How should anesthesia be managed in a pregnant patient with severe pre‑eclampsia and a blood pressure of 180/110 mm Hg who has fetal distress?

Anesthetic Management of Severe Preeclampsia with BP 180/110 and Fetal Distress

This patient requires immediate magnesium sulfate for seizure prophylaxis, urgent IV antihypertensive therapy to reduce blood pressure below 160/110 mmHg within 30-60 minutes, and expedited delivery after maternal stabilization—with neuraxial anesthesia preferred if the patient is conscious, seizure-free, and has adequate platelet count. 1

Immediate Maternal Stabilization (First 30-60 Minutes)

Magnesium Sulfate Administration

• Administer magnesium sulfate immediately as a 4-5g IV loading dose over 5 minutes, followed by continuous infusion of 1-2g/hour 1
• This prevents progression to eclampsia and reduces seizure risk by approximately 50% 2
• Continue magnesium sulfate for 24 hours postpartum 1
• Monitor for toxicity by assessing deep tendon reflexes before each dose, respiratory rate (watch for depression), and urine output (target ≥30 mL/hour or ≥100 mL/4 hours) 1

Urgent Blood Pressure Control

• Initiate IV labetalol as first-line agent: 20mg IV bolus, then 40mg after 10 minutes if needed, followed by 80mg every 10 minutes to maximum cumulative dose of 220mg 1
• Alternative IV options include hydralazine or nicardipine if labetalol is contraindicated or unavailable 2, 1
• Target blood pressure: systolic 110-140 mmHg and diastolic approximately 85 mmHg (minimum goal <160/105 mmHg) 1
• The goal is to decrease mean arterial pressure by 15-25% to prevent maternal cerebral hemorrhage while maintaining uteroplacental perfusion 1
• Avoid short-acting oral nifedipine, especially when combined with magnesium sulfate, due to risk of uncontrolled hypotension and fetal compromise 2, 1

Critical Monitoring During Stabilization

• Continuous blood pressure monitoring until hemodynamically stable 1
• Continuous fetal heart rate monitoring to assess fetal status 1
• Hourly urine output via Foley catheter 1
• Oxygen saturation monitoring (maternal early warning if <95%) 1
• Assess for severe headache, visual changes, epigastric pain, and altered mental status 1

Laboratory Assessment

• Obtain immediately: complete blood count with platelet count, liver transaminases, serum creatinine, and coagulation studies 1
• Platelet count is critical for determining anesthetic options—thrombocytopenia <100,000/μL is a severity criterion 3
• Assess for HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) which carries 3.4% maternal mortality 1

Anesthetic Selection

Neuraxial Anesthesia (Preferred)

• Neuraxial anesthesia (spinal or epidural) is the anesthesia of choice for cesarean delivery in conscious, seizure-free patients with stable vital signs and adequate platelet count 4
• Contraindications to neuraxial anesthesia: active seizures, coagulopathy, thrombocytopenia, or HELLP syndrome 5
• Neuraxial techniques reduce the risk of aspiration and failed intubation attempts that are more common in preeclamptic women 5

General Anesthesia (When Required)

• General anesthesia is indicated when: patient arrives seizing without laboratory results, severe coagulopathy present, or immediate delivery required before stabilization 5
• Critical considerations for general anesthesia:
  • Airway edema is common in severe preeclampsia—anticipate difficult intubation 3
  • Tracheal intubation causes marked blood pressure elevation in preeclamptic patients 3
  • Must be performed by experienced anesthesiologist prepared for difficult airway 5
  • Maintain left lateral positioning during cesarean section to optimize uteroplacental perfusion 5

Delivery Decision and Timing

Absolute Indications for Immediate Delivery

• Fetal distress (non-reassuring fetal heart rate pattern) is an absolute indication for delivery regardless of other factors 1
• Blood pressure ≥160/110 mmHg with severe preeclampsia at any gestational age requires delivery after maternal stabilization 2
• Other absolute indications include: inability to control BP despite ≥3 antihypertensive classes, progressive thrombocytopenia, worsening liver/renal function, pulmonary edema, severe intractable headache, repeated visual scotomata, eclampsia, or placental abruption 1

Mode of Delivery

• Vaginal delivery is preferred unless cesarean is indicated for obstetric reasons 2, 1
• Attempting vaginal delivery is only appropriate if quick completion is possible with stable maternal and fetal status 5
• Immediate cesarean section is most often recommended in the setting of severe preeclampsia with fetal distress 5

Intraoperative Management

Fluid Management

• Strictly limit total fluid intake to 60-80 mL/hour to prevent pulmonary edema 1, 6
• Aim for euvolemia—avoid "running dry" as this increases acute kidney injury risk 6
• Plasma volume expansion is not recommended routinely 1

Blood Pressure Management During Delivery

• Continue antihypertensive treatment during labor and delivery to keep systolic BP <160 mmHg and diastolic BP <110 mmHg 2
• For pulmonary edema, IV nitroglycerin is the drug of choice (starting at 5 mcg/min, gradually increased every 3-5 minutes to maximum 100 mcg/min) 1

Medications to Avoid

• Sodium nitroprusside should only be used as last resort for extreme emergencies due to risk of fetal cyanide and thiocyanate toxicity if used >4 hours 2, 1
• Avoid combining IV magnesium with calcium channel blockers due to risk of myocardial depression 6
• ACE inhibitors and ARBs are absolutely contraindicated due to severe fetotoxicity 1
• Diuretics are contraindicated as they further reduce plasma volume 6

Postpartum Management

Immediate Postpartum Period

• Continue magnesium sulfate for 24 hours postpartum 1
• Monitor blood pressure at least every 4 hours while awake for minimum of 3 days postpartum, as hypertension can worsen between days 3-6 after delivery 1
• Continue close monitoring as eclampsia can still develop postpartum 6
• Avoid NSAIDs in women with preeclampsia, especially if acute kidney injury is present 6

Common Pitfalls to Avoid

• Do not delay magnesium sulfate administration—it should be given immediately upon diagnosis of severe preeclampsia 1
• Do not use sublingual nifedipine due to risk of precipitous blood pressure drops 6
• Do not attempt neuraxial anesthesia without confirming adequate platelet count (generally >70,000-80,000/μL depending on institutional protocols) 5, 4
• Do not assume the patient is stable for vaginal delivery—fetal distress mandates expedited delivery 5
• Do not reduce antihypertensives if diastolic BP falls <80 mmHg 1