0.71; 95% confidence interval, 0.56-0.89; P = 0.003) and severe nausea and vomiting (odds ratio, 0.40; 95% confidence interval, 0.31-0.51; P < 0.001), but median duration of hospital stay did not differ substantially between groups (7.0 vs. 7.1 days; P = 0.06). Among patients admitted to the intensive care unit postoperatively, those in the nitrous oxide-free group were more likely to be discharged from the unit on any given day than those in the nitrous oxide group (hazard ratio, 1.35; 95% confidence interval, 1.05-1.73; P = 0.02). Conclusions: Avoidance of nitrous oxide and the concomitant increase in inspired oxygen concentration decreases the incidence of complications after major surgery, but does not significantly affect the duration of hospital stay. The routine use of nitrous oxide in patients undergoing major surgery should be questioned.