Effects of dexmedetomidine on cardiac electrophysiology in patients undergoing general anesthesia during perioperative period: a randomized controlled trial

Effect of Different Doses of Dexmedetomidine on Atrial Fibrillation in Adults After Cardiac Surgery

ABSTRACT

In this study, we compared the effects of various doses of dexmedetomidine on the incidence of atrial fibrillation (AF) after cardiac surgery in adults. A total of 224 adult patients who underwent elective cardiac surgery were randomly assigned to two groups. The DEX0.5 group received a continuous infusion of dexmedetomidine at a rate of 0.5 μg·kg⁻ 1 ·h⁻ 1 , while the DEX1 group received it at a rate of 1 μg·kg⁻ 1 ·h⁻ 1 during the induction of anesthesia, which was maintained for 24 hours. The primary outcome was the incidence of AF, while the secondary outcomes included other tachyarrhythmias, bradycardia, hypotension, duration of mechanical ventilation, time spent in the cardiac care unit, and length of hospitalization. A total of 101 patients were included in the DEX0.5 group, while 104 patients were included in the DEX1 group. The incidence of AF was significantly lower in the DEX1 group compared with the DEX0.5 group (10.6% vs. 21.8%, P = 0.029). In addition, the duration of mechanical ventilation was shorter in the DEX1 group than in the DEX0.5 group (8.9 vs. 15.2 hours, P = 0.018). Logistic regression analyses were conducted to investigate the factors influencing AF. The results indicated that the dose of dexmedetomidine was the only independent predictor (odds ratio = 0.394, 95% confidence interval 0.172 to 0.903, P = 0.028). Compared with a continuous infusion of 0.5 μg·kg⁻ 1 ·h⁻ 1 , this study suggested that administering dexmedetomidine at a dose of 1 μg·kg⁻ 1 ·h⁻ 1 for 24 hours is effective in reducing the incidence of AF after cardiac surgery.

Risk Stratification of QTc Prolongation in Critically Ill Patients Receiving Antipsychotics for the Management of Delirium Symptoms

BackgroundPatients experiencing significant agitation or perceptual disturbances related to delirium in an intensive care setting may benefit from short-term treatment with an antipsychotic medication. Some antipsychotic medications may prolong the QTc interval, which increases the risk of potentially fatal ventricular arrhythmias. In this targeted review, we describe the evidence regarding the relationships between antipsychotic medications and QTc prolongation and practical methods for monitoring the QTc interval and mitigating arrhythmia risk.MethodsSearches of PubMed and Cochrane Library were performed to identify studies, published before February 2023, investigating the relationships between antipsychotic medications and QTc prolongation or arrhythmias.ResultsMost antipsychotic medications commonly used for the management of delirium symptoms (eg, intravenous haloperidol, olanzapine, quetiapine) cause a moderate degree of QTc prolongation. Among other antipsychotics, those most likely to cause QTc prolongation are iloperidone and ziprasidone, while aripiprazole and lurasidone appear to have minimal risk for QTc prolongation. Genetic vulnerabilities, female sex, older age, pre-existing cardiovascular disease, electrolyte abnormalities, and non-psychiatric medications also increase the risk of QTc prolongation. For individuals at risk of QTc prolongation, it is essential to measure the QTc interval accurately and consistently and consider medication adjustments if needed.ConclusionsAntipsychotic medications are one of many risk factors for QTc prolongation. When managing agitation related to delirium, it is imperative to assess an individual patient's risk for QTc prolongation and to choose a medication and monitoring strategy commensurate to the risks. In intensive care settings, we recommend regular ECG monitoring, using a linear regression formula to correct for heart rate. If substantial QTc prolongation (eg, QTc > 500 msec) is present, a change in pharmacologic treatment can be considered, though a particular medication may still be warranted if the risks of discontinuation (eg, extreme agitation, removal of invasive monitoring devices) outweigh the risks of arrhythmias.AimsThis review aims to summarize the current literature on relationships between antipsychotic medications and QTc prolongation and to make practical clinical recommendations towards the approach of antipsychotic medication use for the management of delirium-related agitation and perceptual disturbances in intensive care settings.

Insight into Cardioprotective Effects and Mechanisms of Dexmedetomidine

PURPOSE

Cardiovascular disease remains the leading cause of death worldwide. Dexmedetomidine is a highly selective α2 adrenergic receptor agonist with sedative, analgesic, anxiolytic, and sympatholytic properties, and several studies have shown its possible protective effects in cardiac injury. The aim of this review is to further elucidate the underlying cardioprotective mechanisms of dexmedetomidine, thus suggesting its potential in the clinical management of cardiac injury.

RESULTS AND CONCLUSION

Our review summarizes the findings related to the involvement of dexmedetomidine in cardiac injury and discusses the results in the light of different mechanisms. We found that numerous mechanisms may contribute to the cardioprotective effects of dexmedetomidine, including the regulation of programmed cell death, autophagy and fibrosis, alleviation of inflammatory response, endothelial dysfunction and microcirculatory derangements, improvement of mitochondrial dysregulation, hemodynamics, and arrhythmias. Dexmedetomidine may play a promising and beneficial role in the treatment of cardiovascular disease.

Dexmedetomidine inhibited arrhythmia susceptibility to adrenergic stress in RyR2R2474S mice through regulating the coupling of membrane potential and intracellular calcium

BACKGROUND

Dexmedetomidine (DEX), a highly selective α2-adrenoceptor agonist, can decrease the incidence of arrhythmias, such as catecholaminergic polymorphic ventricular tachycardia (CPVT). However, the underlying mechanisms by which DEX affects cardiac electrophysiological function remain unclear.

METHODS

Ryanodine receptor (RyR2) heterozygous R2474S mice were used as a model for CPVT. WT and RyR2R2474S/+ mice were treated with isoproterenol (ISO) and DEX, and electrocardiograms were continuously monitored during both in vivo and ex vivo experiments. Dual-dye optical mapping was used to explore the anti-arrhythmic mechanism of DEX.

RESULTS

DEX significantly reduced the occurrence and duration of ISO-induced of VT/VF in RyR2R2474S/+ mice in vivo and ex vivo. DEX remarkably prolonged action potential duration (APD80) and calcium transient duration (CaTD80) in both RyR2R2474S/+ and WT hearts, whereas it reduced APD heterogeneity and CaT alternans in RyR2R2474S/+ hearts. DEX inhibited ectopy and reentry formation, and stabilized voltage-calcium latency.

CONCLUSION

DEX exhibited an antiarrhythmic effect through stabilizing membrane voltage and intracellular Ca2+. DEX can be used as a beneficial perioperative anesthetic for patients with CPVT or other tachy-arrhythmias.

Dexmedetomidine and Perioperative Arrhythmias

The highly selective α2-adrenoceptor agonist dexmedetomidine is a commonly used sedative drug for patients undergoing anesthesia and intensive care treatment. Several studies have indicated that dexmedetomidine may have a potential role in preventing and treating perioperative tachyarrhythmias. However, the specific effect and mechanism of action of dexmedetomidine in this context remain unclear. Dexmedetomidine is known to regulate the electrophysiologic function of the myocardium by inhibiting the function of the sinus node and atrioventricular node, as well as affecting myocardial repolarization. This paper aims to provide a theoretical basis for the prevention and treatment of perioperative arrhythmias by summarizing the effects of dexmedetomidine on myocardial electrophysiologic function and its impact on different types of arrhythmias.

Beneficial Effects of Low-Dose Intravenous Dexmedetomidine Premedication in Patient Undergoing Laparoscopic Cholecystectomy Under General Anesthesia: A Prospective, Double-Blind, Randomized Controlled Trial

Purpose

Dexmedetomidine (Dex) is a potent and highly selective α2-adrenergic receptor agonist. Within an appropriate dose range, Dex can effectively attenuate the surgical stress response, provide intraoperative hemodynamic stability, and improve the patient recovery quality. High-dose Dex can delay patient awakening from anesthesia and increase the incidence of bradycardia. This randomized controlled trial aimed to investigate the effects of low-dose intravenous Dex premedication in patients undergoing laparoscopic cholecystectomy (LC).

Material and Methods

In total, 100 patients undergoing LC were equally randomized into Group C (premedication with saline) and Group D (premedication with 0.5 µg/kg Dex). The patients were premedicated with saline or Dex, depending on the group, before anesthesia induction. Following this, anesthesia induction and endotracheal intubation was performed, and anesthesia was maintained during surgery. Following the completion of the surgery, the patients were transferred the post-anesthesia care unit (PACU) and stayed there until they met the PACU discharge criteria. The hemodynamic parameters, consumption of anesthetics, surgical duration, postoperative awakening time, extubation time, postoperative pain, and complications were recorded.

Results

No significant differences were observed in the heart rate (HR) and mean arterial pressure (MAP) between the two groups before premedication (P>0.05). The MAP and HR immediately after endotracheal intubation and immediately after extubation were significantly lower in Group D than in Group C (P<0.05 for both). The incidence of bradycardia was significantly higher in Group D than in Group C (P<0.05), while atropine was used in neither group. Propofol and remifentanil consumption was significantly lower in Group D than in Group C (P<0.05). The postoperative awakening and extubation times were significantly shorter in Group D than in Group C (P<0.05). The postoperative visual analog scale scores for pain and incidence of nausea, vomiting, and cough were significantly lower in Group D than in Group C (P<0.05 for all).

Conclusion

Our data suggest that premedication with dexmedetomidine (0.5 µg/kg) before general anesthesia induction can effectively attenuate intraoperative stress response and postoperative pain, maintain perioperative hemodynamic stability, and decrease the incidence of adverse events, which might be an effective and safe anesthetic protocol during LC worthy of further clinical application.