What is the recommended procedure for intubation (insertion of an endotracheal tube) in patients requiring mechanical ventilation?

Intubation Procedure for Mechanical Ventilation

For patients requiring mechanical ventilation, perform rapid sequence intubation (RSI) using an induction agent (etomidate 0.3 mg/kg or ketamine 1-2 mg/kg based on hemodynamic status) followed immediately by a neuromuscular blocking agent (succinylcholine 1-2 mg/kg or rocuronium 0.9-1.2 mg/kg), with the goal of achieving intubation within 60-90 seconds while minimizing aspiration risk and maximizing first-pass success. 1, 2, 3

Pre-Intubation Preparation

Patient Positioning and Oxygenation

• Position the patient in semi-Fowler position (head and torso elevated 20-30 degrees) to reduce aspiration risk and improve first-pass intubation success 1
• Preoxygenate with 100% FiO₂ to achieve arterial oxyhemoglobin saturation of at least 94%, avoiding hyperoxia while ensuring adequate oxygen delivery 4
• Have video laryngoscopy, supraglottic airways, and surgical airway equipment immediately available before initiating RSI 1

Gastric Decompression in High-Risk Patients

• Insert a large-bore nasogastric tube before induction in patients at high risk of regurgitation (bowel obstruction, full stomach, emergency surgery) to decompress the stomach 1
• Consider point-of-care ultrasound to assess gastric volume and effectiveness of decompression 1

Pharmacologic Management

Induction Agent Selection

• For hemodynamically unstable patients: Use etomidate 0.3 mg/kg or ketamine 1-2 mg/kg 1, 3
• For hemodynamically stable patients: Propofol can be used, though etomidate may produce less hypotension in shock or sepsis 1, 3
• Maintain deep anesthesia using rapidly reversible agents to optimize mask ventilation and intubation conditions 4

Neuromuscular Blocking Agent (Mandatory)

• A neuromuscular blocking agent MUST be administered when a sedative-hypnotic induction agent is used 1
• Succinylcholine 1-2 mg/kg: Provides rapid onset with median time to intubation of 60-90 seconds; use actual body weight for dosing 4, 1, 2
• Rocuronium 0.9-1.2 mg/kg: Provides comparable intubation conditions to succinylcholine with excellent or good conditions in most patients within 2 minutes 1, 2, 3
• At 0.6 mg/kg rocuronium, neuromuscular block sufficient for intubation (≥80% block) is achieved in median time of 1 minute, with most intubations completed within 2 minutes 2

Pretreatment Medications

• Atropine, lidocaine, and fentanyl have fallen out of favor as pretreatment agents due to limited evidence outside select clinical scenarios 3
• Short-acting opioids may improve intubating conditions but increase risk of prolonged apnea 4

Intubation Technique

Timing and Execution

• Attempt intubation within 60-90 seconds of administering neuromuscular blocking agent 1, 2
• Use video laryngoscopy as first-line approach in unexpected difficult intubation, as it reduces Cormack-Lehane grade III/IV views and has higher success rates than direct laryngoscopy 4
• If direct laryngoscopy is used, optimize with head repositioning, gum elastic bougie (Eschmann stylet), and BURP maneuver 4

Cricoid Pressure Controversy

• Cricoid pressure is NOT routinely recommended as there is insufficient evidence it prevents aspiration, and it may make intubation more difficult 4, 1
• If applied, use initial force of 10 N when patient is awake, increasing to 30 N as consciousness is lost 1
• Release cricoid pressure immediately if it interferes with ventilation or ease of intubation 4, 1

Failed Intubation Protocol

• Limit attempts to maximum of three; if intubation fails, immediately move to failed intubation plan with supraglottic airway or surgical airway 1
• Have a secondary plan to manage the airway before initiating RSI 4

Endotracheal Tube Selection

Pediatric Patients

• Both cuffed and uncuffed endotracheal tubes are acceptable for infants and children 4
• Cuffed tubes are associated with higher likelihood of correct tube size selection, lower reintubation rates, and may decrease aspiration risk without increased perioperative complications 4
• If cuffed tubes are used, monitor and limit cuff inflation pressure to less than 20-25 cm H₂O per manufacturer instructions 4
• In circumstances of poor lung compliance, high airway resistance, or large glottic air leak, cuffed tubes may be preferable 4

Adult Patients

• Use the largest endotracheal tube available (8-9 mm) to minimize airway resistance 5

Post-Intubation Management

Immediate Confirmation and Ventilator Settings

• Confirm tube placement with end-tidal CO₂ monitoring and bilateral breath sounds 4
• Avoid hyperventilation post-intubation; maintain 10 breaths/minute to prevent compromised venous return and cerebral blood flow 6
• Pass nasogastric or orogastric tube after intubation to relieve gastric inflation if oxygenation and ventilation are compromised 4

Sedation and Analgesia

• Provide adequate post-intubation sedation to optimize ventilation and minimize ventilator dyssynchrony 5
• Consider paralytic agents only if ventilator dyssynchrony persists despite adequate sedation 5

Critical Pitfalls to Avoid

• Never delay intubation in patients with clear clinical signs of respiratory failure while waiting for arterial blood gas or radiography 6
• Do not use rocuronium 0.6 mg/kg for rapid sequence induction in Cesarean section patients as it is associated with poor or inadequate intubating conditions when combined with lower thiopental doses 2
• Avoid excessive peak inspiratory pressures during bag-mask ventilation by ventilating slowly and giving only enough tidal volume to achieve visible chest rise 4
• Do not continue cricoid pressure if it interferes with ventilation or intubation speed 4, 1
• In obese patients, dose neuromuscular blocking agents based on actual body weight, not ideal body weight, to achieve adequate intubation conditions 4, 2