Efficacy of Nor-Adrenaline Vs Phenylephrine for the management of Spinal Hypotension among patients undergoing Cesarean Section

Introduction: Most of the Cesarean sections are conducted under regional anesthesia. Spinal anesthesia is the anesthesia of choice except where contraindications are encountered. Spinal anesthesia can lead to significant hypotension with relevant hemodynamic changes. Rescue medications frequently used to manage per-operatively include phenylephrine, ephedrine and noradrenaline. Phenylephrine is an α-agonist commonly used for the prevention and treatment of hypotension. The significant drawback is that it can cause bradycardia and reduced cardiac output. Recently, noradrenaline has been found as effective as phenylephrine to maintain blood pressure while also conferring a greater heart rate and cardiac output. The aim of our study was to compare the effects of intravenous boluses of conventional phenylephrine and noradrenaline for the management   of spinal induced hypotension among patients undergoing cesarean sections in spinal anesthesia.
Methods: The study was conducted at Cantonment General Hospital, Rawalpindi from Jan 2020 to June 2020 over a period of 6 months. A total of 160 patients posted for elective cesarean section were recruited in the study. They were randomized into two groups of 80 each. The standard intravenous bolus dose of Phenylephrine and noradrenaline was defined as 100 microgram (mcg) and 8 microgram (mcg) respectively. Group A received Phenylephrine 100mcg and Group B received Noradrenaline 8mcg intravenously whenever systolic blood pressure was 20% lower than baseline with relevant tachycardia. Systolic blood pressures, diastolic blood pressure, heart rate and Apgar scores were compared between the two groups. SPSS version 17.0 was used to analyze the data.
Results: The incidence of hypotension in group A was comparable to group B (60% vs 65%) and was not statistically significant (p>0.05). The incidence of bradycardia in group A was significantly higher than in group B (35% vs 7.5%) and was statistically significant (p <0.05). There was no difference in Apgar scores between the two groups.
Conclusion: Noradrenaline bolus doses are effective in the management of spinal-induced hypotension during cesarean section. It has better effects on the hemodynamic stability of the patients in terms of heart rate and blood pressure stabilization. Phenylephrine, though, can manage the blood pressure effectively, but can cause significant bradycardia that can cause some deleterious conical effects. In conclusion, noradrenaline is an excellent choice to manage spinal induced hypotension.