Comparison on the effects of I.V. dexmedetomidine versus I.V. lignocaine on haemodynamic responses during tracheal extubation in abdominal surgeries

Extubation of the trachea is the translaryngeal removal of an endotracheal tube from the trachea via the mouth or the nose. It is one of the most uncomfortable stage during general anaesthesia and is almost associated with haemodynamic changes. Extubation during lighter planes of anaesthesia can stimulate reflexes by laryngeal and tracheal stimulation. The laryngopharyngeal stimulationis associated with reflex increase in sympathetic activity leading to haemodynamic changes. These haemodynamic changes are reflected as rise in heart rate and arterial blood pressure and are usually variable.

Dexmedetomidine is a centrally acting alpha 2 receptor agonist with sedative and analgesic  effect . The sedative-hypnotic and analgesic effect is by an action on alpha 2 receptors in locus ceruleus . Dexmedetomidine can act as a sympatholytic and can attenuate stress  respnse to surgery thus maintaining haemodynamic stability.

Lignocaine is a synthetic amide - linked local anaesthetic. agent of immediate potency and duration of action. It has a stabilizing effect on cell membrane of cardiac tissue and decreases the automaticity of myocardium by opposing  depolarisation of phase 4 action potential spontenously and thus helps in attenuating stress responses to surgeries.