ABC Blocks for Cardiac Surgery

A Comparison of the Analgesic Effects of Rectus Sheath and Transversus Thoracis Plane Blocks (ABC Blocks) Versus Saline Injection for Median Sternotomy: a Prospective, Randomized Controlled Trial.

This randomized blinded trial aims to evaluate the effect of parasternal intercostal and rectus sheath blocks ("anterior blocks for cardiac surgery" or ABC blocks) on postoperative recovery in patients undergoing median sternotomy for cardiac surgery. Subjects will be randomized to receive either local anesthetic (liposomal bupivacaine plus bupivacaine 0.25%) or saline sham block.

Study Overview

• Status: Withdrawn
• Conditions: Pain
• Intervention / Treatment: Drug: ABC block with bupivacaine/liposomal bupivacaine; Drug: ABC block with saline

Detailed Description

Subjects will be randomized on the morning of surgery to receive either "anterior blocks for cardiac surgery" or "ABC blocks" using 60 mL of local anesthetic mixture (20 mL of liposomal bupivacaine plus 40 mL of 0.25% bupivacaine) or a sham saline ABC block (60 mL). All subjects will receive standard of care anesthetic regimen for their cardiac surgery at the discretion of his/her attending anesthesiologist. 40 mL of the solution will be administered in the parasternal intercostal space, and 20 mL will be placed in the rectus sheath in the epigastric region.

For the parasternal blocks, a linear high frequency ultrasound probe will be placed parasagitally at the T2-3 level approximately 3cm lateral to the mid-sternum, and all relevant structures will be identified, including the pectoralis major muscle, internal intercostal muscle, ribs, pleura, and any vasculature, including the internal mammary artery and vein. Color Doppler will be used confirm the location of vasculature.

After skin local anesthetic infiltration, a 10 cm 21G insulated block needle (Sonoplex, Pajunk Medical Systems, Norcross, GA) will be inserted from the inferior aspect of the ultrasound probe in a caudal to cranial direction and aligned with the ultrasound scanning plane (in-plane approach). In this way, both the needle shaft and tip can be visualized as the needle approaches the plane between the pectus major and intercostal muscles. The needle will be redirected as needed. Once satisfactory position of the needle time is confirmed and after frequent negative aspiration, 10 mL of study solution will be slowly injected. This injection will be repeated at the T4-5 interspace. Spread of local anesthetic will be documented in the appropriate plane in real time. This procedure will be performed bilaterally.

For the rectus sheath blocks, a linear high frequency ultrasound probe will be placed in a transverse position in the midline, just inferior to the xiphoid process. The probe will be moved laterally to visualize the lateral edge of the rectus abdominis muscle. A 10 cm 21G insulated block needle will be inserted from the lateral aspect of the ultrasound probe in a lateral to medial direction until visualized deep to the muscle immediately adjacent to the posterior rectus sheath. After negative aspiration, 10 mL of study solution will be slowly injected into this plane. This procedure will then be repeated on the contralateral side

All nerve blocks will be performed by a trainee supervised by an anesthesiologist experienced in regional anesthesia. The anesthesiology team and in the OR will be blinded to group allocation.

Subjects will receive a general anesthetic consistent with standard of care for cardiac surgeries at the discretion of his/her attending anesthesiologist. At the conclusion of the case, subjects will be extubated and/or transported to the ICU intubated. The decision to extubate the subject in the OR will be made at the discretion of the attending anesthesiologist.

Evaluation of acute postoperative pain intensity using a 0-10 visual analog scale (VAS) and opioid consumption will be undertaken at the following time points:

• 24 hours postoperatively
• 48 hours postoperatively Review of the medical chart will be made post-operatively to gather other data, including total intraoperative oral morphine equivalent consumption, cumulative opioid consumption at 48 hours, time to tracheal extubation, ICU length of stay, hospital length of stay, and time to first session with physical therapy. Occurrences of any adverse events reported by the subject or medical team will also be collected.

• Study Type: Interventional
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Durham, North Carolina, United States, 27705
      • Duke University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Subjects scheduled for elective cardiac surgery involving primary median sternotomy
• Age 18-85 years of age
• BMI 18-50 kg/m2

Exclusion Criteria:

• Left ventricular ejection fraction (LVEF) < 30%
• Preoperative, intraoperative, or immediate post-operative placement of intra-aortic balloon pump or deployment of extra-corporeal membrane oxygenation (ECMO)
• Inability to understand or speak English
• Allergy to amide local anesthetic
• Contraindication to peripheral nerve block (e.g. local infection, previous trauma to the block site)
• Chronic opioid consumption (daily oral morphine equivalent of >20 mg) in the past three months
• Severe pulmonary disease
• Neurological deficit or disorder
• Suspected or known addition to or abuse of illicit drug(s), prescription medicine(s), or alcohol within the past two years
• Uncontrolled anxiety, schizophrenia, or other severe psychiatric disorder

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: ABC block with bupivacaine and liposomal bupivacaine; The study solution used in the active arm will comprise 20 mL of liposomal bupivacaine (266 mg) admixed with 40 mL of 0.25% bupivacaine HCl. The solution will be administered as bilateral parasternal blocks (40 mL) and bilateral epigastric rectus sheath blocks (20 mL).	Drug: ABC block with bupivacaine/liposomal bupivacaine; Patients will be randomized to receive an ABC block using bupivacaine/liposomal bupivacaine solution
Sham Comparator: ABC block with saline; The study solution used in the active arm will comprise 60 mL of 0.9% saline. The solution will be administered as bilateral parasternal blocks (40 mL) and bilateral epigastric rectus sheath blocks (20 mL).	Drug: ABC block with saline; Patients will be randomized to receive an ABC block using normal saline

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative opioid consumption from extubation to 24 hours post-extubation	Morphine equivalents administered between extubation and 24 hours post-extubation	Extubation to 24 hr post-extubation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Worst pain at rest at 2 hours post-extubation	Pain intensity as measured on Numeric Pain Rating Scale (NRS-11) at 2 hours post-extubation. The NRS-11 ranges from '0' (no pain) to '10' (worst pain imaginable).	2 hours post-extubation
Worst pain at rest at 6 hours post-extubation	Pain intensity as measured on Numeric Pain Rating Scale (NRS-11) at 6 hours post-extubation. The NRS-11 ranges from '0' (no pain) to '10' (worst pain imaginable).	6 hours post-extubation
Worst pain at rest at 24 hours post-extubation	Pain intensity as measured on Numeric Pain Rating Scale (NRS-11) at 24 hours post-extubation. The NRS-11 ranges from '0' (no pain) to '10' (worst pain imaginable).	24 hours post-extubation
Worst pain at rest at 48 hours post-extubation	Pain intensity as measured on Numeric Pain Rating Scale (NRS-11) at 48 hours post-extubation. The NRS-11 ranges from '0' (no pain) to '10' (worst pain imaginable).	48 hours post-extubation
Cumulative opioid consumption from extubation to 48 hours post-extubation	Morphine equivalents administered between extubation and 48 hours post-extubation	Extubation to 48 hr post-extubation
Time from end of case to tracheal extubation	Time from end of surgical case (as defined by nursing record) until tracheal extubation	End of operative case until patient extubated, up to 24 hours
ICU length of stay	Duration of time spent in cardiothoracic ICU from admission to discharge	Postoperative from admission to ICU to discharge to floor, approximately 3 days
Time to first session of physical therapy (PT)	Time from ICU admission until first session of physical therapy	0-48 hours after surgical procedure

Collaborators and Investigators

• Sponsor: Duke University
• Investigators: Principal Investigator: Michael Manning, MD, Duke University

Study record dates

Study Major Dates

• Study Start (Estimated): November 1, 2024
• Primary Completion (Estimated): July 1, 2025
• Study Completion (Estimated): July 1, 2025

Study Registration Dates

• First Submitted: September 28, 2022
• First Submitted That Met QC Criteria: October 18, 2022
• First Posted (Actual): October 21, 2022

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 23, 2025
• Last Verified: March 1, 2024

More Information

Terms related to this study

• Keywords: Pain management; Anesthesia; Heart surgery
• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Peripheral Nervous System Agents; Anesthetics, Local; Anesthetics; Central Nervous System Depressants; Sensory System Agents; Bupivacaine
• Other Study ID Numbers: Pro00104058

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No