Deep Parasternal Intercostal Plane Block Versus Erector Spinae Plane Block in Pediatric Cardiac Patients Undergoing Primary Repair of Septal Defects Via Median Sternotomy

Pediatric cardiac surgery involving median sternotomy can be associated with significant postoperative pain. Poorly controlled pain following cardiac surgery has been shown to be a risk factor for increased morbidity, including severe cardiopulmonary dysfunction, hypercoagulability, and immunosuppression.

Post-operative pain management, which provides effective analgesia, minimizes side effects and contributes to enhanced recovery after surgery, is a unique challenge in the pediatric cardiac surgery population. The ideal post-operative analgesic regimen would enable early separation from mechanical ventilation, decrease opioid consumption, and expedite discharge from the intensive care unit.

Systemic opioids and non-steroidal anti-inflammatory drugs have been the mainstay for treating pain during the perioperative period in children undergoing median sternotomy for cardiac surgery. The traditional high-dose opioid approach is associated with a decreased stress response but at the expense of prolonged mechanical ventilation, and increased opioid-related side effects. NSAIDs are effective as part of a multimodal analgesic approach, but their use can be limited due to concerns regarding coagulopathy or impairment of renal function.

Regional anesthesia is becoming increasingly popular in pediatric cardiac surgery for its opioid sparing effects. By blocking the afferent impulses from surgical sites, the need for supplemental opioids is reduced. Neuraxial catheters, while effective, are often not utilized in the setting of full heparinization and coagulopathy due to the small yet significant risk of epidural hematoma formation. Paravertebral blocks have similar risk and side effect profiles to neuraxial catheters and require blocks to be performed bilaterally with a posterior approach. Truncal blocks such as erector spinae plane blocks, as well as superficial and deep parasternal blocks, have been shown to provide adequate pain relief for cardiac surgery, and have been gaining popularity.

Appropriate pain relief from a sternotomy incision can be achieved by blocking the second to sixth thoracic intercostal nerves. The newer ultrasound-guided deep parasternal block (previously known as transversus thoracic muscle plane block, involves deposition of a local anesthetic between the internal intercostal and transversus thoracic muscles and effectively blocks the anterior branches of intercostal nerves T2-6.

The recent American Association for Thoracic Surgery Congenital Cardiac Surgery Working Group 2021 consensus document on enhanced recovery after pediatric cardiac surgery gives mention to bilateral transversus thoracic muscle plane blocks (now deep parasternal block) as a regional anesthetic option with opioid-sparing effects but states that more data are needed to determine their efficacy.

On the other hand, Erector spinae plane block is an ultrasound- guided interfascial plane block that has been proposed for the management of thoracic pain. When applied bilaterally, ESPB has been demonstrated to provide effective analgesia at the selected dermatomes including the upper chest (T2-T4) and the mid-chest (T5-T7), which might be useful for postoperative analgesia after cardiac surgery.

In this study, we will compare the use of bilateral single injection deep parasternal blocks versus a second group receiving bilateral single injection erector spinae blocks in pediatric patients undergoing median sternotomy for cardiac surgery.