Photoplethysmography for simultaneous recording of heart and respiratory rates in newborn infants

Tell newborn infants, born at 25-41 wk of gestation and nursed in a neonata l intensive care unit or in a neonatal intermediate care unit, underwent mo nitoring of heart and respiratory rates with a new technique using an optic al sensor, 0-60 d postnatally. The aim of this study was to compare the hea rt and respiratory rates recorded in infants by photoplethysmography with a probe positioned on three monitoring sites, namely the leg, buttock and in terscapular region, with the rates recorded by ECC and transthoracic impeda nce, respectively. The recordings were compared in order to determine which individual heart beats and respiratory cycles were recorded with one or bo th I relevant techniques. A high degree of association (r = 0.99) was found between the respiratory rates recorded by photoplethysmography and by tran sthoracic impedance. Recordings of heart rates by ECG were also highly asso ciated with the photoplethysmographic rates as measured at two (r = 0.99) o f the three monitoring sites. It is concluded that heart and respiratory rates in infants can be monitore d satisfactorily by the new method based on photoplethysmography. This meth od offers the advantage of recording several physiological parameters non-i nvasively with a single probe during the neonatal period.