Sadeghi Fathabadi, O and Gale, TJ and Lim, K and Salmon, BP and Dawson, JA and Wheeler, KI and Olivier, JC and Dargaville, PA, Characterisation of the oxygenation response to inspired oxygen adjustments in preterm infants, Neonatology, 109, (1) pp. 37-43. ISSN 1661-7800 (2016) [Refereed Article]
© 2015 S. Karger AG, Basel
Background: Oxygen saturation (SpO2) targeting in the preterm infant may be improved with a better understanding of the SpO2 responses to changes in inspired oxygen (FiO2).
Objective: We investigated the first-order FiO2-SpO2 relationship, aiming to quantify the parameters governing that relationship, the influences on these parameters and their variability.
Methods: In recordings of FiO2 and SpO2 from preterm infants on continuous positive airway pressure and supplemental oxygen, we identified unique FiO2 adjustments and mapped the subsequent SpO2 responses. For responses identified as first-order, the delay, time constant and gain parameters were determined. Clinical and physiological predictors of these parameters were sought in regression analysis, and intra- and inter-subject variability was evaluated.
Results: In 3,788 h of available data from 47 infants at 31 (28-33) post-menstrual weeks [median (interquartile range)], we identified 993 unique FiO2 adjustments followed by a first-order SpO2 response. All response parameters differed between FiO2 increments and decrements, with increments having a shorter delay, longer time constant and higher gain [2.9 (1.7-4.8) vs. 1.3 (0.58-2.6), p < 0.05]. Gain was also higher in less mature infants and in the setting of recent SpO2 instability, and was diminished with increasing severity of lung dysfunction. Intra-subject variability in all parameters was prominent.
Conclusions: First-order SpO2 responses show variable gain, influenced by the direction of FiO2 adjustment and the severity of lung disease, as well as substantial intra-subject parameter variability. These findings should be taken into account in adjustment of FiO2 for SpO2 targeting in preterm infants.
|Item Type:||Refereed Article|
|Keywords:||arterial oxygen saturation, automated control, fraction of inspired oxygen, oxygen inhalation therapy, preterm infant|
|Research Group:||Biomedical Engineering|
|Research Field:||Biomedical Instrumentation|
|Objective Field:||Medical Instruments|
|UTAS Author:||Sadeghi Fathabadi, O (Mr Omid Sadeghi Fathabadi)|
|UTAS Author:||Gale, TJ (Dr Timothy Gale)|
|UTAS Author:||Lim, K (Ms Lim)|
|UTAS Author:||Salmon, BP (Dr Brian Salmon)|
|UTAS Author:||Olivier, JC (Professor JC Olivier)|
|UTAS Author:||Dargaville, PA (Professor Peter Dargaville)|
|Web of Science® Times Cited:||3|
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