This Month in: Anesthesiology

In this, his first issue as Editor-in-Chief of Anesthesiology, Evan D. Kharasch, M.D., Ph.D., presents his thoughts on the role of the Journal in the specialty and the future of the Journal under his care and leadership. After framing the role of Anesthesiology in the specialty of anesthesiology in broad and historical terms, he discusses the essential role of a thriving journal to the future of the specialty and that of the American Society of Anesthesiologists. From this perspective, he looks to the future of Anesthesiology, addressing the domains of content innovation, content reach, and business model innovation within the context of increasing accessibility and impact. He concludes with the promise to “go where the science takes us.”

Low hemoglobin transfusion thresholds may be harmful in individuals less able to tolerate anemia. Previous meta-analyses of transfusion strategy studies were inconclusive, perhaps because most failed to address clinical heterogeneity, thereby limiting their interpretation. A context-specific systematic review and meta-analysis of randomized controlled trials comparing restrictive and liberal transfusion strategies in the perioperative and acute care settings was performed using strict criteria for risk-strata generation and subsequent data pooling. Restrictive transfusion strategies were associated with an increased risk of complications in high-risk patients undergoing major surgery. Those with cardiovascular disease undergoing cardiac or vascular procedures had more events reflecting inadequate oxygen supply, higher mortality rates, or both. Similar results were found in elderly orthopedic patients, but not in critically ill patients. Therefore, the decision to transfuse (or not) may require more than a “one-size-fits-all” approach. See the accompanying Editorial View on page 11.

The perception that awake intubation is complex and time-consuming may lead clinicians to avoid this method of management of the anticipated difficult airway. The time taken to perform awake intubation was compared with the time taken to perform a postinduction intubation in this retrospective study. Intraoperative records for general anesthetics using endotracheal tubes between 2007 and 2014 were reviewed and 1,085 awake intubations were identified. Awake intubation cases were propensity matched with two control cases for which intubations were performed after induction of anesthesia. The median time to intubation was 24 min (interquartile range: 19 to 31 min) for awake intubations and 16 min (interquartile range: 13 to 22 min) for postinduction intubations. The awake intubation complication rate was 1.6% and the rate of failed awake intubation by flexible bronchoscopy was 1%.

Quality of recovery (QoR) scores provide a patient-centered global measure of overall health status after surgery and anesthesia. The 9-item QoR score, the 15-item QoR-15 scale, and the 40-item QoR-40 scale have ranges in scores of 0 to 18, 150, and 200, respectively. A sequential, unselected cohort of 199 patients quantified their recovery using the three QoR scales on two postoperative visits. Changes in patient QoR scores were compared with a global rating of change questionnaire and the change estimates were averaged to determine the minimal clinically important difference for each QoR scale. The minimal clinically important difference for the QoR score, QoR-15, and QoR-40 were 0.9, 8.0, and 6.3, respectively. That is, perioperative interventions that result in such a change can be interpreted to signify a clinically important improvement or deterioration in QoR. See the accompanying Editorial View on page 7.

The nociceptive/antinociceptive state is the most challenging anesthetic component to assess. The Nociception Level (NoL) index is a novel measure of nociception based on a nonlinear combination of nociception-related physiologic variables, including heart rate, heart rate variability, photoplethysmograph wave amplitude, skin conductance level, skin conductance fluctuations, and their time derivatives. The ability of the NoL index to discriminate noxious from nonnoxious stimuli, respond to analgesic administration, and progressively increase in response to increasing noxious stimulation intensity was compared to those of heart rate, pulse plethysmograph amplitude, noninvasive blood pressure, and the surgical pleth index in 58 patients. The NoL index was better at discriminating noxious from nonnoxious stimuli and was the only measure to increase proportionately with all tested clinical stimuli. Its response was blunted by an opioid bolus and differentiated between two remifentanil doses.

A systematic review of the literature that included 13 studies with more than 3,800 patients undergoing a variety of noncardiac surgeries was undertaken to determine whether existing evidence supports perioperative left ventricular diastolic dysfunction (PDD) as an independent predictor of adverse health outcomes in patients undergoing noncardiac surgery. Although there was scant evidence addressing several key outcomes for the immediate postsurgical period, evidence of moderate certainty indicated PDD may be an independent predictor of major adverse cardiovascular events as a composite outcome as well as pulmonary edema/congestive heart failure and myocardial infarction as independent outcomes in the immediate postoperative period. There was also evidence of an association between PDD and cardiovascular death in patients undergoing major surgical procedures, especially open vascular surgeries.

In normal hemostasis, thrombin generation at the site of vascular injury coordinates a balance between competing procoagulant/anticoagulant and fibrinolytic/antifibrinolytic systems. These physiologic processes are altered to various degrees in patients who develop disseminated intravascular coagulation (DIC). This Clinical Concepts and Commentary begins with a brief review of the pathophysiology of the hyperfibrinolytic and procoagulant forms of DIC. Descriptions of typical hemorrhagic features and typical thrombotic features of DIC follow. The laboratory aspects of the clinico-laboratory diagnosis of DIC are then considered, including various diagnostic criteria, specialized laboratory tests, and conditions that can present like DIC in the critical care unit. This overview ends with a discussion of DIC management topics, such as management of underlying conditions that predispose to DIC, anticoagulant therapy, modulation of the hyperfibrinolytic response, supportive care, and clinical and laboratory surveillance.

Hypoxia activates distinct hypoxia-signaling pathways at the cellular level, including a group of transcription factors known as hypoxia inducible factors and adenosine signaling, that are involved in modulation of inflammatory responses and are relevant to inflammatory conditions that are frequently encountered in critically ill patients. Inflammatory conditions are frequently characterized by tissue hypoxia due to both enhanced metabolic demand and decreased metabolic substrates. The present review provides an overview of the immunologic consequences of hypoxia, focusing on studies of inflammatory conditions relevant to the critically ill patient, including a discussion of oxygen-dependent signaling pathways and intermediate signaling systems. The clinical potential of intervening in these mechanisms is also discussed, as is evidence of potential drawbacks of hyperoxia, feasibility of therapeutic permissive hypoxia, and pharmacologic therapies that act on oxygen-dependent pathways.