Bupivacaine Mandibular Nerve Block Affects Intraoperative Blood Pressure and Heart Rate in a Yucatan Miniature Swine Mandibular Condylectomy Model: A Pilot Study

Abstract

Purpose/Aim The primary objective was to evaluate the effect of a bupivacaine mandibular nerve block on intraoperative blood pressure (BP) and heart rate (HR) in response to surgical stimulation and the need for systemic analgesics postoperatively. We hypothesized that a mandibular nerve block would decrease the need for systemic analgesics both intraoperatively and postoperatively. Materials and Methods Fourteen adult male Yucatan pigs were purchased. Pigs were chemically restrained with ketamine, midazolam, and dexmedetomidine and anesthesia was maintained with isoflurane inhalant anesthesia. Pigs were randomized to receive a mandibular block with either bupivacaine (bupivacaine group) or saline (control group). A nerve stimulator was used for administration of the block with observation of masseter muscle twitch to indicate the injection site. Invasive BP and HR were measured with the aid of an arterial catheter in eight pigs. A rescue analgesic protocol consisting of fentanyl and lidocaine was administered if HR or BP values increased 20% from baseline. Postoperative pain was quantified with a customized ethogram. HR and BP were evaluated at base line, pre-rescue, 10 and 20 min post-rescue. Results Pre-rescue mean BP was significantly increased (p = .001) for the bupivacaine group. Mean intraoperative HR was significantly lower (p = .044) in the bupivacaine versus saline group. All other parameters were not significant. Conclusion Addition of a mandibular nerve block to the anesthetic regimen in the miniature pig condylectomy model may improve variations in intraoperative BP and HR. This study establishes the foundation for future studies with larger animal numbers to confirm these preliminary findings.

Local anesthesia in piglets undergoing castration—A comparative study to investigate the analgesic effects of four local anesthetics on the basis of acute physiological responses and limb movements

“…Castration without any pain relief provoked the highest increase in BP. Bova et al [ 27 ] determined that if a BP increase of more than 20% occurs during surgical intervention, relevant pain must be assumed, and rescue analgesia may be necessary. In the NaCl group, BP increased by 24% during skin incision, and an average increase of 45% was observed while cutting the spermatic cord.…”

Development of a lateral ultrasound‐guided approach for the radial, ulnar, median and musculocutaneous (RUMM) nerve block in a calf undergoing surgical fixation of the antebrachium

“…In this case, we defined a noxious stimulus as an increase from baseline in HR and MAP of 20 per cent or more, as has been described by others 20 21. Since both HR and MAP remained stable throughout the procedure without the need for any additional analgesic drug, and anaesthetic depth was considered light to moderate based on clinical evaluation, one may conclude that, in this case, the RUMM block was successful and had a duration of action of at least seven hours.…”