Science, Medicine, and the Anesthesiologist

The long-term risk of stroke after perioperative atrial fibrillation remains uncertain. In this retrospective cohort study using administrative claims data on patients hospitalized for surgery (as defined by surgical diagnosis related group codes), the association between long-term stroke and newly diagnosed perioperative atrial fibrillation was investigated in more than 1 million patients. In a Cox proportional hazards analysis accounting for potential confounders, perioperative atrial fibrillation was associated with subsequent stroke after both noncardiac and cardiac surgery.

In this retrospective cohort study, the effectiveness and safety of perioperative tranexamic acid use was examined in a cohort of nearly 900,000 patients undergoing total hip or knee arthroplasty in the United States. While comparable regarding average age and comorbidity index, patients receiving tranexamic acid showed lower rates of blood transfusions without an increased risk of complications, an X-ray of a hip or knee arthroplasty including thromboembolic events and renal failure. However, uncertainty over vascular occlusive events warrants an adequately powered randomized controlled trial before the routine use of tranexamic acid in general, and in orthopedic surgery specifically, can be recommended.

The IMPROVE multicenter trial has shown that the intraoperative use of low tidal volumes combined to application of high levels of positive end-expiratory pressure (PEEP) reduces the incidence of postoperative pulmonary complications in patients without lung injury. However, whether this beneficial effect comes from prevention of hyperinflation or avoidance of repetitive tidal recruitment remains uncertain. In this randomized controlled trial including 900 patients scheduled for abdominal surgery, a strategy with a high level of PEEP and recruitment maneuvers did not protect against postoperative pulmonary complications. This study further supports that an intraoperative protective ventilation strategy should include a low tidal volume and low PEEP without recruitment maneuvers.

The effects of high sodium intake on blood pressure and cardiovascular disease were evaluated using meta-analyses. Specifically, the effects of sodium on blood pressure, according to age, race, and the presence or absence of hypertension, were calculated from survey data in a new meta-analysis of 107 randomized interventions; and the effects of blood pressure on cardiovascular mortality, according to age, were calculated from a meta-analysis of cohorts from 66 countries in the world. In 2010, 1.65 million deaths from cardiovascular causes worldwide were attributed to sodium consumption above a reference level of 2.0 g of sodium per day.

Extracorporeal life support (ECLS) is often used as a salvage strategy for critically ill adults. Furthermore, after the severe acute respiratory distress syndrome that characterized the 2009 influenza A (H1N1) pandemic there is renewed interest in the use of venovenous extracorporeal membrane oxygenation (ECMO) and extracorporeal carbon dioxide removal to support the respiratory system. Potential advantages of ECLS for respiratory failure include the ability to rest the lungs by avoiding additional injury caused by mechanical ventilation as well as the potential to facilitate early mobilization, which may be advantageous for bridging to recovery or to lung transplantation. The use of venoarterial ECMO has also been expanded and applied to critically ill adults with hemodynamic compromise from a variety of etiologies. Although technology and general care of the ECLS patient have evolved, ECLS is not without potential serious complications and remains largely unproven as a treatment modality. The first paper provides physicians, ECMO center directors and coordinators, hospital directors, health-care organizations, and regional national, and international policy makers a description of the optimal approach to organizing ECMO. The second paper provides an excellent review of the use of ECLS in critically ill patients. Together, these manuscripts suggest restraint in the widespread use of ECMO until there is a better appreciation for both the potential clinical applications and the optimal techniques for performing ECMO.

Clinicians and investigators have an increasing appreciation of the substantial size and frequency of placebo responses. These effects both confound clinical studies and are sometimes used to advantage in clinical practice. Less well appreciated are “nocebo” responses which relate to suggestions that symptoms will worsen after a treatment is administered. In their meta-analysis of 10 nocebo studies involving 334 participants, Petersen et al. demonstrate that nocebo responses are roughly equal in their frequency and size to placebo effects. Nocebo responses were found to be particularly robust if subjects had a negative previous experience with a treatment. These findings highlight the importance of the preparation investigators give subjects before clinical studies are conducted.

Thousands of new journals publish work for a fee, regardless of the quality of the work. To change the tide, the criteria by which scientists and their teams are rewarded for their efforts by agencies that fund them and institutions that host them should be revisited, aligning criteria with the desired outcomes: research that is productive, high quality, reproducible, shareable, and translatable (PQRST). In this viewpoint article, Drs. Ioannidis and Khoury provide suggestions for how to operationalize these principles. Readers interested in education and research are strongly encouraged to read this viewpoint written by one of the best world specialists in research evaluation.