A randomized trial of three lubrication strategies on sore throat after insertion of the LMA® Classic™ supraglottic airway

Abstract

To the Editor, The laryngeal mask supraglottic airway (SGA) is commonly used in anesthesiology and is often lubricated for easy insertion. We studied sore throat (primary outcome), cough, and laryngospasm after insertion of the LMAÒ Classic TM (Teleflex Inc.; Morrisville, NC, USA) comparing three lubricating strategies: water-soluble medical lubricant (M) (Muko TM ; Source Medical, Mississauga ON, Canada) or 2% lidocaine jelly (L) (Lidodan TM ; Odan Laboratories, Montreal QC, Canada) vs no lubricant control (C). After institutional ethical approval, A consenting American Society of Anesthesiologists physical status I-II adult patients having elective surgery where an LMA was planned were recruited. Those with asthma, sore throat, cough, or allergy to lidocaine or Muko were excluded. Participants were randomly assigned after anesthesia induction by opening an opaque envelope, prepared by the research pharmacist, that contained a 3-mL syringe with Muko, lidocaine jelly, or nothing, with instructions to apply the lubricant to the entire inflatable surface of the LMA. Patients, investigators, and other caregivers were blinded to group assignment. The anesthesiologist was blinded to the lubricants, but not to lubricant vs. controls. This letter is accompanied by an editorial. Please see Can J Anesth 2018; 65: this issue.

Evaluation of the efficacy of turmeric-based lozenges for the prevention of postoperative sore throat in surgeries done under laryngeal mask airway insertion

“…To reduce the incidences of POST associated with LMA insertion, various modalities have been used such as different techniques of LMA insertion,[ 17 ] various methods of lubrication,[ 8 ] tramadol gargles,[ 6 ] use of neuromuscular blocking agents,[ 18 ] or the use of medicated lozenges. [ 15 ] Chairatthanawanit et al .…”

“…McKay et al . compared 3 strategies of lubricating the LMA: water-soluble lubricant, 2% lidocaine jelly, and no lubricant as control group[ 8 ] and found that no benefit was provided by lubrication of the LMA. Keller et al .…”

“…Various clinical studies have been done to minimize the morbidity caused by POST such as the use of tramadol gargles,[ 6 ] low dose atracurium,[ 7 ] lidocaine gel,[ 8 ] lidocaine inhalation and intravenous steroids after LMA insertion. [ 9 ] Use of medicated lozenges, before LMA insertion, is also a route available for the prevention of POST.…”