CTRI

Airway management is an integral part of general anaesthesia allowing ventilation, oxygenation, aspiration and working as a mode for delivering anaesthetic gases. Awake fibreoptic intubation is recommended for patients with anticipated difficult airway, difficult intubation and cervical spine injury where optimum positioning for laryngoscopy is difficult to achieve. Anaesthesia of the airway along with psychological assurance is the mainstay for preparation of Awake fibreoptic intubation.

Different techniques are being used to achieve these objectives such as Airway block in form of glossopharyngeal nerve block, superior laryngeal nerve block and transtracheal block to abate gag reflex; glottis closure and cough reflex.These blocks are inadequate and can hamper the patient cooperation and hence compromise ease of doing fibre optic bronchoscopy and intubation.

A combination of techniques is better to adequately anaesthetise upper airway structure for awake fiberoptic intubation ( AFOI). Inhalational technique provides widest coverage ,but does not provide a dense level of anaesthesia.

There are few recent studies which claim that inhalational dexmedetomidine with local anaesthetics or opioids give excellent results in bronchoscopy. Considering their promising results we aimed to ascertain its role in awake FOB with endotracheal intubation.

After Institutional Ethical Committee clearance study will commence for 1 year and 6 months.

Study design: Randomised prospective, double blinded, single centered study. Sample size:

There is no previous study available so this study can be considered. In our institute the total number of FOB performed in the year 2020 was 57. Based on this population, with type 1 error at 0.05 and power of study 0.80, calculated sample size is 50. Patients will be randomised in two groups (25 each) by computer generated random numbers. The random allocation sequence will be concealed in opaque, sealed envelopes until a group is assigned.

Patients will be shifted to operation theatre where intravenous access will be placed, standard monitors will be placed and baseline parameters will be recorded.

Inj. Glycopyrrolate 0.02 mg IV and intra nasal xylometazoline 0.1% will be given 20 min prior to nebulization in all patients. Duration of nebulization will be 20 min followed by FOB ( Karl - storz 11301BN1 5.5mm) . All patients will receive supplemental oxygen at the rate of 2 l/min through the working channel of FOB. In case of cough or gag reflexes hampering the procedure additional sedation with intermittent dose of inj. propofol 0.5 mg /kg IV will be given. Parameters will be recorded during the procedure are pulse rate (PR), mean arterial pressure (MAP), oxygen saturation ( SpO2) at 0 min ( base line), T1 ( at start of procedure), T2 (at 5 min), T3 (at 10 min). Procedures taking more than 10 mins, pronounced intractable cough and high requirement of sedation leading to recurrent fall in oxygen saturation will be abandoned and rescued by conventional induction and intubation by direct laryngoscopy. Duration of surgery will be noted. All patients will be relaxed with non depolarizing muscle relaxants inj. Vecuronium and reversed with inj neostigmine. All patients will be extubated after complete wakefulness and weaning of relaxation effects of muscle relaxants. Any episode of cough and gag reflex will be noted with in 30 min of extubation (Ex ) and patient satisfaction will be notated after 6 hours of extubation. Pain score will be noted in the first 6 hours as per visual analogue scale (VAS).

Episodes of cough and gag reflexes will be noted by independent observers. The cough episodes during the procedure and after extubation will be classified as 1 = no cough, 2 slight ( <= 2 coughs), 3 = moderate ( 3 - 5 coughs), 4 severe ( > cough episodes). Post procedure patient satisfaction ( excellent = 1, good =2, fair = 3, poor = 4) [12].

Adverse effects like lignocaine toxicity, over sedation using Richmond agitation sedation score will be recorded.

Statistical analysis will be performed using SPSS 20 Software. Continuous variables will be expressed as means Â± standard deviation and categorical variables will be expressed as proportions. Analysis of variance (ANOVA) test will be used for comparison of patient characteristics and differences of variables among the two group. For non parametric variables Wilcoxon- Mann - Whitney test will be performed.

P value < 0.05 will be considered statistically significant.