What is the physiological preparation for intubation?

Physiological Preparation for Intubation

The optimal physiological preparation for intubation requires careful positioning, preoxygenation, hemodynamic optimization, and appropriate medication selection to minimize complications and maximize success. 1

Assessment and Positioning

• Patient positioning: Place the patient in a head-up position (25-30° tilt) with the head in sniffing position (flex-extension) to optimize upper airway patency, increase functional residual capacity, and reduce aspiration risk 1
• For obese patients: Use ramping position (external auditory meatus level with sternal notch) 1
• Ensure the bed mattress is firm to optimize cricoid pressure application if needed 1
• Identify patients at risk of difficult intubation using MACOCHA score (score ≥3 predicts difficult intubation) 1

Preoxygenation

• Apply tight-fitting facemask with 10-15 L/min of 100% oxygen for 3-5 minutes 1
• Target end-tidal oxygen concentration >85% (preferably >90%) 1
• For hypoxemic patients: Use CPAP (5-10 cmH₂O) or non-invasive ventilation with supported breaths (7-10 ml/kg tidal volume) 1
• Consider nasal oxygen during the intubation attempt (HFNO) to extend safe apnea time 1
• Avoid using simple "Hudson-type" masks for preoxygenation 1

Hemodynamic Optimization

• Assess cardiovascular status and optimize before induction 1
• Consider preemptive use of vasopressors/inotropes in hemodynamically unstable patients 1
• Have IV fluids running and readily available 1
• Monitor blood pressure, heart rate, ECG, oxygen saturation, and capnography throughout 1

Medication Selection

Induction Agents

• For hemodynamically unstable patients: Ketamine (1-2 mg/kg) is recommended 1
• For stable patients: Propofol (1.5-2.5 mg/kg) or etomidate (0.2-0.3 mg/kg) 1, 2
• Consider adding fentanyl (2 μg/kg) 2 minutes before intubation to blunt hemodynamic response 3

Neuromuscular Blocking Agents

• Recommended agent: Rocuronium 0.6-1.2 mg/kg (higher dose for rapid sequence intubation) 1, 4
• Dosing should be based on actual body weight 4
• Ensure adequate depth of neuromuscular blockade before attempting intubation 1
• For rapid sequence intubation, administer immediately after induction agent 5

Special Considerations

Aspiration Risk

• Identify patients at risk: non-fasted, acute vomiting, ileus, pregnancy (3rd trimester) 6
• Consider pharmacological prophylaxis: proton pump inhibitors or H₂ blockers 6
• Apply cricoid pressure during induction if trained personnel available 1
• Be prepared to quickly suction the airway if regurgitation occurs 1

Difficult Airway

• Have difficult airway equipment immediately available 1
• Consider videolaryngoscopy as first-line approach 1
• Prepare backup airway devices (supraglottic airway, bougie) 1
• Have emergency front-of-neck airway equipment ready 1

Team Preparation

• Conduct pre-intubation briefing using a checklist 1
• Clearly assign roles to team members 1
• Communicate the primary plan and backup strategies 1
• Ensure all necessary equipment and medications are prepared 1

Common Pitfalls to Avoid

• Inadequate preoxygenation: Ensure complete mask seal and sufficient time (3-5 minutes) 1
• Rushing the procedure: Allow sufficient time for medications to take effect 3
• Poor positioning: Incorrect positioning can make intubation significantly more difficult 1
• Hemodynamic instability: Failure to anticipate and prepare for blood pressure drops 1
• Inadequate neuromuscular blockade: Ensure complete paralysis before attempting intubation 1

By following this systematic approach to physiological preparation for intubation, you can minimize complications and maximize the chances of first-pass success, ultimately improving patient outcomes in terms of morbidity and mortality.