Bilateral erector spinae plane blocks in children undergoing cardiac surgery: A randomized, controlled study.
This small, randomized control study of 40 patients investigated the utility of erector spinae plane blocks (ESPB) in paediatric sternotomy for cardiac procedures. The primary outcome was cumulative morphine consumption in the first 24 hours post-operatively. Secondary outcomes included pain & sedation, time to extubation and ICU length of stay.
The mean age of patients presenting for cardiac surgery was 6 years (range 2 – 10 years), with procedures limited to ASD or VSD closures & aortic membrane excision. Notably the duration of surgery was significantly longer in the ESPB group, and this group also received 2 microg/kg more fentanyl than the control group despite an apparent set timing and dose protocol for the administration of Fentanyl intra-op. This was not significant, but no explanation was offered in the paper either.
Strengths and weaknesses
Strengths of the study included that there were only 2 people experienced with performing ESPB doing the blocks in a standardized manner. The assessor measuring pain scores in the first 24 hours was blinded. Blocks were performed at a standardized period in the perioperative journey (prior to surgery & after induction of anaesthesia).
Weakness of the study were the small number of patients included and no explanation as to why 2 patients were excluded. There was no assessment of dermatomes in any patient postoperatively, and despite following up patients until discharge, assessment of morphine consumption stopped at 24 hours.
As a primary outcome, the authors demonstrated a significant reduction (p=0.043) in rescue morphine (mg/kg) dosing, administered as 0.05 mg/kg boluses to a MOPS score of >4, in the first 24 hours post-operatively. The was no difference in any of the secondary outcomes listed above.
The authors acknowledge that this is a small study and suggest that further larger trials are required to determine whether the block is effective in reducing pain scores and opioid consumption post-operatively following cardiac surgery in paediatric patients. One of the arguments the authors list for performing the ESPB is as part of an ERAS program to reduce PONV because of reduced opioid consumption. There was no difference in rates of PONV between the groups, a point acknowledged by the authors, but perhaps the difference in opioid consumption, although statistically significant, fails to make a clinical difference as demonstrated by no reduction in any of the secondary clinical outcomes or PONV. The discussion also highlights that there have been both positive and negative trials previously published in the area of plane blocks performed for sternotomy procedures.
Reviewed by Dr Neil Hauser