A Comparative Study of Phenylepherine and Norepinephrine Infusion in Prevention of Postspinal Hypotension During Spinal Anesthesia in Non-Obstetric Procedures

Abstract Background: Although it is generally established that phenylepherine is the preferred vasopressor for maintaining blood pressure stability during spinal anesthesia, its use has been connected to a reflex decrease in heart rate and an associated decrease in cardiac output. As a result, research into substitute chemicals like norepinephrine has been sparked. When opposed to phenylephrine, norepinephrine may be more effective in controlling blood pressure because it has less of an impact on heart rate and cardiac output while still acting as a strong-adrenergic receptor agonist. Aim of Study: This study is to detect lowest MAP during the first 10 minutes after spinal anesthesia and compare the efficacy of prophylactic intravenous infusions of phenylepher-ine and norepinephrine in controlling hemodynamics in patients undergoing lower abdominal incision minor and intermediate surgical interventions (below T10) with spinal anesthesia. Patients and Methods: In our randomized, double-blinded study, 38 healthy patients undergoing lower abdominal incision surgical interventions under spinal anesthesia were randomized to maintain intraoperative hemodynamics with infusion of norepinephrine 4µg/ml or phenylephrine 100µg/ml. This study compared between both groups to detect lowest mean arterial pressure during the first 10 minutes after spinal anesthesia. Heart rate, cardiac output, stroke volume and index of cardiac output number using electrical cardiometry were also compared. Results: Norepinephrine may be more successful in low-ering blood pressure compared to phenylephrine because it has less of an effect on heart rate and cardiac output while still acting as a potent-adrenergic receptor agonist. Conclusion: The present study showed that prophylactic norepinephrine infusion as an alternative vasopressor to phenylephrine infusion prevented post spinal hypotension in non-obestetric patients and maintained intraoperative hemo-dynamics.