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Published on: November 20, 2016
Differential pressor response to intravenous ephedrine during recovery from deliberate hypotension
Noriaki Kanaya1, Yoshito Nakayama, Masayasu Nakayama
1Department of Anesthesiology, Sapporo Medical University School of Medicine, Sapporo, Japan. kanaya@sapmed.ac.jp
Study Objective:
To determine whether nitroglycerin or trimethaphan alters pressor response to intravenous (i.v.) ephedrine.
Design:
Prospective, randomized study.
Setting:
Operating room of a university hospital.
Patients:
60 ASA physical status I female patients scheduled for mastectomy.
Interventions:
Patients were assigned to one of six groups (n = 10 in each). Group 1: nitroglycerin + normal saline (NS) i.v., Group 2: nitroglycerin + ephedrine 0.1 mg/kg i.v., Group 3: nitroglycerin + ephedrine 0.15 mg/kg i.v., Group 4: trimethaphan + NS i.v., Group 5: trimethaphan + ephedrine 0.1 mg/kg i.v., and Group 6: trimethaphan + ephedrine 0.15 mg/kg i.v.
Measurements:
Hemodynamic responses to ephedrine following withdrawal of vasodilators were observed for 15 minutes.
Main Results:
Ephedrine increased heart rate and mean blood pressure. After ephedrine 0.1 mg/kg i.v., the maximum pressor response in the trimethaphan group was approximately twofold that of the nitroglycerin group (p = 0.038).
Conclusions:
Ephedrine restored BP more easily in those patients who had received trimethaphan compared with those who had received nitroglycerin for deliberate hypotension.
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