What is the recommended approach for intubation in a patient with shock?

Intubation in Shock: Approach and Considerations

Early assisted ventilation should be considered as part of a protocol-driven strategy for septic shock, but there is insufficient evidence to support or refute endotracheal intubation before the onset of respiratory failure in all shock patients. 1

Hemodynamic Considerations During Intubation in Shock

Intubation in shock presents significant risks due to the patient's compromised cardiovascular state. Performing rapid sequence induction and tracheal intubation can cause acute cardiovascular collapse, requiring careful preparation and medication selection.

Pre-intubation Optimization

• Ensure adequate volume resuscitation before intubation when possible
• Position patient optimally (head-up position for respiratory failure, supine with head elevated 30° for most shock states)
• Pre-oxygenate thoroughly:
  • Apply high-flow nasal oxygen at 15 L/min during the procedure 1
  • Consider CPAP mask ventilation before attempting intubation 1
  • Continue nasal oxygen during intubation attempts (apneic oxygenation)

Medication Selection

Induction Agents

• Ketamine (1-2 mg/kg IV) is increasingly favored in shock due to its sympathomimetic effects 1
• Etomidate (0.2-0.3 mg/kg IV) causes less hemodynamic compromise than other induction agents 1
  • Caution: Etomidate may be associated with increased mortality in septic shock due to adrenal suppression 1
• Consider reduced doses (30-50% reduction) in severe shock states
• Co-induction with rapidly-acting opioids (fentanyl 1-2 mcg/kg) enables lower doses of hypnotics, promoting cardiovascular stability 1

Neuromuscular Blocking Agents

• Neuromuscular blocking agents are strongly recommended as they improve intubation conditions 1
• Rocuronium (1-1.2 mg/kg) may be preferable in shock due to:
  • Similar intubation conditions to succinylcholine
  • Avoidance of hyperkalemia risk in critically ill patients 1
• Succinylcholine (1-1.5 mg/kg) is an alternative but has numerous side effects including life-threatening hyperkalemia 1

Protocol for Intubation in Shock

1. Assessment and Preparation:

   • Confirm indication for intubation
   • Establish adequate IV access (preferably two large-bore IVs)
   • Prepare vasopressors at bedside for immediate use if needed
   • Ensure monitoring (continuous ECG, blood pressure, pulse oximetry)

2. Pre-oxygenation:

   • Apply high-flow nasal oxygen at 15 L/min 1
   • Consider CPAP mask ventilation before intubation 1
   • Target SpO₂ >95% if possible

3. Rapid Sequence Induction:

   • Administer induction agent (ketamine preferred in shock)
   • Immediately follow with neuromuscular blocking agent
   • Apply cricoid pressure (if trained assistant available) 1
   • Consider facemask ventilation with CPAP between attempts if hypoxia occurs 1

4. Laryngoscopy and Intubation:

   • Use videolaryngoscopy if available to maximize first-pass success 1
   • Limit attempts to maximum of three before moving to rescue strategies 1
   • Confirm placement with waveform capnography

5. Post-intubation Management:

   • Initiate lung-protective ventilation strategy
   • Titrate vasopressors as needed
   • Provide appropriate post-intubation sedation and analgesia
   • Monitor for pneumothorax, especially with positive pressure ventilation 2

Special Considerations by Shock Type

Septic Shock

• Early assisted ventilation may be considered as part of a protocol-driven strategy 1
• Avoid etomidate if possible due to concerns about adrenal suppression 1
• Ketamine is preferred for induction 1

Cardiogenic Shock

• Use reduced doses of induction agents (30-50% reduction)
• Consider etomidate for its minimal hemodynamic effects
• Have inotropes prepared and ready to administer

Hypovolemic Shock

• Prioritize volume resuscitation before intubation when possible
• If intubation cannot be delayed, use minimal doses of induction agents
• Be prepared for profound hypotension with positive pressure ventilation

Obstructive Shock

• Identify and treat the underlying cause (tension pneumothorax, cardiac tamponade)
• Positive pressure ventilation may worsen hemodynamics in obstructive shock
• Consider awake intubation or reduced doses of induction agents

Pitfalls and Caveats

1. Post-intubation hypotension: Common and potentially fatal in shock patients due to:

   • Vasodilatory effects of induction agents
   • Decreased venous return from positive pressure ventilation
   • Loss of sympathetic tone
   • Prevention: Fluid bolus pre-intubation if tolerated, vasopressors ready at bedside

2. Hypoxemia: Critically ill patients desaturate rapidly

   • Prevention: Thorough pre-oxygenation, apneic oxygenation, consider CPAP between attempts

3. Failed intubation: More common in critically ill patients

   • Prevention: Optimize position, use videolaryngoscopy, limit attempts to three
   • Have rescue devices readily available (supraglottic airway, surgical airway equipment)

4. Awareness: Risk of awareness with paralysis if inadequate sedation

   • Prevention: Ensure adequate dosing of induction agent despite hemodynamic concerns

5. Worsening acidosis: Positive pressure ventilation may decrease cardiac output

   • Prevention: Avoid hyperventilation, use lung-protective ventilation strategies

The decision to intubate a patient in shock requires careful clinical judgment, weighing the benefits of securing the airway and providing respiratory support against the risks of hemodynamic deterioration. Early intubation before respiratory failure develops may be beneficial in septic shock when incorporated into a protocol-driven approach 1.