HELLP Syndrome: Anaesthetic Management

What is HELLP Syndrome?

• H — Haemolysis (microangiopathic)
• EL — Elevated liver enzymes (AST/ALT; rarely exceed 500 IU/L)
• LP — Low platelets (<100,000/mm³)

Anaesthetic Considerations

1. Pre-operative Assessment

2. Regional vs. General Anaesthesia

• Best quality pain relief
• Attenuates hypertensive responses to pain
• Reduces circulating catecholamines
• Does not require fluid preload with dilute local anaesthetic/opioid solutions
• Avoids the hazards of general anaesthesia (difficult airway, aspiration, hypertensive response to laryngoscopy)

"Regional anesthesia is the preferred technique for patients with preeclampsia for labor and delivery." — Miller's Anesthesia, 10e

3. Platelet Thresholds for Neuraxial Anaesthesia

"The SOAP interdisciplinary consensus statement on neuraxial procedures in patients with thrombocytopenia concluded the best available evidence indicates a very low risk of neuraxial hematoma was associated with a platelet count of ≥70,000/mm³." — Miller's Anesthesia, 10e

• The older threshold of 100,000/mm³ has been challenged; 70,000/mm³ is now the accepted safe threshold for obstetric neuraxial procedures
• There is no universally accepted platelet count; decision must incorporate rate of fall, trend, other coagulation abnormalities, and clinical context
• No single platelet function test reliably predicts bleeding risk after regional anaesthesia

4. General Anaesthesia — When Required

• Difficult/failed intubation: Increased risk in obstetrics; airway oedema is worsened in preeclampsia. A clear algorithm for failed intubation must be in place.
• Aspiration risk: Full stomach; RSI with cricoid pressure
• Hypertensive response to laryngoscopy: Dangerous in these patients — blunt with remifentanil, esmolol, lignocaine, or magnesium bolus
• Magnesium interactions:
  • Potentiates non-depolarising neuromuscular blockers — reduce dose and monitor with nerve stimulator
  • Suxamethonium may have prolonged action — reduced pseudocholinesterase activity is reported in HELLP syndrome
• Succinylcholine: Reduced plasma pseudocholinesterase activity documented in HELLP syndrome may prolong block
• Volatile agents: Avoid in the presence of coagulopathy/DIC if possible (may worsen uterine atony)

5. Blood Pressure Management

• Treat SBP ≥160 mmHg or DBP ≥110 mmHg to prevent intracerebral haemorrhage, myocardial ischaemia, renal injury, and heart failure
• First-line agents: IV labetalol, IV hydralazine, oral nifedipine
• Patients with HELLP/preeclampsia are sensitive to both endogenous and exogenous catecholamines — careful use of vasopressors
• Methergonovine (ergometrine) is contraindicated — may cause hypertensive crisis; use oxytocin for uterotonic management instead

6. Fluid Management

• Maternal vasculature in preeclampsia is contracted (vasospasm) but porous (endothelial damage) — not simply underfilled
• Aggressive IV fluid administration risks pulmonary oedema (already a severe feature)
• Conservative fluid management: avoid large preloads; use vasopressors (phenylephrine/ephedrine) judiciously for regional-induced hypotension
• Phenylephrine is associated with less foetal acidosis than ephedrine but requires caution given catecholamine sensitivity

7. Magnesium Sulphate

• Indicated for seizure prophylaxis (eclampsia prevention) in preeclampsia/HELLP
• Anaesthetic implications:
  • Potentiates neuromuscular blockade — monitor TOF; use reduced doses of NDMR
  • May worsen postpartum uterine atony — have oxytocin and additional uterotonics ready
  • Side effects: respiratory depression, loss of deep tendon reflexes (early sign of toxicity), cardiac arrest at very high levels
  • Antidote: calcium gluconate 1g IV

8. Delivery and Postpartum

• HELLP is an indication for delivery but not necessarily caesarean section — vaginal delivery is acceptable if feasible
• Laboratory abnormalities typically improve within 5 days postpartum, though they may initially worsen
• 20% of HELLP cases develop postpartum — continue monitoring liver enzymes, platelets, and BP after delivery
• If epidural catheter was placed, consider timing of removal carefully against platelet trend (recheck count before removal)

9. Summary of Key Anaesthetic Priorities

1. Check and trend platelets — determines regional vs. general approach
2. Neuraxial preferred if platelets ≥70,000/mm³ and no active coagulopathy
3. Control blood pressure before induction/intubation
4. Prepare for difficult airway — always
5. Account for magnesium — adjust NDMR dosing, monitor TOF
6. Avoid Methergine — use oxytocin for uterotonic management
7. Conservative fluid strategy — pulmonary oedema risk
8. Postpartum surveillance continues — HELLP can develop or worsen after delivery