The Pregnant Airway

Learning objectives

After completing this chapter, you should be able to explain pregnancy-related airway and respiratory changes; predict rapid desaturation; assess anticipated difficulty; optimize position and preoxygenation; prepare equipment and team roles; prioritize oxygenation over repeated intubation; use mask and supraglottic rescue; recognize cannot-intubate/cannot-oxygenate physiology; and plan transport, extubation, and reintubation risk.

Opening transport scenario

A 35-week patient with severe preeclampsia develops pulmonary edema and fatigue. She is upright on noninvasive ventilation with SpO₂ 91%, respiratory rate 34/min, and declining mental status. Her neck is short, facial edema is present, and the airway team anticipates rapid desaturation and difficult laryngoscopy. The airway cannot be approached as a routine adult intubation: positioning, preoxygenation, suction, first-pass equipment, backup oxygenation, and a failed-airway plan must be completed before induction.

1. Why the pregnant airway is different

2. Airway assessment and strategy selection

A rapid assessment should identify difficulty with facemask ventilation, laryngoscopy, supraglottic placement, front-of-neck access, and safe apnea. No single bedside test rules difficulty in or out.

• Mouth opening, dentition, tongue size, Mallampati view, jaw protrusion, neck mobility, thyromental distance
• Facial or airway edema, obesity, large breasts, stridor, trauma, burns, secretions, blood, or vomitus
• Baseline oxygenation, work of breathing, pulmonary edema, bronchospasm, metabolic acidosis, shock, and apnea tolerance
• Prior difficult airway, obstructive sleep apnea, previous anesthesia record, and current airway swelling
• Ability to identify the cricothyroid membrane; consider ultrasound or marking before induction when difficult

When both intubation and oxygenation are predicted to be difficult, consider awake airway management or another technique that preserves spontaneous ventilation when time, skill, patient cooperation, and equipment allow.

3. Positioning and maternal hemodynamics

• Use head-up or semi-Fowler positioning to improve preoxygenation and laryngoscopy when feasible.
• Ramp the external auditory meatus toward the sternal notch in obesity or large-breast anatomy.
• Use manual left uterine displacement or safe lateral tilt while preserving airway access.
• Place the patient at a height that allows controlled laryngoscopy and backup maneuvers.
• Secure the patient and equipment before vehicle movement.

4. Preoxygenation and apneic oxygenation

Preoxygenation replaces nitrogen in the functional residual capacity with oxygen. Use a tight mask seal and high inspired oxygen concentration. The OAA/DAS obstetric algorithm targets a high end-tidal oxygen concentration when measurable. Preoxygenation should be treated as a procedure with a quality endpoint, not simply “oxygen applied.”

• Use 100% oxygen with a well-sealed mask for an adequate period or vital-capacity breaths when time is limited.
• Consider noninvasive positive-pressure ventilation for severe hypoxemia or pulmonary edema.
• Use high-flow or standard nasal oxygen for apneic oxygenation when appropriate.
• Correct mask leak, airway obstruction, bronchospasm, pulmonary edema, and positioning problems.
• Do not remove effective noninvasive support until the team is ready to induce.

5. Equipment and team preparation

• Working suction immediately reachable, with a second suction option when contamination risk is high
• Video laryngoscope and appropriate blade, plus direct laryngoscope backup
• Endotracheal tubes including at least one smaller size, stylet/bougie, syringe, securement, waveform capnography
• Oral/nasal airways as appropriate and two-person mask-ventilation capability
• Second-generation supraglottic airway in appropriate sizes
• Front-of-neck access kit and identified cricothyroid membrane
• Vasopressor, IV/IO access, postintubation analgesia/sedation, ventilator, and neonatal/obstetric support when relevant

Conduct a brief: primary operator, assistant, drug administrator, monitor, uterine-displacement role, suction role, Plan A, attempt limit, Plan B oxygenation, wake-versus-proceed decision, and emergency airway plan.

6. Intubation attempts and cricoid pressure

First-pass success is especially important. Optimize the initial attempt with position, video laryngoscopy, an experienced operator, appropriate blade/tube, and external laryngeal manipulation when useful. If the view or tube passage is poor, stop and change something rather than repeating the same attempt.

Cricoid pressure remains used in many obstetric RSI protocols, but it should be reduced or released if it impairs ventilation, laryngoscopy, supraglottic placement, or airway rescue. Gentle mask ventilation with limited pressure may be used when needed to prevent hypoxemia.

7. Failed intubation and failed oxygenation

Oxygenation—not placement of an endotracheal tube—is the immediate goal. Limit repeated attempts. Reoxygenate between attempts, call for help early, and use two-person mask ventilation and a second-generation supraglottic airway.

8. Tube confirmation and securement

Continuous waveform capnography is the standard confirmation method in a perfusing patient. Also assess chest rise, bilateral breath sounds, tube depth, oxygenation, airway pressures, and imaging when available. Secure the tube carefully because edema, movement, transfers, and head-position changes can alter depth.

9. Extubation and reintubation risk

Extubation is an airway procedure. Airway edema may worsen after preeclampsia, prolonged labor, large fluid volumes, trauma, or repeated attempts. Extubate fully awake when appropriate, with optimal positioning, suction, oxygen, skilled help, and an immediate reintubation plan. Some patients require delayed extubation in a critical-care setting.

10. Transport airway readiness

• Confirm tube position after every move and any change in capnography or airway pressure.
• Carry spare oxygen, manual ventilation, suction, SGA, laryngoscope, tubes, bougie, and rescue medications.
• Provide ongoing analgesia and sedation; paralysis does not provide either.
• Use ventilator alarms and continuous SpO₂/EtCO₂ monitoring.
• Define where the vehicle can stop and which facility can provide surgical airway, bronchoscopy, obstetric, or ECMO rescue.

11. Evolving case study

Phase 1: Optimization

The team keeps the patient head-up on noninvasive ventilation, performs left uterine displacement, prepares vasopressor support, identifies the cricothyroid membrane, and assigns a second-generation SGA as Plan B.

Phase 2: First attempt

After induction, video laryngoscopy provides a partial view. The operator uses external laryngeal manipulation and a bougie, placing a smaller tube on the first attempt. Waveform capnography confirms ventilation.

Phase 3: Postintubation

Blood pressure falls and is treated immediately. Analgesia and sedation are started, the tube is secured and rechecked after loading, and fetal status is reassessed after maternal oxygenation and perfusion improve.

12. High-yield chapter summary

1. Pregnancy increases airway edema, aspiration risk, and difficult laryngoscopy.
2. Reduced FRC and increased oxygen consumption shorten safe apnea time.
3. Head-up ramping and uterine displacement improve oxygenation and hemodynamics.
4. Preoxygenation requires a tight seal and an effective endpoint.
5. Plan A, Plan B, and emergency airway rescue must be ready before induction.
6. Limit attempts and change the approach after failure.
7. Gentle mask ventilation is appropriate when needed to prevent hypoxemia.
8. Release cricoid pressure if it impairs oxygenation or airway rescue.
9. Use waveform capnography and reassess after every move.
10. Extubation can be as hazardous as intubation.

References

1. International Board of Specialty Certification. Maternal Fetal Transport Microcredential Candidate Handbook. Updated April 2026.
2. Obstetric Anaesthetists’ Association and Difficult Airway Society. Guidelines for the Management of Difficult and Failed Tracheal Intubation in Obstetrics.
3. American Society of Anesthesiologists. Practice Guidelines for Obstetric Anesthesia.
4. American Society of Anesthesiologists. Practice Guidelines for Management of the Difficult Airway. 2022.
5. Society of Critical Care Medicine. Clinical Practice Guidelines for Rapid Sequence Intubation in the Critically Ill Adult Patient. 2023.