Response to letters regarding article, "perioperative dexmedetomidine improves outcomes of cardiac surgery"

Protocol: dexmedetomidine on myocardial injury after noncardiac surgery-a multicenter, double-blind, controlled trial

AIMS

Myocardial injury after noncardiac surgery (MINS) is common in elderly patients and considered as an independent predictor of 30-day mortality after noncardiac surgery. Dexmedetomidine possesses cardiac-protective profile. Previous clinical studies have found that perioperative application of dexmedetomidine is associated with decreased 1-year mortality in patients undergoing cardiac surgery. The current study protocol aims to investigate the effects of dexmedetomidine on the incidence of MINS, complications, and 30-day mortality in elderly patients subjected to noncardiac surgery.

METHODS

A multicenter, randomized, controlled, double-blind, prospective trial is designed to explore cardiac protection of dexmedetomidine in the elderly patients undergoing noncardiac surgery. A total of 960 patients aged over 65 years will be recruited and randomly assigned to dexmedetomidine group (group Dex) and normal saline placebo group (group NS) in a ratio of 1:1. Patients in group Dex will receive a bolus dose of 0.5 μg/kg dexmedetomidine within 10 min before surgical incision, followed by a consistent infusion at the rate of 0.3-0.5 μg/kg/h throughout the operation. Group NS patients will receive the same volume of normal saline. The primary outcome is the incidence of MINS via detecting the hs-TnT level within 3 days after the operation. The secondary outcome includes myocardial ischemic symptoms, the incidence of major adverse cardiovascular events (MACE) in hospital, length of ICU and postoperative hospital stay, the incidence of inhospital complications, and 30-day all-cause mortality.

DISCUSSION

The results of the current study will illustrate the effect of dexmedetomidine on myocardial injury for elderly patients undergoing major noncardiac surgery.

TRIAL REGISTRATION

The trial was registered with Chinese Clinical Trial Registry (CHICTR) on Aug 24, 2021 (ChiCTR2100049946, http://www.chictr.org.cn/showproj.aspx?proj=131804 ).

Optimal Dose of Dexmedetomidine for Perioperative Blood Glucose Regulation in Non-Diabetic Patients Undergoing Gastrointestinal Malignant Tumor Resection: A Randomized Double-Blinded Controlled Trial

PURPOSE

To evaluate the optimal dose of dexmedetomidine for perioperative blood glucose regulation in non-diabetic patients with gastrointestinal malignant tumor.

METHODS

One hundred patients were randomly divided into four groups: control group (group C), dexmedetomidine 1 μg/kg + 0.25 mcg/kg/h (group D₁); + 0.5 mcg/kg/h (group D₂); and + 1 mcg/kg/h (group D₃). Blood glucose concentrations were measured before dexmedetomidine infusion (T₁), 1 h after surgery beginning (T₂), at the end of surgery (T₃), and 1 h in PACU (T₄). Duration of surgery, extubation time, anesthetics doses, adverse reactions, postoperative pulmonary infection, total peritoneal drainage 2 days after surgery and hospital stay were recorded.

RESULTS

Compared with T₁, blood glucose concentrations were higher at T₄ in group C and at T_2-4 in groups D₁, D₂, and D₃ (p < 0.01). Compared with group C, blood glucose concentrations were higher at T₂ and T₃ in groups D₂ and D₃ (p < 0.05), but significantly lower at T₄ in groups D₁, D₂, and D₃ (p < 0.01). Propofol and remifentanil consumption in groups D₁, D₂, and D₃ decreased significantly compared with group C (p < 0.01). In group D₃, doses of ephedrine (p < 0.05) and atropine (p < 0.01) were higher, and extubation time was prolonged (p < 0.01) compared with the other groups. The incidence of bradycardia was higher in group D₃ than that in group C (p < 0.05).

CONCLUSIONS

Dexmedetomidine loading dose of 1 mcg/kg followed by maintenance with 0.25 mcg/kg/h can regulate perioperative blood glucose well in non-diabetic patients undergoing gastrointestinal malignant tumor resection and reduce doses of anesthetics without extending extubation time.

Risk Factors for Postoperative Delirium in Type A Aortic Dissection Patients: A Retrospective Study

BACKGROUND Postoperative delirium (POD) is a common complication in cardiac surgery among adult patients. This retrospective study was designed to identify the risk factors associated with POD of type A aortic dissection patients. MATERIAL AND METHODS Clinical data of 148 patients with type A aortic dissection in the Department of Critical Care Medicine was retrospectively analyzed. All these patients underwent Sun's procedure with anesthetic treatment. The confusion assessment method for intensive care unit (CAM-ICU) was adapted to evaluate the delirium status of these patients. They were divided into 2 groups: the delirium group and the control group. Univariate analysis and multivariate logistic regression were performed in succession to determine the independent risk factors for POD. RESULTS The average age of these patients was 54.41±11.676 years old. Among the 148 patients, POD was detected in 68 patients, with an incidence of 45.95%. According to univariate analysis, age, irritability, alcohol use, extracorporeal circulation duration (cardiopulmonary bypass, CPB time), antegrade selective cerebral perfusion (ASCP) time, lowest partial pressure of oxygen (lowest PO2), mechanical ventilation time, blood loss, low PO₂ and oxygenation index, hemoglobin (Hb), Intensive Care Unit (ICU) stay, and dihydroxyphenylalanine (DEX) were associated with higher odds of POD among type A aortic dissection patients. According to further analysis of multivariate logistic regression, ASCP time and irritability were confirmed as the independent factors for POD of type A aortic dissection patients. CONCLUSIONS We determined 2 independent risk factors for POD: ASCP time and irritability. Identifying and adjusting these risk factors are very important in reducing the incidence of POD among type A aortic dissection patients.

Can dexmedetomidine reduce atrial fibrillation after cardiac surgery? A systematic review and meta-analysis

Purpose

Cardiac surgery patients always present with atrial fibrillation (AF) after admission to the intensive care unit, leading to high mortality and lengthy hospitalization. Dexmedetomidine (DEX) is a popular medication used for sedation in the intensive care unit; however, whether it can reduce AF needs to be analyzed.

Materials and methods

Three primary databases, Medline, Embase (Ovid SP) and the Cochrane Central Register of Controlled Trials (CENTRAL), were searched. All English language and randomized control designed clinical publications comparing DEX to control medicines for sedation after elective cardiac surgery were included. Two independent colleagues conducted the data extraction and quality assessments. The subgroup analysis was performed according to the medicine used, age, AF history, and whether previous beta-blocker premedication and cardiopulmonary bypass (CPB) were applied. The overall incidence of AF was analyzed.

Results

A total of 1,295 patients in nine studies met the selection criteria among 2,587 studies screened from the database. After quantitative synthesis, our results revealed that the DEX group was not associated with a decreased incidence of AF compared with the placebo (risk ratio [RR] 0.76, 95% CI 0.37, 1.55, P=0.44) and morphine groups (RR 0.86, 95% CI 0.56, 1.31, P=0.48). Subgroup analysis also indicated that the DEX vs propofol comparison exhibited no difference: 1) for patients of age >60 years (P=0.69) or ≤60 years (P=0.69); 2) under CPB surgery (P=0.45) or without CPB surgery (P=0.88); 3) with beta-blocker premedication (P=0.32) or without beta-blocker premedication (P=0.90); and 4) with AF history (RR 1.07, 95% CI 0.85, 1.36, P=0.57) or without AF history (P=0.30).

Conclusion

This meta-analysis revealed that DEX could not reduce the incidence of AF compared to control medicines following cardiac surgery. DEX may have an increased influence on AF occurrence if patients had a history of AF. However, cautious interpretation should be made due to high clinical heterogeneity.