The utility value of SpO2/FiO2 (S/F) and PaO2/FiO2 (P/F) ratios for predicting initiation and efficiency of HFNC in children with respiratory distress admitted in PICU
DOI:
https://doi.org/10.18203/2349-3291.ijcp20250766Keywords:
Oxygen indices, Pulse oximetry, Arterial blood gasAbstract
Background: The PaO₂/FiO₂ (P/F) ratio, defined as the partial pressure of oxygen (PaO₂) divided by the fraction of inspired oxygen (FiO₂), and the SpO₂/FiO₂ (S/F) ratio, defined as pulse oximetric saturation (SpO₂) divided by FiO₂, are key indicators of oxygenation status. This study aimed to evaluate the utility of S/F and P/F ratios in predicting the initiation and effectiveness of HFNC in children with respiratory distress.
Methods: A prospective observational study of 133 children (1 month–14 years) with respiratory distress receiving HFNC was conducted. S/F and P/F ratios were measured at 0, 1, 12, and 24 hours after HFNC initiation. Outcomes assessed included ICU stay, hospital stay, and HFNC duration.
Results: Among 133 children (35.34% females, 64.66% males; mean age 0.9 years, weight 7.8 kg), 62.42% had moderate respiratory distress per P/F ratio, while 76.69% had mild respiratory failure per S/F ratio. Both ratios improved significantly over time (p <0.05). A higher S/F ratio at initiation correlated with shorter ICU and hospital stays. The S/F ratio was a superior predictor of HFNC requirement (sensitivity: 85.29%, accuracy: 88.5%) compared to the P/F ratio (sensitivity: 41.91%, accuracy: 56.67%). ROC analysis confirmed strong predictive power for S/F (AUC 0.966).
Conclusion: The S/F ratio is a reliable, non-invasive surrogate for the P/F ratio in identifying respiratory distress and HFNC need, reducing the necessity for arterial blood sampling.
Metrics
References
Ware LB, Matthay MA. The acute respiratory distress syndrome. N Engl J Med. 2000;342:1334–49. DOI: https://doi.org/10.1056/NEJM200005043421806
Bernard GR, Artigas A, Brigham KL, Carlet J, Falke K, Hudson L. et al. Thoracic SoG-The American European Consensus Conference on ARDS efinitions, mechanisms. Am J Respir Crit Care Med. 1994;149:818–24. DOI: https://doi.org/10.1164/ajrccm.149.3.7509706
Pandharipande PP, Shintani AK, Hagerman HE, Jacques PJ, Rice TW, Sanders NW, et al. Derivation and validation of Spo2/Fio2 ratio to impute for pao2/fio2 ratio in the respiratory component of the sequential organ failure assessment score. Crit Care Med. 2009;37(4):1317–21. DOI: https://doi.org/10.1097/CCM.0b013e31819cefa9
Lohano PD, Baloch SH, Gowa MA, Raza SJ, Soomro L, Nawaz H. Correlation between the ratio of oxygen saturation to fraction of inspired oxygen and the ratio of partial pressure of oxygen to fraction of inspired oxygen in detection and risk stratification of pediatric acute respiratory distress syndrome. Cureus. 2021;13(9):18353. DOI: https://doi.org/10.7759/cureus.18353
Mayordomo-Colunga J, Pon, López Y, et al. Predicting non-invasive ventilation failure in children from the SpO‚ /FiO‚ (SF) ratio. Intensive Care Med. 2013;39:1095-103. DOI: https://doi.org/10.1007/s00134-013-2880-5
Lobete C, Medina A, Rey C, Mayordomo-Colunga J, Concha A, Menéndez S. Correlation of oxygen saturation as measured by pulse oximetry/fraction of inspired oxygen ratio with PaO2/fraction of inspired oxygen ratio in a heterogeneous sample of critically ill children. J Crit Care. 2013;28:538. DOI: https://doi.org/10.1016/j.jcrc.2012.12.006
Babu S, Abhilash KPP, Kandasamy S, Gowri M. Association between SpO2/FiO2 Ratio and PaO2/FiO2 Ratio in Different Modes of Oxygen Supplementation. Indian J Crit Care Med. 2021;25(9):1001–5. DOI: https://doi.org/10.5005/jp-journals-10071-23977
Beniwal R, Batra P, Bhaskar V, Harit D. SpO2/FiO2 and PaO2/FiO2 for Predicting Intensive Care Admission in Wheezy Children: An Observational Study. Indian Pediatr. 2024;61(7):632-6. DOI: https://doi.org/10.1007/s13312-024-3227-8
Khemani RG, Patel NR, Bart RD, Newth CJ. Comparison of the pulse oximetric saturation/fraction of inspired oxygen ratio and the PaO2/fraction of inspired oxygen ratio in children. Chest. 2009;135(3):662-8. DOI: https://doi.org/10.1378/chest.08-2239
Chang CC, Lin YC, Chen TC, Lin JJ, Hsia SH, Chan OW. High-flow nasal cannula therapy in children with acute respiratory distress with hypoxia in a pediatric intensive care unit–a single center experience. Front Pediatr. 2021;9:664180. DOI: https://doi.org/10.3389/fped.2021.664180
Kim, G.E., Choi, S.H., Park, M. et al. SpO2/FiO2 as a predictor of high flow nasal cannula outcomes in children with acute hypoxemic respiratory failure. Sci Rep. 2021;11:13439. DOI: https://doi.org/10.1038/s41598-021-92893-7
Shah N, Sarangi BU, Shankar GH. Comparison of PaO2/FiO2 (PF ratio) to SpO2/FiO2 (SF ratio) and OI to OSI for Predicting Short Term Outcomes in Children with Acute Hypoxemic Respiratory Distress: A Prospective Observational Study. Indian J Pediatr. 2024;3:56-8. DOI: https://doi.org/10.1007/s12098-024-05134-w
Downloads
Published
How to Cite
Issue
Section
