ch05 peb & eklampsia

SECOND EDITION OF THE ALARM INTERNATIONAL PROGRAM SYLLABUS

CHAPTER 5

PREGNANCY INDUCED HYPERTENSION

Learning Objectives: Define pregnancy induced hypertension Review appropriate fetal / maternal assessment Discuss appropriate anti-hypertension and anti-seizure therapy Recognize when and how to transport patients with pregnancy induced hypertension

A 32 year-old G2P1 woman presents for her routine prenatal visit at 32 weeks gestation. Her BP is 140/90. In the past, it has been 115/75 to 130/85 throughout the pregnancy. Her weight is 105 kg. What steps do you perform as part of your initial investigation?__________________________________________________________________________________________________________________________________________________________________________________________

Repeat blood pressures over the next three hours range from 140/90 to 155/95. What is your management plan?__________________________________________________________________________________________________________________________________________________________________________________________

A 25-year-old G1 woman at 38 weeks presents with right upper quadrant pain. Her blood pressure is 170/105 and her urine dips 3+ for protein. What are your initial investigations?__________________________________________________________________________________________________________________________________________________________________________________________

What is your management plan?__________________________________________________________________________________________________________________________________________________________________________________________

Hypertensive disorders in pregnancies are the leading causes of maternal death in emerging countries.

All caregivers must be able to promptly recognize the signs, symptoms and laboratory findings of gestational hypertension with or without proteinuria and with other adverse manifestations. Caregivers must appreciate fully the seriousness of gestational hypertension, its potential for multi-organ involvement and the risks for perinatal and maternal morbidity and mortality.

The appropriate management of gestational hypertension may vary based on the availability of resources. The roles for rural and remote primary obstetrical caregivers may be quite different when factors such as geography, weather and access to specialists or tertiary care centres are considered. Primary caregivers may be faced with emergent situations such as stabilising or treating women with gestational hypertension. The management of gestational hypertension with proteinuria and other adverse manifestations is relevant to all maternity health care givers.

Although gestational hypertension is often viewed as a disease of nulliparous women, several important exceptions occur. Those situations where multiparous women are at increased risk of gestational hypertension include: Women with pre-existing hypertension Women with renal disease Women with diabetes mellitus Women carrying a first pregnancy conceived with a new partner Women with multiple pregnancy

ALARM INTERNATIONAL *Chapter 5 - Pregnancy Induced Hypertension * 85


5.0.1 Classification and Definition of Hypertensive Disorders in Pregnancy

Women may experience hypertension in pregnancy with or without proteinuria and with or without adverse manifestations. Therefore, the current diagnostic classification of hypertension in pregnancy is useful to review.

There are many classifications in the world for hypertensive disorder in pregnancy. The following classifications have been found useful in delivery with hypertension in pregnancy.

1) Classification:

1. Pre-existing hypertension (chronic hypertension) Essential Secondary

2. Gestational hypertension without proteinuria (Pregnancy In Hypertension, transient hypertension, non-proteinuric gestational

hypertension) - without adverse conditions- with adverse conditions (severe preeclampsia, eclampsia)

with proteinuria (PIH, preeclampsia, toxemia)- without adverse conditions- with adverse conditions (severe preeclampsia, eclampsia)

3. Pre-existing hypertension with superimposed gestational hypertension with proteinuria (chronic hypertension with super-imposed pre-eclampsia)

4. Unclassifiable antenatally

2) Definitions

Hypertension

diastolic BP of 90 mmHg is most often used clinically absolute value of 140/90 mmHg

Blood pressure should be determined using

Sitting position with arm at heart level Appropriate size cuff Accurate mercury sphygmomanometer Repeat BP in 4 hours unless very high (diastolic 110 mmHg)

An absolute systolic or diastolic BP reading is the preferred criterion rather than an incremental rise of 30/15 mmHg, although this observation may have clinical significance.

Proteinuria

- urine protein 2+ on dipstick- urine protein 300mg/L on 24 hour collection

Proteinuria indicates glomerular dysfunction 24 hour urine should be considered if urine protein l+ on dipstick

Edema

Edema is no longer part of the diagnosis of gestational hypertension



Manifestations of Severity

The criteria for gestational hypertension with or without proteinuria and with adverse conditions are hypertension plus any of:

Diastolic BP >110 mmHg Platelets <100,000/mm Oliguria <500 mL/d Proteinuria >3g/d Elevated uric acid Elevated liver enzymes Haemolysis, Elevated Liver Enzymes and Low Platelets (HELLP Syndrome) Pulmonary edema Convulsion (eclampsia) Severe nausea and vomiting RUQ/epigastric pain Frontal headache Visual disturbance Abruptio placenta Desseminated Intravascular Coagualtion (DIC)

The appearance of any of these manifestations of multi-organ involvement or the development of gestational hypertension remote from term constitutes an obstetrical emergency. This emergency may need to be managed in conjunction with other consultants (including hematological, neonatal, nursing, obstetric experts), with access to laboratory, blood bank, pharmacy and hospital facilities. Caregivers who lack ready access to many of these resources should develop protocols for their institutions for the rare emergent case that cannot be transferred to a high-risk care centre.

5.0.2 Management and Treatment of Gestational Hypertension

1) Management

The initial evaluation of a woman with gestational hypertension involves assessment of her symptoms, physical condition and laboratory findings as well as assessment of the fetus.

Assessment of Mother – Clinical

Blood Pressure

record the BP in the lateral position be consistent in measuring BP

Central Nervous System

presence and severity of headache visual disturbance- blurring, scotomata tremulousness, irritability, somnolence hyperreflexia

Hematologic

bleeding, petechiae



Hepatic

RUQ and epigastric pain severe nausea and vomiting

Renal

urine output and colour

Non-dependent edema

Assessment of Fetus

Minimal assessment of the fetus includes documentation of fetal movements , fetal heart rate and fundal height.

Additional studies include:

Fetal movement

2) Treatment

Immediate treatment should include managing symptoms such as nausea and vomiting with an antiemetic to minimize maternal discomfort. Maternal pain (right upper quadrant, headache, etc.) should be managed appropriately. A component of maternal hypertension is adrenergic and may be modified by stress reduction.


Assessment of Mother - Laboratory

Hematologic

Hemoglobin, platelets, blood film PTT, PT(INR), Fibrinogen, FDP

Hepatic

ALT, AST, LDH, bilirubin Glucose and ammonia may be tested to rule out acute fatty liver of pregnancy

Renal

Proteinuria Creatinine, urea, uric acid 24 hour urine collection

Fetal heart rate tracing - NST Ultrasound for growth Amniotic fluid volume (AFV) Biophysical profile Doppler flow studies


Stress Reduction

Quiet environment Clear explanation of management plan to patient/family Minimize of negative stimuli Consistent, confident team approach

The decision to institute antihypertensives may vary from one centre to the next because clear evidence is lacking about the benefit of medicating women whose diastolics are in the range of 95-105.

The use of antihypertensives reduces the risk of cardiovascular accident (CVA) in the mother but does not necessarily reduce the risk of seizures (eclampsia) or prevent adverse fetal outcomes such as International U Growth Restriction (IUGR).

Antihypertensives - When to Institute

Diastolic BP 110 mm Hg. Diastolic BP 95 to 109 with other adverse manifestations

The agents used can be divided into those used for acute and ongoing therapy.

Acute therapy

Arteriolar Dilators- hydralazine

-Blockers- labetalol

Calcium Channel Blockers- nifedipine

Maintenance therapy

Centrally Acting Sympatholytic Agents- methyl-dopa

-Blockers- atenolol - labetalol

Calcium Channel Blockers- nifedipine

The Cochrane Database states that “there is no evidence to justify a strong preference for any one of the various drugs that are available for treating severe hypertension in pregnancy.” Obstetrical caregivers should choose the agents with which they are most familiar. Sublingual (adolate) should not be used in gestational hypertension.

REMEMBER THAT ACE INHIBITORS ARE CONTRAINDICATED IN PREGNANCY.

Seizures

Prevention of seizures is the next step in stabilizing a woman who has gestational hypertension. Blood pressure is not a reliable predictor of the risk of seizures. There is a high "number needed to treat" to prevent seizures in women with gestational hypertension with proteinuria. There is no benefit to prophylaxis in the absence of proteinuria. Anticonvulsant agents are not innocuous nor completely effective.



MgS04 is the agent of choice when seizure prophylaxis is indicated.

Two recent studies have shown clearly that magnesium sulfate is superior to phenytoin (Dilantin) for prevention of seizures, and that magnesium sulfate is superior to either diazepam (Valium) or phenytoin for preventing further seizures after seizures have occurred.

Magnesium Sulfate

Dosage - 4g IV followed by 1-4 g/hour IV Side effects - weakness, paralysis, cardiac toxicity Monitor - reflexes, respiration, level of consciousness, urine output Caution should be exercised when combined with calcium channel blockers (i.e. Adalat)

THE ANTIDOTE TO MAGNESIUM IS: 10cc OF 10% CALCIUM GLUCONATE, IV OVER 3 MINUTES (avoiding overdose is preferable!)

Transport

When local resources are limited and maternal and fetal conditions permit, the outcome may be improved by transporting the mother to an appropriate referral centre. Principles to be addressed prior to transport include: Maternal blood pressure stable Fetus stable Seizure prophylaxis if appropriate MgSO4 5gm intra muscular in each buttock is recommended for transportation Delivery - The Cure

Timely delivery minimises maternal and neonatal morbidity and mortality Optimise maternal status before intervention to delivery Delay delivery to allow transfer only when maternal and fetal condition permit Delay delivery to gain fetal maturity only in selected cases, <34 weeks and in a high-risk care centre Gestational hypertension is a progressive disease Expectant management is potentially harmful in the presence of severe gestational hypertension, fetal

maturity or suspected fetal compromise.

When to Deliver

37 weeks with gestational hypertension 34 weeks with severe gestational hypertension < 34 weeks with any of :

- diastolic BP 110 mm Hg despite the use of appropriate antihypertensive agents- laboratory evidence of end organ involvement despite good BP control

- decreasing platelets or increasing liver function enzines - severe proteinuria

suspected fetal compromise recurring seizures symptoms unresponsive to appropriate therapy

- severe headaches or visual disturbance - nausea, vomiting or RUQ/epigastric pain

Peripartum Management

Do not reduce BP too low resulting in decrease uteroplacental perfusion



Do not fluid overload A team approach is essential

POSTPARTUM MANAGEMENT

Gestational hypertension may worsen following delivery. All women must be followed carefully in the postpartum period with ongoing attention to blood pressure control. Gestational hypertension may occasionally also present in the postpartum period.

5.0.3 Summary

Severe gestational hypertension is an obstetrical emergency, which requires prompt recognition, stabilization of mother and fetus and a multi-disciplinary approach to management and treatment. The primary obstetrical caregiver in rural and remote areas may have to assume the role of one or several specialists until help or transfer is available. The cure of severe gestational hypertension is delivery, but the decision to deliver is based on maternal status and fetal maturity and well-being. The rationale for antihypertensive treatment is to prevent maternal CVA, not seizures. Seizure prophylaxis when appropriate should be magnesium sulfate. Currently there is no agent that has been shown to be useful in the prevention of gestational hypertension

Suggested Reading:1. World Health Organization. Detecting pre-Eclampsia: A Practical Guide. Geneva, 1992.


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