Reliability of pulse oximetry in hypoxic newborn pigs. (May 2014)

• Record Type: Journal Article
• Authors: Solevåg, Anne Lee; Dannevig, Ingrid; Šaltytė-Benth, Jūratė; Saugstad, Ola D.; Nakstad, Britt
• Is Part Of: Journal of maternal-fetal & neonatal medicine. Volume 27:Number 8(2014:Aug.)
• Page Start: 833
• Page End: 838
• Publication Date: 2014-05
• Subjects: Obstetrics -- Periodicals; Perinatology -- Periodicals; Infants (Newborn) -- Diseases -- Periodicals; Neonatology -- Periodicals; 618.2
• DOI: 10.3109/14767058.2013.842550
• Languages: English
• ISSNs: 1476-7058

Abstract

<abstract> <title>Abstract</title> <p> <italic>Objective</italic>: The reliability of pulse oximetry in the lower SaO<sub>2</sub>-ranges has not been fully investigated. We wanted to investigate pulse oximeter performance in a pig model of perinatal asphyxia.</p> <p> <italic>Methods</italic>: Asphyxia was induced in 22 newborn pigs. Pulse oximetry-values for SpO<sub>2</sub>, as well as SaO<sub>2</sub> from blood gas analyses were recorded multiple times before, during and after asphyxiation. The relationship between SpO<sub>2</sub> and SaO<sub>2</sub> in normoxia and hypoxia in this model was quantified. Calculations were made for 5% increments of SaO<sub>2</sub> increasing successively from ≥95% to ≥20%.</p> <p> <italic>Results</italic>: The pigs became severely hypoxic, acidotic and hypotensive. The bias in the total data was +13.7 (<italic>p</italic> < 0.001), i.e. SpO<sub>2</sub> was on average higher than SaO<sub>2</sub> for the entire interval of SaO<sub>2</sub>. However, bias was not significantly different from zero in most SpO<sub>2</sub>-ranges. Accuracy and precision were considerably higher than stated by the manufacturer in all SpO<sub>2</sub>-ranges, with both accuracy and precision increasing when SpO<sub>2</sub>-values down to 60% and lower were included.</p> <p> <italic>Conclusion</italic>: Pulse oximetry was less reliable at SaO<sub>2</sub>-values below 60%. Tissue acidosis and reduced peripheral perfusion may have contributed to this. It is unknown whether the difference between SpO<sub>2</sub> and SaO<sub>2</sub> is clinically relevant.</p> </abstract>