Key Papers from the Most Recent Literature Relevant to Anesthesiologists
Drug-induced sleep endoscopy findings in supine vs nonsupine body positions in positional and nonpositional obstructive sleep apnea. JAMA Otolaryngol Head Neck Surg 2018 Dec 20 [Epub ahead of print].
The cause of airway obstruction in positional versus nonpositional sleep apnea may affect management decisions but these mechanisms are poorly understood. This study examined anatomic causes of airway obstruction in the lateral and supine positions during propofol-induced sedation using endoscopy, with the primary structural cause of obstruction classified by VOTE (velum, oropharyngeal lateral walls, tongue, epiglottis) criteria. Of the 65 patients enrolled, 39 had positional sleep apnea by previous testing whereas it was nonpositional in 26. The investigators found that both groups experienced greater anteroposterior narrowing due to the velum (odds ratio, 7.3; 95% CI, 3.5 to 15.0), tongue (odds ratio, 29.4; 95% CI, 12.1 to 71.5), and epiglottis (odds ratio, 11.0; 95% CI, 1.3 to 92.7) in the supine position. When supine, multiple structures contributed to obstruction in the positional obstructive sleep apnea group, whereas it was mainly due to the tongue in the nonpositional group. With lateral positioning, however, the lateral oropharyngeal walls were the primary cause of obstruction in both groups but especially in those with nonpositional obstructive sleep apnea. Few of the study participants were obese, and propofol decreases tone in oropharyngeal muscles, so these results may not generalize to larger populations or natural sleep.
Take home message: In a small study population of primarily nonobese adults, propofol-induced sleep apnea followed the laws of gravity. This suggests that treatments that address velum- and tongue-related obstruction may be more effective in patients with positional obstructive apnea.
Antibiotic allergy. Lancet 2019; 393:183–98.
Antibiotics are the leading cause of life-threatening drug-related allergies. However, not all antibiotic reactions are true allergies and may reflect incomplete patient memory, drug intolerances, unrelated skin reactions, or drug–infection interactions. This is problematic because these relatively minor problems can lead to avoidance of first-line antibiotic therapies in favor of more aggressive treatments that may increase the risk of adverse events, antibiotic resistance, and public health risks. Increased use of broad-spectrum and non-β-lactam antibiotics due to incomplete identifications of penicillin allergy is a major case in point. This is particularly germane to surgery. Surgical site infections account for nearly half of healthcare-associated infections, and patients with a penicillin allergy label have a 50% increase in the odds of developing a surgical site infection, possibly due to an inferior choice of a prophylactic antibiotic. This review summarizes current thinking in global antibiotic allergy epidemiology, classification, mechanisms, and management, and it provides an algorithm for acutely prescribing antibiotics to patients with a history of a penicillin allergy. It concludes that most patients identified as having penicillin allergy do not, and it proposes patients should be appropriately stratified for risk, tested, and re-challenged.
Take home message: The capacity to appropriately address erroneous labels of an antibiotic allergy should be increased. Since antibiotics are often administered preoperatively to prevent surgical site infection, anesthesiologists are well positioned to help educate patients about the definition of a true allergy and should be familiar with treatment options for those with a history of severe or nonsevere allergy to improve stewardship of perioperative antibiotic use.
Effect of early sustained prophylactic hypothermia on neurologic outcomes among patients with severe traumatic brain injury: The POLAR randomized clinical trial. JAMA 2018; 320:2211–20.
There has been great interest in using induced hypothermia to protect the brain after various insults and injury. This international multicenter randomized trial compared management with early prophylactic hypothermia (n = 266) to normothermia (n = 245) after severe traumatic brain injury on neurologic outcome or independent living at 6 months. Hypothermia was initiated quickly (median 1.8 h) and maintained at 33° to 35°C for at least 72 h (up to 7 days if intracranial pressure was elevated), with gradual rewarming thereafter, whereas the temperature was maintained at 37°C in the control group. 466 patients completed the 6-month evaluation, which was conducted by blinded assessors. Favorable neurologic outcomes occurred in 49% (n = 117) of the hypothermia group and 49% (n = 111) of the normothermia group, for a risk difference of 0.4% (95% CI, –9.4% to 8.7%). There was also no benefit of prophylactic hypothermia in any of the secondary outcomes, including control of intracranial hypertension and mortality.
Take home message: Previous evidence for a benefit of prophylactic hypothermia after traumatic brain injury is mixed. This study overcomes weaknesses of some previous trials by inducing hypothermia quickly, maintaining it longer, and rewarming slowly. This study does not support the use of prophylactic hypothermia in patients with traumatic brain injury.
Taking control of your surgery: Impact of a prehabilitation program on major abdominal surgery. J Am Coll Surg 2019; 228:72–80.
Standard preoperative workups focus on identifying risk factors, not on improving cardiopulmonary or functional reserve, although reserve can influence outcome. This study collected intraoperative and postoperative data on 40 patients participating before major elective abdominal surgery in an institutional prehabiliation program, and it compared results to 76 controls having similar procedures and 40 having such procedures emergently. The prehabilitation program focused on four domains: physical activity, pulmonary rehabilitation, nutritional optimization, and stress reduction. Compliance with the prehabiliation program was self-reported at 70% and outcomes consisted of intraoperative physiology (blood pressure, heart rate), postoperative complications, and hospital costs. Intraoperative physiology was trivially different between the prehabilitated and control patients and length of stay was no different, but the former tended to have fewer complications overall. Based on hospital charges, the cost of care was lower in the prehabilitated group than the others, but the difference was statistically significant only compared to the emergency surgery group.
Take home message: Patients undergoing prehabilitation before colectomy may have positive physiologic benefits, fewer complications, and a lower cost of care, but the results need to be replicated in a larger study with objective measures of compliance with a prehabilitation program before surgery.
The major causes of death in children and adolescents in the United States. N Engl J Med 2018; 379:2468–75.
This special report found that preventable injury-related causes of death accounted for more than 60% of childhood and adolescent mortality in the United States in 2016. Fatal motor vehicle crashes, whose rates have declined for decades but are now inching up, were the leading cause of death in this age group, at 20.0% (5.2 deaths per 100,000; 95% CI, 5.1 to 5.4). Firearm-related injuries were the second at 15% of all deaths (4.0 deaths per 100,000; 95% CI, 3.9 to 4.2), which is a 28% relative increase between 2013 and 2016. Malignant neoplasms ranked third at 9.1% of deaths (2.4 deaths per 100,000; 95% CI, 2.3 to 2.5), which is a relative bright spot considering it represents about a 30% decrease since 1990. The remaining causes of death, in order, were suffocation, drowning, drug overdose or poisoning, congenital anomalies, heart disease, burns, and chronic lower respiratory disease. The authors concluded that further progress in prevention of childhood and adolescent death will require a shift in public perception from “accidents” to preventable behaviors and that different public health approaches will be required depending on patient age group.
Take home message: The leading causes of death in children and adolescence are preventable and expanded public health approaches to doing so are warranted.
Mentorship is not enough: Exploring sponsorship and its role in career advancement in academic medicine. Acad Med 2019; 94:94–100.
Mentorship is inarguably a key requirement for career advancement. Sponsorship, defined as active support by someone who has influence on decision-making processes and advocates for, protects, and fights for career advancement of an individual, is also gaining traction in this regard. This study explored the role of sponsorships in professional relationships within academic medicine. Department chairs (sponsors) and faculty participants of an executive leadership development program (protégés) at a leading medical school sat for semi-structured interviews. Interview transcripts were coded for thematic content, and a coding framework and themes were developed iteratively. Based on 23 interviews, five themes identified: (1) mentorship is different from sponsorship, which focuses on specific opportunities; (2) effective sponsors are career established and well-connected talent scouts; (3) effective protégés remain loyal as they grow and develop; (4) successful sponsorship relationships include trust, respect, and the ability to assess risk; and (5) sponsorship is critical to career advancement. The authors also observed that some perceive women as being less likely to seek sponsorship, even though it may be critical in their success.
Take home message: In addition to mentorship, sponsorship is critical for career advancement. Understanding sponsorship as a distinct professional relationship may help faculty and academic leaders make more informed decisions about using sponsorship as a deliberate career-advancement strategy.
Assessment of instruments for measurement of delirium severity: A systematic review. JAMA Intern Med 2018 Dec 17 [Epub ahead of print].
Delirium is common in hospitalized older patients and the ability to measure the severity of delirium is important for determining prognosis and treatment options and for estimating the burden of care during and after hospitalization. This systematic review examined delirium severity instruments, including the original validation studies, and identified the top instruments. The authors reviewed 228 articles and identified 42 instruments to measure delirium severity, of which 11 provided quantitative delirium severity ratings. The authors performed a methodologic quality review of these 11 using prespecified criteria including frequency of use, methodologic quality, construct or predictive validity, and broad domain coverage. Using an iterative modified Delphi process, an expert panel then selected six high-quality instruments: the Confusion Assessment Method–Severity Score, Confusional State Examination, Delirium-O-Meter, Delirium Observation Scale, Delirium Rating Scale, and Memorial Delirium Assessment Scale. There was, however, no single best instrument for universal use.
Take home message: Targeted use of validated delirium severity instruments may enhance the clinical care of delirious patients and improve the science of delirium research.
Periprocedural stroke and myocardial infarction as risks for long-term mortality in CREST. Circ Cardiovasc Qual Outcomes 2018; 11:e004663.
Patients who have had a periprocedural stroke or cardiac event during carotid stenting were more likely to die during 4-yr follow-up when compared to patients undergoing carotid endarterectomy. This study followed these patients up to 10 yr after their initial event to assess the association between mortality and periprocedural stroke, myocardial infarction, or biomarker-only events. Patients with periprocedural stroke have an increased risk of death when compared to those without stroke (adjusted hazard ratio = 1.7; 95% CI, 1.2 to 2.5; P < 0.003) primarily due to an increased mortality between 0 and 90 days (adjusted hazard ratio = 14.4; 95% CI, 5.3 to 38.9; P < 0.001). There was no corresponding increase in mortality after 90 days (adjusted hazard ratio = 1.4; 95% CI, 0.9 to 2.1; P = 0.11). Patients with procedure-related myocardial infarction had an increased risk of death compared to those without (adjusted hazard ratio = 3.6; 95% CI, 2.3 to 5.7; P < 0.001). This increased risk occurred both early (adjusted hazard ratio = 8.2; 95% CI, 1.9 to 36.2; P = 0.006) and late (adjusted hazard ratio = 3.4; 95% CI, 2.1 to 5.5; P < 0.001). Patients with a biomarker-only event were also at increased risk of death (adjusted hazard ratio = 2.0; 95% CI, 1.1 to 3.8; P = 0.03) than those without myocardial infarction. The risk increased early after the procedure (adjusted hazard ratio = 8.4; 95% CI, 1.1 to 65.5; P = 0.04) but was not statistically significant after 90 days.
Take home message: Periprocedural strokes and myocardial infarction in the setting of carotid stenting and endarterectomy are associated with a substantial increase in mortality.
Visualization of asymptomatic atherosclerotic disease for optimum cardiovascular prevention (VIPVIZA): A pragmatic, open-label, randomized controlled trial. Lancet 2019; 393:133–42.
Poor adherence to guidelines for the prevention of cardiovascular disease is common. This study investigated whether providing primary care physicians and patients with ultrasound images about subclinical carotid atherosclerosis would improve cardiovascular disease prevention. After undergoing clinical examination, blood sampling, and carotid ultrasound, participants aged 40, 50, or 60 were randomized to receive either an image representation of carotid ultrasound plus a follow-up nurse phone call (n = 1,749) or standard care (n = 1,783). Investigators assessed 3,175 participants at 1 yr for the primary outcomes, Framingham Risk Score and European Systematic Coronary Risk Evaluation. They found significant differences between the intervention and control groups in both the Framingham Risk Score (1.1; 95% CI, 0.1 to 2.0; P = 0.002) and European Systematic Coronary Risk Evaluation (0.2; 95% CI, 0.02 to 0.3; P = 0.001), suggesting that adding a pictorial depiction of silent atherosclerosis may contribute to improved cardiovascular disease prevention.
Take home message: Providing patients and practitioners with pictorial images of atherosclerosis may enhance adherence to medication and lifestyle modification of atherosclerotic disease.
Effects of fluoxetine on functional outcomes after acute stroke (FOCUS): A pragmatic, double-blind, randomised, controlled trial. Lancet 2019; 393:265–74.
A number of small clinical trials suggest that administration of fluoxetine to patients with a stroke may enhance functional outcomes. This large double-blind, randomized, placebo-controlled trial investigated how fluoxetine might improve functional outcomes after stroke. Patients with a stroke and focal neurological deficits were randomized to receive either fluoxetine 20 mg (n = 1,564) or placebo (n = 1,563). The primary outcome was functional status as measured with the modified Rankin Scale. At 6 months, modified Rankin Scale data were available for 1,553 (99.3%) patients in each group. Both groups had similar distribution across modified Rankin Scale categories (common odds ratio adjusted for minimization variables 0.95; 95% CI, 0.84 to 1.08; P = 0.44). However, patients on fluoxetine were less likely to develop new depression by 6 months (P = 0.003) but were more likely to have bone fractures (P = 0.007).
Take home message: Administration of fluoxetine after stroke may not enhance functional outcomes after stroke. Although it may decrease the risk of poststroke depression, the authors noted that their results do not support the routine use of fluoxetine after stroke.
Development and application of a risk prediction model for in-hospital stroke after transcatheter aortic valve replacement—A report from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry. Ann Thorac Surg 2018 Dec 7 [Epub ahead of print].
Transcatheter aortic valve replacement is associated with periprocedural stroke. This study described a risk model for in-hospital stroke after transcatheter aortic valve replacement. The study included data from 97,600 transcatheter aortic valve replacement procedures from 521 sites and used logistic regression to estimate the association between baseline covariates and in-hospital stroke. In-hospital stroke occurred in 1.9% of patients. Variables associated with stroke after transcatheter aortic valve replacement include advanced age (P < 0.001), lower body surface area (P < 0.001), lower glomerular filtration rate (P < 0.001), access site (P < 0.001), previous stroke (P < 0.001), previous transient ischemic attack (P < 0.001), peripheral artery disease (P < 0.001), smoking (P = 0.008), and higher acuity (P < 0.001). Interestingly, previous valvular procedure was protective from the development of stroke after transcatheter aortic valve replacement.
Take home message: This risk model for in-hospital stroke after transcatheter aortic valve replacement may serve as a resource for quality improvement, clinical decision-making, and patient counseling about the risk of stroke after the procedure.
Effect of pre-hospital use of the assessment of blood consumption score and pre-thawed fresh frozen plasma on resuscitation and trauma mortality. J Am Coll Surg 2019; 228:141–7.
Early blood product administration to bleeding trauma patients and activation of massive transfusion protocols has been associated with decreased mortality. This study tested the hypothesis that an improved process to allow for immediate bedside use of blood products would improve patient mortality from hemorrhage. This retrospective study compared mortality and massive transfusion protocol component ratios for 15 months before and after they added an assessment of blood consumption score during prehospital triage and a process making thawed plasma available. As a result of these changes, activation of the massive transfusion protocol increased sixfold, whereas the specificity of the process remained the same. In patients receiving massive transfusion protocols, appropriate blood product transfusion ratios increased 44%. Overall trauma mortality improved by 23% and penetrating trauma mortality improved by 41%. Based on injury severity score, penetrating trauma mortality decreased by 65% for injury severity score subgroup 15 to 24 and by 38% for injury severity score subgroup greater than 25. Interestingly, hospital length of stay, intensive care unit length of stay, and readmission rates did not differ significantly between the groups.
Take home message: Process improvements to identify hemorrhage and increase blood product availability may reduce mortality in trauma patients.