Effect of Pre- and Postoperative ESP Block on Frontal QRS-T Angle in Laparoscopic Cholecystectomy

Harran University120 enrolled

Overview

This study aims to investigate the effects of preoperative and postoperative Erector Spinae Plane (ESP) block on the frontal QRS-T angle, a marker of cardiac electrophysiological instability, in patients undergoing laparoscopic cholecystectomy. A total of 120 patients aged 18-65 with ASA I-II status will be randomized into three groups: Control (no ESP), Preoperative ESP, and Postoperative ESP. Electrocardiograms (ECGs) will be obtained preoperatively and one hour postoperatively to assess changes in QRS-T angle and other repolarization parameters. This randomized controlled trial will help clarify the potential cardiac effects of ESP block depending on its timing and may provide insight into optimizing anesthetic safety in surgical patients.

Erector Spinae Plane (ESP) block is widely used in laparoscopic surgeries for postoperative pain control due to its simplicity and efficacy. However, its influence on the autonomic nervous system and subsequent cardiovascular effects, including changes in cardiac electrophysiological parameters, remains insufficiently understood. The frontal QRS-T angle has emerged as a novel and reliable ECG-derived marker associated with increased cardiac risk and ventricular repolarization heterogeneity. This prospective, randomized, controlled, single-center trial aims to evaluate the impact of ESP block timing on the frontal QRS-T angle. A total of 120 adult patients scheduled for elective laparoscopic cholecystectomy will be randomly assigned into three groups: Control group (no ESP block), Preoperative ESP block group, Postoperative ESP block group. Bilateral ESP blocks will be administered using 0.25% bupivacaine under ultrasound guidance at the T7 level. Standard general anesthesia will be applied to all patients. ECG recordings will be obtained preoperatively and at the first postoperative hour to calculate the frontal QRS-T angle, QT interval, QTc, Tp-e, Tp-e/QT, and Tp-e/QTc ratios. The primary outcome is the change in the frontal QRS-T angle. Secondary outcomes include pain scores (VAS), analgesic consumption, and other ECG-based repolarization markers. The findings may enhance perioperative cardiac risk stratification and inform decisions on the optimal timing of ESP block administration in surgical patients with potential cardiac vulnerability.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Interventions

Preoperative Erector Spinae Plane BlockPROCEDURE

This procedure involves bilateral ultrasound-guided erector spinae plane block at the T7 level using 20 mL of 0.25% bupivacaine per side (total 40 mL) before the induction of general anesthesia. The intervention aims to evaluate the effects of preoperative ESP block on changes in frontal QRS-T angle and other ECG-derived cardiac electrophysiological parameters.

Postoperative Erector Spinae Plane BlockPROCEDURE

Patients in this group will undergo standard general anesthesia. At the end of the surgery, bilateral ESP block will be performed under ultrasound guidance at the T7 level using 0.25% bupivacaine (20 mL per side, total 40 mL). The aim is to evaluate the effect of postoperative ESP block on changes in frontal QRS-T angle and other cardiac electrophysiological parameters.

Standard General AnesthesiaPROCEDURE

This group will receive standard general anesthesia without any additional regional block. ECG data will be collected preoperatively and 1 hour postoperatively to serve as a comparison for electrophysiological changes observed in the intervention groups.

BupivacaineDRUG

0.25% bupivacaine, 20 mL per side (total 40 mL), administered bilaterally at T7 level under ultrasound guidance as part of ESP block.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Age between 18-65 years * ASA physical status I-II * Scheduled for elective laparoscopic cholecystectomy * Voluntary written informed consent obtained * Normal preoperative 12-lead ECG (no conduction abnormalities or arrhythmias) Exclusion Criteria: * History of cardiac disease (e.g., arrhythmia, myocardial infarction, heart failure) * Current use of medications affecting cardiac conduction (e.g., antiarrhythmics, beta-blockers) * Known allergy to local anesthetics * Coagulation disorders or current anticoagulant therapy * Pregnancy or breastfeeding * Local infection or anatomical deformity at the ESP block injection site * Patients with psychiatric or neurological disorders impairing cooperation

Outcomes

Primary Outcomes

Change in Frontal QRS-T Angle Between Preoperative and Postoperative ECG

The primary outcome is the change in frontal QRS-T angle measured on 12-lead ECG before surgery (baseline) and 1 hour after laparoscopic cholecystectomy. This angle is a marker of ventricular repolarization heterogeneity and potential cardiac risk.

Time frame: From 1 hour before surgery to 1 hour after surgery

Secondary Outcomes

Change in QT Interval (QTc) Pre- and Postoperatively

The corrected QT interval (QTc) will be measured on 12-lead ECG before and 1 hour after surgery to evaluate changes in ventricular repolarization associated with ESP block.

Time frame: From 1 hour before surgery to 1 hour after surgery

Postoperative Pain Intensity Based on Visual Analog Scale (VAS)

Pain intensity will be assessed using the 10 cm Visual Analog Scale (VAS), ranging from 0 (no pain) to 10 (worst imaginable pain), at rest and during coughing at 2, 6, 12, and 24 hours postoperatively. Higher scores indicate worse pain.

Time frame: At 2, 6, 12, and 24 hours postoperatively