Spectral analysis of impedance respirogram in newborn infants.
Respiratory rate (RR), transthoracic electric impedance (TEZ) and transcutaneous PO2 and PCO2 were monitored during the 5 first postnatal days in 54 neonates on three separate occasions. There was no difference in the overall RR between the term and healthy preterm babies on different days of recordings but RR of the babies with RDS (who were all ventilated) was lower on day 1 (p less than 0.01). When the power spectrum of the TEZ respirogram was computed and the spectral density was divided into low-frequency (LF, less than 0.20 Hz) and high-frequency (HF, greater than 0.20 Hz) areas, the LF/HF ratio of healthy preterm babies was greater than that of term babies on day 1 (p less than 0.01). The preterm babies with RDS did not differ from the term babies in this respect. The LF/HF ratio was negatively correlated with gestational age and it had a positive correlation to PtcO2 (p less than 0.05) and PtcCO2 (p less than 0.01) (R2 = 0.07). The result evidences that the control of respiration changes in relation to maturity and the LF/HF ratio is a quantitative indicator of respiratory variability reflecting this development.
Aärimaa
T
T
Department of Pediatrics, University Central Hospital, University of Turku, Finland.
Välimäki
I A
IA
D001785:Blood Gas Monitoring, Transcutaneous; D002307:Cardiography, Impedance; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D010992:Plethysmography, Impedance; D012119:Respiration; D012129:Respiratory Function Tests