Hemodynamic effects of oral nifedipine in preeclamptic hypertensive emergencies.

OBJECTIVE Our purpose was to evaluate the hemodynamic effects of oral nifedipine in preeclamptic hypertensive emergencies. STUDY DESIGN A prospective observational study of the hemodynamic effects of oral nifedipine was conducted with severely preeclamptic patients receiving magnesium sulfate infusion during a hypertensive emergency. Patients were eligible for the study if systolic blood pressure was > or = 170 m Hg or the diastolic blood pressure was > or = 105 mm Hg on repeat measurements 15 minutes apart at > or = 24 weeks' gestation. Nifedipine was given with an initial dose of 10 mg orally followed by 20 mg orally every 20 minutes until systolic blood pressure was > 160 mm Hg and the diastolic blood pressure was < 100 mm Hg, or for a total of five doses. Patients were hemodynamically monitored in the lateral recumbent position by thoracic electrical bioimpedance before during, and after oral nifedipine dosing. Cardiac index, systemic vascular resistance index, mean arterial pressure, heart rate, and stroke index were all recorded at baseline and during treatment. Data were analyzed by analysis of variance for repeated measures (alpha 0.05) and paired t tests, baseline versus 15 minutes (alpha 0.01). RESULTS Ten severely preeclamptic patients at 33.2 +/- 3.0 (mean +/- SD) weeks' gestation were enrolled in the study. Mean arterial pressure measurements taken at baseline, 0.25, 0.5, 1, and 4 hours were 133 +/- 10, 119 +/- 8, 109 +/- 8 89 +/- 12, and 100 +/- 13 mm Hg (mean +/- SD, p < 0.0001, analysis of variance repeated measures). Cardiac index increased over time (p = 0.0011, analysis of variance repeated measures). There was no significant effect on maternal heart rate or stroke index. No periodic fetal heart rate changes were noted. One patient had nausea. CONCLUSION Oral nifedipine appears to be an effective antihypertensive agent in preeclamptic hypertensive emergencies. A steady decrease in mean arterial pressure, systemic vascular resistance, and a mirrored increase in cardiac index are noted.

[1]  B. Sibai.  Management of preeclampsia. , 1991, Clinics of Perinatology.

[2]  R. Erbel,et al.  Emergency treatment of hypertensive crisis with sublingual nifedipine. , 1983, Postgraduate medical journal.

[3]  R. Hayashi,et al.  Systemic and pulmonary blood pressure during caesarean section in parturients with gestational hypertension , 1980, Canadian Anaesthetists' Society journal.

[4]  William C. Shoemaker,et al.  Multicenter trial of a new thoracic electrical bioimpedance device for cardiac output estimation , 1994, Critical care medicine.

[5]  A. Ellrodt,et al.  Efficacy and safety of sublingual nifedipine in hypertensive emergencies. , 1985, The American journal of medicine.

[6]  L. M. Mayorga,et al.  Magnesium Plus Nifedipine: Potentiation of Hypotensive Effect in Preeclampsia? , 1988, American journal of obstetrics and gynecology.

[7]  R. Newman,et al.  Favorable hemodynamic effects of magnesium sulfate in preeclampsia. , 1995, American journal of obstetrics and gynecology.

[8]  M. Cardwell,et al.  Neuromuscular blockade with magnesium sulfate and nifedipine , 1989 .

[9]  J. Ouzounian,et al.  Measurement of cardiac output in pregnancy by thoracic electrical bioimpedance and thermodilution. A preliminary report. , 1989, American journal of obstetrics and gynecology.

[10]  W. Frishman,et al.  Calcium entry blockers for the treatment of severe hypertension and hypertensive crisis. , 1984, The American journal of medicine.

[11]  B. Sibai,et al.  A randomized prospective comparison of nifedipine and bed rest versus bed rest alone in the management of preeclampsia remote from term. , 1992 .

[12]  J. Pivarnik,et al.  A Comparison of Cardiac Index in Normal Term Pregnancy Using Thoracic Electrical Bio‐Impedance and Oxygen Extraction (Fick) Techniques , 1994, Obstetrics and gynecology.

[13]  T. Raffin,et al.  Reliability of the thermodilution method in the determination of cardiac output in clinical practice. , 2015, The American review of respiratory disease.

[14]  S. Lindow,et al.  The effect of sublingual nifedipine on uteroplacental blood flow in hypertensive pregnancy , 1988, British journal of obstetrics and gynaecology.

[15]  R. G. Mcallister.  Kinetics and dynamics of nifedipine after oral and sublingual doses. , 1986, The American journal of medicine.

[16]  S. Lurie,et al.  Effect of Nifedipine on Fetal Heart Rate in the Treatment of Severe Pregnancy-Induced Hypertension , 1990, American journal of perinatology.

[17]  Redman Cw.  The use of antihypertensive drugs in hypertension in pregnancy. , 1977 .

[18]  B. Walters,et al.  Treatment of severe pregnancy‐associated hypertension with the calcium antagonist nifedipine , 1984, British journal of obstetrics and gynaecology.

[19]  S. Lurie,et al.  Nifedipine in the Treatment of Severe Preeclampsia , 1991, Obstetrics and gynecology.

[20]  W. Rj,et al.  [Management of severe pre-eclampsia/eclampsia. Comparison between nifedipine and hydralazine as antihypertensive agents]. , 1993, Ginecologia y obstetricia de Mexico.