How should I manage a postpartum preeclamptic woman with ongoing hemorrhage and hypotension after cesarean delivery who has received 2 L of crystalloid, has a urine output of 450 mL in the first six hours, and is on magnesium sulfate?

Management of Postpartum Preeclamptic Woman with Ongoing Hemorrhage and Hypotension

This patient requires immediate aggressive resuscitation with additional crystalloid boluses, blood product transfusion, vasopressor support if hypotension persists after adequate fluid resuscitation, and continuation of magnesium sulfate—while strictly limiting total fluid intake to 60-80 mL/hour once hemodynamically stable to prevent pulmonary edema. 1, 2

Immediate Fluid Resuscitation Strategy

Initial Crystalloid Administration

• Administer additional crystalloid boluses of 500-1000 mL over 15-30 minutes to achieve hemodynamic stability, as this patient has received only 2 L and remains hypotensive with ongoing hemorrhage 1
• The urine output of 450 mL over 6 hours (75 mL/hour) is adequate and does not indicate oliguria, which would be <30 mL/hour 1, 3
• Use balanced crystalloid solutions (lactated Ringer's or Plasma-Lyte) rather than normal saline to avoid hyperchloremic acidosis and potential acute kidney injury 1

Critical Fluid Management Caveat

• Once hemorrhage is controlled and hemodynamic stability achieved, immediately restrict total IV fluid intake to 60-80 mL/hour because preeclamptic patients have reduced colloid oncotic pressure and markedly increased risk of pulmonary edema 1, 2, 4
• This represents a critical transition point: aggressive resuscitation during active hemorrhage followed by strict fluid restriction once bleeding is controlled 2

Hemorrhage Management

Blood Product Transfusion

• Transfuse packed red blood cells if hemoglobin <10 g/dL to maintain oxygen-carrying capacity 1
• Check coagulation parameters immediately: platelet count, PT/PTT, fibrinogen, and consider HELLP syndrome workup (hemolysis markers, liver enzymes) 1
• Transfuse platelets if count <50,000/mm³ in the setting of ongoing hemorrhage or need for surgical intervention 1

Uterotonic Management

• Administer intravenous oxytocin as first-line therapy for uterine atony 1, 5
• Avoid prostaglandin F2α (carboprost) if possible as it may cause bronchoconstriction, though this is primarily a concern in asthmatic patients 1, 5
• Avoid ergometrine as it can cause severe hypertension and bronchospasm, particularly problematic in preeclamptic patients 1

Vasopressor Support

Indications and Initiation

• Start norepinephrine if hypotension persists after 2-3 L of crystalloid or if patient is not a candidate for further aggressive fluid resuscitation due to developing pulmonary edema 1
• Target mean arterial pressure (MAP) of 65 mm Hg as the initial goal 1
• Initiate norepinephrine peripherally at 0.02 μg/kg/min while establishing central venous access 1

Escalation Strategy

• Add vasopressin 0.04 units/min if MAP remains inadequate despite norepinephrine 0.1-0.2 μg/kg/min 1
• Although vasopressin theoretically interacts with oxytocin receptors, it remains a reasonable second-line agent with appropriate fetal monitoring 1

Magnesium Sulfate Management

Continuation During Resuscitation

• Continue magnesium sulfate infusion at 1-2 g/hour throughout resuscitation and hemorrhage management 4, 6
• Evidence demonstrates that continuing magnesium sulfate during cesarean delivery is non-inferior to interrupting it regarding postpartum hemorrhage rates 6
• Magnesium sulfate does not impair fetal cardiovascular redistribution during maternal hemorrhage and should not be discontinued 7

Critical Safety Monitoring

• Monitor for magnesium toxicity: check deep tendon reflexes (loss occurs at 3.5-5 mmol/L), respiratory rate (paralysis at 5-6.5 mmol/L), and urine output (maintain >30 mL/hour) 4, 3
• Avoid combining magnesium sulfate with calcium channel blockers (especially nifedipine) due to risk of severe hypotension and myocardial depression 2, 4
• This patient's hypotension may be exacerbated by the vasodilatory effects of magnesium sulfate in the setting of preeclampsia-induced hypovolemia 8

Duration of Therapy

• Continue magnesium sulfate for 24 hours postpartum for seizure prophylaxis 2, 4

Monitoring and Assessment

Hemodynamic Monitoring

• Consider central venous catheter or pulmonary artery catheter placement for ongoing fluid management guidance in this critically ill patient 1
• Perform volume status and tissue perfusion assessment including repeat lactate measurement if initial lactate ≥4 mmol/L or if hypotension persists after fluid administration 1

Laboratory Surveillance

• Measure serum lactate immediately and repeat within 6 hours to assess tissue perfusion 1
• Check complete blood count, coagulation studies, liver enzymes, and renal function to evaluate for HELLP syndrome and guide transfusion 1
• Monitor blood glucose as severe hypoglycemia has been reported in association with HELLP syndrome 1

Respiratory Monitoring

• Obtain chest X-ray to exclude pulmonary edema before aggressive fluid administration if clinically indicated 1
• Maintain oxygen saturation >95% with supplemental oxygen as needed 2

Common Pitfalls to Avoid

• Do not continue aggressive fluid resuscitation beyond what is needed for hemodynamic stability—the 30 mL/kg recommendation from sepsis guidelines must be modified in preeclamptic patients due to capillary leak and pulmonary edema risk 1, 2
• Do not discontinue magnesium sulfate during hemorrhage management as it does not increase bleeding risk and provides essential seizure prophylaxis 6, 7
• Do not use NSAIDs for postpartum analgesia in this preeclamptic patient as they worsen hypertension and increase acute kidney injury risk 2, 4
• Do not assume adequate urine output (75 mL/hour) indicates adequate resuscitation when the patient remains hypotensive with ongoing hemorrhage—this requires blood pressure and perfusion-guided therapy 1