Cardiovascular and arousal responses to laryngoscopy and tracheal intubation in patients with complete spinal cord injury.

ABSTRACT

BACKGROUND: We aimed to determine whether the autonomic and arousal responses to laryngoscopy and tracheal intubation were altered in patients with spinal cord injury (SCI). METHODS: One hundred and sixteen patients with traumatic complete SCI were grouped according to the time elapsed after the injury (<3 days and >9 months) and the level of injury (above T5 and below T5) acute high (AH, n=25), chronic high (CH, n=26), acute low (AL, n=20), and chronic low (CL, n=45). Twenty-five patients without SCI served as a control group. Bispectral index (BIS) response, systolic arterial pressure (SAP), heart rate (HR), and plasma concentrations of catecholamines and arginine vasopressin were measured. RESULTS: Both CH and CL groups showed a greater reduction in BIS values after induction of anaesthesia with thiopental compared with controls (P<0.05). However, BIS values after intubation increased similarly in all groups from the value measured just before laryngoscopy. SAP increased in the AL and CL and control groups but not in the AH and CH groups. HR increased significantly in all groups; though to a lesser degree in the AH compared with the other groups. Plasma norepinephrine concentrations increased in all except the AH group, but vasopressin concentrations were unchanged. CONCLUSIONS: The arousal response to laryngoscopy and tracheal intubation as measured by BIS is not altered in SCI, but cardiovascular and catecholamine responses may be changed depending on time elapsed and the level of the injury. However, an identical dose of thiopental may reduce BIS value after intubation more profoundly in patients with chronic SCI.