OBJECTIVE: To dynamic monitor and analyze the characteristic of polysomnography (PSG) and melatonin levels of delirium patients in intensive care unit (ICU).
METHODS: A prospective observational study was performed from December 2013 to April 2014. The patients admitted to ICU of Affiliated Hospital of Binzhou Medical College for more than 72 hours were evaluated with confusion assessment method for the ICU (CAM-ICU), and were divided into delirium group and non-delirium group. Sleep patterns of all the patients underwent continuous PSG for up to 24 hours were evaluated. Melatonin levels were determined every 4 hours with enzyme linked immunosorbent assay (ELISA) duration sleep monitoring.
RESULTS: Eighteen patients were enrolled, and 9 were delirium patients. All the patients had sleep disorders: a decrease in rapid eye movement (REM) sleep [(5.91 ± 5.26)%], an increase in the sleep fragmentations [arousal index was (15.40 ± 12.79) times/h], and the N3 sleep stage was on the lower limit of normal [(14.67 ± 11.10)%]. Compared with non-delirium group, the REM sleep was significantly decreased in delirium group [(0.10 ± 0.20)% vs. (8.83 ± 3.81)%, t=4.782, P=0.001]. Melatonin levels lost rhythm between day and night, and there was no difference in melatonin between delirium group and non-delirium group(time effect: F=1.370, P=0.287; between-group effect: F=1.646, P=0.250; interaction effect: F=1.558, P=0.247). The peak of melatonin levels of delirium group appeared on 06:00 [(137.84 ± 62.21) ng/L] and 14:00 [(148.24 ± 58.8) ng/L], the minimum value on 22:00 [(64.47 ± 26.97) ng/L]. But in non-delirium group, the peak of melatonin levels appeared on 02:00 [(63.52 ± 39.75) ng/L], the minimum value on 10:00 [(44.87 ± 11.19) ng/L].
CONCLUSIONS: ICU patients have sleep disorders, and the delirium patients have less REM stage. Normal rhythmic melatonin secretion changes of ICU patients were lost. The delirium peak of patients appears in the daytime.
