A Comparative Study of Intravenous Labetalol with Oral Antihypertensive Combination Nifedipine and Alphamethyldopa in the Acute Preoperative Management of High Blood Pressure in Severe Pregnancy Induced Hypertension Patients

INTRODUCTION: Normal pregnancy is characterized by unique physiological changes. It is mandatory for an anesthesiologist to understand these changes and their anesthetic implications. Pregnancy induced hypertension (PIH) is a disorder of unknown etiology affecting 5-10% of all pregnancies characterized by the development of hypertension with proteinuria after 20 weeks of gestation. Hypertension-Sustained systolic pressure of at least 140mmHg or a sustained diastolic pressure of at least 90 mmHg that occurs after 20 weeks of gestation in a woman with previously normal blood pressure. Maternal complications of severe pregnancy induced hypertension include pulmonary edema, intracerebral hemorrhage and renal failure. Fetal complications include intra uterine growth retardation (IUGR), perinatal mortality. Management of severe pregnancy induced hypertension requires multidisciplinary approach. Definitive treatment consists of termination of pregnancy along with prevention of seizures and control of blood pressure. The drugs used in the control of blood pressure are oral antihypertensives like Alphamethyldopa and intravenous agents like Hydralazine, Labetalol, Nitroglycerin etc. Intravenous Labetalol injection is a unique drug with both alpha and beta adrenergic receptor blocking properties. It has both blood pressure and heart rate reducing properties. This makes it a good choice in treating high blood pressure in severe pregnancy induced hypertension patients. Our study is to find out the efficacy of intravenous Labetalol injection in the acute preoperative control of high blood pressure in severe pregnancy induced hypertension (PIH) patients. AIM OF STUDY: The aim of this study is to find out and compare the efficacy of intravenous Labetalol injection with the routinely used regimen of oral antihypertensives tablet Alphamethyldopa and tablet Nifedipine in the acute preoperative control of high blood pressure in severe pregnancy induced hypertension patients. MATERIALS AND METHODS: After obtaining the necessary institutional and ethical committee clearance following study was conducted in the Institute of obstetrics and gynecology, (IOG), Madras Medical College & Research Institute, Chennai . All antenatal mothers were screened for severe pregnancy induced hypertension (PIH) in the casualty department and 40 patients with severe PIH were selected. Informed consent was obtained from them and randomly divided into 2 groups namely group A and group L of 20 each. Inclusion criteria: (any one of the following): 1. Systolic blood pressure> 160mmHg, 2. Diastolic blood pressure>110mmHg, 3. Proteinuria (dipsticks)>+3or+4, 4. History of oliguria or urine output < 500ml in 24 hours, 5. Presenting with imminent features– blurring of vision, epigastric pain, hyperreflexia, HELLP. Exclusion criteria: 1. Secondary hypertension, 2. Cardiac arrhythmia, 3. Bronchial asthma, 4. Diabetes mellitus, 5. Complications due to severe Pregnancy induced hypertension like intracerebral hemorrhage, acute left ventricular failure, coagulopathy, bleeding disorders, 6. Patients already on oral antihypertensives are not included in-group L. SUMMARY: Comparative clinical study of acute preoperative management of high blood pressure in severe pregnancy induced hypertension patients using two methods: one by (Group A) an oral combination of tablets Alphamethyldopa and Nifedepine and other by (Group L) intravenous Labetalol was undertaken at the Institute of Obstetrics and Gynaecology, Madras medical college & research institute, Chennai during the year 2006-2008. Summarizing the findings in the study: 1. Oral antihypertensive combination of tablets Alphamethyldopa and Nifedepine achieved blood pressure control that often necessitated intravenous Nitroglycerin as rescue drug. 2. Intravenous Labetalol achieves adequate and faster blood pressure control with better heart rate maintenance than the routinely used oral antihypertensive combination. CONCLUSION: In conclusion, intravenous Labetalol achieves adequete and faster blood pressure control with better heart rate maintenance than the routinely used oral antihypertensive combination of tablets Alphamethyldopa and Nifedipine in the control of blood pressure in preoperative severe pregnancy induced hypertension patients