Obstetrics – the patient undergoing non-obstetric surgery

 

Issues:

Big questions

D/w patient + obstetrician + other party:

·      Can this wait?

·      Should baby be delivered now?

·      Plan if foetal distress?

Physiology

·      Ventilation:

o  etCO2 30mmHg -> hyperventilate

o  Caution with laparoscopy

·      Oxygenation:

o  Supine shunt -> titrate FiO2, PEEP

·      Circulation:

o  Placenta is pressure-passive -> metaraminol infusion

o  Accelerated distribution -> BIS

o  Aortocaval compression from 20/40 -> hip wedge

Airway difficulty

Problems:

·      Poor positioning

·      Large breasts

·      Swollen airway

·      Regurgitation

·      Faster desaturation

Plan:

·      Oxford ramp

·      RSI

·      Video laryngoscope

Drug choices

·      Organogenesis by 8/40

·      Anaesthetic teratogens: N2O, droperidol

·      Other harm: avoid NSAID, beta blocker

·      Keep it simple: propofol TCI, alfentanil, sux, morphine

Foetal monitoring

·      CTG possible from 18/40

·      Effect of GA: ↓variability

·      No evidence of outcome benefit

·      Need to consider how to act upon bradycardia

Pre-term labour

·      Risk factors: uterine manipulation (5%), intra-abdo infection

·      Tocolytic: yes to rescue, no to prophylaxis