Analgesic Efficacy of Parasternal Block Versus Parasternal Plus Serratus Anterior Plane Block After Coronary Bypass Surgery

Evaluation of the Analgesic Efficacy of Parasternal Block and Parasternal Plus Serratus Anterior Plane Block in Patients Undergoing Coronary Artery Bypass Grafting Surgery

This single-centre randomized clinical trial will compare two regional anaesthesia techniques for postoperative pain control in adult patients undergoing elective coronary artery bypass grafting (CABG) with sternotomy. All patients will receive a bilateral parasternal block as part of routine multimodal analgesia. Patients will be randomized to receive either parasternal block alone or a combination of parasternal block and serratus anterior plane block. The primary objective is to evaluate whether adding a serratus anterior plane block improves postoperative pain scores compared with parasternal block alone. Secondary objectives include comparing opioid consumption, need for rescue analgesics, opioid-related side effects, and length of stay in the intensive care unit and hospital.

Study Overview

• Status: Completed
• Conditions: Coronary Artery Bypass Grafting
• Intervention / Treatment: Procedure: parasternal block; Procedure: parasternal block + serratus anterior plane block

Detailed Description

Background: Postoperative pain after coronary artery bypass surgery arises from both the sternotomy incision and the chest tube insertion sites and may impair mobilisation, deep breathing, and coughing. Fascial plane blocks of the chest wall, such as parasternal block and serratus anterior plane block, are increasingly used because they are technically simple and have a low complication risk. Previous observational data suggested that combining bilateral parasternal block and serratus anterior plane block provides effective analgesia after CABG, but sample size was small and no randomized comparison has been performed.

Objectives: The primary objective is to compare postoperative pain intensity between parasternal block alone and parasternal plus serratus anterior plane block in adult patients undergoing elective CABG with sternotomy. Secondary objectives are to compare total opioid consumption (tramadol via patient-controlled analgesia), need for rescue analgesics, incidence of opioid-related adverse events (e.g. nausea and vomiting), and intensive care unit and hospital length of stay between the two groups.

Methods: This is a prospective, randomized, parallel-group, low-risk interventional study conducted in the Anaesthesiology and Reanimation Department of Ankara Etlik City Hospital. Adult patients (≥18 years) scheduled for elective coronary bypass surgery due to coronary artery disease and classified as ASA II-IV will be screened for eligibility. After induction of general anaesthesia and before surgical incision, all patients will receive an ultrasound-guided bilateral parasternal block. Patients randomized to the experimental arm will additionally receive a bilateral serratus anterior plane block. Local anaesthetic dosing will follow routine clinical practice, with a total dose not exceeding 2 mg/kg of 0.25% bupivacaine. All patients will receive 40 ml of 0.25% bupivacaine. The parasternal group will receive a bilateral parasternal block via administering 20 ml of 0.25% bupivacaine bilaterally. The parasternal+serratus anterior plane block group will receive 10 ml of 0.25% bupivacaine to bilateral parasternal and deep serratus planes.

Pain intensity will be assessed using the Numeric Rating Scale (NRS, 0-10) at extubation (T0) and postoperative 4, 6, 12, and 24 hours (T4, T6, T12, T24). Postoperative analgesia will include standard intravenous acetaminophen and tramadol via patient-controlled analgesia; total tramadol dose (demand and delivered), rescue analgesic requirement, and adverse events will be recorded in the first 24 postoperative hours.

Sample size: Based on a two-group comparison with an effect size of 0.6, α = 0.0,5, and β = 0.2, 72 patients are required to achieve 80% power.

• Study Type: Interventional
• Enrollment (Actual): 72
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Ankara
    • Yenimahalle, Ankara, Turkey (Türkiye), 06810
      • Etlik City Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria

• Age ≥ 18 years
• American Society of Anesthesiologists (ASA) physical status III-IV
• Scheduled for elective coronary artery bypass grafting surgery with sternotomy for coronary artery disease
• Able to provide written informed consent

Exclusion Criteria

• Allergy or contraindication to local anaesthetic agents
• Minimally invasive bypass surgery or off-pump procedures planned
• Emergency cardiac surgery
• Preoperative Numeric Rating Scale (NRS) pain score ≥ 3
• Chronic opioid use in the preoperative period
• Infection or structural abnormality at planned block sites
• Any condition preventing postoperative pain assessment or PCA use (e.g. severe cognitive impairment)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Arm A: Parasternal Block; After induction of general anaesthesia and before skin incision, an ultrasound-guided bilateral parasternal intercostal plane block will be performed.	Procedure: parasternal block; After induction of general anaesthesia and before skin incision, an ultrasound-guided bilateral parasternal intercostal plane block will be performed. A linear ultrasound probe will be placed parasagittally at the 2nd and 4th intercostal spaces approximately 2-3 cm lateral to the sternum. A block needle will be advanced in-plane beneath the pectoralis major muscle and above the internal intercostal muscles, and local anaesthetic (0.25% bupivacaine) will be injected bilaterally. Total dose will not exceed 2 mg/kg. Postoperative systemic analgesia (patient-controlled analgesia) will be identical in both groups.
Experimental: Arm B: Serratus Anterior Plane Block; In addition to the bilateral parasternal block described for the comparator arm, patients randomized to the experimental arm will receive an ultrasound-guided bilateral serratus anterior plane block.	Procedure: parasternal block; After induction of general anaesthesia and before skin incision, an ultrasound-guided bilateral parasternal intercostal plane block will be performed. A linear ultrasound probe will be placed parasagittally at the 2nd and 4th intercostal spaces approximately 2-3 cm lateral to the sternum. A block needle will be advanced in-plane beneath the pectoralis major muscle and above the internal intercostal muscles, and local anaesthetic (0.25% bupivacaine) will be injected bilaterally. Total dose will not exceed 2 mg/kg. Postoperative systemic analgesia (patient-controlled analgesia) will be identical in both groups.; Procedure: parasternal block + serratus anterior plane block; In addition to the bilateral parasternal block described for the comparator arm, patients randomized to the experimental arm will receive an ultrasound-guided bilateral serratus anterior plane block. With the patient in supine position, the linear ultrasound probe will be placed over the 6th rib in the anterior axillary line. The needle will be advanced in-plane beneath the serratus anterior muscle and above the rib, and 0.25% bupivacaine will be injected into the fascial plane on each side. The combined total dose of local anaesthetic for both blocks will not exceed 2 mg/kg. Postoperative systemic analgesia will be identical in both groups.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Tramadol Consumption	Cumulative dose of tramadol (mg) delivered by patient-controlled analgesia (PCA) in the first 24 hours post-extubation	24-hour post-extubation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Resting Numeric Rating Scale (NRS) Pain Score	NRS score during rest (0= no pain, 10= worst imaginable pain)	24 hour post-extubation
Dynamic Numeric Rating Scale (NRS) Pain Score	NRS score during coughing or deep inspiration (0= no pain, 10= worst imaginable pain)	24-hour post-extubation

Collaborators and Investigators

• Sponsor: Dr Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital

Publications and helpful links

General Publications

• Zengin EN, Yigit H, Cobas M, Salman N, Asli Demir Z. The analgesic effects of combined bilateral parasternal block and serratus anterior plane block for coronary artery bypass grafting surgery. BMC Anesthesiol. 2024 Aug 5;24(1):274. doi: 10.1186/s12871-024-02659-7.

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2025
• Primary Completion (Actual): December 1, 2025
• Study Completion (Actual): January 1, 2026

Study Registration Dates

• First Submitted: December 10, 2025
• First Submitted That Met QC Criteria: December 10, 2025
• First Posted (Estimated): December 23, 2025

Study Record Updates

• Last Update Posted (Actual): January 13, 2026
• Last Update Submitted That Met QC Criteria: January 11, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: PS_SAPB

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data underlying the primary publication may be shared upon reasonable request to the principal investigator after publication of the results.
• IPD Sharing Time Frame: De-identified individual participant data underlying the primary publication may be shared upon reasonable request to the principal investigator after publication of the results.
• IPD Sharing Access Criteria: De-identified individual participant data underlying the primary publication may be shared upon reasonable request to the principal investigator after publication of the results.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No