2023 FSA Podium and Poster Abstracts
S007: CASE REPORT: AN INNOVATIVE USE OF REMIMAZOLAM AND REMIFENTANIL IN THE MANAGEMENT OF A PATIENT WITH ANTICIPATED DIFFICULT AIRWAY
Bao Tran Ho, DO; Mayo Clinic
Introduction/ Background: Remimazolam is a novel GABA-alpha receptor agonist with favorable pharmacodynamic effects including less respiratory depression and unwanted cardiovascular side effects when compared to other GABA receptor hypnotics like propofol. It contains a carboxylic ester linkage which confers increased susceptibility to hydrolysis and has a context-sensitive half-life of 7-8 minutes after a 2-hour infusion. Moreso, it may be reversed by flumazenil, procuring its safety and efficacy as a sedative for use as an anesthetic. Remimazolam has been shown to have synergism with other sedatives including remifentanil with favorable anesthetic effects. Remifentanil is a synthetic mu-opioid receptor agonist with similar characteristics to fentanyl. Unlike other synthetic opioids which primarily undergo hepatic metabolism, remifentanil also contains an ester linkage that is metabolized by non-specific plasma esterases independent of infusion time with a context-sensitive half-life of 3 to 4 minutes. It produces a metabolite with very weak opioid receptor activity that does not contribute to further drug effects. These characteristics result in a rapid onset to drug effect, short latency to peak effect, and rapid recovery time which allows for remifentanil to be used in situations requiring potent analgesia within a short duration of time. The characteristics of both remimazolam and remifentanil facilitate an innovative use for sedation of patients with an anticipated difficult airway in the event that reversal may be warranted for difficulty ventilation and/or failure to intubate.
Methods/ Case Presentation: We report a case of a 55-year-old man with a past medical history significant for squamous cell carcinoma of the base of the tongue with supraglottic metastasis, paroxysmal atrial fibrillation, and obstructive sleep apnea. Anesthesia was requested for the placement of a gastrojejunostomy tube by Interventional radiology for further nutrition support secondary to intolerance of oral intake. Pre-Anesthesia medical exam reveals a Mallampati IV, TM distance <3, and limited neck range of motion in a patient with a BMI of 37. Previous flexible laryngoscopy by otorhinolaryngology shows an enlarged mass at the right tongue base and an extensive tumor burden obstructing his airway (Figure A). The risks of awake intubation were discussed. Remifentanil infusion at 0.05 mcg/kg/min and remimazolam injection at approximately 2 mg every 15 mins, for a total duration of 1 hour, were administered under monitored anesthesia care (MAC) with airway topicalization and spontaneous respiratory effort.
.png)
Results: Placement of a successful gastrojejunostomy tube was achieved, no adverse intraoperative complications or drug side effects were observed, and the patient recovered well postoperatively without complications.
Discussion: Difficulty in managing the airway is one of the major causes of anesthesia-related morbidity and mortality. Awake tracheal intubation should be cautiously considered in select patients with difficult airways; risks include the need for multiple attempts, patient discomfort including cough and gagging during intubation, and difficulty with tube passage. Monitored Anesthesia Care with a combination of remimazolam and remifentanil may provide an alternative, innovative strategy for anesthesia in patients with an anticipated difficult airway.