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Kathy O’Connell, MN RN

Perinatal Clinical Nurse Specialist

University of Washington Medical Center

koconnll@uw.edu

Objectives

Describe the risk factors, signs and symptoms, patho-

physiology and the nursing management of women with

hypertensive disorders of pregnancy.

Recognize the nursing implications of anticonvulsant and

antihypertensive drugs commonly used in the treatment of

hypertensive disorders of pregnancy.

Discuss the signs and symptoms of HELLP.

Normal Hemodynamic Changes of Pregnancy Blood volume gradually increases by

approximately 40%

Heart rate and stroke volume increase gradually over the course of the pregnancy

Cardiac output increases by approximately 50% by mid third trimester

Peripheral resistance decreases

BP drops slightly, especially during the second trimester

Physiologic Changes of Pregnancy

Heart Rate 20% ↑ by late pregnancy

May be caused by ↓ in SVR

Cardiac Output HR X SV ↑ ( 29% and 18% respectively)

Increases by 10 weeks and peaks @ 30-50% late 2nd Δ

Systemic Vascular Resistance Lowest values between 14-24 weeks

Physiologic Changes of Pregnancy Blood Volume:

Plasma volume ↑ 30-50%

Plasma volume increases by 11% by 7th week with plateau by 32 wks

Red cell volume ↑ 20%

Dilutional anemia of pregnancy

Greater increases in multiple gestations

Blood Pressure Decreases by 9% by 7th week (Clapp, 1988)

Lowest in 2nd Δ

Physiologic Changes of Pregnancy Renal blood flow

↑ 30% by mid pregnancy

GFR ↑ 30-50%

Renal vascular resistance ↓ mediated by progesterone and prostacyclin

Affected by upright posture → lateral bedrest promotes diuresis and ↓ blood pressure

BUN, creatinine, uric acid ↓ by 40%

Amino acid excretion ↑, glucose overwhelms transport mechanisms→urine tr protein, + glycosuria

Pulmonary blood flow ↑ by 32% (Kitabatake, 1983)

↓ pulmonary vascular resistance by 34% (Clark, 1989)

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Physiologic Changes of Pregnancy

Basal Metabolic Rate ↑ 14%

Oxygen Consumption ↑ 21%

Uterine blood flow ↑ 50ml/min @ 10 wks to 500 ml/min @ term (Assali, 1960)

Related to estrogen/progesterone (Ueland, 1966)

Laboratory Values in Normal Pregnancy

Renal Function changes Creatinine Clearance:

122ml/min»170 ml/min (↑ 40%)

BUN: 13 mg/dl»8 mg/dl (↓ 40%)

Creatinine: 0.88mg/dl»0.5 mg/dl (↓ 40%)

Uric Acid: 5 mg/dl»3mg/dl (↓ 40%)

24 hour urine protein: <50 mg/24 hrs » <300 mg/24 hrs Moore TR in Gynecology and Obstetrics: A Longitudinal Approach, 1993

How common is hypertension? 50 million Americans and approximately 1 billion

individuals worldwide

Most common primary diagnosis in the US

Approximately 27% of Americans are hypertensive, but only 23% of that group are taking medications that control their condition

Why do we care about hypertension in pregnancy?

Hypertensive disease occurs in 12-22% of pregnancies

Preeclampsia occurs in 6-8% of pregnancies

Hypertension is responsible for 17.6% of maternal deaths in the US

Hypertension accounts for 15% of antepartum hospitalizations

Negative impact on neonatal morbidity and mortality

Hypertension

Pinched Flow

Resistance

Flow

versus

Hypertension Threshold

Normal Blood Pressure

MAP = CO TPR/80

Pre

ssu

re

High Flow Pinched Flow

Blood Flow & Fetal Growth

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Placental Injury

Definitions and Classifications Chronic Hypertension

Gestational Hypertension

Preeclampsia

Preeclampsia with severe features

Preeclampsia Superimposed on CHTN

HELLP

Eclampsia

Chronic Hypertension (CHTN)

Blood Pressure 140/90 Before pregnancy

Developing before 20 weeks of pregnancy

After 6 weeks postpartum

Gestational Hypertension Elevated blood pressure without proteinuria

developing after 20 weeks Systolic BP 140

Diastolic BP 90

Approximately 25% will develop proteinuria

Gestational Hypertension Elevated blood pressure without proteinuria

developing after 20 weeks Systolic BP 140

Diastolic BP 90

Approximately 25% will develop proteinuria

Preeclampsia Preeclampsia: BP >140 systolic OR > 90 diastolic (on 2 occasions > 4 hours

apart after 20 weeks GA)…. If BP is > 160 OR > 110, preeclampsia is confirmed

And….either….

Proteinuria of 300 mg/24hr (or)

Protein/creatinine ratio > 0.3 (or)

Dipstick 1+

OR (in the absence of proteinuria, new onset HTN w/new onset of ANY of the following):

Thrombocytopenia <100K

Creatinine >1.1 (or doubling of creatinine in absence of renal dz)

↑ AST/ALT to 2X normal

Pulmonary edema

Cerebral or visual symptoms

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Severe Features Severe Features of Preeclampsia: BP >160 systolic OR >

110 diastolic (on 2 occasions > 4 hours apart)

Thrombocytopenia <100K

Creatinine >1.1 (or doubling of creatinine in absence of renal dz)

↑ AST/ALT to 2X normal or severe RUQ or epigastric pain not accounted for by other dx

Pulmonary edema

New onset Cerebral or visual symptoms

High Risk Groups for developing preeclampsia CHTN

Renal Disease

Diabetes

Vascular and connective tissue disease

Antiphospholipid antibody syndrome

Thrombophilias

Preeclampsia in a previous pregnancy

Nulliparous

Age 35 or older

Multiple gestations

African-American race

Obesity

Symptoms of Preeclampsia Swelling or rapid weight gain

Headaches that are more frequent or different than usual

Visual disturbances

Epigastric or right upper quadrant pain, sometimes associated with nausea and vomiting

Preeclampsia Superimposed on CHTN Hypertension before 20 weeks of pregnancy with:

New onset proteinuria

Increase in proteinuria if already present in early pregnancy

Sudden increase in hypertension

Development of HELLP

Headaches, scotomata or epigastric pain

HELLP Syndrome

Severe variant of preeclampsia/eclampsia

Affects up to 12% of patients

H hemolysis

EL elevated liver enzymes (AST >70u/l)

LP low platelets (<100k)

HELLP: Pathophysiology

Vasoconstriction of hepatic bed

Increased hepatic artery resistance

May develop in the absence of significant hypertension and proteinuria

Potential for hepatic infarction and rupture

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HELLP Syndrome Affects primips/multips alike

BP not always severely affected

Liver dysfunction 2° vasospasm

Symptoms include Nausea

Vomiting

Malaise

Epigastric pain

Eclampsia Preeclampsia + seizures = Eclampsia

Etiology?

Hypertensive encephalopathy

Vasospasm

Hemorrhage

Ischemia

Cerebral edema

Eclampsia Seizures occur prior to delivery in 80% of cases

Severe headache/visual disturbances in 83% of cases

Obstetric/fetal emergency Maintain/protect airway

Oxygen

Lateral positioning

Medications

EFM

Management of Preeclampsia Laboratory evaluation

CBC, platelets, creatinine, liver function studies,12/24° urine protein

Limit activity/lateral bedrest

Antihypertensive meds Beta adrenergic blockers (atenolol, labetalol)

Peripheral vasodilators (hydralazine)

Nutrition counseling No added salt (but not restricted)

Rule out renal/endocrine etiologies

Hospital management of Preeclampsia

Bedrest

Expectant Management Stabilization

Steroids as indicated

Titrate meds to clinical picture

Fetal monitoring/baby watch/BPP

Laboratory analysis

Amniocentesis/deliver when mature or disease progresses

Nursing Considerations Frequent VS: BP, P, R, DTRs

Accurate I&O: daily weight

EFM

↓ environmental stimuli

Assure patient safety: siderails/seizure precautions

Lateral positioning

Medications: effects/adverse effects

Emergency equipment

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Medications Magnesium Sulfate

Medication of choice for seizure prevention

Neuromuscular blocking agent » blocks release of acetylcholine at neuromuscular junction

Not antihypertensive but is peripheral vasodilator

Excreted by kidneys

Magnesium Sulfate: Nursing Considerations

Therapeutic levels: 5-8 mg/dl

Frequent VS monitoring Especially respirations >12/min

Intake and Output

DTRs

Assess breath sounds

Loss of DTRs @ 9-13mg/dl

Respiratory Depression @ 14-18 mg/dl

Cardiac arrest @ >18 mg/dl

Magnesium Sulfate

Calcium Gluconate 1gm/IV reverses Mg

Maternal side effects include Nausea

Vomiting

Muscular weakness

Visual changes

Diminished DTRs

Magnesium Sulfate: Fetal Effects

Readily crosses placenta Fetal steady state concentration in several hours

Fetal hypermagnesemia 2° delayed fetal urination

CNS depression

Nonreactive NST

Diminished FBM

Medications: Antihypertensives

Beta adrenergic antagonists Atenolol

Labetolol

Actions ↓ cardiac output by ↓ HR

↓ SVR (Lund-Johnson, 1983)

Fetal effects ↓ fetal weight

Medications: Antihypertensives

Hydralazine (Apresoline) Reduces total peripheral resistance

Relaxes arteriolar smooth muscle

Causes reflex tachycardia

May be given IV or PO

Nifedipine Calcium channel blocker

Relaxes arterial smooth muscle

Can cause exaggerated hypotensive response with magnesium

Rapid onset of action

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Post Partum

Not out of the woods once she’s delivered!!!

Continue Magnesium for 24°

Can seize up to 1 week after delivery

Continue to assess fluid status

Postpartum Preeclampsia

Preeclampsia can develop postpartum

60% of women with preeclampsia worsen within 48 hours

Most maternal deaths from preeclampsia occur postpartum

Postpartum Care of the Inpatient Preeclamptic Woman Goals of treatment

maintain good blood pressure control adjust antihypertensive medications

maintain fluid balance total fluid replacement should not exceed 80-100cc/hr

administration of diuretics as needed

prevention of eclamptic seizures Magnesium sulfate continued for at least 24 hours

Discharge Teaching and Follow Up Educate re: s/s preeclampsia post partum and call

provider if any occur

Limit activity until BP WNL

Follow up with OB provider post partum (soon)

Continue with BP checks post partum and notify provider if > 140/90

Teaching, cont’d Recommend seeing their Primary Care Provider if

normal BP not achieved after 6 - 8 weeks post partum

Discuss lifestyle changes: healthy diet

minimize sodium intake

exercise regularly

maintain normal weight

Case Study 18 year old G1 P1 called L&D on PP day 6 reporting “worst headache” of

her life s/p uncomplicated NSVD at term. Advised to go to ER.

Received neuro work up in ER. Seized while getting an MRI scan, Rx with Hydralazine and Dilantin. Readmitted to L&D and started on MgSO4 and antihypertensives. Discharged 2 days later on Atenolol and Lasix.

Readmit through ER on PP day 11 with splitting HA with BP 190/130s. Rx’d on MgSO4 until BP controlled. Discharged 4 days later on Atenolol, Lasix & Nifedipine.

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Remote Postpartum and Preconception Strategies Achieving or maintaining normal BP

Have BP taken regularly

Lifestyle modifications Weight reduction/increased physical activity

Dietary sodium reduction

Diet high in fruits and vegetables, and low in fat

Moderate alcohol consumption

Antihypertensives as indicated

Recognize increased risk for chronic hypertension associated with hypertension in pregnancy (risk equivalent to smoking)