Opioid-sparing effect of Continuous Erector Spinae Plane Block in Robotic Cardiac Surgery: Preliminary Results of a Randomized Clinical Trial

Objective

Robotic cardiac surgery (RCS) has been demonstrated to be feasible and safe by many groups. Several studies reported better outcomes of RCS (lower complication rate, reduced length of stay, improved quality of life) compared to non-robotic technique In minimally invasive cardiac surgery locoregional aneasthesia (LRA) has been demonstrated to improve postoperative pain control. Specific to RCS, the optimal LRA technique has yet to be determined. Erector spinae plane (ESP) block is an easy-to-perform technique that can provide an adequate pain control in chest surgery, reducing the postoperative dose of opioids.

The aim of the present study is to assess the beneficial effects of continuous unilateral ESP block in the management of the postoperative pain after RCS.

Design and method

Design

A randomized controlled trial.

Setting

Single-center, university tertiary-care institution.

Participants

Patients undergoing non-coronary robotic-assisted cardiac surgery.

Interventions

Patients were randomized to the “ESP” group, receiving an ESP block (intraoperative loading dose of 20 ml followed by continuous infusion of ropivacaine 0.2% for 24 hours) versus “control” group, receiving conventional perioperative pain management (continuous infusion of intravenous morphine). In addition, all patients received multimodal analgesia including acetaminophen, dexamethasone and patient-controlled analgesia with intravenous morphine.

Measurements

The primary outcomes were morphine consumption at 12 and 24 hours, as well as the total postoperative dose. The secondary outcomes were pain scores on a Numeric Rating Scale (NRS) at 6, 12, 24, and 48 hours after surgery.

Results and conclusions

Main Results

Fifty-four patients were randomized. However, 24 patients were withdrawn from the trial for various reasons. The main reasons included inability to assess analgesia (n=5), seizures (n=3), and other issues (n=16), such as catheter dysfunction or removal, reconversion to sternotomy, and postoperative bleeding. The data from the remaining 30 patients were analysed appropriately.

ESP block was successfully performed in all patients in the intervention group without observing any perioperative adverse effects. In comparison with the control group, a trend of lower opioid consumption was observed in the ESP group, with a significant difference in morphine use 12 hours after surgery (p = 0.049, Table 1 and Figure 1). No difference was observed in postoperative pain scores measured by the NRS (Table 2 and Figure 2).

Table 1: Comparison of the postoperative opioid consumption between ESP group and control group. Data expressed as median (interquartile range).

Figure 1: Box-plot representing the data of Table 1.

Table 2: Comparison of the postoperative pain between ESP group and control group. Data expressed as median (interquartile range).

Figure 2: Box-plot representing the data of Table 2.

Conclusion

In RCS continuous ESP block is a safe and feasible, providing an adequate pain relief. Compared to conventional multimodal analgesia, this technique can improve perioperative pain management decreasing opioid consumption, especially during the first postoperative period. If validated by the analysis of the complete study sample, these preliminary findings suggest that continuous ESP block could be considered an affordable opioid-sparing strategy in patients undergoing RCS.