Stepwise Management | Pre-eclampsia

Step 1

Assessment

Immediate Actions

Multidisciplinary involvement
Enhanced maternal care (if severe PE):
- Continuous monitoring: BP (arterial line if severe), SpO₂, ECG
- Hourly urine output measurement
- IV access (large bore × 2)

Labs (q12h minimum)

CBC with platelet count
Coagulation screen (if severe PE or platelets <100)
Renal function: Creatinine, urea, electrolytes, urate
Liver function: ALT, AST, bilirubin (not ALP—elevated in pregnancy)
Group & Screen / Crossmatch

Clinical Assessment

Airway

Facial edema, stridor, dysphonia (glottic edema risk)

Chest

Auscultate q4h for pulmonary edema

Neurological

AVPU, visual symptoms, hyperreflexia, clonus

Fluid Balance

Strict I/O monitoring

Thromboprophylaxis

TED stockings + enoxaparin (unless delivery imminent or contraindicated)

Step 2

BP Control

Target BP

135/85 mmHg or less

never allow MAP >140 mmHg acutely

Severe hypertension

>= 160/110 mmHg

Medical emergency

Acute IV Agents (First Line)

IV Labetalol

Loading: 50 mg IV over 5 min
Repeat: 50 mg q10min if SBP >160 (max 200mg loading)
Maintenance Infusion:
- Prepare: 100 mg in 20 mL (5 mg/mL neat)
- Start: 20 mg/h (4 mL/h)
- Double q30min to usual max 160 mg/h (32 mL/h)
Caution: 10% resistant—switch to hydralazine
Contraindication: Avoid in asthma, cardiac disease

IV Hydralazine (Second Line)

Use if asthma or inadequate labetalol response

Loading: 5-10 mg IV slowly
Wait 20 minutes: (delayed onset—repeated doses cause severe hypotension)
Side effects: Tachycardia, headache, anxiety, hyperreflexia (mimics worsening PE)
Duration limit: Maximum 6h before switching to oral/IV labetalol

Oral Maintenance

Labetalol 100 mg PO BD → up to 200 mg QID

Start dose 200 mg in severe PE

Nifedipine 10-20 mg PO

NOT sublingual—causes precipitous hypotension. Modified-release for maintenance. Caution: Profound hypotension with concurrent magnesium.

Methyldopa 250 mg PO TDS → up to 1g TDS

3rd choice; STOP within 2 days postpartum

AVOID:

ACE inhibitors (fetal renal failure),
Esmolol (fetal bradycardia)

Step 3

Magnesium

Magnesium Sulfate

Treatment of choice for seizure prophylaxis (superior to phenytoin/diazepam).

ALWAYS

Severe features of preeclampsia: Administer to all women

CONSIDER

No severe features (BP >140/90 and <160/110): No consensus. Prophylaxis reduces eclampsia (NNT 1/100-129) but side effects increase. ACOG: Decision of "physician or institution, considering patient values... and risk-benefit trade-off".

Magnesium Sulfate – How to Use

ACOG recommended dosing

Loading: 4–6 g IV over 20–30 mins (infusion pump)
Maintenance: 1–2 g/h continuous IV infusion
Duration: Continue 24 hours postpartum

Recurrent Seizures

2-4 g Bolus IV over 5 minutes

Refractory Seizures

Thiopental or phenytoin: 1,250 mg IV at 50 mg/minute
Manage in ICU; Consider neuroimaging

IM Option (Limited IV Access)

10 g Loading (5 g each buttock). Then 5 g every 4 hours. Mix with 1 mL xylocaine 2% to alleviate pain.

Delivery

Vaginal delivery: Continue infusion 24 hours postpartum
Cesarean: Begin infusion (if not yet running) before surgery. Continue 24h postpartum.
Discontinuing prior to delivery to avoid uterine atony/drug interactions is NOT recommended.

Prevention of Magnesium Sulfate Toxicity

Place Foley to monitor renal function (hourly output)
Confirm normal serum creatinine
Serial evaluation of patellar deep tendon reflexes
Monitor respiratory rate
Serum Mg levels: Not routinely required. Monitor if renal dysfunction or absent reflexes. Target: 5-9 mg/dL (4-7 mEq/L).

Predictive Symptoms of Toxicity:

Predictive Symptoms of Toxicity

Loss of reflexes: >9 mg/dL (>7 mEq/L)
Respiratory depression: >12 mg/dL (>10 mEq/L)
Cardiac arrest: >30 mg/dL (>25 mEq/L)

Pending Toxicity Management

Notify appropriate health care provider
Discontinue magnesium infusion
Administer supplemental oxygen
Obtain serum magnesium level
Reverse magnesium: 10 mL of 10% calcium gluconate IV (1 g total) over 3 min (avoid hypotension/bradycardia). Note: Effect can wear off.
Furosemide may help increase excretion
Respiratory arrest: Intubation/ventilation as indicated

Other Prophylactic Agents

Magnesium sulfate is superior to diazepam, phenytoin and lytic cocktail (Cochrane Review 2010).

Significant reduction in pneumonia, ventilation, ICU admission vs phenytoin.
Does not cause maternal/newborn CNS depression (unlike diazepam/lorazepam).
Consider Diazepam/Phenytoin only if: Patient on them for epilepsy OR Magnesium contraindicated (Myasthenia gravis, Hypocalcemia, Renal failure, Cardiac ischemia/block/myocarditis).

Step 4

Delivery Timing

Gestation	Plan
< 34 weeks	Conservative management UNLESS refractory severe HTN or maternal/fetal indications
34⁺⁰ - 36⁺⁶	Based on maternal/fetal condition and risk factors
>= 37⁺⁰ weeks	Deliver within 24-48h (immediate if severe HTN)

NOTE: After 34 weeks with severe HTN: Deliver after BP controlled + steroids complete

Step 5

Anesthesia

Key Principle

Neuraxial anesthesia is preferred over GA to avoid airway manipulation and hypertensive response.

1

Epidural Analgesia in Labor

Grade A recommendation

Benefits:
- Reduces pain-induced hypertension and catecholamine release
- Improves uteroplacental perfusion
- Decreases need for GA at cesarean section
- May improve placental intervillous blood flow
Requirements:
- Platelet count ≥75 × 10⁹/L AND not falling rapidly
- Normal coagulation screen (if severe PE or platelets <100)
- NO fluid preloading (risk of pulmonary edema)
Management:
- Use low-dose technique
- Vasopressors as needed (patients MORE sensitive—use cautiously)
- Infusion may be preferable to boluses in severe PE

2

Cesarean Section Anesthesia

Preoperative assessment:

Labs: Platelets, coagulation (if indicated)
Airway: Check for facial/glottic edema (Mallampati score can change rapidly)
Cerebral irritability signs; Urine output; BP control status

SPINAL (Preferred): For mild/moderate/severe PE (if no contraindications).
Dose: Bupivacaine 0.5% heavy 1.6-2.0 mL (adjust for height/weight). Caution: Less hypotension than normal pregnancy BUT patients more sensitive to vasopressors.
EPIDURAL (Alternative): Allows postop continuation. Loading in increments (not single bolus).
GENERAL ANESTHESIA Mandatory if:
- Coagulopathy/platelets contraindicate neuraxial
- Ongoing seizures or decreased LOC
- Immediate delivery needed + uncontrolled BP
- Patient refusal or technical contraindication

3

General Anesthesia Technique

Pre-induction:
- Arterial line (for severe PE)
- Pre-oxygenate 3 min
- Attenuate intubation response: esmolol IV, local anesthesia spray of vocal cords, quick intubation (most experienced anesthesia provider)
Induction:
- Propofol 2 mg/kg OR etomidate 0.2 mg/kg (NOT ketamine)
- Suxamethonium 1-1.5 mg/kg
- No precurarization (especially with magnesium)
Airway:
- Smaller ETT available (start with 7.0 mm—glottic edema risk)
- Difficult airway equipment ready
Maintenance:
- Isoflurane/sevoflurane 0.5-1 MAC (preferred if ↑ICP concern)
- Muscle relaxants: Use reduced doses with neuromuscular monitoring (magnesium potentiates)
Extubation:
- Anticipate hypertensive response
- Consider: Esmolol, or short-acting vasodilators
- Delayed extubation may be needed (laryngeal edema, eclampsia, severe disease)

4

Uterotonics

Oxytocin: Use cautiously (unpredictable in severe PE—avoid bolus). Give slow infusion after delivery.
Ergometrine: Use with extreme caution. Can cause severe hypertension.

5

Transfer to ICU if:

Level 3 care needed (ventilation)
Eclampsia
HELLP syndrome
Evidence of cardiac failure
Severe oliguria/renal failure
Abnormal neurology