All subjects gave written, informed consent, as approved by the University of Kentucky College of Medicine Institutional Review Board. asthma inhalers
Nocturnal Procedures
Lights were turned out as closely to 11:00 pm as possible, and patients were awakened between 6:00 and 6:30 am.
Apparatus included a polygraph (Crass). Sleep was recorded using the following referential montage: C3-A*, C4-A|, Cz-0|, Oj-A*, Ot-A„ an electrooculogram, and a chin myogram. Electrodes were placed according to the International 10/20 system. Electrocardiograms were recorded from a standard one-lead montage. Airflow was sensed from oral and nasal thermistors and a carbon dioxide meter, while oxygen saturation was analyzed by ear oximeter. Respiratory movement was assessed by respiratory inductive plethysmography. All nocturnal physiologic signals were continuously recorded on chart paper at 10 mm/s. Sleep was staged in 30 second epochs using a modified version of Rechtschaffen and Kales criteria. Oxygen saturation data were quantified in a fashion previously described by Berry et al, which results in a mean high and low Sa02 across the night, as well as a summation of the number of falls in SaOs of 4 percent or greater. Personnel scoring nocturnal variables were blind to daytime results and treatment conditions.