🌩️ Anesthetic Considerations in Preeclampsia

🔷 INTRODUCTION

Preeclampsia is a multisystem hypertensive disorder of pregnancy, defined as the new onset of hypertension and end-organ dysfunction (with or without proteinuria) after 20 weeks gestation. It can progress to eclampsia, HELLP syndrome, or other life-threatening complications if not managed promptly.

It presents major anesthetic concerns due to vascular instability, altered pharmacodynamics, risk of seizures, coagulopathy, airway edema, and poor end-organ perfusion.

🔷 DEFINITION

• Hypertension in pregnancy: SBP ≥140 mmHg or DBP ≥90 mmHg on 2 occasions ≥4 hours apart after 20 weeks gestation.
• Preeclampsia: Hypertension PLUS one of the following:
• Proteinuria ≥300 mg/24 hrs or ≥1+ on dipstick,Protein to Creat Ratio_>0.3
• Platelet count <100,000/mm³
• Elevated liver enzymes (AST/ALT), right upper quadrant pain
• Renal insufficiency (serum creatinine >1.1 mg/dL)
• Pulmonary edema
• Cerebral or visual disturbances

🔹 Severe Preeclampsia

• SBP ≥160 mmHg or DBP ≥110 mmHg
• Marked end-organ dysfunction

🔹 Eclampsia

• Criteria of preeclampsia + new-onset seizures (generalized tonic-clonic)
• No pre-existing seizure disorder

🔷 ETIOPATHOGENESIS 

• Abnormal trophoblastic invasion → spiral artery remodeling failure
• High-resistance uteroplacental circulation → placental hypoxia
• Endothelial dysfunction → release of vasoactive substances
• Vasospasm, capillary leak, and microthrombi → multisystem involvement

🔷 SYSTEMIC EFFECTS OF PREECLAMPSIA

🔷 INVESTIGATIONS

• CBC: Platelets, Hb
• Liver enzymes: AST, ALT
• Renal function: Creatinine, Uric acid
• Coagulation: PT, aPTT, INR
• Urinalysis: Proteinuria (24-hour collection or dipstick)
• Fundoscopy: Retinal vasospasm
• Fetal monitoring: USG, CTG

🔷 DRUG THERAPY BEFORE DELIVERY

⚠️ Avoid NSAIDs (renal compromise), Ergot alkaloids (vasospasm)

🔷 ANESTHETIC GOALS

• Avoid sudden rise/fall in BP
• Prevent seizures
• Maintain uteroplacental perfusion
• Maintain airway patency (edema risk)
• Volume control – avoid overload (risk of pulmonary edema)
• Be ready for emergency delivery
• Ensure adequate fetal monitoring
• Be cautious with drug dosages due to altered pharmacokinetics

🔷 REGIONAL ANESTHESIA

✅ Preferred if no contraindications

🔹 Spinal Anesthesia

• Acceptable in stable, well-controlled preeclampsia
• Use reduced dose of bupivacaine (due to decreased CSF volume)
• Combine with opioids for enhanced analgesia

Contraindications: Platelet <75,000/mm³, coagulopathy, hemodynamic instability

🔹 Epidural Anesthesia

• Preferred in laboring patients
• Slower onset, better hemodynamic control
• Can be titrated for cesarean delivery if needed

🔹 Combined Spinal-Epidural (CSE)

• Useful in labor analgesia or cesarean
• Offers rapid onset and titration

🔷 GENERAL ANESTHESIA

❌ High-risk, used only when regional is contraindicated

🔹 Indications

• Eclampsia (seizing or postictal)
• Coagulopathy (low platelets)
• Emergency cesarean delivery
• Failed regional block

🔹 Considerations

• Difficult airway: Anticipate edema and poor visibility
• Rapid desaturation: Preoxygenate thoroughly
• Pressor response to laryngoscopy: Use fentanyl, esmolol, lidocaine
• Drug interaction with MgSO₄:
• Potentiates NMBs (especially non-depolarizing)
• Decreased ACh release → prolonged paralysis
• Use lower doses of muscle relaxants and monitor neuromuscular function
• Cricoid pressure, aspiration prophylaxis mandatory

🔷 INTRAOPERATIVE MONITORING

• Standard ASA monitors
• Invasive BP monitoring (ART line) for severe cases
• CVP if fluid management is challenging
• Urine output hourly (foley catheter)
• Neuromuscular monitoring if MgSO₄ is used
• Fetal monitoring (CTG) if gestational age permits

🔷 FLUID MANAGEMENT

• Preeclamptics are intravascularly dry but extracellularly overloaded
• Restrictive fluid strategy: ~75–100 mL/hr of crystalloid unless hypovolemic
• Avoid overhydration (pulmonary edema risk)
• Colloids may be considered during volume shifts (e.g., hemorrhage)

🔷 POSTOPERATIVE CARE

• Continue magnesium sulfate for 24 hours postpartum
• Monitor for seizures, pulmonary edema, PPH
• Continue BP control
• Vigilant monitoring in high-dependency or ICU setting
• Early ambulation, DVT prophylaxis
• Pain control: Epidural infusion if catheter retained

🔷 COMPLICATIONS

🔹 Magnesium Sulfate Toxicity

• Antidote: 10 mL of 10% Calcium Gluconate IV over 10 mins

🔷 MCQ PEARLS

🔷 CONCLUSION

Preeclampsia is a multisystem disorder with profound anesthetic implications. Careful preoperative evaluation, choice of safe anesthesia technique (regional > GA), meticulous intraoperative management, and vigilant postoperative monitoring are critical for maternal and fetal safety. The anesthesiologist plays a central role in managing this high-risk obstetric condition.