Key Papers from the Most Recent Literature Relevant to Anesthesiologists

There is growing consensus that opioids have been overprescribed in an attempt to control pain. Marijuana is considered by some to be a potential alternative treatment to chronic opioid therapy among patients with chronic pain. This study examined associations between opioid prescribing and implementation of state marijuana laws using Medicaid-covered opioid prescribing rates. Overall, implementation of state laws allowing marijuana use was associated with a 5.88% (95% CI, −11.55% to −0.21%) decline in opioid prescribing. If an adult-use or recreational law was enacted in a state already having a medical marijuana law, an additional 6.38% (95% CI, −12.20% to −0.56%) decrease in opioid prescribing was noted. The authors suggest that liberalizing access to marijuana may enhance pain control while reducing the number of patients exposed to opioids and the risk of developing an opioid use disorder or experiencing an opioid overdose. These data do not directly demonstrate a substitution of cannabis for opioids nor do they demonstrate the effectiveness of cannabis as an analgesic.

Take home message: Implementation of state laws allowing medical or recreational use of marijuana may be associated with decreased opioid prescribing for Medicaid patients.

Similar to anesthesiologists, surgeons are known to have a high prevalence of burnout and depression. This study measured the prevalence of burnout and depression in surgical residents using the Maslach Burnout Inventory and the Patient Health Questionnaire in 92 surgical residents. Seventy-five percent of the residents answering the Maslach Burnout Inventory met the criteria for burnout and among these 48% were at high risk for depression. Overall, 39% of those participating in the Patient Health Questionnaire met the criteria for depression and 12% had experienced suicidal ideation in the previous 2 weeks. While 53% of the residents correctly recognized that more than 50% of residents were experiencing burnout, only 23% of the attending surgeons estimated that it was this common (P < 0.001). Fifty-one percent of residents and 75% of attending surgeons underestimated the true prevalence of depression (P = 0.002) in surgical residents.

Take home message: Burnout and depression are high in surgical residents and both attending and resident surgeons underestimate their prevalence in resident surgeons.

Recommendations from multiple guidelines suggest benefits with the use of radial artery grafts for coronary artery bypass surgery. However, incorporating these guidelines into clinical practice has been limited and the use of saphenous vein grafts remains high. This study describes a patient-level combined analysis of six randomized trials with at least 2 yr of follow-up that evaluated a primary composite outcome of death, myocardial infarction, or repeat revascularization using mixed-effects Cox regression models. Data were obtained on 1,036 patients (534 radial artery grafts and 502 saphenous vein grafts). The frequency of adverse events was significantly lower in the radial artery group (hazard ratio 0.67; 95% CI, 0.49 to 0.90; P = 0.01), and graft patency at follow-up angiography was also higher (hazard ratio 0.44; 95% CI, 0.28 to 0.70; P < 0.001). Radial artery grafting was associated with lower incidence of myocardial infarction (hazard ratio 0.72; 95% CI, 0.53 to 0.99; P = 0.04), repeat revascularization (hazard ratio 0.50; 95% CI, 0.40 to 0.63; P < 0.001), but no differences in all-cause mortality (hazard ratio 0.90; 95% CI, 0.59 to 1.41; P = 0.68).

Take home message: Compared with saphenous vein grafts, use of radial artery grafts for coronary artery bypass surgery may result in lower rates of adverse cardiac events and higher patency rates up to 5 yr after surgery.

Sedation in the intensive care unit (ICU) with dexmedetomidine has been shown to reduce the risk of delirium when compared to sedation with either benzodiazepines or propofol. This study describes a two-center, double-blind, prospective placebo-controlled study that compares administration of placebo or dexmedetomidine during the nocturnal period (9:30 pm to 6:15 am) to ICU patients who were previously sedated with other agents. Baseline sedative infusions were cut in half, but opioid infusions were left unchanged. Dexmedetomidine infusions were targeted to a Richmond Agitation and Sedation Scale score of –1 but not to exceed 0.7 ug · kg–1 · h–1. Nocturnal intravenous infusion of dexmedetomidine was associated with a decreased incidence of delirium (relative risk 0.44; 95% CI, 0.23 to 0.82; P = 0.006), less supplemental propofol (P < 0.001), but similar sleep quality scores. This study suggests that nocturnal administration of dexmedetomidine in previously sedated patients in the ICU may reduce the risk of delirium.

Take home message: Administration of nocturnal dexmedetomidine to patients who were previously sedated in an ICU may decrease the risk of delirium.

Controversy exists regarding the safety and efficacy of liberal oxygen administration in the setting of acute illness. This study describes a systematic review and meta-analysis of randomized controlled trials comparing liberal and conservative oxygen therapy in acutely ill patients. Twenty-five randomized controlled trials involving 16,037 patients with sepsis, critical illness, stroke, trauma, myocardial infarction, cardiac arrest, or patients undergoing emergency surgery were included in the meta-analysis. Room air or oxygen was delivered by nasal prongs in four trials, by facemask in 13 and by invasive mechanical ventilation in eight trials. A liberal oxygen strategy that maintained median baseline oxygen saturation at 96% increased in-hospital (relative risk 1.21; 95% CI, 1.03 to 1.43), 30-day (relative risk 1.14; 95% CI, 1.01 to 1.29), and longer-term mortality (relative risk 1.10; 95% CI, 1.00 to 1.21) when compared to more conservative oxygen strategies. Morbidity outcomes were similar between the groups.

Take home message: In acutely ill adults, liberal oxygen therapy that maintains peripheral oxygen saturations greater than 94 to 96% may increase mortality without improving other outcomes.

Many academic anesthesiologists have little education research training. This article contrasts this with the acknowledgment that “rigorous medical education research provides evidence for approaches to improve the education of our learners and shares with clinical, basic, and translational research the ultimate goal of improved patient outcomes.” The authors provide a focused overview of the essential components of education research and intend to provide medical educators with the framework for sound investigative work. The article stresses that successful medical education research requires a systematic stepwise approach, including (1) defining the hypothesis to be investigated, (2) fitting the idea into a medical education conceptual framework, (3) expressing the research question, (4) reviewing the existing literature, (5) gathering necessary study resources, (6) gaining institutional review board approval, (7) selecting research methods and a study population that will facilitate answering the question, (8) analyzing the results, and (9) publishing the results and conclusions with the medical education community.

Take home message: Effective education research will likely require the same investigative approaches as those applied to basic and clinical science research.

While a large number of preclinical studies suggest a role for neuroinflammation in chronic pain states, translation of these data to patients has been slow due to the lack of ability to directly assess human glial activation. To address this problem, this study used positron emission tomography/magnetic resonance imaging and the radioligand [11C]PBR28, which binds to the inflammatory marker 18 kDa translocator protein to indicate a state of glial activation. In patients with chronic radicular pain, binding of the tracer in the neuroforamina (P = 0.016) and associated spinal cord segments (P = 0.002) was higher than in control patients. In a subset of this group, epidural steroid injections appeared to be more likely to provide pain relief if enhanced tracer uptake could be shown. While this was a small study (n = 16 patients, n = 10 controls), the data suggest that we may be moving closer to having a method for detecting pain-related neuroinflammation.

Take home message: Increased neuroinflammation may be measurable in the spinal cord and neuroforamina of patients with chronic pain.

Prolonged oxygen desaturations are common after elective intubation in premature infants. This prospective randomized study involving 173 neonates was designed to compare desaturations after elective intubation in premature infants pretreated with atropine and propofol when compared to those who were pretreated with atropine, atracurium, and sufentanil. While intubation took longer in patients premedicated with propofol and atropine and the quality of sedation was less optimal, there were no differences in the number of oxygen saturations between the two groups (absolute differences –6; 95% CI, –21 to 8; P = 0.38). However, the duration of intubation was longer in the atropine, propofol group when compared to the atropine, atracurium, sufentanil group (absolute differences 2 min; 95% CI, 0 to 3 min; P = 0.04). Severe adverse events occurred in 11% of the atropine propofol group and 20% of the atropine, atracurium, sufentanil group. However, the authors note that the study was terminated prematurely due to logistical reasons before meeting the full planned enrollment and may have been underpowered to detect the primary outcome.

Take home message: The frequency of prolonged desaturations may not differ between premedication with atropine and propofol when compared to atropine, atracurium, and sufentanil, but this study may have been underpowered to detect this difference.

Older patients are at risk of developing frailty, which is associated with adverse hospital outcomes. This article describes the development and validation of a Hospital Frailty Risk Score using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, diagnostic codes and comparing whether this score was as predictive of adverse outcomes as the Fried and Rockwood Frailty scales. The Hospital Frailty Risk Score showed moderate agreement with the Rockwood Frailty Index (Pearson correlation coefficient 0.41; 95% CI, 0.38 to 0.47) and fair agreement with the Fried (kappa scores 0.22; 95% CI, 0.15 to 0.30) and Rockwood (kappa scores 0.30; 95% CI, 0.22 to 0.38) frailty scores. Perhaps more importantly, the Hospital Frailty Risk Score was associated with an increased risk of 30-day mortality (odds ratio 1.7; 95% CI, 1.7 to 1.8), hospital length of stay (odds ratio 6.0; 95% CI, 5.9 to 6.1), and an increased number of hospital readmissions (odds ratio 1.5; 95% CI, 1.5 to 1.5).

Take home message: An automated frailty score may be effective in identifying older patients at risk for adverse outcomes.

Acute kidney injury after major surgery has been associated with suboptimal volume status and administration of nephrotoxic medications. This prospective randomized study screened surgical patients admitted to an intensive care unit with at least one risk factor for acute kidney injury and urine inhibitor of metalloproteinase-2 × insulin-like growth factor-binding protein 7 levels greater than 0.3 and then randomized them to standard care or a Kidney Disease: Improving Global Outcomes care bundle consisting of increased continuous intravenous fluid administration guided by central venous pressure and a nephrology consultation. The overall incidence of acute kidney injury did not differ according to the type of care during the 7 days after surgery; 32% in the Kidney Disease: Improving Global Outcomes care group and 48% in the standard care group (P = 0.08). However, among patients with inhibitor of metalloproteinase-2 × insulin-like growth factor-binding protein 7 values between 0.3 and 2.0, there was a significant reduction in the incidence of acute kidney injury in the intervention group (27%) when compared to the standard care group (48%, P = 0.03).

Take home message: Identification of patients admitted to an intensive care unit after surgery who are at risk for acute kidney injury and treating them with central venous pressure–guided volume administration and a nephrology consult may reduce the incidence of acute kidney injury.

Medical decisions for patients in critical care units are often made by family members. This study used qualitative analysis of interviews with 79 surrogates for 59 patients being cared for in an intensive care unit with chronic critical illness, defined as a patient who has been mechanically ventilated for 7 or more days and expected to remain mechani cally ventilated for 3 or more days. The goal of these interviews was to aid our understanding of how surrogates perceive their medical decision-making role. The surrogate decision-makers described their roles as including being the voice of the patient, being an advocate for the patient, being an advocate for others, and advocating for themselves. They make their decision by balancing patient needs and concerns for others by sharing the decision-making role, maintaining balance and perspective, drawing from previous experiences, finding strengths, and acknowledging the burden.

Take home message: Surrogate medical decision-makers are often family members who balance the voice of the patient with the needs of others.

Surgical site infections are associated with patient morbidity and mortality. Accordingly, a growing number of operating room attire policies have been developed in an attempt to reduce the number of surgical site infections. This study compared data from two institutions where there was initiation of an operating room attire change that was intended to result in a decrease in surgical site infection. The authors used the American College of Surgeons National Surgical Quality Improvement Program database to determine infection rates for the 9 months before and after these changes. Interestingly, there were no differences in surgical site infections in the 9 months after the attire changes when compared to the 9 months before the attire change (odds ratio 1.2; 95% CI, 0.70 to 1.96; P = 0.56). Despite the findings that patients having surgery in the 9 months after implementation were older (57 vs. 55 yr, P < 0.001) and were more likely to have an American Society of Anesthesiologists functional status of IV (7% vs. 6%, P = 0.014).

Take home message: Implementation of stringent operating room attire policies may not decrease the risk of surgical site infections.