SA3 - Does Intraoperative Dexmedetomidine Administration During Orthognathic Surgery Influence Postoperative Opioid Consumption?

Abstract: Achieving optimal post-operative pain control while minimizing opioid consumption is a key tenet of enhanced recovery after surgery (ERAS) pathways. Dexmedetomidine (DEX), a centrally acting alpha-2 adrenergic agonist with sedative properties, has been widely incorporated in such protocols due to its ability to provide analgesia without inducing respiratory depression or hemodynamic instability. However, its opioid-sparing effect following orthognathic surgery remains incompletely understood. The purpose of this study is to measure the association between intraoperative dexmedetomidine administration during orthognathic surgery and post-operative opioid consumption.

A single-blinded, randomized controlled trial was designed and implemented. Patients undergoing Lefort I osteotomy and bilateral sagittal split ramus osteotomy, with or without geniotomy, from January 2022 through December 2023 were identified. American Society of Anesthesiologists (ASA) physical status I, 2, or 3 adults were included. Exclusion criteria were age < 18, opioid dependence, prescription opioid use within 2 years, and allergy/ intolerance to study medications. Block randomization was used to attain equal procedure distribution (geniotomy versus no geniotomy) between the two cohorts.

Subjects randomized to the DEX cohort received an initial 0.7mcg/kg bolus prior to anesthesia induction followed by continuous infusion at 0.7mcg/kg/hr, which was discontinued at the start of wound closure. The “No DEX” cohort received no dexmedetomidine. No subjects received long-acting local anesthetics or long-acting opioids intraoperatively. Post-operatively, all subjects were issued a hydromorphone patient-controlled analgesia (PCA) pump (0.2mg per bolus, 6-minute lockout period) with “standing” oral ibuprofen 600mg and acetaminophen 500mg administration. PCA was discontinued at 7:00am on post-operative day1 and replaced with oral oxycodone 5mg or 10mg as needed for moderate or severe pain, respectively. Visual analog scale (0-10) pain scores were assessed six hours post-operatively (VAS6) and prior to PCA discontinuation (VASPCA). Opioid consumption was calculated at 24 hours post-operatively using milligram morphine equivalents (MME).

The primary predictor variable was the use of DEX. The primary outcome variable was 24-hour MME consumption post-operatively. Secondary outcome variables included two visual analog scale pain scores—VAS6 and VASPCA, and ratio of PCA attempts to PCA boluses given (RATIO). Shapiro-Wilk test was used to assess sample normality. T-test was used to analyze relationships between demographic covariates and the primary predictor variable. Outcomes were analyzed using Mann-Whitney U test. P < .05 was statistically significant.

Of the 54 included subjects, 40 completed the study – 20 for each cohort. DEX (mean age 44.3 +/-13.2) and NO DEX (mean age 36.5 +/-13.3) cohorts showed no significant differences in age (P = .07), gender (P = .34), race (P = .06), or body mass index (P = .17). There was no significant difference in median MME at 24 hours post-operatively between the DEX (16.8mg) and NO DEX (16.6mg) cohorts (P = .77). Median VAS6 scores for DEX and NO DEX cohorts were 4.5 and 5.5, respectively (P = .67); median VASPCA scores were 4 and 5, respectively (p= .04). Median RATIO values were 1.22 for each cohort (P =.77)

The results suggest that standardized, weight-based intraoperative DEX administration was not associated with decreased postoperative opioid consumption following orthognathic surgery. Subjects’ requirements for “catch-up” analgesia, measured as the ratio of PCA attempts to PCA boluses given, were similarly not significant between cohorts. Amongst its potential perioperative benefits, dexmedetomidine’s opioid-sparing effect was not demonstrated in this prospective trial. However, further investigation regarding its analgesic effect is ongoing.



References:

Labafchi A, Shooshtari Z, Grillo R, Sharifian Attar A, Eshghpour M, Samieirad S. The Beneficial Effect of Preoperative Dexmedetomidine in Controlling Postoperative Pain, Nausea, and Vomiting After Orthognathic Surgery: A Triple-blind Randomized Clinical Trial. J Oral Maxillofac Surg. 2023;81(8):941-949.



Knackstedt R, Patel N. Enhanced Recovery Protocol after Fronto-orbital Advancement Reduces Transfusions, Narcotic Usage, and Length of Stay. Plast Reconstr Surg Glob Open. 2020;8(10):e3205.