What are the immediate steps to manage a decreased respiratory rate in pregnancy?

Management of Decreased Respiratory Rate in Pregnancy

Immediately initiate bag-mask ventilation with 100% oxygen, as pregnant patients develop hypoxemia far more rapidly than non-pregnant patients due to decreased oxygen reserves and increased metabolic demands. 1

Immediate Assessment and Oxygenation

• Recognize the critical urgency: Hypoxemia develops rapidly in pregnancy due to decreased functional residual capacity, increased oxygen consumption, and increased intrapulmonary shunting (12.8-15.3% vs 2-5% in non-pregnant state). 1

• Begin bag-mask ventilation immediately with 100% oxygen at 15 L/min using a two-handed technique as soon as a second provider is available, as this is more effective than single-handed ventilation. 1

• Monitor oxygen saturation continuously and prepare for rapid deterioration, as desaturation during apnea occurs significantly faster in pregnant patients compared to non-pregnant patients. 1

Airway Management Algorithm

Critical consideration: Airway management is significantly more difficult in pregnancy due to airway edema, friability, hypersecretion, hyperemia, and a smaller upper airway in the third trimester. 1

Stepwise Approach (Maximum 2 Attempts Per Technique):

• First-line: Bag-mask ventilation with 100% oxygen while assessing need for advanced airway. 1

• If intubation required:

  • Use a smaller endotracheal tube (6.0-7.0 mm inner diameter) as the glottis is often smaller due to edema. 1
  • Limit to maximum 2 intubation attempts (direct or video laryngoscopy) by the most experienced provider available, as forceful laryngoscopy can cause bleeding and airway edema. 1
  • Provide bag-mask ventilation between attempts to preserve oxygenation. 1

• After failed intubation: Insert supraglottic airway device (preferably with esophageal drain) - maximum 2 attempts. 1

• If "cannot intubate, cannot ventilate":

  • Call for specialist help (ENT surgeon, intensivist) immediately. 1
  • Proceed to emergency front-of-neck access (cricothyroidotomy) following current Difficult Airway Society guidelines. 1

Ventilation Parameters

• Ventilate at 8-10 breaths per minute to avoid hyperventilation, which decreases survival in cardiac arrest. 1

• Reduce tidal volumes as needed, since the diaphragm is elevated by the gravid uterus. 1

• Monitor with continuous capnography to ensure adequate ventilation and avoid hyperventilation. 1

Positioning to Optimize Maternal Hemodynamics

• Apply manual left uterine displacement or position patient in 30° left lateral tilt using a firm wedge to relieve aortocaval compression (in pregnancies ≥20 weeks gestation). 1

• This positioning is critical as aortocaval compression by the gravid uterus significantly reduces cardiac output. 1

Neuromuscular Blockade Considerations

• If laryngeal spasm or poor chest wall compliance persists despite optimal ventilation attempts, ensure full neuromuscular blockade. 1

• If rocuronium was used: Reverse with sugammadex (16 mg/kg) if available, which achieves full reversal within 3 minutes. 1, 2

• The rocuronium/sugammadex combination is preferred for ensuring adequate neuromuscular blockade and rapid reversal when needed. 1

Identify and Treat Underlying Cause

While providing respiratory support, rapidly assess for:

• Opioid overdose: Consider naloxone if opioid-induced respiratory depression is suspected, though be cautious as it may precipitate acute withdrawal. 3

• Pulmonary embolism, amniotic fluid embolism, or air embolism: Consider in any pregnant woman with sudden cardiorespiratory collapse, particularly with central line manipulation. 4

• Acute respiratory distress syndrome (ARDS): Can be precipitated by pulmonary and non-pulmonary insults in pregnancy. 5

• Sepsis or DIC: These are significant risk factors for maternal mortality in respiratory failure. 6

Critical Pitfalls to Avoid

• Do not delay oxygenation for advanced airway placement - bag-mask ventilation with 100% oxygen is the priority. 1

• Avoid multiple intubation attempts - each attempt increases trauma risk and worsens airway edema. 1

• Do not use cricoid pressure during resuscitation, as it is not recommended and may impede ventilation. 1

• Never transport a pregnant patient in cardiac arrest to another location for interventions - manage at the site of arrest. 1

Preparation for Cardiac Arrest

• If no return of spontaneous circulation by 4 minutes of resuscitative efforts in a pregnancy ≥20 weeks gestation, prepare for immediate perimortem cesarean delivery at the site of arrest. 1, 4

• Activate the maternal cardiac arrest team using a universal call (e.g., "maternal code blue") to ensure all necessary personnel and specialized equipment arrive simultaneously. 1