The role of esmolol in sepsis: a meta-analysis based on randomized controlled trials

BACKGROUND

Sepsis is associated with a high incidence and mortality and poses a significant challenge to the treatment. Although esmolol has shown promise in sepsis treatment, its efficacy and safety remain contentious. This meta-analysis aims to clarify the role of esmolol in sepsis management.

METHODS

PubMed, Embase, Web of Science, Cochrane library, clinicaltrials.gov and the Chinese Clinical Trial Registry were searched and references of relevant reviews and meta-analysis were also screened for appropriate studies. Keywords and free words of 'sepsis', 'esmolol' and 'randomized controlled trials' were used for search. Meta-analysis was performed using RevMan 5.3 software.

RESULTS

Fifteen studies involving 1100 patients were included. Compared with the control group, patients receiving esmolol exhibited significantly decreased 28-day mortality (RR, 0.69; 95% CI, 0.60 to 0.81; P < 0.0001), heart rate (HR) (SMD, -1.15; 95% CI, -1.34 to -0.96; P < 0.0001), cardiac troponin I levels (cTnI) (SMD, -0.88; 95% CI, -1.13 to -0.64; P < 0.0001), length of intensive care unit (ICU) stay (SMD, -0.46; 95% CI, -0.62 to -0.3; P < 0.0001) and duration of mechanical ventilation (SMD, -0.28; 95% CI, -0.48 to -0.09; P = 0.004) and significantly increased central venous oxygen saturation (ScvO2) (SMD, 0.66; 95% CI, 0.44 to 0.88; P < 0.0001).While, esmolol had no significant influence on norepinephrine dosage (SMD, 0.08; 95% CI, -0.13 to 0.29; P = 0.46), mean arterial pressure (MAP) (SMD, 0.17; 95% CI, -0.07 to 0.4; P = 0.16), central venous pressure (CVP) (SMD, 0.16; 95% CI, -0.04 to 0.35; P = 0.11) and left ventricular ejection fraction (LVEF) (SMD, 0.21; 95% CI, -2.9 to 0.7; P = 0.41).

CONCLUSION

Esmolol reduces 28-day mortality, length of ICU stay and duration of mechanical ventilation in sepsis patients. Furthermore, esmolol improves oxygen metabolism, mitigates myocardial injury and decreases heart rate without significantly affecting hemodynamic parameters.

TRIAL REGISTRATION

This study was registered on the PROSPERO website (registration number: CRD42023484884).

Myocardial protection in cardiac surgery-hindsight from the 2020s

Myocardial protection and specifically cardioplegia have been extensively investigated in the beginnings of cardiac surgery. After cardiopulmonary bypass had become routine, more and more cardiac operations were possible, requiring reliable and reproducible protection for times of blood flow interruptions to the most energy-demanding organ of the body. The concepts of hypothermia and cardioplegia evolved as tools to extend cardiac ischaemia tolerance to a degree considered safe for the required operation. A plethora of different solutions and delivery techniques were developed achieving remarkable outcomes with cross-clamp times of up to 120 min and more. With the beginning of the new millennium, interest in myocardial protection research declined and, as a consequence, conventional cardiac surgery is currently performed using myocardial protection strategies that have not changed in decades. However, the context, in which cardiac surgery is currently performed, has changed during this time. Patients are now older and suffer from more comorbidities and, thus, other organs move more and more into the centre of risk assessment. Yet, systemic effects of cardioplegic solutions have never been in the focus of attention. They say hindsight is always 20-20. We therefore review the biochemical principles of ischaemia, reperfusion and cardioplegic extension of ischaemia tolerance and address the concepts of myocardial protection with 'hindsight from the 2020s'. In light of rising patient risk profiles, minimizing surgical trauma and improving perioperative morbidity management becomes key today. For cardioplegia, this means accounting not only for cardiac, but also for systemic effects of cardioplegic solutions.

Beta-Adrenergic Blockade in Critical Illness

Catecholamine upregulation is a core pathophysiological feature in critical illness. Sustained catecholamine β-adrenergic induction produces adverse effects relevant to critical illness management. β-blockers (βB) have proposed roles in various critically ill disease states, including sepsis, trauma, burns, and cardiac arrest. Mounting evidence suggests βB improve hemodynamic and metabolic parameters culminating in decreased burn healing time, reduced mortality in traumatic brain injury, and improved neurologic outcomes following cardiac arrest. In sepsis, βB appear hemodynamically benign after acute resuscitation and may augment cardiac function. The emergence of ultra-rapid βB provides new territory for βB, and early data suggest significant improvements in mitigating atrial fibrillation in persistently tachycardic septic patients. This review summarizes the evidence regarding the pharmacotherapeutic role of βB on relevant pathophysiology and clinical outcomes in various types of critical illness.

Cardioplegia between Evolution and Revolution: From Depolarized to Polarized Cardiac Arrest in Adult Cardiac Surgery

Despite current advances in perioperative care, intraoperative myocardial protection during cardiac surgery has not kept the same pace. High potassium cardioplegic solutions were introduced in the 1950s, and in the early 1960s they were soon recognized as harmful. Since that time, surgeons have minimized many of the adverse effects by lowering the temperature of the heart, lowering K⁺ concentration, reducing contact K⁺ time, changing the vehicle from a crystalloid solution to whole-blood, adding many pharmacological protectants and modifying reperfusion conditions. Despite these attempts, high potassium remains a suboptimalway to arrest the heart. We briefly review the historical advances and failures of finding alternatives to high potassium, the drawbacks of a prolonged depolarized membrane, altered Ca²⁺ intracellular circuits and heterogeneity in atrial-ventricular K⁺ repolarization during reanimation. Many of these untoward effects may be alleviated by a polarized membrane, and we will discuss the basic science and clinical experience from a number of institutions trialling different alternatives, and our institution with a non-depolarizing adenosine, lidocaine and magnesium (ALM) cardioplegia. The future of polarized arrest is an exciting one and may play an important role in treating the next generation of patients who are older, and sicker with multiple comorbidities and require more complex operations with prolonged cross-clamping times.

Esmolol in Cardiac Surgery: A Randomized Controlled Trial

OBJECTIVE

To assess whether the administration of the ultra-short-acting β-blocker esmolol in cardiac surgery could have a cardioprotective effect that translates into improved postoperative outcomes.

DESIGN

Single-center, double-blinded, parallel-group randomized controlled trial.

SETTING

A tertiary care referral center.

PARTICIPANTS

Patients undergoing elective cardiac surgery with preoperative evidence of left ventricular end-diastolic diameter >60 mm and/or left ventricular ejection fraction <50%.

INTERVENTIONS

Patients were assigned randomly to receive either esmolol (1 mg/kg as a bolus before aortic cross-clamping and 2 mg/kg mixed in the cardioplegia solution) or placebo in a 1:1 allocation ratio.

MEASUREMENTS AND MAIN RESULTS

The primary composite endpoint of prolonged intensive care unit stay and/or in-hospital mortality occurred in 36/98 patients (36%) in the placebo group versus 27/102 patients (27%) in the esmolol group (p = 0.13). In the esmolol group, a reduction in the maximum inotropic score during the first 24 postoperative hours was observed (10 [interquartile range 5-15] v 7 [interquartile range 5-10.5]; p = 0.04), as well as a trend toward a reduction in postoperative low-cardiac-output syndrome (13/98 v 6/102; p = 0.08) and the rate of hospital admission at one year (26/95 v 16/96; p = 0.08). A trend toward an increase in the number of patients with ejection fraction ≥60% at hospital discharge also was observed (4/95 v 11/92; p = 0.06).

CONCLUSIONS

In the present trial, esmolol as a cardioplegia adjuvant enhanced postoperative cardiac performance but did not reduce a composite endpoint of prolonged intensive care unit stay and/or mortality.

Adrenergic Downregulation in Critical Care: Molecular Mechanisms and Therapeutic Evidence

Catecholamines remain the mainstay of therapy for acute cardiovascular dysfunction. However, adrenergic receptors quickly undergo desensitization and downregulation after prolonged stimulation. Moreover, prolonged exposure to high circulating catecholamines levels is associated with several adverse effects on different organ systems. Unfortunately, in critically ill patients, adrenergic downregulation translates into progressive reduction of cardiovascular response to exogenous catecholamine administration, leading to refractory shock. Accordingly, there has been a growing interest in recent years toward use of noncatecholaminergic inotropes and vasopressors. Several studies investigating a wide variety of catecholamine-sparing strategies (eg, levosimendan, vasopressin, β-blockers, steroids, and use of mechanical circulatory support) have been published recently. Use of these agents was associated with improvement in hemodynamics and decreased catecholamine use but without a clear beneficial effect on major clinical outcomes. Accordingly, additional research is needed to define the optimal management of catecholamine-resistant shock.

Perioperative beta-blockers for preventing surgery-related mortality and morbidity in adults undergoing cardiac surgery

BACKGROUND

Randomized controlled trials (RCTs) have yielded conflicting results regarding the ability of beta-blockers to influence perioperative cardiovascular morbidity and mortality. Thus routine prescription of these drugs in unselected patients remains a controversial issue. A previous version of this review assessing the effectiveness of perioperative beta-blockers in cardiac and non-cardiac surgery was last published in 2018. The previous review has now been split into two reviews according to type of surgery. This is an update and assesses the evidence in cardiac surgery only.

OBJECTIVES

To assess the effectiveness of perioperatively administered beta-blockers for the prevention of surgery-related mortality and morbidity in adults undergoing cardiac surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, Biosis Previews and Conference Proceedings Citation Index-Science on 28 June 2019. We searched clinical trials registers and grey literature, and conducted backward- and forward-citation searching of relevant articles.

SELECTION CRITERIA

We included RCTs and quasi-randomized studies comparing beta-blockers with a control (placebo or standard care) administered during the perioperative period to adults undergoing cardiac surgery. We excluded studies in which all participants in the standard care control group were given a pharmacological agent that was not given to participants in the intervention group, studies in which all participants in the control group were given a beta-blocker, and studies in which beta-blockers were given with an additional agent (e.g. magnesium). We excluded studies that did not measure or report review outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, and assessed risks of bias. We assessed the certainty of evidence with GRADE.

MAIN RESULTS

We included 63 studies with 7768 participants; six studies were quasi-randomized and the remaining were RCTs. All participants were undergoing cardiac surgery, and in most studies, at least some of the participants were previously taking beta-blockers. Types of beta-blockers were: propranolol, metoprolol, sotalol, esmolol, landiolol, acebutolol, timolol, carvedilol, nadolol, and atenolol. In twelve studies, beta-blockers were titrated according to heart rate or blood pressure. Duration of administration varied between studies, as did the time at which drugs were administered; in nine studies this was before surgery, in 20 studies during surgery, and in the remaining studies beta-blockers were started postoperatively. Overall, we found that most studies did not report sufficient details for us to adequately assess risk of bias. In particular, few studies reported methods used to randomize participants to groups. In some studies, participants in the control group were given beta-blockers as rescue therapy during the study period, and all studies in which the control was standard care were at high risk of performance bias because of the open-label study design. No studies were prospectively registered with clinical trials registers, which limited the assessment of reporting bias. We judged 68% studies to be at high risk of bias in at least one domain.Study authors reported few deaths (7 per 1000 in both the intervention and control groups), and we found low-certainty evidence that beta-blockers may make little or no difference to all-cause mortality at 30 days (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.47 to 1.90; 29 studies, 4099 participants). For myocardial infarctions, we found no evidence of a difference in events (RR 1.05, 95% CI 0.72 to 1.52; 25 studies, 3946 participants; low-certainty evidence). Few study authors reported cerebrovascular events, and the evidence was uncertain (RR 1.37, 95% CI 0.51 to 3.67; 5 studies, 1471 participants; very low-certainty evidence). Based on a control risk of 54 per 1000, we found low-certainty evidence that beta-blockers may reduce episodes of ventricular arrhythmias by 32 episodes per 1000 (RR 0.40, 95% CI 0.25 to 0.63; 12 studies, 2296 participants). For atrial fibrillation or flutter, there may be 163 fewer incidences with beta-blockers, based on a control risk of 327 incidences per 1000 (RR 0.50, 95% CI 0.42 to 0.59; 40 studies, 5650 participants; low-certainty evidence). However, the evidence for bradycardia and hypotension was less certain. We found that beta-blockers may make little or no difference to bradycardia (RR 1.63, 95% CI 0.92 to 2.91; 12 studies, 1640 participants; low-certainty evidence), or hypotension (RR 1.84, 95% CI 0.89 to 3.80; 10 studies, 1538 participants; low-certainty evidence).We used GRADE to downgrade the certainty of evidence. Owing to studies at high risk of bias in at least one domain, we downgraded each outcome for study limitations. Based on effect size calculations in the previous review, we found an insufficient number of participants in all outcomes (except atrial fibrillation) and, for some outcomes, we noted a wide confidence interval; therefore, we also downgraded outcomes owing to imprecision. The evidence for atrial fibrillation and length of hospital stay had a moderate level of statistical heterogeneity which we could not explain, and we, therefore, downgraded these outcomes for inconsistency.

AUTHORS' CONCLUSIONS

We found no evidence of a difference in early all-cause mortality, myocardial infarction, cerebrovascular events, hypotension and bradycardia. However, there may be a reduction in atrial fibrillation and ventricular arrhythmias when beta-blockers are used. A larger sample size is likely to increase the certainty of this evidence. Four studies awaiting classification may alter the conclusions of this review.