Attenuation of Airway and Cardiovascular Responses to Extubation in Chronic Smokers by Prior Treatment With Dexmedetomidine, Fentanyl and Their Combination

Tracheal extubation is associated with acute, transient, significant and undesirable hemodynamic and airway responses that may persist into the recovery period. Respiratory complications after tracheal extubation are three times more common than complications occurring during tracheal intubation and induction of anesthesia (4.6% vs 12.6%) .

The peak changes are noticed about 1 minute following extubation and may continue until 10 minutes . The reflexes ranges from coughing, bucking, agitation to bronchospasm, laryngospasm, laryngeal oedema, negative pressure pulmonary oedema, tachycardia, hypertension, arrhythmias, left ventricular failure, myocardial ischemia, increased bleeding, raised intracranial and intraocular pressure and cerebrovascular hemorrhage in susceptible individuals. Although most patients can tolerate these transient effects without any significant consequences, but this could be detrimental in patients operated for cardiac, neuro or ophthalmic lesions especially if hypertensive or diabetic. However, Tracheal extubation in smokers will increase difficulty.

Smoking is a risk factor for intraoperative and postoperative complications mainly related to pulmonary and cardiovascular systems. Long-term exposure to cigarettes causes an increased response to the mechanical stimulation caused by extubation.

Smoking affects oxygen transport and delivery , Irritants in smoke increase mucous secretion which becomes hyper viscous with impaired tracheobronchial clearance . Smoking increases sympathetic activation due to increased release of catecholamines and the delay in nicotine clearance from the neuroeffector junction leading to higher blood pressure, tachycardia, and increase peripheral vascular resistance .

For a smooth extubation, there should be no straining, movement, coughing, breath holding or laryngospasm. Extubation at light levels of anesthesia or sedation can stimulate reflex responses via tracheal and laryngeal irritation . A variety of drugs such as esmolol, alfentanil, diltiazem, verapamil, fentanyl, and lidocaine have been used to control hemodynamic changes and upper airway tract events, but they all have limitations and side effects.