Dexmedetomidine, the ideal drug for attenuating the pressor response. (Pham)

Abstract: Laryngoscopy and endotracheal intubation is often associated with hypertension and tachycardia because of the sympathoadrenal stimulation which is usually transient and lasts for 5-10 minutes. In patients with cardiovascular and cerebrovascular disease, this sudden rise in Heart Rate (HR) and blood pressure can produce deleterious effects in the form of myocardial ischemia, pulmonary edema and cerebral hemorrhage. Many methods have been tried to obtund the haemodynamic response in adult and pediatric patients, but none proved to be ideal. Dexmedetomidine has been particularly effective in blunting the haemodynamic response to laryngoscopy and tracheal intubation.

Aims: To study the efficacy of 0.6 μg/kg dexmedetomidine IV, given 10 minutes (min) before induction to obtund the pressor response of laryngoscopy and tracheal intubation.

Methods: 100 normotensive patients aged 14-55 years old were assigned randomly into two groups. 10 min before induction these two groups received, group C (n=50): received 10 ml normal saline (NS) IV over 10 min, group D (n=50): received dexmedetomidine 0.6μg/kg body weight diluted to 10 ml NS IV over 10 min. After induction of anaesthesia, HR, SBP, DBP and MAP were recorded at various time intervals like before induction, after induction and 1, 3, 5 and 10 min after laryngoscopy and intubation.

Results: It was noted that in group C, following laryngoscopy and intubation, the mean rise in HR, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) were found to be 36.24 bpm, 30.02 mmHg, 22.34 mmHg and 26.42 mmHg respectively, one minute after intubation. In group D, the mean of HR, SBP, DBP and MAP were decreased by 2.86 bpm, 15.86 mmHg, 9.54 mmHg and 1.98 mmHg respectively compared to basal values which was statistically highly significant (p=0.000). In addition dexmedetomidine reduces the requirement of thiopentone and vecuronium bromide and produces arousable sedation after extubation with minimal incidence of bradycardia and hypotension.

Conclusions: Dexmedetomidine (0.6μg/kg) IV, given 10 min before induction was seen to effectively attenuate the pressor response to laryngoscopy and tracheal intubation without any side effect.

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