The use of pulse oximetry in the prevention of hyperoxaemia in preterm infants

When deciding an appropriate upper limit for pulse oxygen saturation (SpO₂) in preterm infants the usefuleness of current data is limited by the fact that previous studies have examined a population of more mature infants and children or have applied various exclusion criteria which produce results unrepresentative of clinical practice. We tested the hypothesis of previous workers that maintaining the SpO₂ below 98% would ensure an arterial oxygen tension (PaO₂) less than 12 kPa. A total of 477 simultaneous measurements ofPaO₂ and SpO₂ were made using Ohmeda Biox oximeters on 43 infants who were less than 33 weeks gestation and receiving supplementary oxygen. Of 435 measurements performed when the SpO₂ was 97% or less, 26 (6%) had aPaO₂ greater than 12 kPa. Further examination of the data showed that of 108 estimations performed when the SpO₂ was less than 94%, none had aPaO₂ greater than 12kPa.Conclusion When using Ohmeda Biox pulse oximeters an upper limit of 97% for SaO₂ is not effective in preventing hyperoxaemia; however, a linit of 93% is likely to maintain thePaO₂ below 12 kPa.