Comparison of Lignocaine Nebulization versus Lignocaine with Dexmedetomidine Nebulization for Awake Fiberoptic Intubation: A Double Blind Randomized Controlled Trial

Awake Fiberoptic Intubation (AFOI) is a newer, emerging and effective technique for establishing airway access in patients having both anticipated and unanticipated difficult airway with respect to compromised airway, inadequate mouth opening as in temporomandibular joint disease, mandibular-maxillary fixation, severe facial trauma and burns, oropharyngeal mass, limited surgical field, when neck extension is to be avoided, vertebral artery insufficiency etc. Preparing the patient before AFOI is the crucial step for adequate airway anesthesia and for ease intubation. Topical application of local anaesthesia by nebulization technique is one of the promising techniques used to anaesthetize the airway. The purpose of the study is to evaluate the effect of adding dexmedetomidine to lignocaine for optimum airway anesthesia in awake fibre optic intubation and to evaluate the beneficial effects of dexmedetomidine like anxiolytic, hypnotic, sedative.Since the patient will be awake during intubation, we assume that adding dexmedetomidine will be beneficial and provide better patient tolerability during the procedure. Enrolled patients will be allotted to one of the groups (AorB). Based on the randomization sequence, the patients will be allocated into two groups, Group A and Group B.Group A patients will receive 4%Lignocaine 5ml nebulization and the patient belonging to Group B will receive Dexmedetomidine 1.5mcg/kg + 4%Lignocaine 5ml nebulization. According to the sequence,the drugs(Lignocaine&Dexmedetomidine-Lignocaine) will be handed over to the anesthesiologist and advised to give respective drug nebulization as per code received by patient.

Preanesthetic evaluation will be conducted with thorough airway examination including modified Mallampati grading, thyromental distance and upper lip bite test. The procedure of awake fiberoptic intubation will be explained to all patients and informed consent will be obtained. After shifting the patient to preoperative room, an intravenous line will be secured with 18 G IV cannula and baseline parameters such as heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure(DBP), mean arterial blood pressure(MAP) and oxygen saturation (SpO2 ) will be measured. Inj. Glycopyrrolate 0.2mg IV will be given 30 minutes before surgery and two drops of Xylometazoline 0.1% will be instilled in both nostrils. Patients will be nebulized for 20 mins before nasal intubation along with oxygenation with face mask @ 4 L/min flow. All patients will receive Inj. Midazolam 1 mg intravenously at 15th minute of nebulization. To ensure double blindness, patients will be nebulized by an anesthesiologist who is not involved in further study. Another anesthesiologist will perform the procedure and record the data. Continuous monitoring of vitals will be done at baseline, at 5, 10, 15, 20 min during nebulization, just before procedure, at 1, 2, 3, 4, 5 min during procedure and post procedure at 1, 3, 5, 10 and 15 mins. Sedation level will be assessed at baseline, at 5, 10, 15, 20 min during nebulization and just before procedure with Ramsay Sedation score.Adequacy of local anaesthesia will be confirmed by heaviness of the tongue and dryness of posterior pharynx of patients. Patient will be pre-oxygenated with 100% oxygen at 8L/min for 3-5 minutes. After application of lignocaine gel, Awake fiberoptic intubation will be performed using flexible videoendoscope , 5.0 mm outer diameter preloaded with 7.0 mm ID ET tube for female patient and 7.5 mm ID ET tube for male patient respectively. During videoendoscopy, 2 ml lignocaine 4% will be administered by spray as you go technique. Patient tolerance during and after AFOI will be assessed by grading system. ET tube position will be confirmed by auscultation and capnography. The amount of total lignocaine required in each patient will be also noted.

Intubation time was defined as the time from passing the videoendoscope tip through the nostril to the first reading obtained by the capnograph after endotracheal intubation. The mean intubation time will be assessed. A Grading system will be used for assessing intubating conditions, vocal cord positions and patient tolerance during and after intubation. General anaesthesia will be administered with Inj. Fentanyl 2-3 mcg/kg IV, Inj. Propofol 2-3 mg/kg IV and Inj.Vecuronium 0.1 mg/kg IV or Inj. Atracurium 0.5 mg/kg IV. Anaesthesia will be maintained with Oxygen and Nitrous Oxide (50:50), Sevoflurane up to 2% v/v and intermittent dose of Vecuronium 0.02 mg/kg IV for muscle relaxation. Reversal will be given with Inj.Neostigmine 2.5 mg and Inj. Glycopyrrolate 0.5 mg IV at the end of the surgery. Postoperatively, after 24 hours patient satisfaction will be assessed using the grading system.