Arterial Catheters for Early Detection and Treatment of Hypotension During Major Noncardiac Surgery: A Randomized Trial.

BACKGROUND: Continuous blood pressure monitoring may facilitate early detection and prompt treatment of hypotension. We tested the hypothesis that area under the curve (AUC) mean arterial pressure (MAP) <65 mm Hg is reduced by continuous invasive arterial pressure monitoring. METHODS: Adults having noncardiac surgery were randomly assigned to continuous invasive arterial pressure or intermittent oscillometric blood pressure monitoring. Arterial catheter pressures were recorded at 1-minute intervals; oscillometric pressures were typically recorded at 5-minute intervals. We estimated the arterial catheter effect on AUC-MAP <65 mm Hg using a multivariable proportional odds model adjusting for imbalanced baseline variables and duration of surgery. Pressures <65 mm Hg were categorized as 0, 1-17, 18-91, and >91 mm Hg × minutes of AUC-MAP <65 mm Hg (ie, no hypotension and 3 equally sized groups of increasing hypotension). RESULTS: One hundred fifty-two patients were randomly assigned to arterial catheter use and 154 to oscillometric monitoring. For various clinical reasons, 143 patients received an arterial catheter, while 163 were monitored oscillometrically. There were a median [Q1, Q3] of 246 [187, 308] pressure measurements in patients with arterial catheters versus 55 (46, 75) measurements in patients monitored oscillometrically. In the primary intent-to-treat analysis, catheter-based monitoring increased detection of AUC-MAP <65 mm Hg, with an estimated proportional odds ratio (ie, odds of being in a worse hypotension category) of 1.78 (95% confidence interval [CI], 1.18-2.70; P = .006). The result was robust over an as-treated analysis and for sensitivity analyses with thresholds of 60 and 70 mm Hg. CONCLUSIONS: Intraoperative blood pressure monitoring with arterial catheters detected nearly twice as much hypotension as oscillometric measurements.

Early Resumption of ß Blockers Is Associated with Decreased Atrial Fibrillation after Noncardiothoracic and Nonvascular Surgery: A Cohort Analysis.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Beta (ß) blockers reduce the risk of postoperative atrial fibrillation and should be restarted after surgery, but it remains unclear when best to resume ß blockers postoperatively. The authors thus evaluated the relationship between timing of resumption of ß blockers and atrial fibrillation in patients recovering from noncardiothoracic and nonvascular surgery. METHODS: The authors evaluated 8,201 adult ß-blocker users with no previous history of atrial fibrillation who stayed at least two nights after noncardiothoracic and nonvascular surgery as a retrospective observational cohort. After propensity score matching on baseline and intraoperative variables, 1,924 patients who did resume ß blockers by the end of postoperative day 1 were compared with 973 patients who had not resumed by that time on postoperative atrial fibrillation using logistic regression. A secondary matched analysis compared 3,198 patients who resumed ß blockers on the day of surgery with 3,198 who resumed thereafter. RESULTS: Of propensity score-matched patients who resumed ß blockers by end of postoperative day 1, 4.9% (94 of 1,924) developed atrial fibrillation, compared with 7.0% (68 of 973) of those who resumed thereafter (adjusted odds ratio, 0.69; 95% CI, 0.50-0.95; P = 0.026). Patients who resumed ß blockers on day of surgery had an atrial fibrillation incidence of 4.9% versus 5.8% for those who started thereafter (odds ratio, 0.84; 95% CI, 0.67-1.04; P = 0.104). CONCLUSIONS: Resuming ß blockers in chronic users by the end of the first postoperative day may be associated with lower odds of in-hospital atrial fibrillation. However, there seems to be little advantage to restarting on the day of surgery itself.