Cesarean — Spinal vs GA, Hypotension

T4 sensory level target — confirm with ice/cold test before incision; adequate level is dermatomal coverage of the upper abdominal field.

Adjust dose for height + BMI (smaller for short patients, larger for tall).

Hypotension is expected; phenylephrine pre-loaded in syringe.

Faster onset than epidural.

No general anesthetic exposure to neonate.

Maternal awake bonding immediately.

Standard of care for elective + most urgent C-sections.

CSE is alternative when prolonged surgery expected or backup catheter desired.

PHENYLEPHRINE 50-100 mcg IV bolus or infusion 25-50 mcg/min — OB preferred over ephedrine in modern guidelines (less neonatal acidosis from less placental transfer + less fetal beta-stimulation).

Co-load (not pre-load) 500-1000 mL crystalloid simultaneous with onset of spinal — more effective than pre-load.

Left lateral tilt 15° MANDATORY for any patient ≥20 weeks.

Vasopressin 1-2 U IV for refractory hypotension.

Tilt immediately after positioning for spinal and maintain through delivery.

Manual leftward displacement of uterus by surgical assistant if positional tilt inadequate.

Universal precaution — fetal compromise can be silent.

Mom may report dizziness/nausea on the supine table as the first sign.

RSI with cricoid pressure (controversial, but still standard in OB), shortened pre-oxygenation if STAT (3 vital-capacity breaths if 8 normal breaths impossible), induction with etomidate 0.3 mg/kg or propofol 1.5-2 mg/kg (reduce dose if hemodynamically unstable), succinylcholine 1.5 mg/kg or rocuronium 1.2 mg/kg + sugammadex backup, intubate.

OPIOID AFTER CORD CLAMP (minimize neonatal sedation).

Oxytocin 5 U slow IV post-delivery + 20-40 U/L infusion for uterine tone.

Mallampati often worsens through pregnancy + labor.

Difficult-intubation rate in OB ~1:200 vs ~1:2000 general OR.

Failed intubation drill: insert SGA (iGel size 4 typical), if oxygenating → continue cesarean via SGA + sellick, plan AFOI for next surgery; if not oxygenating → FONA.

Video laryngoscopy first-line for OB GA at most institutions now.

RSI position is upright/ramped for obese, not supine.

Have small ETT sizes (6.5, 7.0) — edema can narrow the airway.

🤰Blunt induction response in severe preeclampsia: esmolol 1 mg/kg + lidocaine 1.5 mg/kg + remifentanil 0.5-1 mcg/kg (single dose; risks neonatal depression but reduces maternal HTN crisis).

AVOID rapid bolus (hypotension, arrhythmia).

Second-line: methylergonovine (Methergine) 0.2 mg IM (avoid in HTN, preeclampsia, CAD).

Third: carboprost (Hemabate) 250 mcg IM every 15 min, max 8 doses (avoid in asthma — bronchoconstriction).

Misoprostol 800-1000 mcg PR.

Activate MTP early if blood loss >1500 mL or ongoing instability.

TXA 1 g IV (WOMAN trial — give within 3 hr).

Multimodal: INTRATHECAL MORPHINE 100-200 mcg (peak respiratory depression 6-12 hr — monitor SpO2 + RR q1h × 12 hr, then q2h; have naloxone available) + scheduled acetaminophen 1 g q6h + NSAID (ketorolac 15-30 mg q6h × 24 hr if no contraindication) + TAP block or QL block as adjunct (especially when no intrathecal morphine used) + breakthrough oral opioid only as needed.

Opioid-sparing reduces sedation, ileus, breastfeeding interference.

Tramadol contraindicated in breastfeeding (CYP2D6 ultrarapid → infant overdose risk via milk).

Avoid codeine for same reason.

Encourage early breastfeeding initiation, ambulation, and PO intake.