Metabolic and cutaneous events associated with hypoglycemia detected by sleep sentry

Eighteen insulin-dependent diabetic subjects [age (mean +/- SD) 33.2 +/- 10.6 yr] participated in a study designed to determine the metabolic and cutaneous parameters associated with activation of the nocturnal hypoglycemia monitor Sleep Sentry. Plasma glucose, glucagon, epinephrine, norepinephrine, and pancreatic polypeptide concentrations were determined every 10 min during a 2-h constant intravenous insulin infusion (40 mU.kg-1.h-1). In addition, skin temperature and electrical conductance were monitored at the same time intervals, and subjects were asked to rate the degree to which they felt cold and/or sweaty. Ten of the subjects (alarmers) activated the device with a mean plasma glucose nadir of 52.8 +/- 13.8 mg/dl, whereas eight (nonalarmers) failed to do so despite a mean plasma glucose nadir of 50.5 +/- 8.2 mg/dl. There were no significant differences between alarmers and nonalarmers with respect to initial or nadir plasma glucose levels, rate of fall of plasma glucose, or changes in plasma epinephrine, norepinephrine, or pancreatic polypeptide concentrations. In addition, changes in skin temperature and conductance were similar in both groups as were descriptive variables including age, disease duration, gender, and level of glucose control. No subject reported an increase in coldness, whereas 80% of both groups reported an increase in sweatiness. Three subjects studied on more than one occasion over a year failed to exhibit consistent activation of the alarm. This study suggests that it may not be possible to identify patients for whom the Sleep Sentry would be a reliable addition to their self-management regimen and that physicians should exercise caution in recommending its use.