The airway becomes more difficult to manage, for numerous reasons.
Bag-mask ventilation becomes more difficult:
- The nasal mucosa is engorged, which means there is greater resistance to flow
- The upper airway mucosa is oedematous
- There has been weight gain
Laryngoscopy becomes more difficult:
- Upper airway oedema
- Breast enlargement
- The Mallampatti grade changes during pregnancy, largely because of oedema of the pharynx, and due to weight gain. It gets even worse with labour.
Less time is available for intubation:
- Decreased FRC, less time to intubate
- Increased oxygen consumption, less time to intubate
Intubation is more risky
- Increased risk of aspiration, decreased stomach emptying