Results were published in BMC Anesthesiology from a study that compared plasma levobupivacaine concentrations with and without epinephrine following erector spinae plane (ESP) blocks for breast cancer surgery.
This was a prospective, double-blinded, randomized controlled trial by design that consisted of 29 patients who underwent elective unilateral partial mastectomy with sentinel lymph node biopsy. The patients were randomized to either group L (ESP block with 2 mg/kg levobupivacaine) or group LE (ESP block with 2 mg/kg levobupivacaine and 5 μg/mL epinephrine). The investigators acquired blood samples at 2.5, 5, 7.5, 10, 12.5, 15, 30, 60, and 120 minutes after the ESP block and compared their plasma concentrations of levobupivacaine.
The results showed that the 2 groups had no discernible differences in numerical rating scale scores immediately after extubation, 5 and 9 hours following the ESP block, nor in the interval from the ESP block to the first rescue analgesia. Moreover, the researchers noted that no patient developed symptoms suggestive of LAST.
“A single bolus of 2 mg/kg levobupivacaine in the ESP block resulted in a short Tmax with high Cmax. Adding epinephrine to levobupivacaine decreased the Cmax and delayed the Tmax after ESP blocks but had no effect on postoperative analgesia,” the researchers concluded.
Keywords: epinephrine, erector spinae plane block, plasma levobupivacaine concentrations