A Prospective Comparative Study Between Dexmedetomidine And Remifentanil For Sedation In Awake Fibreoptic Nasotracheal Intubation

The Difficult Airway Society (DAS) recommends considering awake fiberoptic nasotracheal intubation (AFONTI) for patients with a predicted difficult airway as they are at risk of complications during airway management under general anaesthesia. The core principles of AFONTI include maintaining oxygenation, ensuring adequate topical anaesthesia of the airway, performing the procedure efficiently, and, when necessary, using sedation as majority of the patients are uncooperative. AFONTI performed in the absence of a sedative is extremely uncomfortable, calling for the need of controlled sedation.

Sedation used cautiously can help reduce anxiety and discomfort, provide amnesia, and enhance procedural tolerance. The ideal sedative should be short-acting, easy to titrate, and provide adequate sedation with amnesia while ensuring spontaneous ventilation by reducing the patient’s airway reflex response like coughing and laryngospasm. Controlled sedation maintains physiological hemodynamic parameters thereby guaranteeing patient cooperation and comfort. However, sedation also carries risks such as airway obstruction, oxygen desaturation, and cardiovascular instability. Therefore, careful selection of drug regimens is crucial to ensure safe and effective AFONTI. The most commonly used sedatives for this setting include benzodiazepines, ketamine, propofol, sevoflurane, dexmedetomidine, and remifentanil.

Dexmedetomidine (D), a selective alpha 2 adrenergic G protein coupled receptor agonist, acting on the postsynaptic alpha 2 receptors in the locus coeruleus attributing its sedative, anxiolytic, amnestic and sympatholytic properties. D also influences the release of substance P from dorsal horn of spinal cord attributing its analgesic properties. D has a short distribution half-life of 6 minutes and a terminal elimination half life of 2 hours.

Remifentanil (R) is an ultra-short-acting opioid with selective mu receptor agonist properties, offering sedative, strong analgesic effects and antitussive properties. R has rapid onset and redistribution half-life of 3 minutes as it is metabolized by non-specific plasma esterases and elimination half-life of 6 minutes ensuring quick recovery and attenuation of stress responses allowing easier patient communication. Pharmacokinetics of R vary with age and lean body mass while pharmacodynamics varies only with age.

In this study, which is a randomized control trial with a sample size of 50 that will be conducted in MS Ramaiah Medical College, Bangalore, we aim to compare the effectiveness of Dexmedetomidine and Remifentanil as sole sedative agents for AFONTI with the hypothesis that Remifentanil with its higher analgesic efficacy and anti-tussive property, may provide more favourable intubation conditions yielding higher first attempt success rates.

The primary outcome will be the first attempt success rate and quality of intubation assessed by a 5 point intubation score depicted by 1for No movement, 2 for Grimacing, 3 for Mild cough , 4 for Major limb movement and 5 for Prolonged coughing.

The secondary outcome will be based on,

• Time required to achieve a Ramsay Sedation Score (RSS) of 2 with RSS ranging from 1 to 6 depicted by 1 for Patient is anxious, agitated, or restless, 2 for Patient is cooperative, oriented, and tranquil, 3 for Patient responds to commands only, 4 for Patient exhibits a brisk response to a light glabellar (between the eyebrows) tap or a loud auditory stimulus, 5 for Patient exhibits a sluggish response to a light glabellar tap or a loud auditory stimulus and 6 for Patient exhibits no response to stimulus. • Patient tolerance to endotracheal tube. • Total duration for successful tracheal intubation. • Hemodynamic parameters