The Association between Preoperative Blood Pressures and Postoperative Adverse Events.

BACKGROUND: The relationship between postoperative adverse events and blood pressures in the preoperative period remains poorly understood. This study tested the hypothesis that day-of-surgery preoperative blood pressures are associated with postoperative adverse events. METHODS: We conducted a retrospective, observational study of adult patients having elective procedures requiring an inpatient stay between November 2017 and July 2021 at Vanderbilt University Medical Center to examine the independent associations between preoperative systolic and diastolic blood pressures (SBP, DBP) recorded immediately before anesthesia care and number of postoperative adverse events - myocardial injury, stroke, acute kidney injury (AKI), and mortality, while adjusting for potential confounders. We used multivariable ordinal logistic regression to model the relationship. RESULTS: The analysis included 57,389 cases. The overall incidence of myocardial injury, stroke, AKI, and mortality within 30 days of surgery was 3.4% (1,967 events), 0.4% (223), 10.2% (5,871), and 2.1% (1,223), respectively. The independent associations between both SBP and DBP measurements and number of postoperative adverse events were found to be U-shaped, with greater risk both above and below SBP 143 mmHg and DBP 86 mmHg - the troughs of the curves. The associations were strongest at SBP 173 mmHg (adjusted odds ratio [aOR] 1.212 versus 143 mmHg; 95% CI, 1.021 to 1.439; p = 0.028), SBP 93 mmHg (aOR 1.339 versus 143 mmHg; 95% CI, 1.211 to 1.479; p < 0.001), DBP 106 mmHg (aOR 1.294 versus 86 mmHg; 95% CI, 1.003 to 1.17671; p = 0.048), and DBP 46 mmHg (aOR 1.399 versus 86 mmHg; 95% CI, 1.244 to 1.558; p < 0.001). CONCLUSIONS: Preoperative blood pressures both below and above a specific threshold were independently associated with a higher number of postoperative adverse events, but the data do not support specific strategies for managing patients with low or high blood pressure on the day of surgery.

Angiotensin-II for vasoplegia following cardiac surgery.

INTRODUCTION: The objective of this study was to describe the implementation and outcomes of a protocol outlining angiotensin-II utilization for vasoplegia following cardiac surgery. METHODS: This was a retrospective chart review at a single-center university hospital. Included patients received angiotensin-II for vasoplegia refractory to standard interventions, including norepinephrine 20 mcg/min and vasopressin 0.04 units/min, following cardiac surgery between April 2021 and April 2022. RESULTS: 30 patients received angiotensin-II for refractory vasoplegia. Adjunctive agents at angiotensin-II initiation included corticosteroids (26 patients; 87%), epinephrine (26 patients; 87%), dobutamine (17 patients; 57%), dopamine (9 patients; 30%), milrinone (2 patients; 7%), and hydroxocobalamin (4 patients; 13%). At 3 hours, the median mean arterial pressure increased from baseline (70 vs 61.5 mmHg, p = .0006). Median norepinephrine doses at angiotensin-II initiation, 1 hour, 3 hours, and angiotensin-II discontinuation were 0.22, 0.16 (p = .0023), 0.10 (p < .0001), and 0.07 (p < .0001) mcg/kg/min. Median dobutamine doses decreased throughout angiotensin-II infusion from eight to six mcg/kg/min (p = .0313). Other vasoactive medication doses were unchanged. Three patients (10%) subsequently received hydroxocobalamin. Thirteen (43.3%) and five (16.7%) patients experienced mortality by day 28 and venous or arterial thrombosis events, respectively. CONCLUSIONS: The administration of angiotensin-II to vasoplegic patients following cardiac surgery was associated with increased mean arterial pressure, reduced norepinephrine dosages, and reduced dobutamine dosages.

Surgical outcomes and complications of bedside tracheostomy in the ICU for patients on ECMO.

OBJECTIVE: Extracorporeal membrane oxygenation (ECMO) is increasingly employed in the management of patients with severe cardiac and pulmonary dysfunction. Patients commonly require tracheostomy for ventilator liberation. Though bedside percutaneous tracheostomy is commonly performed, it has the potential for increased complications, both surgical and with the ECMO circuit. We examined surgical outcomes of bedside percutaneous tracheostomy in the ECMO population. METHODS: Patients were identified from an institutional database for bedside procedures. Demographics and data on complications were recorded. Descriptive statistics were calculated. RESULTS: 37 patients on ECMO at the time of tracheostomy were identified. Median age and BMI were 43.2 and 28.0, respectively. 33 patients (89%) were on VV ECMO, and 4 (11%) were on VA ECMO. All were on anticoagulation prior to tracheostomy, which was held for 4 h before and after the procedure in all cases. There were no procedure-related deaths or airway losses. No patients experienced periprocedural clotting events of their ECMO circuit or oxygenator within 24 h. 3 patients (8%) required reintervention (re-exploration or bronchoscopy) for bleeding. Four other patients (10%) had minor bleeding controlled with packing. One patient had pneumomediastinum which resolved without intervention, and one had an occlusion of their tracheostomy which was treated with tracheostomy exchange. CONCLUSIONS: Bedside percutaneous tracheostomy is feasible for patients on ECMO. Further study is needed to determine specific risk factors for complications and means to mitigate these. Bedside percutaneous tracheostomy may be considered as part of the management of patients on ECMO to help facilitate liberation from mechanical support.

Case report of high-dose hydroxocobalamin in the treatment of vasoplegic syndrome during liver transplantation.

A 66-year-old man with cryptogenic cirrhosis secondary to nonalcoholic steatohepatitis presented for orthotopic liver transplantation. Following organ reperfusion, the patient developed vasoplegic syndrome, with arterial blood pressures of approximately 60-70/30-40 mm Hg (mean arterial pressure [MAP] <45 mm Hg) for >90 minutes. He required high-dose norepinephrine and vasopressin infusions, as well as i.v. bolus doses of norepinephrine and vasopressin to reach a goal MAP> 60 mm Hg. There was minimal response to a 2 mg/kg i.v. bolus of methylene blue. Following the administration of 5 g of i.v.hydroxocobalamin, the patient had a profound improvement in arterial blood pressure, with subsequent discontinuation of the vasopressin infusion and rapid reduction of norepinephrine infusion from 20 to 2 µg/min. While there have been several reports of the efficacy of hydroxocobalamin for vasoplegia after cardiopulmonary bypass, there have been only limited cases of hydroxocobalamin used in liver transplantation, and none with high-dose administration. We present a case of vasoplegic syndrome during liver transplantation that was refractory to high-dose vasopressors and methylene blue but responsive to high-dose i.v. hydroxocobalamin.