Computerized monitoring of physical activity and sleep in postoperative abdominal surgery patients

Objective. Assessment of early postoperative activity is important in the documentation of improvements of peri-operative care. This study was designed to validate computerized activity-based monitoring of physical activity and sleep (actigraphy) in patients after abdominal surgery. Methods. The study included twelve hospitalized patients after major abdominal surgery studied on day 2 to 4 after operation and twelve unhospitalized healthy volunteers. Measurements were performed for 24 consecutive hours. The actigraphy measurements were compared with self-reported activity- and sleep registration. The actigraphy output was obtained by the zero-crossing mode (ZCM) and time-above-threshold mode (TATM). Results. The overall results showed comparable mean agreement between actigraphy and self-reported activity registrations for patients of 80% (SD 12%) and volunteers of 84% (SD 6%) (p = 0.15). In both study groups, all correlation coefficients between actigraphy measurements and self-reported activity data were statistically signicant (r(s) values for patients 0.4 to 0.8 and volunteers 0.6 to 0.9). A higher mean agreement between automated actigraphy sleep detection and self-reported sleep registration were found in the volunteers (85%, SD 15%) compared with the patients (77%, SD 11%) (p < 0.05). The mean activity value awake was higher in the volunteers than in the patients (p < 0.05). Conclusion. Computerized activity monitoring by actigraphy is a reliable and easy method for monitoring physical activity and sleep-wake cycles after major abdominal surgery.