Difficult airway: C-section
- GA for C-section is most often done in an emergency situation (fetal distress, failed regional technique, high spinal, aspiration, cardiac arrest) and is associated with a higher mortality rate than regional techniques.
- mortality during GA is most often from hypoxemia, i.e. failed intubation, failure to recognize esophageal intubation, or failure to ventilate
- anatomic and physiologic changes of pregnancy predispose pts to increased risk of difficult airway: weight gain, increased breast size, respiratory mucosal edema, engorged vasculature increasing risk of bleeding, decreased FRC, increased O2 consumption, and assumption of a full stomach.
- key to decreasing risk of GA is assessing airway (over 10% of failed intubations did not perform an adequate airway exam): risk factors associated with difficult intubation include = Mallampati class 4, short neck, protruding maxillary incisors, and mandibular recession.
- certain conditions may also predispose to difficult airway, such as preeclampsia (edematous airway or pulmonary edema), OSA
- airway exam should be repeated prior to initiation of c-section as labor may be associated with changes in the airway
- one key difference between difficult airways in general vs pregnant women is the urgency of baby delivery needs to be factored in, which has led to an adapted difficult airway algorithm
- perform airway exam early and frequently
- have appropriate equipment (oral airways, bougie, multiple sized ETT – preferably smaller than typical, short handled laryngoscope blades, alternative airway devices (LMA, fiberoptic, etc)
- ensure adequate positioning (neck flexed and extended, head propped up on pillows)
- sufficient and effective pre-oxygenation for at least 3 minutes or 4 deep vital capacity breaths if time doesn’t allow
- RSI w/ aspiration prophylaxis