What is the best course of management for a 32-year-old female (G3P2), at 32 weeks and 5/7 weeks gestation, with a history of previous pregnancies and post-cesarean section, presenting with preterm labor, pre-eclampsia with severe features, acute dyspnea, wheezing, cardiomegaly, impaired renal function, and positive troponin?

Management of Severe Preeclampsia with Cardiopulmonary Complications at 32 Weeks

This patient requires immediate delivery after maternal stabilization with magnesium sulfate and aggressive blood pressure control, as she has already undergone cesarean section and presents with multiple absolute indications for delivery including pulmonary edema, positive troponin suggesting cardiac involvement, and inability to safely continue expectant management at this gestational age. 1

Immediate Stabilization Protocol

Magnesium Sulfate Administration

• Initiate magnesium sulfate immediately with loading dose of 4-5g IV over 5 minutes, followed by maintenance infusion of 1-2g/hour for seizure prophylaxis 1, 2
• Continue for 24 hours after delivery or last seizure, whichever is later 2
• Monitor for toxicity by checking deep tendon reflexes before each dose, maintaining respiratory rate >16 breaths/min, and ensuring urine output >100 mL/4 hours 3
• Keep injectable calcium salt immediately available to counteract potential magnesium toxicity 3
• Therapeutic magnesium levels range from 3-6 mg/100 mL (2.5-5 mEq/L); reflexes diminish at >4 mEq/L and may be absent at 10 mEq/L where respiratory paralysis becomes a hazard 3

Aggressive Blood Pressure Control

• Target blood pressure: systolic 110-140 mmHg and diastolic 85 mmHg (absolute minimum <160/105 mmHg) 1
• First-line IV antihypertensive: Labetalol - 20mg IV bolus, then 40mg after 10 minutes, followed by 80mg every 10 minutes to maximum 220mg 4, 1
• Alternative: Nicardipine infusion starting at 5 mg/h, increased by 2.5 mg/h every 5-15 minutes to maximum 15 mg/h 4, 2
• Avoid short-acting oral nifedipine, especially when combined with magnesium sulfate, due to risk of uncontrolled hypotension and fetal compromise 1
• Avoid sodium nitroprusside except as absolute last resort due to fetal cyanide toxicity risk 4, 1

Management of Cardiopulmonary Complications

Pulmonary Edema Management

• Restrict total fluid intake to 60-80 mL/hour to prevent worsening pulmonary edema - replace only insensible losses (30 mL/hour) plus anticipated urinary output (0.5-1 mL/kg/hour) 2
• Preeclamptic patients have capillary leak and are at extremely high risk for pulmonary edema with excessive fluids 2
• Drug of choice for pulmonary edema: IV nitroglycerin starting at 5 mcg/min, gradually increased every 3-5 minutes to maximum 100 mcg/min 1
• Do not use plasma volume expansion 1
• Avoid diuretics as they further reduce plasma volume which is already compromised in preeclampsia 4

Cardiac Monitoring

• The positive troponin (0.12) and cardiomegaly indicate cardiac involvement, which represents severe end-organ damage 1
• Continuous cardiac monitoring is essential given the tachycardia and elevated troponin 1
• Magnesium sulfate should be administered with extreme caution in the setting of cardiac involvement, as serious changes in cardiac conduction can occur 3

Critical Monitoring Requirements

Maternal Monitoring

• Hourly urine output via Foley catheter with target ≥100 mL/4 hours (or >35 mL/hour) 1, 3
• Continuous blood pressure monitoring 2
• Oxygen saturation monitoring (maternal early warning if <95%) 1
• Deep tendon reflexes assessment before each magnesium dose 1, 3
• Respiratory rate monitoring to detect magnesium toxicity 1

Laboratory Monitoring

• Repeat labs at least twice weekly or more frequently with clinical deterioration: hemoglobin, platelet count, liver transaminases (AST/ALT), creatinine, LDH 1
• Current labs show concerning features: elevated creatinine (109 µmol/L), elevated AST (57), elevated ALT (38), elevated LDH (403), and 3+ proteinuria - all indicating multi-organ involvement 1

Absolute Indications for Immediate Delivery (Already Present)

This patient has multiple absolute indications for immediate delivery 1:

• Pulmonary edema (bilateral lower-lobe infiltrates, dyspnea, wheezing, hypoxemia) 1
• Cardiac involvement (positive troponin, cardiomegaly) 1
• Gestational age 32 5/7 weeks - at this gestational age after 32 weeks, expectant management carries significant maternal morbidity with minimal neonatal benefit 5
• Post-cesarean section status - delivery has already occurred 1

Post-Delivery Management

Immediate Postpartum Period

• Continue magnesium sulfate for 24 hours after delivery 2
• Continue antihypertensive therapy during postpartum period 2
• Monitor blood pressure every 4-6 hours for at least 3 days postpartum 2
• Avoid NSAIDs for pain control given acute kidney injury (elevated creatinine); use alternative analgesia 2

Fluid Management Postpartum

• Maintain strict fluid restriction (60-80 mL/hour) until pulmonary edema resolves 2
• Monitor for postpartum eclampsia, which can occur in 25-30% of cases 2

Long-term Follow-up

• Blood pressure and urine should be checked at 6 weeks postpartum 4
• Persistent hypertension should be confirmed by 24-hour ambulatory monitoring 4
• Women under age 40 with persistent hypertension should be assessed for secondary causes of hypertension 4
• Women with persistent hypertension or proteinuria 6 weeks after delivery should be referred to a specialist 4

Critical Pitfalls to Avoid

• Do not combine magnesium sulfate with calcium channel blockers due to risk of severe hypotension and myocardial depression 4, 2
• Do not administer excessive IV fluids - this patient already has pulmonary edema and capillary leak 2
• Do not use ACE inhibitors or ARBs - absolutely contraindicated due to severe fetotoxicity (though delivery has already occurred, avoid for breastfeeding) 1
• Do not delay delivery in the presence of pulmonary edema and cardiac involvement - these are life-threatening maternal complications 1
• Do not reduce antihypertensives if diastolic BP falls <80 mmHg 1

Special Considerations for This Case

The combination of pulmonary edema, positive troponin, cardiomegaly, and wheezing suggests peripartum cardiomyopathy or severe cardiac strain from preeclampsia 1. The bilateral lower-lobe infiltrates with cardiomegaly (CTR 0.57) and mild hypoxemia on 6L O₂ indicate significant pulmonary edema requiring aggressive management 1. The elevated LDH (403), elevated liver enzymes, and proteinuria suggest multi-organ involvement, though platelet count would need to be assessed to fully evaluate for HELLP syndrome 1.