Defining acute lung disease in children with the oxygenation saturation index.
OBJECTIVE
To evaluate whether a formula could be derived using oxygen saturation (Spo2) to replace Pao2 that would allow identification of children with acute lung injury and acute respiratory distress syndrome. Definitions of acute lung injury and acute respiratory distress syndrome require arterial blood gases to determine the Pao2/Fio2 ratio of 300 (acute lung injury) and 200 (acute respiratory distress syndrome).


METHODS
Post hoc data analysis of measurements abstracted from two prospective databases of randomized controlled trials.


METHODS
Academic pediatric intensive care units.


METHODS
A total of 255 children enrolled in two large prospective trials of therapeutic intervention for acute lung disease: calfactant and prone positioning.


METHODS
Data were abstracted including Pao2, Paco2, pH, Fio2, and mean airway pressure. Repeated-measures analyses, using linear mixed-effects models, were used to build separate prediction equations for the Spo2/Fio2 ratio, oxygenation index [(Fio2 x Mean Airway Pressure)/Pao2], and oxygen saturation index [(Fio2 x Mean Airway Pressure)/Spo2 ]. A generalization of R was used to measure goodness-of-fit. Generalized estimating equations with a logit link were used to calculate the sensitivity and specificity for the cutoffs of Pao2/Fio2 ratio of 200 and 300 and equivalent values of Spo2/Fio2 ratio, oxygenation index, and oxygen saturation index.


RESULTS
An Spo2/Fio2 ratio of 253 and 212 would equal criteria for acute lung injury and acute respiratory distress syndrome, respectively. An oxygenation index of 5.3 would equal acute lung injury criteria, and an oxygenation index of 8.1 would qualify for acute respiratory distress syndrome. An oxygen saturation index, which includes the mean airway pressure and the noninvasive measure of oxygenation, of 6.5 would be equivalent to the acute lung injury criteria, and an oxygen saturation index of 7.8 would equal acute respiratory distress syndrome criteria.


CONCLUSIONS
Noninvasive methods of assessing oxygenation may be utilized with reasonable sensitivity and specificity to define acute lung injury and acute respiratory distress syndrome, and, with prospective validation, have the potential to increase the number of children enrolled into clinical trials.
Thomas
Neal J
NJ
Department of Pediatrics and Public Health Sciences, Penn State Center for Host defense, Inflammation, and Lung Disease Research, Penn State Hershey Children's Hospital and Pennsylvania State University College of Medicine, Hershey, PA, USA.
Shaffer
Michele L
ML
Willson
Douglas F
DF
Shih
Mei-Chiung
MC
Curley
Martha A Q
MA
D055371:Acute Lung Injury / Q000175:diagnosis*; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D019992:Databases as Topic; D005260:Female; D006801:Humans; D008297:Male; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange / Q000502:physiology; D016032:Randomized Controlled Trials as Topic; D012128:Respiratory Distress Syndrome / Q000175:diagnosis*
D010100:Oxygen