Krishna SN, Chauhan S, Bhoi D, Kaushal B, Hasija S, Sangdup T, Bisoi AK. Krishna SN, et al. J Cardiothorac Vasc Anesth. 2019 Feb;33(2):368-375. doi: 10.1053/j.jvca.2018.05.050. Epub 2018 Jun 4.J Cardiothorac Vasc Anesth. 2019. PMID: 30055991 Clinical Trial.
Take Home Points:
- Postoperative pain management following pediatric cardiac surgery is largely dependent on parenteral opioid medications. Novel regional anesthetic techniques offer the promise of improved postoperative pain with reduced opioid consumption.
- The authors conducted a single-center, single-blind, randomized controlled trial of preoperative erector spinae plane blocks compared to standard medical management. They found improved pain scores in the first 10 hours post-extubation, lower overall fentanyl consumption in the first 12 hours, longer time to first rescue analgesia, and lower sedation scores.
- The study is limited by the fact that it includes only otherwise healthy patients undergoing relatively simple cardiac surgeries, and who were extubated in the immediate post-operative period. Though the results demonstrated statistically significant differences in the outcomes measured, their clinical relevance and generalizability remains unclear.
Commentary by Richard Hubbard, MD and Nischal Gautam, MD, pediatric cardiac anesthesiologists at the McGovern Medical School/Children’s Memorial Hermann Hospital in Houston, Texas.
For anesthesiologists caring for children with congenital heart disease (CHD), the challenge of balancing adequate analgesia with over sedation in the acute postoperative period is well-known. Neuraxial anesthesia can significantly improve pain control, lower opioid requirements, and improve respiratory function; however, the specter of epidural hematoma in patients requiring full anticoagulation for surgery is a major concern.1 Paravertebral blocks are a valid alternative, but they carry the risk of pneumothorax.2 Fascial plane blocks offer the benefit of an improved safety profile while still providing significant analgesia for major thoracic, abdominal, pelvic, and lower extremity surgery.
The erector spinae block (ESB) is one such technique. Utilizing ultrasound guidance, local anesthetic is deposited deep to the erector spinae muscle and superficial to the transverse process.3 The resulting multi-dermatomal sensory block is believed to be caused by migration of local anesthetic to the paravertebral space, blocking the dorsal and ventral rami of the spinal nerves.3,4 Both single-shot and catheter-based techniques have been described.3-5 The ESB has been used with success in pediatric patients undergoing major thoracic, abdominal, and even lower extremity procedures.3,5,6 It has also shown promise in reducing postoperative pain following sternotomy for cardiac surgery in adults.2,7
Kaushal and colleagues attempted to determine if presurgical single-shot, bilateral ESBs were effective in reducing postoperative pain and sedation in pediatric patients undergoing cardiac surgery via midline sternotomy. This was a single-center, randomized, observer-blinded study. Exclusion criteria included the following: need for redo or emergency surgery, intubation for three or more hours postoperatively, ASA class III and above, heart failure, inotropic support requirement, history of ventricular arrhythmias, and allergy to amide anesthetics. Patients were randomized into a control group (scheduled intravenous (IV) acetaminophen and rescue fentanyl) and a block intervention group (bilateral ESBs plus scheduled IV acetaminophen and rescue fentanyl). The blocks were conducted with ultrasound guidance at the T3 level, with 1.5 mg/kg of 0.2% ropivacaine deposited on each side. Outcomes included pain scores using the Modified Objective Pain Scale (MOPS) for the first 12 hours postoperatively, intraoperative and postoperative fentanyl requirements, time to first rescue analgesic medication, extubation time, Ramsay sedation score, intensive care unit (ICU) length of stay, and adverse events. The MOPS grades crying, movement, agitation, posture, and verbal for a maximum of 10 points (0-2 points per category). To provide a perspective on the pain assessment using this scale, the following patients could be graded as such:
- An asleep, calm, comfortable child is graded 0
- A consolable, restless, mildly agitated child is graded 3
- A consolable, restless, mildly agitated child complaining of non-localizing pain is graded 4
- A consolable, restless, mildly agitated child complaining and localizing pain is graded 6
- A non-consolable, thrashing, hysterical child, localizing pain with breath-holding is graded 10.
Out of 100 patients recruited, 80 met inclusion criteria, and 40 patients were included in each control and block group. Groups were similar in terms of patient age (just over two years), surgery type (mix of atrial septal defect (ASDs) and ventricular septal defect (VSDs)), and short bypass and cross clamp times (approximately 40 and 20 minutes, respectively). Statistically, the block group had lower pain scores up to (but not including) 12 hour after extubation, longer time to rescue analgesia, lower postoperative fentanyl requirement, lower sedation scores, and shorter ICU length of stay.
Clinically, the most impressive differences between the two groups was that while all the patients in the control group received fentanyl within 12 hours after extubation, 30% of patients in the block group did not receive any fentanyl during this period. The block group also had a longer period free from the first analgesic rescue (1.8 hrs. vs 4.5 hrs.) and had a lower fentanyl requirement (1.1 versus 5.5μg/kg). Within the first 12 hours after extubation, none of the patients in either group were noted to have a pain score of more than 5, indicating good pain control with either therapy. There were no differences seen in major postoperative complications.
What This Means for Our Practice
The authors showed that single-shot, bilateral ESBs reduced opioid requirements with slightly lower pain scores in the initial postoperative period. Although pain scores were lower in the block group, the efficacy of the block lasted for only 10 hours. This may be explained by the limited duration of action of single-shot fascial plane blocks when compared to indwelling catheters. A major critique of this work is its generalizability to the majority of pediatric patients presenting for congenital heart surgery. The exclusion criteria essentially eliminated all but the healthiest patients, and the surgeries performed were the simplest and fastest cardiopulmonary bypass cases performed in children. While the authors in this study show that single-shot ESBs appear to be helpful in patients who will be fast-tracked for extubation their validity for post-sternotomy pain in a diverse group of patients, particularly those with borderline cardiopulmonary reserve (cyanotic patients for Glenn, Fontan procedure), requires significantly more investigation before it can be adopted broadly. This block may have limited utility in more complex, longer duration procedures in which children are likely to require continued intubation in the immediate postoperative period. Many of these less complex cardiac lesions can be corrected without the need for a sternotomy, either via device closure in the catheterization laboratory or via a minimally invasive approach, which may also limit the utility of the ESB. Additionally, outcomes 12 hours after the procedure and other metrics until hospital discharge were not presented in the manuscript.
The ESB remains a promising modality to prevent post-sternotomy pain. The attractiveness of the block is the ease of its performance under ultrasound guidance. The target is easy to visualize, fast to perform, and the needle trajectory is straightforward. In addition, the risk of injury to nerves, dura, pleura, lungs, or vascular structures is minimal, as none of these structures are in the needle path or adjacent to the plane of injection. The idea of bilateral erector spinae continuous block with dual catheters for longer analgesia in post-sternotomy pain is promising, and provides an avenue for future research in this area.
- Rosen D, Hawkinberry D, Rosen K, et al. An epidural hematoma in an adolescent patient after cardiac surgery. Anesth Analg. 2004; 98(4): 966-969.
- Muñoz-Leyva F, Chin J, Mendiola W, et al. Bilateral Continuous Erector Spinae Plane (ESP) Blockade for Perioperative Opioid-Sparing in Median Sternotomy. J Cardiothorac Vasc An. 2019; 33(6): 1698-1703.
- Muñoz, F., Cubillos, J., Bonilla, A.J. et al. Erector spinae plane block for postoperative analgesia in pediatric oncological thoracic surgery. Can J Anesth/J Can Anesth 2017; 64: 880–882.
- Kaushal B, Chauhan S, Magoon R, Krishna NS, et al. Efficacy of bilateral erector spinae plane block in management of acute postoperative surgical pain after pediatric cardiac surgeries through a midline sternotomy. J Cardiothorac Vasc An. 2020; 34: 981-986.
- De la Cuadra-Fontaine JC, Concha M, Vuletin F, Arancibia H. Continuous Erector Spinae Plane block for thoracic surgery in a pediatric patient. Paediatr Anaesth. 2018; 28(1): 74-75.
6.Munshey F, Caruso T, Wang E, Tsui B. Programmed Intermittent Bolus Regimen for Erector Spinae Plane Blocks in Children: A Retrospective Review of a Single-Institution Experience. Anesth Analg. 2020; 130(3): e63-e66.
- Krishna NS, Chauhan S, Bhoi D, et al. Bilateral Erector Spinae Plane Block for Acute Post-Surgical Pain in Adult Cardiac Surgical Patients: A Randomized Controlled Trial. J Cardiothorac Vasc An. 2019; 33: 368-375