Author: Ajai Raj
Anesthesiology News
The addition of clonidine and dexamethasone to paravertebral block (PVB) in cancer patients undergoing complex breast surgery resulted in “greater decreases in both opioid and antiemetic use” compared with PVB alone, according to preliminary findings.
Researchers from Memorial Sloan Kettering Cancer Center’s (MSKCC’s) Josie Robertson Surgery Center presented a retrospective review assessing the effect of adding clonidine and dexamethasone (C+D) to PVB compared with PVB alone in cancer patients undergoing mastectomy with immediate reconstruction (MTE) at their center between January and December 2017. Findings were presented at the 2018 annual meeting of the Society for Ambulatory Anesthesia (abstract 1844).
Outcome measures included:
- total intraoperative fentanyl;
- hours to first IV narcotic;
- postoperative nausea and vomiting (PONV) rescue;
- postoperative opioid consumption within the first 12 hours and until discharge, measured in morphine milligram equivalents (MMEs);
- hours to first ambulation; and
- length of stay.
Data from 421 MTE patients were analyzed, of whom 155 received PVB alone and 266 received PVB (C+D). All patients received general anesthesia with a multimodal analgesic and antiemetic regimen. Demographic characteristics, including age, ASA physical status and type of surgical procedure were similar between the two groups. All PVBs were placed under preoperative ultrasound guidance, and patients were given a total of 15 to 20 cc of 0.375% to 0.5% bupivacaine or ropivacaine. The PVB (C+D) group was given a total of 100 mcg of clonidine and 4 mg of dexamethasone sodium phosphate, split equally on either side in patients receiving a bilateral block.
The two groups were “significantly different” in terms of intraoperative fentanyl, postoperative MMEs, PONV rescue and time to ambulation, the authors noted. Patients in the PVB (C+D) group received a median of 100 mg of intraoperative fentanyl (100-175 mg), compared with 150 mg (100-200 mg) for patients in the PVB-alone group (P<0.001). The PVB (C+D) group also had lower postoperative opioid consumption than the PVB-alone group at the 24-hour mark (22.0 [95% CI, 7.5-33.9] vs. 26.5 MMEs [95% CI, 17.0-38.8]; P=0.006), as well as at 12 hours (P=0.006).
A smaller percentage of patients in the adjuvant group required PONV rescue (25.6% vs. 38.1%; P=0.01), and had a shorter median time to ambulation (5.9 [95% CI, 4.4-9.4] vs. 6.6 hours [95% CI, 4.8-12.4]; P=0.032). Length of stay did not differ significantly between the two groups. Analysis of a subgroup of patients (n=171) who specifically received a total IV anesthesia technique found that these patients “demonstrated significantly lower MMEs at all times (P=0.005),” the authors said.
Of Interest for Ambulatory Surgery Centers
Emily Lin, MD, MS, a regional anesthesiologist at MSKCC, in New York City, and the study’s first author, said, “While both of these adjuvants have been shown to extend analgesic duration in other nerve blocks, this combination has not yet been studied in the PVB compared to PVB alone. We know that PVB in patients undergoing complex breast surgery improves postoperative analgesia and enhances quality of recovery. We were therefore delighted to discover that an even greater reduction in narcotic consumption could be achieved from the PVB with the addition of clonidine and dexamethasone for ambulatory breast surgery.”
Given the retrospective nature of the analysis, Dr. Lin said further randomized controlled trials are necessary to assess optimal dose, route and contribution of clonidine and dexamethasone individually. “With that said, given the cost-effectiveness and safety of this intervention, other ambulatory surgery centers may want to consider incorporating these adjuvants into their practice,” she added. “This is especially true for those who do not have a catheter program in place for more complex breast surgeries in which the duration of postoperative pain can outlast the duration of the block.
“If prospective trials are confirmatory, these changes would be of particular value as we face both opioid shortages and a growing opioid epidemic,” Dr. Lin said.
Jeff Gadsden, MD, the chief of the Division of Orthopedic, Plastic and Regional Anesthesiology at Duke University Medical Center, in Durham, N.C., called the difference in opioid consumption between the two groups “compelling,” adding that he would like to see longer term data to this effect.
“Does the addition of these adjuvants affect not only early recovery outcomes but longer term outcomes as well? This is especially important in an era when we’re doing everything we possibly can to reduce or eliminate opioid use,” Dr. Gadsden said, echoing Dr. Lin’s comments.
“However,” he added, “even these early improvements in the recovery profile are reason enough to want to consider co-administering these medications with the local anesthetic when performing paravertebral blocks for these patients.”