Preeclampsia

By R1 張家穎

Preeclampsi

a

Introduction

Preeclampsia complicates up to 8% of pregnancies.

Classic triad : hypertension, proteinuria and edema.Not a smooth progression form mild disea

se to severe preeclampsia to eclampsia cause 25%~40% will have normal blood pressure at the time of their 1st eclamptic seizure.

Why mother dies?

Intra-cranial hemorrhage is the largest single cause of death.

Eclampsia is an important risk factor for maternal morbidity and even mortality.

Pathophysiology

The disease of therories.1st stage-failure of the normal process of trophoblastic invasion. decreased placental perfusion.2nd stage-widespread endothelial dysfunction and systemic maternal disease. imbalance between thromboxane and prostacyclin.

Anesthetic management

Severity of the condition.Associated features and systemic

involvement.Evaluation of the airway.Fluid status- an inverse relationship

between intravascular volume and the severity of hypertension.

Blood pressure control.

Anesthesiologist evaluation(1)

Upper airway may become edematous.Subglottic edema can result in airway obst

ruction following extubation.Prepare smaller size of endotracheal tube

and LMA.Pulmonary edema occurs in up to 3% of th

ese patients with average onset 71 hours following delivery.

Anesthesiologist evaluation(2)

The cardiovascular effects of preeclampsia may vary.

_hyperdynamic circulation, high cardiac output, normal to increased SVR.

_Normal cardiac output, increased SVR._Highly elevated SVR, reduced blood v

olume and decreased left ventricular function.

Anesthesiologist evaluation(3)

Oliguria or hyperuricemia reflects tissue ischemia and oxidative stress.

Acute renal failure is rare, but it may occur, especially with HELLP syndrome, DIC and placental abruption.

Anesthesiologist evaluation(4)

Liver rupture is a known rare complication of preeclampsia.

Hepatic dysfunction can result in reduced drug clearance but clinically has little impact on choice of anesthetic choice.

HELLP: Hemolysis Elevated Liver enzymes Low Platelet.

Anesthesiologist evaluation(5)

Thrombocytopenia is common in preeclampsia.(15~30%)

Assuming no other coagulopathy, hemostasis is typically not problematic unless the platelet count decreases below 40,000/ml.

Anesthesiologist evaluation(6)

Antihypertensive use- labetalol, NTG, nitroprusside. Magnesium sulfate. _for seizure control and prevention of recurrent ecla

mptic seizures. _a direct smooth muscle relaxant at relatively high co

ncentrations, it does not significantly reduce systemic blood pressure at the serum concentrations that are efficacious in treating preeclampsia.

_narrow therapeutic index.

Invastigations.

CBC- platelet count. Renal profile. Liver function tests. Routine coagulation screening is not recom

meded, but if coagulopathy is suspected clinically, coagulation studies should be performed.

Epidural analgesia

1-no other method of analgesia can provide the same degree of patient comfort.2-Attenuate the hypertensive response to pain.3-Improve maternal BP control.4-Improve uteroplacental blood flow.5-Avoid general anesthesia.

Painless

Regional anesthesia

Reduce the risk of airway complications and avoid the hemodynamic alternations associated with intubation.

Platelet count >10,000/ml. Spinal V.S. Epidural

Which is superior?

Theoretical risk of severe hypotension induced by spinal anesthesia but no published scientific studies.

Compare the dosage of ephedrine between spinal anesthesia and epidural anesthesia.

Quality of block and onset time.

Spinal v.s. Epidural

Ephedrine dosage.

28 women with preeclampsia. 11 spinal : 6 - no ephedrine use. average - 5.2 mg 10 epidural: 5 - no ephedrine use. average - 6.3 mg 7 was excluded.

Regional anaesthesia for cesarean section in severe preeclampsia: spinal anaesthesia is the preffered choice. Int J Obstet Anesth 1999;8:85-89.

Quality of block

28 women with preeclampsia. 11 spinal …..1- mild intraoperative pain. 10 epidural ...3- mild pain. 4- severe pain to warrant intraoperative analgesia. 7 was excluded.. 2 from epidural due to inadequet analgesia.No differences in neonatal outcomes.Regional anaesthesia for cesarean section in severe preeclampsia: spinal anaesthesia is the preffered choice. Int J Obstet Anesth 1999;8:85-89.

How they do?

Ranitidine was given preoperatively. Sodium citrate 0.3M 30ml was administered orall

y in the anesthetic room. Left lateral position. 24 gauge Sprotte needle L2~L3 level. 2.75 ml of heavy 0.5% bupivacaine.(13.75mg.)

General anesthesia3 challenges: 1. hypertensive response to direct laryngoscopy. 2. potential difficulty of intubation. 3. uterine tone. Magnesium and gas.

The activity of muscle relaxant will be potentiated.

Drugs with sympathomimetic effects should obviously be avoided.(ketamine, ergot.)

Invasive monitoring

A-line: Swing BP. Central venous line- main problem with preeclampsia is

in the peripheral circulation. Pulmonary artery catheter. Indications: severe oliguria Pul. Edema refractory hypertension.

References. Miller’s Anesthesia. 6th edition. P2329~2333.

Update on Anesthetic Management of the Preeclamptic Patient A S A Annual Review 2003;54:R141

Pre-eclampsia: fluids, drugs, and anesthetic management Anesthesiology Clinics of North America 2003;21(1):145-63

Anesthetic management of hypertension in pregnancy Clinical Obstetrics & Gynecology 2003;46(3):688-99

Update on Pre-eclampsia International Anesthesiology Clinics 2002;40(4):115-35

New insights in hypertensive disorders of pregnancy Current Opinion in Anaesthesiology 2001;14(3):291-7

Recent developments in the pathophysiology and management of pre-eclampsia British Journal of Anaesthesia 1996;76(1):133-48

Regional anaesthesia for cesarean section in severe preeclampsia: spinal anaesthesia is the preffered choice. Int J Obstet Anesth 1999;8:85-89.