Testing the role of ketamine on occurrence of CSD, and address the concern of possible increased ICP with Ketamine.

ketamine has been considered contraindicated in the setting of potential elevated ICP. Multiple systemic reviews showed that ketamine doesn’t increase ICP in TBI. None of these data are based on randomized dosing of ketamine. We used data from our trial of the effect of ketamine on waves of harmful CSD to determine if there was any additional effect of ketamine on ICP.

10 subjects with severe TBI or SAH were recruited. Subjects were then placed on an alternating every 6 hour schedule of ketamine or other sedation agent. The order of treatment was randomized. The ketamine dose was adjusted to clinical effect or maintained at a (0.1mg/kg/h) if no sedation was required. The ICP values was recorded hourly. CSD was scored using standard criteria, blinded to ketamine dosing. 

Neuromonitoring and ECog recordings for 10 subjects 8 SAH, 2 TBI. There was 1642 hr of observations with 833 off ketamine and 809 on ketamine. In our mixed effects model of the effect of ketamine on ICP, we found no significant overall effect (p=0.6052). In individual subject regression analysis, only two subjects were found to have a positive association of ketamine with ICP, while most were neutral and three subjects seemed to show a protective effect of higher doses of ketamine on ICP.

We found no overall effect of ketamine dose on ICP, actually more subjects with trends toward decreased ICP with higher doses of ketamine. Ketamine effectively inhibits SD over a wide range of doses. This data is valuable because each patient had alternating doses of ketamine every 6 hours so have very strong internal controls to confirm the lack of significant effect on ICP.