Labetalol decreases cerebral perfusion pressure without negatively affecting cerebral blood flow in hypertensive gravidas.
OBJECTIVE
To research the cerebral hemodynamic effects of labetalol in pregnant women with hypertension.


METHODS
Prospective observational study.


METHODS
Tertiary Care Medical Center.


METHODS
Pregnant patients with hypertension.


METHODS
Transcranial Doppler (TCD) ultrasound was used to measure the blood velocity in the middle cerebral arteries (MCA) of eight pregnant patients with hypertension, before and after the administration of a 200 mg oral dose of labetalol. Five patients had severe preeclampsia, and three had chronic hypertension with superimposed preeclampsia. MCA blood velocity and systemic blood pressure were measured simultaneously at the baseline, and at 60 and 180 min after labetalol. Selected cerebral hemodynamic parameters were compared with normative curves. Values outside of the 5th and 95th percentiles were regarded as abnormal.


METHODS
Cerebral perfusion pressure (CPP), resistance area product (RAP), and cerebral flow index (CFI).


RESULTS
Patient age, gestational age, and parity were similar to those of the normal women from whom the normative data were obtained. Women with hypertension had higher baseline CPP, MAP, and RAP than normal pregnant women, but their CFI was within the normal range. Labetalol reduced the CPP, as well as the systolic, diastolic, and mean BP significantly at 60 and 180 min without significantly affecting the heart rate, MCA velocities, RAP, or CFI.


CONCLUSIONS
Labetalol effectively reduces CPP, without affecting cerebral perfusion, primarily by a decrease in systemic blood pressure. This makes it an ideal agent for blood pressure control in severely hypertensive pregnant women.
Belfort
Michael A
MA
Division of Maternal-Fetal Medicine, Department of Obstetrics, University of Utah School of Medicine, Salt Lake City, UT, USA. uvmbelfo@ihc.com
Tooke-Miller
Cathy
C
Allen
John C
JC
Dizon-Townson
Donna
D
Varner
Michael A
MA
D000328:Adult; D000704:Analysis of Variance; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D005260:Female; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D007741:Labetalol / Q000494:pharmacology*; D011225:Pre-Eclampsia / Q000188:drug therapy / Q000503:physiopathology*; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000188:drug therapy / Q000503:physiopathology*; D011446:Prospective Studies; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial; D014655:Vascular Resistance
D000959:Antihypertensive Agents; D007741:Labetalol