Pectoral Nerve Blocks for Breast Augmentation Surgery

A Randomized, Double-Blind, Dual-Centered Controlled Trial

Yassir Aarab, M.D., M.Sc.; Severin Ramin, M.D., M.Sc.; Thomas Odonnat, M.D.; Océane Garnier, M.Sc.; Audrey Boissin, M.Sc.; Nicolas Molinari, Ph.D.; Grégory Marin, Ph.D.; Pierre-Francois Perrigault, M.D.; Philippe Cuvillon, M.D., Ph.D.; Gérald Chanques, M.D., Ph.D.

Disclosures

Anesthesiology. 2021;135(3):442-453. 

In This Article

Results

Among 136 patients scheduled for breast augmentation surgery and assessed for eligibility, 74 patients were enrolled and randomly assigned to one of the two groups. Enrollment ceased when the target sample size of 72 patients who were analyzable for the primary outcome was obtained. One patient withdrew her consent after randomization. No data were recorded, and this patient was excluded according to French law (Figure 1).[31] Finally, 73 patients were included in the final intent-to-treat analysis. We observed four protocol deviations: one patient who was enrolled despite a surgery for prosthesis change, and three patients who received an unplanned subcutaneous infiltration of local anesthetic by the surgeon at the end of surgery. Thus, intent-to-treat analysis was performed on 73 patents, and per-protocol analysis was performed on 69 patients.

Figure 1.

Consolidated Standards of Reporting Trials diagram showing flow of study participants. n = 136 met eligibility for study, with n = 74 being recruited and randomized. One patient withdrew consent in the pectoral nerve block group after randomization but before anesthesia and surgery.

Numerical rating scale scores (primary outcome) were obtained for all patients. Out of 511 planned measurements (73 patients × 7 assessments) for the primary outcome, we have 46 missing data. All patients had at least four pain assessments; all missing data were framed by two 0-to-10 numerical rating scale assessments and occurred after discharge from the PACU. For a priori secondary outcomes recorded on day 1 (hour 6 to day 1 period), we had no missing data. According to secondary outcomes recorded at day 5 (day 1 to day 5 period), 12 individuals had missing data (could not be reached by phone).

The maximal numerical rating scale score in the first 6 h after extubation (primary outcome measure) was statistically significant between groups (3.9 [± 2.5] for PECS group vs. 5.2 [± 2.2] for control group; P = 0.036; absolute difference, −1.2 [–2.3 to −0.1]; Table 2). The mean numerical rating scales recorded every 30 min for 2 h and then every 2 h until hour 6 are shown in Figure 2. Comparisons by analysis of repeated measures revealed that pain scores during the first postoperative 6 h were statistically lower in the PECS group (P = 0.044). The maximal difference between both groups was found before the first hour after extubation.

Figure 2.

Line graph with mean (SD) of numerical rating scale for pain at rest on the y axis over time (h) on the x axis. The means (SDs) of the pectoral nerve block and control groups are represented. The mixed model shows that, regardless of the group, the numerical rating scale changes significantly over time (P < 0.001). Likewise, considering all times overall, the two groups have significantly different numerical rating scale values (P = 0.044), with the graph showing lower values for pectoral nerve block patients. On the other hand, the evolution of the numerical rating scale over time is not different between the two groups (the interaction term is not significant, P = 0.817).

Regarding the a priori secondary outcomes measured after the surgery, the time before first rescue analgesic and cumulative amount of overall opioids consumption (oral morphine equivalent) during these 6 h were not different (37 min [15 to 61] vs. 31 min [26 to 60]; P = 0.644; absolute difference, 6.0 [–4.0 to 11.0]) and 9.0 mg [0.0 to 15.0] vs. 12.0 mg [0.0 to 30.0]; P = 0.201; absolute difference, −3.0 [–12.0 to 0.0]), respectively, in the PECS group and in the control group (Figure 3). During the "hour 6 to day 1" period (6 h after extubation to surgeon's consultation), the maximal numerical rating scale was not statistically significant (4.5 [± 2.1] vs. 5.3 [± 2.2]; P = 0.159; absolute difference, −0.7 [–1.7 to 0.3]; Table 2), but the PECS group had statistically lower opioid consumption (0.0 mg [0.0 to 21.0] vs. 21.0 mg [0.0 to 31.5]; P = 0.006; absolute difference, −10.5 [–21 to 0.0]; Figure 3). During the "day 1 to day 5" period (from surgeon's consultation to phone interview), the maximal numerical rating scale and opioid consumption were lower in the PECS group (2.2 [± 1.9] vs. 3.2 [± 1.7]; P = 0.032; absolute difference, −0.9 [–1.8 to −0.2] and 0.0 mg [0.0 to 21.0] vs. 21.0 mg [0.0 to 51.0]; P = 0.002; absolute difference, −21 [–30 to −15.0]), respectively, when compared with the control group (Table 2; Figure 3). Regarding opioid-related side effects, there was no statistically significant difference between the groups for postoperative nausea and vomiting, pruritus, or constipation at all time points (Table 3).

Figure 3.

Equivalent morphine consumption (mg) on the y axis over time (h) on the x axis. The medians are represented by boxes, and the upper 75th percentile is represented by the upper bar. The difference between groups was significant for the periods from hour 6 to day 1 and from day 1 to day 5. *Statistically significant, P < 0.05.

Patient satisfaction was very good in both groups (8.5 [8.0 to 9.0] for the PECS group vs. 8.0 [7.0 to 8.0] for the control group; P = 0.052). The proportion of patients with at least good satisfaction (numerical scale of more than 7 of 10) was statistically higher in the PECS group (P = 0.044; Table 3).

Regarding other a priori outcomes related to anesthesia and surgery, remifentanil effect-site target concentration during surgery was statistically lower in the PECS group (2.5 ng/ml [2.0 to 2.9] vs. 3.0 ng/ml [2.5 to 3.5], P < 0.004; absolute difference, −0.5 [–0.9 to −0.2]). There was no statistically significant difference between the groups with respect to heart rate, systolic or mean arterial pressure, and use of vasopressors (ephedrine and neosynephrine; Table 3). No PECS block-related complications, such as pneumothorax, vascular puncture, or local anesthetic toxicity, were recorded. One patient in the PECS group had a surgery- related postoperative hematoma requiring surgical intervention at the first hour after extubation.

Finally, a per-protocol analysis was performed including 69 patients among 73. Similar results were found for the primary outcome (maximal numerical rating scale in the first 6 h after extubation): (4.0 [± 2.5] vs. 5.3 [± 2.2]; P = 0.034; absolute difference, −1.2 [–2.4 to −0.1]). Similar results were also found for the mean numerical rating scale recorded every 30 min for 2 h and then every 2 h until hour 6 (P = 0.023). The maximal numerical rating scales from hour 6 to day 1 and from day 1 to day 5 were lower in the PECS group, but the difference was not significant (4.6 [± 2.1] vs. 5.4 [± 2.2]; P = 0.121; absolute difference, −0.8 [–1.9 to 0.2]) and (2.4 [± 1.8] vs. 3.1 [± 1.8]; P = 0.086; absolute difference, −0.7 [–1.6 to 0.2]), respectively. Maximal remifentanil site effect (2.5 ng/ml [2.0 to 2.9] vs. 3.0 ng/ml [2.5 to 3.5]; P = 0.004; absolute difference, −0.5 [–0.9 to −0.2]) and opioid consumption in oral morphine equivalent from hour 6 to day 1 (0.0 [0.0 to 21.0] vs. 21.0 [5.25 to 35.25]; P = 0.004; absolute difference, −10.5 [–21.0 to 0.0]) and from day 1 to day 5 (0.0 [0.0 to 21.0] vs. 21.0 [10.5 to 51.0]; P = 0.002; absolute difference, −21.0 [–31.5 to 0.0]) were all statistically significantly lower in the PECS group, whereas opioid consumption in the first 6 h was not (9.0 [0.0 to 15.0] vs. 12.0 [0.0 to 30.0]; P = 0.086; absolute difference, −3.0 [–12.0 to 0.0]), as for the intention-to-treat analysis.

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