Decreased Variability and Low Values of Perfusion Index on Day One Are Associated with Adverse Outcome in Extremely Preterm Infants.
OBJECTIVE
To develop new quantitative features for the Perfusion Index signal recorded continuously over the first 24 hours of life in a cohort of extremely low gestational age newborns and to assess the association of these features with normal and adverse short-term outcome.


METHODS
A cohort study of extremely low gestational age newborns. Adverse outcome was defined as early mortality before 72 hours of life, acquired severe periventricular-intraventricular hemorrhage, or severe cystic leukomalacia. Perfusion Index values were obtained from the plethysmographic signal of a pulse oximeter. Perfusion Index signals were separated into low-frequency (trend) and high-frequency (detrend) components. Three features were extracted during four 6-hour epochs: mean of the trend component (mean-trend), SD of the trend component (SD-trend), and SD of the detrend component (SD-detrend). The SD features represent long-term variability (SD-trend) and short-term variability (SD-detrend) of the Perfusion Index. A mixed-effects model was fitted to each feature.


RESULTS
Ninety-nine infants were included in the analysis. Quadratic-time mixed-effects models provided the best fit for all 3 features. The mean-trend component was lower for the adverse outcome compared with the normal outcome group with a difference of 0.142 Perfusion Index (P = .001). SD-detrend component was also lower for the adverse compared with the normal outcome group, although this difference of 0.031 Perfusion Index/days2was dependent on time (P < .001).


CONCLUSIONS
Low values and reduced short-term variability of Perfusion Index on day 1 are associated with adverse outcome.
Department of Neonatal Intensive Care, University Hospital Antwerp, Edegem, Belgium; Department of Medicine and Health Sciences, University of Antwerp, Antwerpen, Belgium. Electronic address: David.Vanlaere@uza.be.
David
D
Van Laere
Irish Centre for Fetal and Neonatal Translational Research, University College Cork, Cork, Ireland.
John M
JM
O'Toole
Department of Neonatal Intensive Care, University Hospital Antwerp, Edegem, Belgium; Department of Medicine and Health Sciences, University of Antwerp, Antwerpen, Belgium.
Michiel
M
Voeten
Irish Centre for Fetal and Neonatal Translational Research, University College Cork, Cork, Ireland.
Joanne
J
McKiernan
Irish Centre for Fetal and Neonatal Translational Research, University College Cork, Cork, Ireland.
Geraldine B
GB
Boylan
Irish Centre for Fetal and Neonatal Translational Research, University College Cork, Cork, Ireland.
Eugene
E
Dempsey
D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000453:epidemiology*; D008297:Male; D010092:Oximetry; D010991:Plethysmography / Q000379:methods
Infant, premature; circulation; plethysmography