Effect of Intravenous Dynastat on Postoperative Sore Throat: A Randomized Double-blinded Controlled Trial

The investigators' study will be designed a two-arm, individually randomized, double-blind, placebo-controlled trial comparing two doses of 40mg Dynastat with placebo (0.9% saline) in participants who will receive noncardiac surgery under general anesthesia with tracheal intubation. The investigators will include participants of American Society of Anesthesiologists physical status 1 and 2, 20-65 years of age, requiring general anesthesia with endotracheal intubation (ETGA) for elective non-cardiac surgery will be enrolled. Besides, the anesthetic time after intubation will need 90 minutes at least. Those with a preexisting cough, hoarseness or a sore throat, smoker, history of asthma or chronic obstructive pulmonary disorder, vocal performer by occupation, recent or recurrent respiratory tract infection, risk factors for postoperative aspiration, obesity, pregnancy, and contraindication to Dynastat medications will be excluded. Anticipated difficult intubation, Mallampati grade >2, difficult mask ventilation requiring oral or nasal airway, Cormack and Lehane grade III and IV on laryngoscopy, intubation attempt >1, moderate to severe liver dysfunction (Child-Pugh score >7), severe renal dysfunction (Ccr < 30 ml/min), congestive heart failure (NYHA II-IV), and those requiring orogastric or nasogastric tubes will be other exclusion criteria. In the operating room, participants will receive study drug according to the group allocation. General anesthesia will be induced with IV fentanyl 2 μg/kg and propofol 2 mg/kg, followed by rocuronium 0.8 mg/kg. After achieving adequate time of neuromuscular blockade onset, an anesthesiologist (endotracheal tube intubation numbers > 500 times), unaware of the group allocation, will perform laryngoscopy in all the groups using standard 3 or 4 Macintosh blades. Polyvinylchloride endotracheal tubes (ETTs) with a 7-mm ID for male and 6.5-mm ID for female will be used for orotracheal intubation. Lubrication will be applied on the ETT. The cuff will be inflated with air to the point just capable of sealing leakage. The cuff pressure will be checked and adjusted to 25-30 cmH2O with the help of pressure gauge. At the end of surgery, the residual neuromuscular block will be antagonized with IV neostigmine 0.05 mg/kg and glycopyrrolate 0.01 mg/kg. Gentle suctioning of oral secretions will be done with 12F soft suction catheter while limiting the suction pressure to 50 cmH2O before tracheal extubation. After tracheal extubation, participants will be transferred to the postanesthetic care unit. The following variables at the time of tracheal intubation and extubation will be recorded: Cormack and Lehane laryngoscopy score; resistance to ETT insertion (none/mild/moderate); the time to achieve intubation will be defined as the time from opening of mouth for insertion of laryngoscope blade to confirmed placement of ETT (assessed with chest auscultation and capnograph); application of external laryngeal pressure to aid endotracheal intubation; duration of tracheal intubation defined as the time from placement of ETT to its removal; repositioning of ETT; blood tinge on the suction catheter during oral suctioning; blood stain on ET after its removal; and total opioid consumption in the postoperative period. The investigators' primary subject will be the incidence of POST, and the main effects of Dynastat will be the primary interest. The incidence of POST will be also compared among the 2 groups. Secondary outcomes included the severity of POST, incidences and severity of cough, hoarseness, and dysphagia.