A new fiberoptical respiratory rate monitor for the neonatal intensive care unit.

摘要

A new technique for respiratory rate measurement in the neonatal intensive care unit, fiberoptic respirometry (FORE), was tested using a specially designed nasal adapter. The aim was to investigate the system's accuracy and compare it to the transthoracic impedance (TTI) method and manual counting (MC). Further, the relationship between accuracy and degree of body movement was investigated. Seventeen neonates of median gestational age 35 weeks were included in the study. Video recordings (synchronized with data recordings) were used for classification of body movement. Breaths per minute data were obtained for 23-32-min periods per child, and a subset of these included MC performed by experienced nurses. A Bland-Altman analysis showed low accuracy of both FORE and TTI. A >20% deviation from MC was found in 22.7% and 23.8% of observations for the two methods, respectively. Both methods had accuracy problems during body movement. FORE tended to underestimate respiratory rate due to probe displacement, while TTI overestimated due to motion artefacts. The accuracy was also strongly subject-dependent. The neonates were undisturbed by the FORE device. In some cases, though, it was difficult to keep the adapter positioned in the airway. Further development should, therefore, focus on FORE adapter improvements to maintain probe position over time.