Monitoring pulse oximetry via radiotelemetry in freely-moving lambs

This study was aimed at validating the use of a custom-made wireless pulse oximeter in freely moving lambs, using radiotelemetry transmission. First, measurements obtained simultaneously using the new, wireless oximeter and a standard commercially-available pulse oximeter (Nonin 8500) were compared in five lambs during 5 min episodes of normoxia, hypoxia and hyperoxia. Correlation between the two oximeters for both SpO2 and heart rate was very good, regardless of oxygenation conditions. Secondly, the capabilities of our device were assessed during more than 45 h of polysomnographic recordings in seven lambs. According to the plethysmographic pulse waveform, reliable SpO2 values were obtained in more than 85% of recording time. Multiple decreases in SpO2 were readily observed after spontaneous apneas in preterm lambs. It is concluded that our wireless pulse oximeter performs as reliably as a standard pulse oximeter for monitoring SpO2 variations in lambs, and offers new perspectives for researchers interested in continuous monitoring of oxygenation throughout sleep stages and wakefulness.