The effect of ketamine administration on nocturnal sleep architecture

Substantial evidence exists in the acute, rehabilitative and outpatient settings demonstrating the presence of significant sleep pattern disturbances after burn injury. Although the etiology is multifactorial and includes environmental, injury, and treatment mediators, previous clinical studies have not analyzed the critically important relationship of various medications to sleep architecture. The purpose of this investigation was to describe the after-effect of ketamine on sleep patterns in seriously ill burn patients. Forty pediatric patients with a mean TBSA burn of 50.1 ± 2.9% (range, 22-89%) and full-thickness injury of 43.2 ± 3.6% (range, 24-89%) were enrolled in this sleep study. Twenty-three of the 40 patients received ketamine on the day of polysomnography testing. Standard polysomnographic sleep variables were measured from 10:00 pm until 7:00 am. Chi-square test and t-test were used for comparison of descriptive variables between the ketamine and nonketamine groups. A logarithmic transformation was used for analysis when necessary. Ketamine administration was associated with reduced rapid eye movement (REM) sleep when compared with patients who did not receive ketamine on the day of the sleep study (P < 0.04). Both ketamine and nonketamine groups were clearly REM deficient when compared with nonburn norms. There was no relationship between ketamine use and effect on nocturnal total sleep time, number of awakenings, or percent of time awake or in stage 1, 2, or 3 + 4 sleep. In conclusion, ketamine was associated with altered sleep architecture as evidenced by a reduction in REM sleep. This finding does not seem to be clinically significant when considering the magnitude of overall REM sleep pattern disturbance observed in both the ketamine and nonketamine groups compared with nonburn norms. Further research is required to identify potential mechanisms of disturbed sleep so that appropriate interventions can be developed.