Differential pressor response to intravenous ephedrine during recovery from deliberate hypotension.
OBJECTIVE
To determine whether nitroglycerin or trimethaphan alters pressor response to intravenous (i.v.) ephedrine.


METHODS
Prospective, randomized study.


METHODS
Operating room of a university hospital.


METHODS
60 ASA physical status I female patients scheduled for mastectomy.


METHODS
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.


METHODS
Hemodynamic responses to ephedrine following withdrawal of vasodilators were observed for 15 minutes.


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.
Kanaya
Noriaki
N
Department of Anesthesiology, Sapporo Medical University School of Medicine, Sapporo, Japan. kanaya@sapmed.ac.jp
Nakayama
Yoshito
Y
Nakayama
Masayasu
M
Okazaki
Kayoko
K
Hattori
Jun-ichi
J
Kurosawa
Saori
S
Edanaga
Mitsutaka
M
Namiki
Akiyoshi
A
D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects*; D004809:Ephedrine / Q000008:administration & dosage; D005730:Ganglionic Blockers / Q000008:administration & dosage; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007023:Hypotension, Controlled; D007275:Injections, Intravenous; D008875:Middle Aged; D005996:Nitroglycerin / Q000008:administration & dosage; D011446:Prospective Studies; D013997:Time Factors; D014294:Trimethaphan / Q000008:administration & dosage; D014662:Vasoconstrictor Agents / Q000008:administration & dosage; D014665:Vasodilator Agents / Q000008:administration & dosage
D005730:Ganglionic Blockers; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D014294:Trimethaphan; D005996:Nitroglycerin; D004809:Ephedrine