Introduction We aimed to develop and validate a prediction table for a simplified measure of rightward shift of the fetal oxyhaemoglobin saturation (SpO2) versus inspired oxygen pressure (PIO2) curve as an objective marker of lung disease severity in very preterm infants, independent of unit altitude or oxygen prescribing policies.
Methods Very preterm infants (n=219) had an oxygen reduction test at median (IQR) test age of 354 (345–360) weeks’ postmenstrual age (PMA). Shift was derived from at least three paired SpO2 versus PIO2 measurements using a computer algorithm, using the fetal oxyhaemoglobin dissociation curve as the reference. Linear regression of resultant shift values enabled construction of a table to predict shift using a single paired SpO2 versus PIO2 measurement, validated subsequently in a separate infant cohort using Bland-Altman analysis. Receiver operating curve analysis provided threshold values equating to a clinical diagnosis of mild bronchopulmonary dysplasia (BPD) or moderate to severe BPD.
Results The median (IQR) age of 63 infants in the validation cohort was 360 (356–362) weeks’ PMA. Mean difference (95% CI) between predicted and measured shift was 2.1 (−0.8% to 4.9%) with wide limits of agreement (−20.7% to 24.8%). Predicted shift >10.1 kPa identified mild BPD with 71% sensitivity and 88% specificity while values>13.0 kPa identified moderate to severe BPD with 81% sensitivity and 100% specificity.
Discussion Shift predicted from a single paired SpO2 versus PIO2 measurement using our validated table enables objective bedside screening of lung disease severity in very preterm infant cohorts at 36 weeks’ PMA.
- paediatric lung disaese
- lung physiology
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BS and YJC are joint first authors.
Correction notice This article has been corrected since it was published Online First. Author last name for GJ has been amended and first initial for JC has been added. A duplicate reference has also been removed.
Contributors BS collected and analysed the data, interpreted the data, assisted with the REDCap database design and development, drafted the initial manuscript, performed literature search, drafted the figures and approved the final manuscript as submitted. JC collected and analysed the data, interpreted the data, drafted the figures, reviewed and revised the manuscript, and approved the final manuscript as submitted. AR collected the data, reviewed and approved the final version of the manuscript as submitted. JS collected the data, analysed the data, reviewed and approved the final version of the manuscript as submitted. GJ developed the algorithms used for the calculation of shunt, shift and VA/Q, reviewed and revised the manuscript, and approved the final manuscript as submitted. JP was the principal investigator obtaining funding, leading study design including development of the REDCap database, obtained the study funding, verified all statistical calculations, interpreted the data, critically reviewed and revised the manuscript and approved the final manuscript as submitted.
Funding All phases of this study were supported by the University of Western Australia and the Women and Newborn Health Service of Western Australia. Funded by National Health and Medical Research Council (NHMRC) of Australia (GNT1047689, GNT1057514) and the Metropolitan Health Research Infrastructure Fund (MHRIF). BS was supported by the Swiss National Science Foundation (P2BSP3_158837) and a Research Training Program scholarship from The University of Western Australia. JS was supported by The Swedish Society of Medicine, The Samaritan Foundation, The Princess Lovisa Memory Foundation, The Society of Child Care (Sällskapet Barnavård), and The Fernstrom Foundation. JP was supported by an NHMRC Senior Research Fellowship (RF1077691).
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Each clinical study received ethics approval from the Women and Newborn Health Service Human Research Ethics Committee (HREC: 1883EW and 20 130 193EW respectively) and the University of Western Australia (RA/3/1/5942 and RA/4/1/426, respectively). Studies were conducted in the Neonatal Clinical Care Unit at the King Edward Memorial Hospital in Perth, Western Australia.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as online supplemental information. We have collected deidentified participant data and we will make our data available on reasonable request. ORCID-ID: 0000-0003-0021-0262.
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