Abstract

The tracheal intubation following laryngoscopy is not only accompanied by increased sympathetic activity but also increased sympathoadrenal activity. Increased hypothalamic activity and traffic in sympathetic efferent tracts are observed. Release of trophic hormones from hypothalamus stimulate release of ACTH, TSH, GH, FSH, luteinizing hormone and prolactin in addition to ADH from the pituitary. A clinical comparative single blinded study of attenuation of sympathetic response to laryngoscopy and intubation was done in 90patients posted for elective surgeries selected randomly. Patients undergoing various Orthopaedic, ENT, and General surgical procedures were selected. Repeated measure ANOVA study showed significant variations in heart rate before and after induction and at time intervals of 1, 3, 5, 7 and 10 minutes from the onset of laryngoscopy and intubation (p< 0.001). In our study, heart rate increased by 41.1% when compared with preinduction value in control group (p< 0.001). Similar increase was seen with the esmolol and clonidine groups - 15.4% and was 25.8%. The difference in heart rate between control and clonidine group remains statistically significant at all times of assessment (p< 0.001). Both esmolol and clonidine attenuated the heart rate which was highly significantly (P 0.001).

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