Abstracts

Rationale: To investigate whether non-medical, environmental factors influence the frequency of admissions of patients with status epilepticus (SE) to the intensive care unit (ICU).Methods: Cohort Study during July 2003-June 2006 of all patients admitted to a single university hospital ICU for the treatment of SE. Retrospective analysis using Poisson-regression and likelihood ratio tests for the determination of associations between environmental factors (daytime, weekday, season, moon cycle, and weather conditions) and the incidence of SE.Results: Data from 184 patients (mean age 57 years (18-89)) showed a significant (p<.001) diurnal pattern with a peak of admissions between 4 to 5 p.m. and a minimum in the early morning. A significant weekly pattern was also observed (p=.045) with admissions peaking on Wednesdays/Thursdays and being lowest at weekends. There was no seasonal pattern. Admissions varied significantly across moon cycle (p=0.003), peaking at day 3 after new moon, with a weaker peak 7 days after full moon, and a minimum 3 days before new moon. While sunshine, precipitation, and wind force did not significantly influence the admissions, high relative humidity (p<0.01), high temperature (p<0.05) and dark days (p=0.02) were significantly protective factors. Bright days (p=0.04), and daily sunshine duration (p=0.03) increased the incidence of SE.Conclusions: Admissions of patients with SE on ICU are significantly associated with several environmental protective and precipitating factors, like diurnal, weekly and moon cycle, and weather variables. Contrary to common belief, SE did neither peak at full moon nor at new moon, but some days after new moon. The reasons for the associations observed remain to be further elucidated.