Comparing Dexmedetomidine with Labetalol for Haemodynamic Response to General Anaesthesia during Elective Cardiac Surgery at Tertiary Care Hospital

Abstract

Objectives: Laryngoscopy and tracheal intubation induce mechanical stimulation of the oropharynx and larynx, triggering a sympathetic surge that elevates heart rate, blood pressure, and arterial pressure. These haemodynamic alterations may manifest as tachycardia, bradycardia, hypotension, or hypertension. This study compared the efficacy of dexmedetomidine versus labetalol in attenuating such responses during elective cardiac surgery under general anaesthesia. Methodology: This randomized controlled trial (RCT) was conducted from June 2022 to December 2022 in the Department of Anaesthesia, National Institute of Cardiovascular Diseases, Karachi. A total of 180 patients, aged 18–80 years of either gender, undergoing elective cardiac surgery under general anaesthesia, were randomized equally into two groups: Group 1 received dexmedetomidine, and Group 2 received labetalol. Standard anaesthetic protocols were followed, and the incidence of tachycardia, bradycardia, hypotension, and hypertension within five minutes of intubation was recorded. Results: Of the 180 patients, 120 (66.7%) were male and 60 (33.3%) were female; 100 (55.6%) were aged ≥40 years. Obesity was the most common comorbidity (51, 28.3%). Tachycardia occurred more frequently in the labetalol group compared to the dexmedetomidine group (12.2% vs. 3.3%, p=0.026). Bradycardia was also higher in the labetalol group (21.1% vs. 6.7%, p=0.005). Hypotension was more common in the labetalol group (16.7% vs. 7.8%), but the difference was not statistically significant (p=0.069). Conversely, hypertension occurred more often in the dexmedetomidine group (13.3% vs. 4.4%, p=0.036). Conclusion: Dexmedetomidine was more effective than labetalol in attenuating haemodynamic fluctuations during laryngoscopy and intubation for elective cardiac surgery, suggesting it may be the preferred agent in this setting.