In high-risk patients undergoing noncardiac surgery, early postoperative myocardial ischemia is an important correlate of adverse cardiac outcomes.

Consistent anatomic accessibility, ease of cannulation, and a low rate of complications have made the radial artery the preferred site for arterial cannulation. Radial artery catheterization is a relatively safe procedure with an incidence of permanent ischemic complications of 0.09%. Although its anatomy in the forearm and the hand is variable, adequate collateral flow in the event of radial artery thrombosis is present in most patients. Harvesting of the radial artery as a conduit for coronary artery bypass grafting, advances in plastic and reconstructive surgery of the hand, and its use as an entry site for cardiac catheterization has provided new insight into the collateral blood flow to the hand and the impact of radial arterial instrumentation. The Modified Allen's Test has been the most frequently used method to clinically assess adequacy of ulnar artery collateral flow despite the lack of evidence that it can predict ischemic complications in the setting of radial artery occlusion. Doppler ultrasound can be used to evaluate collateral hand perfusion in an effort to stratify risk of potential ischemic injury from cannulation. Limited research has demonstrated a beneficial effect of heparinized flush solutions on arterial catheter patency but only in patients with prolonged monitoring (>24 h). Conservative management may be equally as effective as surgical intervention in treating ischemic complications resulting from radial artery cannulation. Limited clinical experience with the ultrasound-guided arterial cannulation method suggests that this technique is associated with increased success of cannulation with fewer attempts. Whether use of the latter technique is associated with a decrease in complications has not yet been verified in prospective studies. Research is needed to assess the safety of using the ulnar artery as an alternative to radial artery cannulation because the proximity and attachments of the ulnar artery to the ulnar nerve may potentially expose it to a higher risk of injury.

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To determine the incidence and characteristics of perioperative myocardial ischemia, the electrocardiographic (ECG) changes consistent with ischemia during the 4 day perioperative period were documented and characterized in 100 patients with or at risk for coronary artery disease undergoing noncardiac surgery. Using continuous two channel ECG monitoring (leads CC5 and CM5), the frequency and severity of ECG ischemic episodes defined by ST segment depression greater than or equal to 1 mm or elevation greater than or equal to 2 mm during the preoperative (up to 2 days), intraoperative and early postoperative (first 2 days) periods were compared. Preoperatively, 28 patients (28%) exhibited 105 episodes of ischemia; intraoperatively, 27 patients exhibited 39 episodes and postoperatively, 42 patients exhibited 187 episodes. There was no difference between the pre- and intraoperative episode characteristics. However, postoperative ischemic episodes were the most severe. The mean ST change was 1.5, 2 and 2.6 mm for pre-, intra- and postoperative episodes, respectively (p less than 0.0001 postoperative versus pre- or intraoperative); duration of ischemic episodes was 69, 45 and 207 min, respectively (p less than 0.005 postoperative versus preoperative, p less than 0.001 versus intraoperative) and area under the ST curve was 88, 74 and 383 mm.min (p less than 0.009 postoperative versus preoperative, p less than 0.005 versus intraoperative). Ninety-four percent of all postoperative ischemic episodes were silent; 80% of all episodes occurred without acute change (+/- 20% of control) in heart rate and 77% of intraoperative episodes occurred without acute change in blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

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Healthcare systems worldwide are responding to Coronavirus Disease 2019 (COVID-19), an emerging infectious syndrome caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus. Patients with COVID-19 can progress from asymptomatic or mild illness to hypoxemic respiratory failure or multisystem organ failure, necessitating intubation and intensive care management. Healthcare providers, and particularly anesthesiologists, are at the frontline of this epidemic, and they need to be aware of the best available evidence to guide therapeutic management of patients with COVID-19 and to keep themselves safe while doing so. Here, the authors review COVID-19 pathogenesis, presentation, diagnosis, and potential therapeutics, with a focus on management of COVID-19–associated respiratory failure. The authors draw on literature from other viral epidemics, treatment of acute respiratory distress syndrome, and recent publications on COVID-19, as well as guidelines from major health organizations. This review provides a comprehensive summary of the evidence currently available to guide management of critically ill patients with COVID-19.

ImportanceThe effectiveness of perioperative ␤-blockade in patients undergoing noncardiac surgery remains controversial.Objective To determine the associations of early perioperative exposure to ␤-blockers with 30-day postoperative outcome in patients undergoing noncardiac surgery. Design, Setting, and PatientsA retrospective cohort analysis evaluating exposure to ␤-blockers on the day of or following major noncardiac surgery among a populationbased sample of 136 745 patients who were 1:1 matched on propensity scores (37 805 matched pairs) treated at 104 VA medical centers from January 2005 through August 2010.Main Outcomes and Measures All cause 30-day mortality and cardiac morbidity (cardiac arrest or Q-wave myocardial infarction). ResultsOverall 55 138 patients (40.3%) were exposed to ␤-blockers. Exposure was higher in the 66.7% of 13 863 patients undergoing vascular surgery (95% CI, 65.9%-67.5%) than in the 37.4% of 122 882 patients undergoing nonvascular surgery (95% CI, 37.1%-37.6%; PϽ.001). Exposure increased as Revised Cardiac Risk Index factors increased, with 25.3% (95% CI, 24.9%-25.6%) of those with no risk vs 71.3% (95% CI, 69.5%-73.2%) of those with 4 risk factors or more exposed to ␤-blockers (PϽ.001). Death occurred among 1.1% (95% CI, 1.1%-1.2%) and cardiac morbidity occurred among 0.9% (95% CI, 0.8%-0.9%) of patients. In the propensity matched cohort, exposure was associated with lower mortality (relative risk [RR], 0.73; 95% CI, 0.65-0.83; PϽ.001; number need to treat [NNT], 241; 95% CI, 173-397). When stratified by cumulative numbers of Revised Cardiac Risk Index factors, ␤-blocker exposure was associated with significantly lower mortality among patients with 2 factors (RR, 0.63 [95% CI, 0.50-0.80]; PϽ.001; NNT, 105 [95% CI, 69-212]), 3 factors (RR, 0.54 [95% CI, 0.39-0.73]; PϽ.001; NNT, 41 [95% CI, 28-80]), or 4 factors or more (RR, 0.40 [95% CI, 0.25-0.73]; PϽ.001; NNT, 18 [95% CI,). This association was limited to patients undergoing nonvascular surgery. ␤-Blocker exposure was also associated with a lower rate of nonfatal Q-wave infarction or cardiac arrest (RR, 0.67 [95% CI, 0.57-0.79]; PϽ.001; NNT, 339 [95% CI,), again limited to patients undergoing nonvascular surgery.Conclusions and Relevance Among propensity-matched patients undergoing noncardiac, nonvascular surgery, perioperative ␤-blocker exposure was associated with lower rates of 30-day all-cause mortality in patients with 2 or more Revised Cardiac Risk Index factors. Our findings support use of a cumulative number of Revised Cardiac Risk Index predictors in decision making regarding institution and continuation of perioperative ␤-blockade. A multicenter randomized trial involving patients at a low to intermediate risk by these factors would be of interest to validate these observational findings.