hypertensive disorders of pregnancy - north puget sound …€¦ · hypertensive disorders of...
TRANSCRIPT
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Kathy O’Connell, MN RN
Perinatal Clinical Nurse Specialist
University of Washington Medical Center
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)