[Evaluation of the cardiorespiratory monitor SpiroGuard C for infants. Improved registration of respiratory events by new sensors and intelligent alarm management system].

OBJECTIVES

The SpiroGuard C is a commercially available cardiorespiratory monitor working with field plethysmography, wireless signal transmission and a novel alarm management system. In order to determine the recognition rates for central, mixed and obstructive apneas, a prospective clinical trial was performed comparing frequency and kind of signals from the monitor with those simultaneously registered by polysomnographic studies.

DESIGN

Normal respiratory and alarm signals of the monitor under investigation were integrated into a polysomnographic setting. All central, mixed and obstructive apneas lasting more than 10 seconds as well as all alarms obtained from the monitor were evaluated.

RESULTS

47 series of monitor recordings could be evaluated in parallel to polysomnographic studies: the detection rate for central apneas was 298/328 (90.85%), for mixed apneas 9/41 (21.95%) and for obstructive apneas 0/36 (0%). Out of the total of 708 registered alarms 359 (50.71%) were false alarms, 307 (43.36%) were apnea-related and 42/708 (5.93%) were alarms due to technical problems. 177 of the 359 false alarms (49.30%) occurred during apneas that were shorter than 10 seconds, 119 (33.15%) were related to bad signal quality, and 55 (15.32%) were caused by movement artifacts.

CONCLUSION

The recognition rate for central apneas was high (> 90%), while sensitivity for mixed and obstructive apneas was not satisfactory. Approximately half of the alarms were false alarms. These could be reduced by setting the apnea detection time to > 15 seconds, by tighter fastening of the respiration belt (improving the signal transmission), and by turning off the instrument when the child is awake and physically active. The wireless system renders the SpiroGuard C an attractive alternative for home monitoring.