Saturday September 23, 2006
Preventing sympathetic surge during head injury patient's intubation

Orotracheal intubation cause sympathetic surges resulting in increase ICP (intracranial pressure). Despite no definite answer, endeavours continue to minimize iatrogenic expansion of hematoma. 3 drugs have shown some neuroprotective benefit during intubation of spontaneous or traumatic brain injury although they remained controversial and their benefit never get purely established.

1. Lidocaine: One study 25 years ago (but later studies were negative) showed that about 100 mg of Lidocaine (1.5 mg/kg), blunt ICP by approximately 15 mm Hg with tracheal suctioning 1. Mechanism of action is not entirely clear but probably lidocaine decreases cough reflex and dysrhythmias. No studies document any harmful effects of prophylactic lidocaine 2.

2. Fentanyl: Idea is to achieve sympatholysis and block hypertension and tachycardia. Dose of 2.5-3 μg/kg has been found to be without risk of hypotension.

3. Esmolol: Here again, goal is to achieve sympatholysis. Esmolol with dose of 100-200 mg has effect said to be superior to fentanyl and markedly superior to lidocaine 3, 4.

Combinations of above drugs have been described to have synergestic and better effect than using them alone, either esmolol and fentanyl or fentanyl and lidociane.

Related previous pearl: ICP (Intracranial pressure) wave forms

Related Link: Airway Management of the Critically Ill Patient (Chest. 2005;127:1397-1412)

References:

1. Intravenously administered lidocaine prevents intracranial hypertension during endotracheal suctioning. Anesthesiology 1980;52:516-8
2. Prophylactic lidocaine use preintubation: a review - J Emerg Med. 1994 Jul-Aug;12(4):499-506.
3. Attenuation of hemodynamic responses to rapid sequence induction and intubation in healthy patients with a single bolus of esmolol. J Clin Anesth 1990;2:343-52.
4. A comparison of lidocaine, fentanyl, and esmolol for attenuation of cardiovascular response to laryngoscopy and tracheal intubation. Acta Anaesthesiol Sin 1996;34(2):61-7.