Low melatonin excretion during mechanical ventilation in the intensive care unit.

Biochemical markers for the circadian rhythm were studied in patients treated at the ICU (intensive care unit) of two regional hospitals. A normal rhythm is characterized by a relatively higher melatonin and a lower cortisol excretion at night. Disturbances affect sleep, mood and cognitive performance. All urine excreted between 07:00 and 22:00 hours (day) and between 22:00 and 07:00 hours (night) was collected and sampled throughout the entire ICU period (median, 10 days) in 16 patients for the excretion of 6-SMT (6-sulphatoxymelatonin), which is a metabolite of melatonin, and free cortisol. The overall excretion of 6-SMT was slightly lower and the cortisol excretion higher than reported for healthy reference populations. Mechanical ventilation was associated with a markedly lower 6-SMT excretion (median, 198 ng/h) compared with periods without such help (555 ng/h; P<0.0001), whereas infusion of adrenergic drugs increased the 6-SMT excretion (P<0.01). Five patients (31%) showed a virtually absent melatonin excretion for 24 h or more. The diurnal rhythms were consistently or periodically disturbed in 65% and 75% of the patients. These alterations cannot be explained by excessive exposure to light at night. In conclusion, there was hyposecretion of melatonin during mechanical ventilation, an overall high cortisol excretion and a disturbed diurnal rhythm of both of these hormones in most patients treated in two ICU departments.

Patients' sleep in an intensive care unit--patients' and nurses' perception.

The main purpose of this study was to describe how patients treated in an intensive care unit (ICU) perceive their sleep and to compare patients' and nurses' perceptions of the patients' sleep. The study also determined the percentage of patients in the ICU who were able to fill in the Richard Campell Sleep Questionnaire (RCSQ). This instrument consists of six items and utilises a visual analogue scale (VAS). The results of five of the RCSQ questions are used to calculate a total sleep score, ranging between 0 and 100 (0=the worst possible sleep, 100=the best sleep).Approximately half of the patients were able to answer the RCSQ (n=31). The patients' rating of their sleep varied widely (total sleep score: range 0-97, mean 45.5). Patients who had received hypnotics or sedatives during the night (n=12) had a significantly lower total sleep score (mean=31.6) than the rest of the patients (mean 54.3; P=0.037). On comparing the patients' and the nurses' perceptions of the patients' sleep, no significant difference between the groups was seen. This indicates that nurses can use the RCSQ to assess the sleep of patients who are unable to report their sleep themselves.