Respiratory function in severe gestational proteinuric hypertension: the effects of rapid volume expansion and subsequent vasodilatation with verapamil

Hypertensive disorders of pregnancy: what the physician needs to know

Hypertension developing during pregnancy may be caused by a variety of different pathophysiological mechanisms. The occurrence of proteinuric hypertension during the second half of pregnancy identifies a group of women whose hypertensive disorder is most likely to be caused by the pregnancy itself and for whom the risk of complications, including maternal mortality, is highest. Physicians identifying patients with hypertension in pregnancy need to discriminate between pre-eclampsia and other forms of hypertensive disease. Pre-eclamptic disease requires obstetric intervention before it will resolve and it must be managed in a multidisciplinary environment. The principles of diagnosis and management of these different entities are outlined in this review.

Decompensated Heart Failure in Pregnancy

Heart disease is a common cause of morbidity and mortality during pregnancy. Symptoms and signs of heart failure in a pregnant woman are an indication for urgent assessment to establish a diagnosis and appropriate management. This is best accomplished through a multidisciplinary approach in which both cardiologists and obstetricians need to participate in order to provide expert counselling and care in pursuit of safe motherhood. Congenital heart disease, although common, once corrected is an unusual source of complications, which are more likely to develop as a consequence of ventricular failure, pulmonary hypertension and aortic arch disease. Rheumatic valvular heart disease is a challenge because of the need for anticoagulation during pregnancy and the risk of sepsis associated with childbirth. This review outlines a contemporary approach to heart failure presenting during pregnancy.

Fluid management in pre-eclampsia

Intravenous fluid given to women with pre-eclampsia may be a necessary form of treatment; however, intravenous fluid therapy can also cause iatrogenic pulmonary oedema. The indications for the use of intravenous fluids, the titration of the amount of fluid given and the use of invasive monitoring have not been subject to adequate examination in randomised studies. Clinical experience, combined with available evidence and a reasoned approach are the basis for a suggested management algorithm.

Management of eclampsia at Assiut University Hospital, Egypt

OBJECTIVE

To evaluate the protocol used for management of eclampsia at Assiut University Hospital, Assiut, Egypt.

METHODS

In a prospective cross-sectional study, data were collected from 1998 women treated for eclampsia at Assiut University Hospital between January 1990 and January 2010, including 1594 cases of prepartum eclampsia, 75 of intrapartum eclampsia, 16 of intercurrent eclampsia, and 313 of postpartum eclampsia. The treatment regimen included use of nifedipine as an antihypertensive, magnesium sulfate as an anticonvulsant, rapid interruption of pregnancy, and admission to the ICU. Data were evaluated for control of blood pressure, prevention and control of convulsions, and maternal and perinatal outcomes.

RESULTS

Magnesium sulfate was effective in controlling convulsions in 98.1% of women. Nifedipine initiated a smooth decline in blood pressure (P>0.0001). There were 79 maternal deaths (3.95%). Maternal morbidity occurred in 439 (22%) women. Twenty-seven percent of women delivered vaginally (most of these women were admitted postpartum). Perinatal mortality occurred in 7.9% of cases.

CONCLUSION

A combination of nifedipine as an antihypertensive drug, magnesium sulfate as an anticonvulsant, rapid interruption of pregnancy, and managing the patients in the ICU resulted in a marked improvement in the outcome for both mother and fetus at Assiut University Hospital.

The role of calcium channel blockers in the treatment of women with preeclampsia

Preeclampsia was originally known as a process whereby an unknown “toxin” was responsible for a variety of responses. While this toxin has yet to be determined, many theories have prevailed as to the appropriate therapy for this condition.

Recently, antihypertensive therapy has become increasingly regarded as an important component of the medical management of women with preeclampsia. Initially, the ideal therapy for peripartum acute hypertensive emergencies was felt to be a smooth muscle relaxant and the most commonly prescribed agent was hydralazine. This drug was felt to be beneficial because of its action on vascular smooth muscle, decreasing vasospasm. Outside of the United States diazoxide was also used for this purpose, although this drug has been replaced because of the high incidence of fetal distress. Another agent that was frequently used was α-methyldopa which was initially considered to be the treatment of choice in the treatment of patieats with moderate and severe preeclampsia. Recently, α-methyldopa has been reserved for the outpatient management of gestational hypertension, especially in women with mild preeclampsia or chronic hypertension.

Critical care management of severe pre-eclampsia

Severe pre-eclampsia is a common disorder in developing countries but still remains a significant problem in developed societies. The management of severe pre-eclampsia in developing countries is frequently hampered by lack of adequate facilities; paradoxically those countries with sufficient resources have a lower incidence of the disease and consequently lack experience in the treatment of severe pre-eclampsia. The management of these patients is further compromised because obstetricians generally lack the necessary knowledge and skills in critical care and conversely critical care specialists may lack appreciation and knowledge of pregnancy physiology and pathophysiology. Patients with severe pre-eclampsia therefore present an interdisciplinary challenge to obstetricians and physicians, who need to be familiar with pregnancy physiology and the current concepts in the pathogenesis and pathophysiology of severe pre-eclampsia. Patients who develop multisystem disease are most appropriately managed by an experienced obstetrician in an obstetric intensive care unit with a physician in consultation.

Cardiopulmonary complications of pregnancy

OBJECTIVES

To provide an up-to-date review of the literature on the assessment and management of pulmonary and cardiac conditions that may affect women during pregnancy and the postpartum period.

DESIGN

A review of the current literature was performed.

RESULTS

Pregnancy may be complicated by a variety of pregnancy-specific and other cardiopulmonary complications. Management requires knowledge of the cardiopulmonary physiologic changes occurring in pregnancy, the pregnancy-specific conditions that may occur, and the effect of a fetus on maternal care.

CONCLUSIONS

Admission of the pregnant or postpartum woman to the intensive care unit is uncommon but may require specialized knowledge for successful management.

Haemodynamic, invasive and echocardiographic monitoring in the hypertensive parturient

AIM

To determine the clinical usefulness of invasive and non-invasive haemodynamic assessment in pre-eclampsia.

METHOD

A systematic review of the literature was undertaken, using a MEDLINE electronic search using a combination of MESH headings and textwords. Over 1500 abstracts were perused; we obtained 156 full papers that were related to the subject matter. Of the full papers, 55 yielded relevant information. Hand-searching the reference lists of the retrieved papers completed the search.

RESULTS

There are no data from randomized controlled clinical trials illustrating the clinical usefulness of pulmonary artery catheters or echocardiographic techniques in hypertensive pregnancy. There are a wealth of data illustrating the haemodynamic profiles of both untreated and treated pre-eclamptic women. Data are also available comparing right heart and left heart filling pressures, demonstrating a relatively poor correlation between the two values. The clinical impact of either measurement is unclear. Data are available illustrating the correlation between echocardiographic techniques and pulmonary artery catheterization.

Care of the critically ill parturient: oliguria and renal failure

The incidence of acute renal failure in pregnancy has decreased. This decrease is less marked in developing countries in which resources are more scarce. The clinical diagnosis of acute renal failure is crude due to the variability of clinical signs and the late occurrence of basic biochemical abnormalities. Obstetric and gynaecological diseases are found among the traditional pre-renal, intra-renal and post-renal causes of acute renal failure. The cornerstone of management is the identification of high-risk cases and the prevention of acute renal failure by maintaining intravascular volume. The evidence for the efficacy of other prophylactic medical interventions, such as the use of loop diuretics, mannitol, low-dose dopamine and others, is poor. Management of established acute renal failure includes restoration of intravascular volume, treatment of any reversible causes, especially pregnancy complications such as pre-eclampsia, strict fluid balance and correction of any electrolyte abnormality or metabolic acidosis. Dialysis is a supportive measure until the kidneys recover.

Pharmacological treatment of severe hypertension in pregnancy and the role of serotonin(2)-receptor blockers

Hypertensive disorders of pregnancy are the leading cause of maternal and perinatal mortality and morbidity in developing and developed countries. The etiology of preeclampsia is still unknown. Delivering the baby is the only definite treatment. The benefits of acute pharmacological control of severe hypertension prior to and/or post-delivery are generally accepted. Most drugs commonly used in the management of severe hypertension in pregnancy have significant maternal and/or neonatal adverse side effects. Furthermore, some are not effective to acutely lower the blood pressure in patients with a hypertensive crisis. Until recently not one of the commonly used antihypertensive drugs has been tailored to the pathophysiology of severe preeclampsia, being a clinical syndrome characterized by endothelial cell dysfunction, vasospasm and platelet aggregation. Ketanserin, a serotonin(2)-receptor blocker, is a drug that appears to be tailored for treating this pregnancy-associated enthothelial cell dysfunction. The results of several prospective trials show that there is a definite place for serotonin(2)-receptor blockers in the treatment of pregnancy-induced hypertensive disorders. This review provides a summary on the more established drugs as well as on some of the newer antihypertensive drugs used in pregnancy with emphasis on the existing experience with ketanserin.

Anesthetic management of preeclampsia/eclampsia

Preeclampsia/eclampsia affects only a small proportion of all pregnancies, yet accounts for much of the obstetric morbidity and mortality seen in the USA and UK. A full understanding of preeclampsia/eclampsia, its variable presentation and complex pathophysiology allows the consulting anesthesiologist to optimize a plan for anesthetic management of the afflicted patient.

Cerebrovascular disorders complicating pregnancy--beyond eclampsia

OBJECTIVE

Our purpose was to investigate the problems encountered in the diagnosis and management of cerebrovascular disorders associated with pregnancy and the puerperium.

STUDY DESIGN

Pregnancies complicated by cerebrovascular disorders were identified by retrospective chart review (1985 to 1995). Events associated with trauma, neoplasm, drug ingestion, and infection were excluded.

RESULTS

The study population comprised 24 women with a variety of cerebrovascular disorders: 14 with infarction (5 arterial, 9 venous), 6 with intracranial hemorrhage (3 anatomic malformation, 3 unknown etiology), 3 with hypertensive encephalopathy, and 1 with an unruptured aneurysm. Blood pressure reflected physical condition at presentation and did not predict diagnosis or outcome except in the 3 women with hypertensive encephalopathy. Only 4 of 14 women with infarction and 1 of 6 with intracranial hemorrhage had a diastolic blood pressure > or = 110 mm Hg. Presumption of eclampsia delayed the diagnosis in 10 women (41.7%). In addition, patient delay in seeking medical attention complicated 10 cases. After review, none of the adverse maternal outcomes were deemed preventable by earlier physician intervention. Seven maternal deaths occurred (29.2%). Neonatal outcome was related to the gestational age and the maternal condition at presentation.

CONCLUSION

Cerebrovascular disorders are an uncommon and unpredictable complication of pregnancy that are associated with substantial maternal and fetal mortality. Suspected eclampsia unresponsive to magnesium sulfate therapy warrants an immediate neuroimaging study. Interestingly, in women with intracranial hemorrhage, severe hypertension was not an associated predictive factor.

Use of the pulmonary artery catheter in severe preeclampsia: a review

The use of a balloon-tipped, flow-directed pulmonary artery catheter in critically ill and surgical patients has become commonplace in the United States since its introduction into clinical medicine in 1970. The capability of acquiring continuous hemodynamic and, more recently, oxygen transport data, has led to an enhanced understanding of pathophysiologic processes in disease states and to an improved ability to guide therapeutic decision making. The purpose of this paper is to review experience with the pulmonary artery catheter in subsets of women with severe preeclampsia.

Nimodipine in the management of preeclampsia: maternal and fetal effects

OBJECTIVE

Our purpose was to determine the effects of orally administered nimodipine on selected maternal and fetal parameters in patients with preeclampsia.

STUDY DESIGN

Ten consecutive patients were given 30 mg of nimodipine orally every 4 hours from admission until 24 hours after delivery. Maternal and fetal cerebral blood velocity, umbilical artery blood velocity, fetal heart rate variability, maternal blood pressure and heart rate, and transplacental passage of the drug were studied. All 10 patients were delivered within 24 hours of the first dose of nimodipine.

RESULTS

There was an acute and significant reduction in the pulsatility index in the smaller diameter maternal cerebral arteries (ophthalmic and central retinal) and in the fetal middle cerebral artery. The umbilical artery systolic/diastolic ratio was also significantly reduced. Maternal blood pressure was controlled without the need for other antihypertensive medication, and although there was an increase in heart rate after administration of the drug, it was well tolerated. Nimodipine reached significant maternal and fetal levels within 2 hours.

CONCLUSIONS

Nimodipine is rapidly absorbed after oral administration and has significant maternal and fetal cerebral vasodilator activity. It is an effective, easily administered antihypertensive agent when used in patients with preeclampsia.

Oxygen delivery and consumption in critically ill pregnant patients: association with ophthalmic artery diastolic velocity

OBJECTIVES

We aimed to investigate the relation between orbital vessel flow velocity and oxygen delivery, oxygen consumption, cardiac index, and systemic vascular resistance index in critically ill pregnant patients.

STUDY DESIGN

Eighteen pregnant or early postpartum patients requiring invasive monitoring were prospectively studied with Doppler ultrasonography. The blood flow velocity and resistance index from the central retinal and ophthalmic arteries were plotted against the oxygen delivery index, oxygen consumption index, cardiac index, and systemic vascular resistance index. Linear and polynomial regression analysis and receiver-operator characteristic curves were used to examine the data.

RESULTS

The ophthalmic artery resistance index correlated with oxygen consumption, oxygen delivery index, and cardiac index. Only the cardiac index was independently related to the the ophthalmic artery resistance index. The ophthalmic artery diastolic velocity correlated with oxygen consumption index, oxygen delivery index, and cardiac index. The ophthalmic artery diastolic velocity correlated independently with mixed venous oxygen content and arteriovenous oxygen content difference. The central retinal artery Doppler index did not correlate with any of the invasively measured parameters. An ophthalmic artery diastolic velocity of > 7.12 cm/sec identified 75% of patients with an oxygen consumption index of < 140 ml/min per square meter and 91% of patients with an oxygen delivery index of < 600 ml/min per square meter.

CONCLUSIONS

These data suggest that the ophthalmic artery flow velocity is correlated with systemic oxygen delivery and consumption. This relationship may have potential research applications in the noninvasive assessment of oxygen delivery index and oxygen consumption index in critically ill pregnant patients.

The effect of acute volume expansion and vasodilatation with verapamil on uterine and umbilical artery Doppler indices in severe preeclampsia

Preeclampsia is associated with increased peripheral, uterine, and umbilical artery resistance. Acute blood pressure reduction may result in shunting of blood and sudden fetal distress. We therefore investigated the effects of volume expansion and verapamil therapy on uteroplacental and umbilical resistance during treatment of preeclampsia.

MATERIALS AND METHODS

Five severe preeclamptics underwent volume expansion and subsequent vasodilatation with an infusion of verapamil. Invasive hemodynamic monitoring and Doppler ultrasonography were used to study changes in maternal, uterine, and umbilical hemodynamics.

RESULTS

Volume expansion and subsequent verapamil therapy was associated with significant changes in maternal hemodynamics without significant change in uteroplacental or umbilical resistance. Uterine artery waveform changes were noted, with disappearance of notching in some cases.

CONCLUSIONS

Volume expansion and verapamil therapy effectively reduces maternal blood pressure in preeclampsia, without adversely affecting uteroplacental or umbilical artery resistance. Uterine artery waveform changes may be associated with improved fetal outcome.

The oxygen consumption/oxygen delivery curve in severe preeclampsia: evidence for a fixed oxygen extraction state

OBJECTIVE

Increased total body oxygen consumption requirements are usually met by increased oxygen delivery and increased oxygen extraction. In certain conditions (e.g., adult respiratory distress syndrome) the ability to increase oxygen extraction is lost, and any increase in oxygen consumption depends on increased oxygen delivery. The objective of this study was to investigate the oxygen delivery/oxygen consumption relationship in severe preeclampsia.

STUDY DESIGN

Thirty-two patients with severe preeclampsia (blood pressure > 160/110 mm Hg; 3 to 4+ proteinuria) were monitored with a pulmonary artery catheter. Baseline oxygen consumption and delivery in a group without volume expansion or pharmacologic vasodilatation were compared with those in a group who had received a magnesium sulfate infusion.

RESULTS

Oxygen consumption, oxygen delivery, arterial-venous-oxygen difference, and the oxygen extraction ratio were low when compared to that for normal 32 to 38 week pregnancy. The oxygen extraction ratio, defined as the ratio of oxygen consumption to oxygen delivery, was abnormally low for pregnancy, especially considering the low oxygen delivery levels in these patients. Oxygen consumption was dependent on oxygen delivery over the entire range of values seen.

CONCLUSIONS

Severe preeclampsia is associated with an abnormality of tissue oxygen extraction, as evidenced by a low and unresponsive oxygen extraction ratio. Oxygen consumption increases proportionately with increases in oxygen delivery without reaching an oxygen delivery-independent state. Even at high oxygen delivery levels the oxygen consumption in preeclamptic patients is still abnormally low for pregnancy.