Comparison of inhaled versus intravenous anesthesia for laryngoscopy and laryngeal electromyography in a rat model

Abstract

BackgroundPropofol and remifentanil intravenous combination is one popular form of total intravenous anesthesia (TIVA) in mainstream clinical practice, but it has rarely been applied to a rat model for laryngoscopy and laryngeal electromyography (LEMG). Our objective was to establish a safe and reproducible general anesthetic protocol for laryngoscopy and endoscopic LEMG in a rat model. Our hypothesis is that TIVA allows a minimally morbid, and feasible laryngoscopy and LEMG.MethodsSprague Dawley rats were subjected to either inhalational anesthesia (IA) (isoflurane) or TIVA (propofol and remifentanil) and underwent laryngoscopy and LEMG. The primary outcome was a complete minimally interrupted rigid laryngoscopy and obtaining reproducible motor unit potentials from the posterior cricoarytenoid muscles. The secondary outcome was morbidity and mortality.ResultsSeventeen out of twenty-two rats underwent both TIVA and IA. Only two underwent IA only. All nineteen rats that underwent IA had a successful experiment. Seventeen rats underwent TIVA, however, only nine completed a successful experiment due to difficulty achieving a surgical plane, and respiratory events. Upon comparing the success of the two anaesthetic regimens, IA was superior to TIVA (P = 0.0008). There was no statistical difference between the amplitudes (p = 0.1985) or motor units burst duration (p = 0.82605) of both methods. Three mortalities were encountered, one of which was due to lidocaine toxicity and two were during anesthetic induction. Respiratory related morbidity was encountered in two rats, all seen with TIVA.ConclusionsTIVA is not an ideal anesthetic regimen for laryngeal endoscopy and LEMG in rat models. Contrary to our hypothesis, IA did not affect the quality of the LEMG and allowed a seamless rigid endoscopy.Electronic supplementary materialThe online version of this article (10.1186/s40463-018-0312-9) contains supplementary material, which is available to authorized users.

Laryngeal function in normal dogs administered isoflurane following partial clearance of alfaxalone or propofol

“…However, how this may influence ventilatory drive or respiratory pattern and subsequently affect laryngeal motion is unknown (Mutoh et al 1999). Interestingly, there is controversy over ideal anesthetics for airway endoscopy in humans (Lerman & J€ ohr 2009;Malherbe et al 2010;Gazzaz et al 2018). Laryngeal electromyography (LEMG) is used to facilitate the diagnosis of laryngeal mobility disorders in humans (Berkowitz et al 2009;Lerman & J€ ohr 2009;Malherbe et al 2010;Gazzaz et al 2018).…”

“…Interestingly, there is controversy over ideal anesthetics for airway endoscopy in humans (Lerman & J€ ohr 2009;Malherbe et al 2010;Gazzaz et al 2018). Laryngeal electromyography (LEMG) is used to facilitate the diagnosis of laryngeal mobility disorders in humans (Berkowitz et al 2009;Lerman & J€ ohr 2009;Malherbe et al 2010;Gazzaz et al 2018). In a rat model for video laryngoscopy, during administration of propofol, the CAD LEMG amplitudes were only 66.9% of the amplitudes obtained during isoflurane anesthesia (Gazzaz et al 2018), suggesting that inhalation anesthetics preserve CAD muscle function.…”