What are the anesthetic implications of eclampsia?

Anesthetic Implications of Eclampsia

Regional anesthesia (spinal or epidural) is the preferred anesthetic technique for eclamptic patients requiring delivery, with general anesthesia reserved only for absolute contraindications such as severe coagulopathy or maternal instability requiring immediate airway control. 1, 2

Critical Pre-Anesthetic Assessment

Airway Evaluation

• Laryngeal and pharyngeal edema is a hallmark complication of eclampsia that significantly increases difficult intubation risk. 1
• Perform comprehensive airway assessment including Mallampati score, thyromental distance, neck mobility, and mouth opening. 1
• Consider awake fiberoptic laryngoscopy or nasendoscopy to directly visualize the airway if severe edema is suspected. 1
• Mark the cricothyroid membrane with ultrasound guidance before induction if general anesthesia is anticipated. 1
• Airway edema may worsen during labor and active pushing, making intubation progressively more difficult. 1

Coagulation Status

• Check platelet count immediately before neuraxial procedure, as thrombocytopenia can change rapidly in eclampsia. 1
• The consensus threshold for neuraxial anesthesia in eclampsia remains controversial, with expert panels unable to agree on a specific platelet count due to the unpredictable nature of the disease. 1
• For other hypertensive disorders of pregnancy without severe features, a platelet count ≥70 × 10⁹/L is considered acceptable for neuraxial procedures. 1
• Assess coagulation parameters (PT, PTT, fibrinogen) if HELLP syndrome is suspected or platelet count is declining. 1, 2

Hemodynamic Assessment

• Measure and document baseline blood pressure, as eclamptic patients require aggressive blood pressure control to prevent cerebrovascular hemorrhage. 1, 3
• Consider transthoracic echocardiography to assess cardiac function and guide fluid management, particularly in severe cases. 2, 4

Regional Anesthesia Management (Preferred Approach)

Labor Analgesia

• Establish early epidural analgesia during labor to reduce catecholamine surge from pain and provide a mechanism for rapid conversion to surgical anesthesia if needed. 1
• Use combined spinal-epidural or dural puncture epidural techniques for more reliable cerebrospinal fluid identification in patients with edema or obesity. 1
• Test the block thoroughly with dermatomal assessment to ensure adequate coverage for potential operative conversion. 1

Cesarean Section Anesthesia

• Spinal anesthesia is appropriate and often preferred for cesarean delivery in eclamptic patients, even in severe cases, provided coagulation parameters are acceptable. 5, 6, 4
• Use phenylephrine as the first-line vasopressor for spinal-induced hypotension, as it is noninferior to ephedrine and may offer benefits in preeclamptic patients. 4
• Administer vasopressors cautiously with smaller boluses to avoid severe hypertensive episodes. 2, 4
• Avoid ergometrine for uterotonic therapy due to its hypertensive effects; use oxytocin with slow infusion to prevent hypotension. 2

Fluid Management

• Restrict intravenous fluids aggressively to prevent pulmonary edema, which is a major cause of maternal mortality in eclampsia. 2, 4
• Maintain strict fluid balance monitoring with input/output charting. 1, 2

General Anesthesia Management (When Unavoidable)

Indications

• Absolute contraindications to neuraxial anesthesia (severe coagulopathy, patient refusal). 1
• Maternal cardiac arrest or extreme instability requiring immediate delivery. 1
• Failed neuraxial technique with urgent delivery indication. 1

Airway Management Strategy

• Prepare for difficult intubation with multiple airway adjuncts immediately available, including videolaryngoscopy, supraglottic airway devices, and front-of-neck access equipment. 1
• Have senior anesthetic backup immediately present before induction. 1
• Consider awake fiberoptic intubation if severe airway edema is present. 1

Hemodynamic Control During Induction

• Blunt the hypertensive response to laryngoscopy and intubation aggressively to prevent intracranial hemorrhage. 2, 4
• Options include remifentanil, fentanyl, lidocaine, or short-acting beta-blockers administered before laryngoscopy. 2, 4
• General anesthesia can precipitate uncontrolled hypertension in eclamptic patients, making this a critical intervention. 1

Maintenance

• Use volatile anesthetics (sevoflurane preferred) or total intravenous anesthesia with propofol. 1
• Propofol may be preferred if uterine atony is a concern, as it does not decrease uterine muscle tone. 1

Extubation Considerations

• Extubate only when the patient is fully awake, responsive to commands, and generating adequate tidal volume. 1
• Consider delayed extubation with ICU transfer if significant laryngeal edema, traumatic intubation, or concerns about re-intubation exist. 1
• Perform supplementary airway evaluation (direct laryngoscopy, fiberoptic examination, or cuff leak test) before extubation if re-intubation might be difficult. 1
• Extubate in head-up position to optimize airway patency and respiratory function. 1

Magnesium Sulfate Management

Indications and Administration

• Administer magnesium sulfate to all eclamptic patients for seizure treatment and prevention of recurrent seizures. 1, 3, 7
• Continue magnesium sulfate for 24 hours postpartum to prevent late eclamptic seizures. 1, 2

Anesthetic Interactions

• Magnesium potentiates both depolarizing and non-depolarizing neuromuscular blocking agents, requiring dose reduction. 2, 6
• Monitor neuromuscular blockade with train-of-four if muscle relaxants are used. 2
• Be prepared for prolonged neuromuscular blockade and delayed emergence. 2, 6

Toxicity Monitoring

• Monitor deep tendon reflexes, respiratory rate, and urine output as clinical indicators of magnesium levels. 2, 6
• Have calcium gluconate immediately available as the antidote for magnesium toxicity. 2, 6

Postpartum Management

Monitoring Duration

• Continue intensive monitoring for at least 24 hours postpartum, as hemodynamic instability and pulmonary edema risk persist. 1, 2
• Monitor for signs of acute pulmonary edema (dyspnea, hypoxemia, crackles on auscultation). 2, 4

Analgesia

• Neuraxial opioids (intrathecal morphine or epidural fentanyl) provide excellent postoperative analgesia. 2
• NSAIDs should be used cautiously due to effects on renal function and platelet function. 2

Critical Care Considerations

• Transfer to ICU if severe features persist, including pulmonary edema, renal failure, or hemodynamic instability. 2, 4
• Women with severe eclampsia require critical-care support meeting the same standards as other acutely unwell patients. 4

Multidisciplinary Coordination

• Establish early communication between obstetric, anesthetic, and critical care teams to optimize timing and mode of delivery. 1
• Ensure immediate availability of senior anesthetic staff, particularly for out-of-hours cases. 1
• Document all airway management details thoroughly for future anesthetic planning. 1