Effect of burn wound bacterial colonization on sleep and respiratory pattern

This study examined the effect of bacterial colonization of a burn wound on the sleep pattern and respiration during sleep. Sleep patterns of adult rats were monitored for one week before and two weeks after a 30 percent total body surface, full skin thickness burn with and without seeding the fresh wound with nonvirulent Pseudomonas aeruginosa. Unseeded rats were euthermic and exhibited a normal sleep pattern during the first-week post burn; however, rapid eye movement (REM) sleep percent was significantly decreased by the second week due to a reduction in the frequency rather than duration of REM periods. Rats with seeded wounds were febrile and had a significantly lower REM sleep percent throughout the two-weeks post burn due to a reduction in frequency but not duration of REM periods. The increase in respiratory rate from the non-REM to REM sleep state observed before injury was abolished in the seeded group post burn. There was an immediate but transient 24 h drop in REM sleep following thermal injury. Bacterial colonization of the burn wound by either immediate, artificial seeding or by delayed, spontaneous means significantly decreased REM sleep with and without fever, respectively. These results indicate that noninvasive bacterial colonization of a burn wound was capable of decreasing REM sleep without causing fever and that REM sleep reduction was a more sensitive indicator of the extent of burn wound bacterial colonization than was colonic temperature.