Hypertension in Pregnancy

1. Hypertension in Pregnancy

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. Hypertension after 20 weeks of gestation Proteinuria- 300mg Edema Preeclampsia

11. Hypertension after 20 weeks of gestation Proteinuria- 300mg Edema BP > 160 systolic or >110 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 Preeclampsia

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. BP > 160-180 systolic or 110 diastolic Proteinuria > 5 g per day Pulmonary edema Oliguria Elevated liver enzymes Low platelets Growth restriction Decreased AFV Headache Epigastric pain Severe Preeclampsia

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 < 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 > 105-110 • Systolic BP > 200 • Avoid rapid reduction in BP • Do not attempt to normalize BP • Goal is DBP < 105 not < 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 • 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 DTR’s • 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 < 12 • DTR’s not detectable • Altered sensorium • Urine output < 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