A comparison of two prophylactic doses of ephedrine to attenuate the hemodynamic responses in adults receiving propofol in general anesthesia; a South Indian perspective

Background and Aims: Propofol is a potent intravenous (i.v.) anesthetic that attenuates pharyngeal, laryngeal, and tracheal reflexes and provides an adequate depth of anesthesia for intubation. However, its major disadvantage is the fall in blood pressure (BP) and heart rate (HR). Ephedrine being a potent alpha-adrenergic vasoconstrictor and a beta-adrenergic cardiac stimulant can combat this hemodynamic effect of propofol. The objective of this study was to compare the decrease in hypotension and bradycardia caused by propofol with two prophylactic doses of ephedrine. Further, the intubating conditions with prophylactic ephedrine with atracurium were noted. Settings and Design: Patients posted for elective surgeries under general anesthesia in a tertiary care hospital in South India were recruited by randomized computer-generated tables and allocated using sealed envelopes into three groups after written informed consent. A randomized control study was done between three groups of patients who received saline, 100 μg.kg−1 or 150 μg.kg−1 of ephedrine. Materials and Methods: A total of 87 patients between 18 and 59 years of the American Society of Anesthesiologists physical status classes I and II were recruited and randomized into three groups of 29 each. Each group received normal saline (S1), 100 μg.kg−1 (E1) and 150 μg.kg−1 (E2) of ephedrine i.v. All patients were given i.v fentanyl 2 μg.kg−1, followed by the study drug depending on the group they were in. This was immediately followed by 2 μg.kg−1 of propofol i.v over 30s. Muscle relaxation was given with atracurium and patients were intubated 3 min later. The patients’ HR, systolic and diastolic BPs (SBP and DBP), and mean arterial pressures (MAPs) were recorded at preinduction, 2 min after induction, 1 min after intubation, then 3 min, 5 min, 10 min, 15 min, and 30 min later. Further, the anesthesiologist intubating assessed the conditions of intubation and later scored it. Statistical Analysis: The Chi-square test was used as the test of significance for the qualitative data. Continuous data were represented as mean and standard deviation. Analysis of variance was the test of significance used to identify the mean difference between more than two groups for quantitative and qualitative data. “Paired t-test” was used as the test of significance for paired data. P value (Probability that the result is true) of <0.05 was considered statistically significant after assuming all the rules of statistical tests. Results: Mean HR was significantly higher in the E2 Group than in the E1 and S1 Groups. Mean SBP, DBP, and MAP were higher in the E2 Group, followed by E1 and lower in the S1 Group during these intervals. Hence, all groups had hypotension effects from induction but the least was noted with the group that received 150 μg.kg−1 of ephedrine. All groups had similar intubating conditions with no significant difference between the groups. Conclusion: 100 μg.kg−1 and 150 μg.kg−1 of ephedrine had significant effects in reducing the hypotension associated with propofol, however, high doses also caused significant tachycardia.