Hypertension in Pregnancy

1
Hypertension in Pregnancy

• Teresa G. Berg, M.D.
• Maternal-Fetal Medicine
• University Medical Associates

2
OBJECTIVES

• List criteria for the diagnosis of preeclampsia
• List criteria for the diagnosis of severe
  preeclampsia/HELLP syndrome
• Discuss current management considerations

3
Hypertension

• Sustained BP elevation of 140/90 or greater
• Proper cuff size
• Measurement taken while seated
• Use 5th Korotkoff sound

4
Forms of HTN in Pregnancy

• Gestational Hypertension
• Formerly called Pregnancy-Induced Hypertension
• No proteinuria

5
Forms of HTN in Pregnancy

• Gestational Hypertension
• Preeclampsia
• Hypertension with proteinuria
• May have other evidence of end-organ disease
• Edema
• Visual changes
• Headache
• Epigastric pain
• Laboratory changes

6
Older Criteria for Gestational HTN

• 30/15 increase in BP over baseline levels
• No longer appropriate
• 73 of patients will exceed 30 mm systolic and
  57 will exceed 20 mm diastolic

7
Patient Categories
25
8
Forms of HTN in Pregnancy

• Gestational Hypertension
• Preeclampsia
• Chronic Hypertension
• As a group these occur in 12 to 22 of pregnant
  patients and are directly responsible for
  approximately 18 of maternal mortality
  nationally.

9
Chronic Hypertension

• Pre-existing hypertension
• Hypertension before 20 weeks in the absence of
  gestation
• If hypertension persists beyond 6 weeks postpartum

10
Preeclampsia

• Hypertension after 20 weeks of gestation
• Proteinuria- 300mg
• Edema

11
Preeclampsia

• Hypertension after 20 weeks of gestation
• Proteinuria- 300mg
• Edema

• BP gt 160 systolic or gt110 diastolic
• 5grams of protein in 24 hour urine
• Oliguria
• Cerebral of visual distrubances
• Pulmonary edema or cyanosis
• Epigastric or RUQ pain
• Impaired liver function
• Thrombocytopenia
• IUGR

12
Risk Factors
13
Risk Factors
14
Prevention

• Low dose ASA ineffective in patients at low risk
• Calcium supplementation is ineffective (2.0 g of
  calcium gluconate per day)
• No compelling evidence that either are harmful
• Recent study done with antioxidant (1,000mg VitC
  and 400mg VitE).
• Small study that needs to be confirmed.

15
Cardiovascular Effects

• Hypertension
• Increased cardiac output
• Increased systemic vascular resistance
• Hypovolemia

16
Neurologic Effects

• Seizures-eclampsia
• Headache
• Cerebral edema
• Hyper-reflexia

17
Pulmonary Effects

• Capillary leak
• Reduced colloid osmotic pressure
• Pulmonary edema

18
Hematologic Effects

• Volume contraction
• Elevated hematocrit
• Low platelets
• Anemia due to hemolysis

19
Renal Effects

• Decreased glomerular filtration rate
• Increased BUN/creatinine
• Proteinuria
• Oliguria
• Acute tubular necrosis

20
Fetal Effects

• Increased perinatal morbidity
• Placental abruption
• Fetal growth restriction
• Oligohydramnios
• Fetal distress

21
Severe Preeclampsia

• BP gt 160-180 systolic or 110 diastolic
• Proteinuria gt 5 g per day
• Pulmonary edema
• Oliguria
• Elevated liver enzymes

• Low platelets
• Growth restriction
• Decreased AFV
• Headache
• Epigastric pain

22
Management

• The ultimate cure is delivery
• Assess gestational age
• Assess cervix
• Fetal well-being
• Laboratory assessment
• Rule out severe disease!!

23
Gestational HTN at Term

• Delivery is always a reasonable option if term
• If cervix is unfavorable and maternal disease is
  mild, expectant management with close observation
  is possible

24
Mild Gestational HTN not at Term

• Rule out severe disease
• Conservative management
• Serial labs
• Twice weekly visits
• Antenatal fetal surveillance
• Outpatient versus inpatient

25
Indications for Delivery

• Worsening BP
• Nonreassuring fetal condition
• Development of severe PIH
• Fetal lung maturity
• Favorable cervix

26
Unfavorable Cervix

• No contraindication to prostaglandin agents
• If lt 32 weeks, consider cesarean
• When favorable, oxytocin

27
Hypertensive Emergencies

• Fetal monitoring
• IV access
• IV hydration
• The reason to treat is maternal, not fetal
• May require ICU

28
Criteria for Treatment

• Diastolic BP gt 105-110
• Systolic BP gt 200
• Avoid rapid reduction in BP
• Do not attempt to normalize BP
• Goal is DBP lt 105 not lt 90
• May precipitate fetal distress

29
Characteristics of Severe HTN

• Crises are associated with hypovolemia
• Clinical assessment of hydration is inaccurate
• Unprotected vascular beds are at risk, eg, uterine

30
Key Steps Using Vasodilators

• 250-500 cc of fluid, IV
• Avoid multiple doses in rapid succession
• Allow time for drug to work
• Maintain LLD position
• Avoid over treatment

31
Acute Medical Therapy

• Hydralazine
• Labetalol
• Nifedipine
• Nitroprusside
• Diazoxide
• Clonidine

32
Hydralazine

• Dose 5-10 mg every 20 minutes
• Onset 10-20 minutes
• Duration 3-8 hours
• Side effects headache, flushing, tachycardia,
  lupus like symptoms
• Mechanism peripheral vasodilator

33
Labetalol

• Dose 20mg, then 40, then 80 every 20 minutes,
  for a total of 220mg
• Onset 1-2 minutes
• Duration 6-16 hours
• Side effects hypotension
• Mechanism Alpha and Beta block

34
Nifedipine

• Dose 10 mg po, not sublingual
• Onset 5-10 minutes
• Duration 4-8 hours
• Side effects chest pain, headache, tachycardia
• Mechanism CA channel block

35
Clonidine

• Dose 1 mg po
• Onset 10-20 minutes
• Duration 4-6 hours
• Side effects unpredictable, avoid rapid
  withdrawal
• Mechanism Alpha agonist, works centrally

36
Nitroprusside

• Dose 0.2 0.8 mg/min IV
• Onset 1-2 minutes
• Duration 3-5 minutes
• Side effects cyanide accumulation, hypotension
• Mechanism direct vasodilator

37
Seizure Prophylaxis

• Magnesium sulfate
• 4-6 g bolus
• 1-2 g/hour
• Monitor urine output and DTRs
• With renal dysfunction, may require a lower dose

38
Magnesium Sulfate

• Is not a hypotensive agent
• Works as a centrally acting anticonvulsant
• Also blocks neuromuscular conduction
• Serum levels 6-8 mg/dL

39
Toxicity

• Respiratory rate lt 12
• DTRs not detectable
• Altered sensorium
• Urine output lt 25-30 cc/hour
• Antidote 10 ml of 10 solution of calcium
  gluconate 1 v over 3 minutes

40
Treatment of Eclampsia

• Few people die of seizures
• Protect patient
• Avoid insertion of airways and padded tongue
  blades
• IV access
• MGSO4 4-6 bolus, if not effective, give another 2
  g

41
THE FIRST THING TO DO AT A SEIZURE IS TO TAKE
YOUR OWN PULSE!
42
Alternate Anticonvulsants

• Diazepam 5-10 mg IV
• Sodium Amytal 100 mg IV
• Pentobarbital 125 mg IV
• Dilantin 500-1000 mg IV infusion

43
After the Seizure

• Assess maternal labs
• Fetal well-being
• Effect delivery
• Transport when indicated
• No need for immediate cesarean delivery

44
Other Complications

• Pulmonary edema
• Oliguria
• Persistent hypertension
• DIC

45
Pulmonary Edema

• Fluid overload
• Reduced colloid osmotic pressure
• Occurs more commonly following delivery as
  colloid oncotic pressure drops further and fluid
  is mobilized

46
Treatment of Pulmonary Edema

• Avoid over-hydration
• Restrict fluids
• Lasix 10-20 mg IV
• Usually no need for albumin or Hetastarch (Hespan)

47
Oliguria

• 25-30 cc per hour is acceptable
• If less, small fluid boluses of 250-500 cc as
  needed
• Lasix is not necessary
• Postpartum diuresis is common
• Persistent oliguria almost never requires a PA
  cath

48
Persistent Hypertension

• BP may remain elevated for several days
• Diastolic BP less than 100 do not require
  treatment
• By definition, preeclampsia resolves by 6 weeks

49
Disseminated Intravascular Coagulopathy

• Rarely occurs without abruption
• Low platelets is not DIC
• Requires replacement blood products and delivery

50
Anesthesia Issues

• Continuous lumbar epidural is preferred if
  platelets normal
• Need adequate pre-hydration of 1000 cc
• Level should always be advanced slowly to avoid
  low BP
• Avoid spinal with severe disease

51
HELLP Syndrome

• He-hemolysis
• EL-elevated liver enzymes
• LP-low platelets

52
HELLP Syndrome

• Is a variant of severe preeclampsia
• Platelets lt 100,000
• LFTs - 2 x normal
• May occur against a background of what appears to
  be mild disease

53
Conservative Management

• Controversial
• Steroids
• Requires tertiary care
• Must have stable labs and reassuring fetal status
• May use antihypertensives

54
SUMMARY

• Criteria for diagnosis
• Laboratory and fetal assessment
• Magnesium sulfate seizure prophylaxis
• Timing and place of delivery