BACKGROUND: The most common surgical procedure for breast cancer is the modified radical mastectomy (MRM), but it is associated with significant postoperative pain. Regional anesthesia can reduce the stress response associated with surgical trauma.
OBJECTIVES: Our aim is to explore the efficacy of 1 µg/kg dexmedetomedine added to an ultrasound (US)-modified pectoral (Pecs) block on postoperative pain and stress response in patients undergoing MRM.
STUDY DESIGN: A randomized, double-blind, prospective study.
SETTING: An academic medical center.
METHODS: Sixty patients with American Society of Anesthesiologists (ASA) physical status I-II (18-60 years old and weighing 50-90 kg) scheduled for MRM were enrolled and randomly assigned into 2 groups (30 in each) to receive a preoperative US Pecs block with 30 mL of 0.25% bupivacaine only (group 1, bupivacaine group [GB]) or 30 mL of 0.25% bupivacaine plus 1 µg/kg dexmedetomidine (group II, dexmedetomidine group [GD]). The patients were followed-up 48 hours postoperatively for vital signs (heart rate [HR], noninvasive blood pressure [NIBP], respiratory rate [RR], and oxygen saturation [Sao2]), visual analog scale (VAS) scores, time to first request of rescue analgesia, total morphine consumption, and side effects. Serum levels of cortisol and prolactin were assessed at baseline and at 1 and 24 hours postoperatively.
RESULTS: A significant reduction in the intraoperative HR, systolic blood pressure (SBP), and diastolic blood pressure (DBP) starting at 30 minutes until 120 minutes in the GD group compared to the GB group (P < 0.05) was observed. The VAS scores showed a statistically significant reduction in the GD group compared to the GB group, which started immediately up until 12 hours postoperatively (P < 0.05). There was a delayed time to first request of analgesia in the GD group (25.4 ± 16.4 hrs) compared to the GB group (17 ± 12 hrs) (P = 0.029), and there was a significant decrease of the total amount of morphine consumption in the GD group (9 + 3.6 mg) compared to the GB group (12 + 3.6 mg) (P = 0.001). There was a significant reduction in the mean serum cortisol and prolactin levels at 1 and 24 hours postoperative in the GD patients compared to the GB patients (P < 0.05).
LIMITATIONS: This study was limited by its sample size.
CONCLUSION: The addition of 1 µg/kg dexmedetomidine to an US-modified Pecs block has superior analgesia and more attenuation to stress hormone levels without serious side effects, compared to a regular Pecs block in patients who underwent MRM.
KEY WORDS: Postoperative pain, dexmedetomidine, Pecs block, stress response, breast surgery.
Really good article.
The decrease pain scores and morphine use in the study group may have been simply due to the sedative properties of dexmedetomidine. The patients in the GD group did seem to have more sedation and nausea. This information may be useful for anesthesiologists if they are considering adding dexmedetomidine to their regional anesthetics.
This is a double blinded RCT on the effect of adding dexmedetomidine 1 microg/kg to a pectoral block with bupivacaine for radical mastectomy. Dexmedetomidine seemed to improve pain until 12h after surgery and decreases total morphine consumption, and delay first analgesic request. Stress hormones determinations (cortisol, prolactine, only 3 measurements) showed no increase in the study group. Methods considerations: -Blinding details were insufficiently reported. -Intraoperative hemodynamic parameters decreased in the study group, but the actual figures are not reported. -The authors did not provide the range of the time of first analgesia request (but the mean, SD) and the data seemed to long for the half life of the local anesthetic (25.4h and 17h respectively). No NSAIDs were used. No PONV prevention was offered, and near 30-40% of patients had nausea/vomiting. In some countries and by some medications agencies, the use of dexmedetomidine by this route of administration is not allowed.
Small series but is in keeping with the opioid sparing and sedative aspects described for this drug.
Clinical information such as tumor size and lymph node status was lacking in this study.
Interesting study. Limits: Sample size calculation somewhat under-stable (which value of morphine was used as reference?). No IV group for dexmedetomidine to identify the mechanism. No discussion about the relationship between sedation and prolactin/cortisol levels (not only associated with pain).
As a breast surgeon, I think that loco-regional blocks represent a substantial improvement for breast cancer patients in terms of early recovery and post-operative pain control and the association of dexmedetomidine could further improve outcomes