What is an appropriate protocol for rapid sequence intubation (RSI) in an adult patient with severe traumatic brain injury after preoxygenation?

Rapid Sequence Intubation Protocol for Severe Traumatic Brain Injury

The appropriate RSI protocol for an adult patient with severe traumatic brain injury after preoxygenation is fentanyl, etomidate, and succinylcholine, though the evidence specifically supporting fentanyl pretreatment in TBI is limited and the core requirement is etomidate followed by succinylcholine. 1

Core Medication Regimen

Induction Agent: Etomidate

• Etomidate (0.3 mg/kg IV) is the preferred induction agent for TBI patients due to its favorable hemodynamic profile, which is critical in maintaining cerebral perfusion pressure 1, 2
• Etomidate provides hemodynamic stability even in patients with low baseline blood pressure, with studies showing blood pressure elevation rather than depression post-intubation 3
• No mortality difference exists between etomidate and other induction agents (ketamine, midazolam, propofol) in critically ill patients, but etomidate's cardiovascular stability makes it particularly suitable for TBI 1, 4

Neuromuscular Blocking Agent: Succinylcholine vs Rocuronium

• Either succinylcholine (1-1.5 mg/kg IV) or rocuronium (0.9-1.2 mg/kg IV) is appropriate when no contraindications exist 1, 4
• The 2023 Society of Critical Care Medicine guidelines acknowledge that future studies are needed to compare these agents specifically in TBI patients, noting one observational study suggested increased mortality with succinylcholine in severe TBI, though this requires further validation 5
• Recent evidence suggests rocuronium may be safer than succinylcholine in TBI patients, as succinylcholine can increase intracranial pressure and cause hyperkalemia 6
• When using rocuronium, sugammadex should be immediately available for reversal if needed 1, 7

Adjunctive Medications: The Role of Fentanyl and Lidocaine

• Fentanyl pretreatment is commonly used to blunt the sympathetic response to laryngoscopy, which can increase intracranial pressure in TBI patients 1
• Lidocaine has historically been used as pretreatment in head trauma patients to attenuate ICP increases, with 65.1% of patients receiving it in one large ED study 3
• The evidence base for routine lidocaine or fentanyl pretreatment in TBI is not as robust as for the core induction agent and NMBA 8

Critical Sequencing

• A sedative-hypnotic induction agent MUST be administered before the neuromuscular blocking agent to prevent awareness during paralysis 1, 4
• The standard sequence is: preoxygenation → (optional pretreatment with fentanyl/lidocaine) → etomidate → succinylcholine or rocuronium → intubation 1

Special Considerations for TBI

Hemodynamic Management

• Maintain normotension throughout the procedure, as hypotension significantly increases mortality in head-injured patients 2
• Have vasopressors immediately available, as even hemodynamically stable agents can cause transient hypotension in critically ill patients 1

ICP Considerations

• Rapid sequence intubation is the standard of care for TBI patients to prevent increases in intracranial pressure during intubation 8
• Avoid fasciculations from succinylcholine by considering defasciculating doses, though the clinical significance of fasciculations on ICP remains debated 9

Oxygenation and Ventilation

• Maintain normocapnia and mild hyperoxemia to prevent secondary brain injury 8
• Use semi-Fowler positioning (head and torso inclined) to reduce aspiration risk and potentially improve first-pass success 1, 4

Common Pitfalls and How to Avoid Them

• Inadequate sedation before paralysis: Always administer etomidate before the NMBA, as failure to do so results in awareness during paralysis in approximately 2.6% of ED intubations 7
• Delayed post-intubation analgosedation: If using rocuronium, its longer duration may prevent patient movement that would otherwise cue staff to provide analgosedation; consider having a clinical pharmacist involved or use protocolized post-intubation sedation 5
• Hyperkalemia with succinylcholine: Avoid succinylcholine in patients with burns, crush injuries, prolonged immobilization, or neuromuscular disease where upregulation of acetylcholine receptors has occurred 6
• Inadequate preoxygenation: Ensure proper preoxygenation technique; consider high-flow nasal oxygen when challenging laryngoscopy is anticipated 1, 4

Answer to the Specific Question

Among the four options provided:

1. Atropine; etomidate; succinylcholine - Atropine is not routinely indicated in adult RSI for TBI
2. Etomidate; pancuronium - Pancuronium has too slow an onset for RSI 9
3. Fentanyl; etomidate; succinylcholine - This is the most appropriate option, representing standard practice with pretreatment
4. Lidocaine; etomidate; succinylcholine - Also reasonable, though fentanyl is more commonly used for sympathetic blunting

The best answer is fentanyl, etomidate, and succinylcholine, though lidocaine, etomidate, and succinylcholine is also acceptable. The core requirement is etomidate as the induction agent followed by succinylcholine (or rocuronium if contraindications exist). 1, 8, 3