Anaesthetic Implications and Management in Preeclampsia & Eclampsia

1. Anaesthetic Implications and Management in Preeclampsia & Eclampsia Dr. Shilpa Agarwal Moderator: Dr. JP Sharma University College of Medical Sciences & GTB Hospital, Delhi www.anaesthesia.co.in email: anaesthesia.co.in@gmail.com

2. Contents • Classification of hypertensive disorders of pregnancy • Diagnosis of preeclampsia • Risk factors • Obstetric and Anaesthetic management • Complications of preeclampsia • Diagnosis and risk factors of Eclampsia • Obstetric and Anaesthetic management in Eclampsia • Complications of Eclampsia

3. Introduction • Hypertensive disorders complicate nearly 5-10% of all pregnancies • Deadly triad with infection and haemorrhage • In developed countries, 16% of maternal deaths due to hypertensive disorders • Preeclampsia – a multifactorial, multi-system hypertensive disorder of pregnancy ,is most dangerous • etiology remains unknown • evidence-based management

4. History

5. Classification • In 2000, National High Blood Pressure Education Program classified hypertensive disorders complicating pregnancy as: • Gestational hypertension • Preclampsia- eclampsia • chronic hypertension • chronic hypertension with superimposed preeclampsia

6. Gestational Hypertension • Blood Pressure ≥ 140/90 on two or more occasions - in a previously normotensive patient - after 20 weeks gestation - without proteinuria - returning to normal 12 weeks after delivery • Almost half of these develop preeclampsia syndrome

7. Chronic Hypertension • Blood Pressure ≥ 140/90 before 20 weeks of gestation Or • Persistence of hypertension beyond 12 weeks after delivery.

8. Preeclampsia superimposed on Chronic Hypertension • New-onset proteinuria ≥ 300 mg/24 hours in hypertensive women but no proteinuria before 20 weeks’ gestation • A sudden increase in proteinuria or blood pressure or platelet count <1 lakh/mm3 in women with hypertension and proteinuria before 20 weeks’ gestation • More adverse outcome than preeclampsia alone

9. Preeclampsia • New onset of hypertension & proteinuria in a previously normotensive woman • after 20 weeks of gestation • Returning to normal after 12 weeks of pregnancy. • Edema not a part of diagnosis now. • A retrospective diagnosis • Eclampsia : new onset of seizures or unexplained coma during pregnancy or postpartum period in patients with pre-existing preeclampsia and without pre-existing neurological disorder.

10. PREECLAMPSIA

11. Epidemiology • Preeclampsia complicates nearly 6% - 10% of all pregnancies. • maternal ICU admission • Leading cause of preterm delivery-NICU • Birth of LBW babies- economic, social and medical burden • Leading cause of maternal and fetal morbidity and mortality.

12. Classification of Preeclampsia

13. Risk Factors • Preconception - Partner related • Nulliparity • limited exposure to paternal sperms • Partner who fathered a preeclamptic pregnancy in another women -Non partner related • History of Preeclampsia in previous pregnancy • Advanced maternal age • Family history of Preeclampsia • History of placental abruptio, IUGR, fetal death • Non hispanic black race

14. Risk factors contd.. -Maternaldisease related • Obesity, BMI>35 doubles the risk • Hypertension • Diabetes • Thrombotic vascular diseases -Behaviour- • Smoking : - preventive -Pregnancy associated- • Multiple gestation • Molar pregnancy

15. ETIOPATHOGENESIS • Exact mechanism unknown, disease of theories. • ABNORMAL PLACENTATION • Stage1: failure of trophoblastic invasion into myometrium Penetrates only decidua superficial placentation  ↓placental perfusion • stage2 : endothelial damage systemic manifestations of Preeclampsia

16. 1.Abnormal placentation

17. 2. Inflammatory mediators ↓PGI2 ↑TXA2 Vasoconstriction Platelet aggregation ↑Vasopressor response ↑uterine activity

18. 3. GENETIC Family history of pre eclampsia: genetic origin Mutations in Complement Regulatory Protein gene Genes assoc.: MTHFR, F5 leiden, AGT, HLA, NOS3, F2(prothrombin), ACE

19. 4. IMMUNOLOGIC • Exposure to sperms of different partner • long term exposure to paternal antigen in sperms of same partner- protective • activated auto antibodies to angiotensin receptor-1 AA-AT1activate AT1 receptorsincreased sensitivity to angiotensins  hypertension

20. 5.ANTIANGIOGENIC PROTIENS

21. Markers of Preeclampsia • ↑ plasma Homocystiene • ↑ serum sFlt1(soluble fms-like tyosine kinase) • ↓serum and urinary Platelet Growth Factor • ↓ Vascular Endothelial Growth Factor

22. Pathophysiology

23. Respiratory • Airway is edematous; • ↓ internal diameter of trachea • Pharyngolaryngeal edema •  risk of pulmonary edema; 3% women with preeclampsia.

24. CNS • CNS manifestations include: headache, visual disturbances, hyperexcitability, hyperreflexia, coma,seizures Cause: cerebral edema and hypoperfusion

25. CVS • Vasospasm and exaggerated responses to catecholamines • Increased vascular permeability • ↓ Colloid Oncotic Pressure • hypertension • endorgan ischemia • Intravascular volume deficit

26. Haemat ology • Hemoconcentration (pts with anemia may appear to have normal hematocrit) • Thombocytopaenia  most common • Platelet count correlates with disease severity and incidence of abruptio placentae • DIC due to activation of coagulation cascadeoverconsumption of coagulants and platelets spontaneous haemorrhage.

27. Hepatic • HELLP syndrome • Periportalhaemorrhage • subcapsular bleeding • hepatic rupture: 32% maternal mortality

28. Renal Decreased GFR - oliguria - renal failure - uric acid, creatinine is elevated Glomerulopathy - proteinuria

29. Uteroplacental circulation • Uteroplacental insufficiency • Fetal complications: - hypoxia -IUGR -Prematurity -IUD -Placental abruptio

30. Prediction of Preeclampsia No screening test is really helpful Various screening methods are: • Diastolic notch at 24weeks by dopplerultrasonography • Absence or reversal of end diastolic flow • Average mean arterial pressure ≥ 90 mmHg in second trimester • Angiotensin infusion test: angiotensin infusion required to raise the blood pressure >20 mm Hg from baseline • Roll over test: rise in blood pressure >20 mmHg from baseline on turning supine at 28-32 weeks gestation is positive.

31. Prevention • Regular Antenatal checkup: rapid gain in weight rising blood pressure edema proteinuria/deranged liver or renal profile • Low dose Aspirin in High risk group: ↑PGs and↓TXA2 • Calcium supplementation: no effects unless women are calcium deficient • Antioxidants- Vitamin C and E • Nutritional supplementation: zinc, magnesium, fish oil, low salt diet

32. Obstetric Management

33. Obstetrics management 1. Maternal evaluation : Hemoglobin and hematocrit platelet count : decreased, if < 1 lakh coagulation profile LFTs : indicated in all patients KFTs : raised (S.urea creatinine is decresaed in Normal pregnancy) Urine Routine : proteinuria

34. Obstetrics management contd.. 2. Fetal evaluation: • Daily fetal movement count • Ultrasound • Doppler ultrasound for fetal blood flow • Velocimetry

35. Obs. Manag contd.. 3. Treatment of Acute Hypertension: • Goal: to prevent adverse maternal sequalae • Aim: to keep DBP below 100 mm Hg and to lower MAP not >15-25%

36. Anti Hypertensive Drugs

37. Anti Hypertensives contd.. Bed rest Avoid Diuretics, ACE inhibitors, ARBs Avoid uterotonics

38. ObsManag contd.. 4. Seizure Prophylaxis • Routinely used in severe PE • Magnesium sulphate: most commonly used • Initiated with onset of labor till 24h postpsrtum • For caesarean, started 2hrs before the section till 12hrs postpartum

39. Recommended regime for MgSO4 • Zuspan or sibai regime: 4-6 gm i.v over 15 min f/b infusion of 1-2 gm/hr • Pritchard regime: 4 gm i.v over 3-5min f/b 5 gm in each buttock with maintenance of 5 gm i.m in alternate buttock 4 hrly

40. Side effects of MgSO4 • Maternal : flushing, perspiration, headache, muscle weakness, pulmonary edema • Neonatal: lethargy, hypotonia, respiratory depression

41. Magnesium levels Monitoring • Normal Serum levels- 1.7- 2.4 mg/dl • Therapeutic range- 5- 9mg/dl • Patellar reflex lost- >12mg/dl • Respiratory depression- 15-20 mg/dl • Cardiac arrest- >25mg/dl

42. Management of MgSO4 Toxicity • Stop infusion • Intravenous Calcium 10 ml 10% over 10 minutes • Endotracheal intubation in respiratory depression

43. Anaesthetic implications during MgSO4 therapy • MgSO4 potentiate and prolong the action of both depolarizing non-depolarizing muscle relaxants • At higher doses Mg2+ rapidly crosses the placental barrier, has been found to significantly ↓ FHR variability • Should be given cautiously with Ca2+ as may antagonize the anticonvulsant effect of MgSO4 • Also be cautious in patients with renal impairment • May ↑ the possibility of hypotension during regional block

44. Obs. Manag. Contd.. 5. Delivery • The only definitive treatment • Preeclamptic patients divided into 3 categories A- Preeclampsia features fully subside B- partial control, but BP maintains a steady high level C- persistently increasing BP to severe level or addition of other features

45. Management: Gp A: can wait till spontaneous onset of labor don’t exceed Expected Date of Delivery Gp B: >37wk terminate w/o delay <37wk, expectant management at least till 34wks Gp C: terminate irrespective of POG, start seizure prophylaxis and steroids if<34wks

46. Anaesthetic management

47. Pre anaesthetic Evaluation 1.Airway 2. Haemodynamic monitoring : blood pressure, ECG, Pulse oxymetry 3. Fluid status: volume depleted patients higher risk of hypotension with induction of anaesthesia 4. BP control 5. Coagulation status

48. Invasive Haemodynamic monitoring • Invasive central blood pressure monitoring not routinely indicated • Does not improve patient outcome • Indications: -oliguria patients -pulmonary edema -poorly controlled maternal blood pressure - massive hemorrhage -frequent arterial blood gas measurements • Poor correlation between central venous and pulmonary capillary wedge pressure

49. Anesthetic Goals of Labor Analgesia in Preeclampsia • To establish & maintain hemodynamic stability (control hypertension & avoid hypotension) • To provide excellent labor analgesia • To prevent complications of preeclampsia • Pulmonary edema • Eclampsia • Intracerebralhaemorrhage • Renal failure • To be able to rapidly provide anesthesia for Caesarean Section

50. Analgesia For Labor & delivery • Neuraxial analgesia: Lumbar Epidural- gradual onset of sympathetic blockade cardiovascular stability ↓ stress response maintains uteroplacental circulation avoids neonatal depression extended analgesia if cesarean required excellent post op analgesia