Respiratory physiology & neurobiology
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Respir Physiol Neurobiol · May 2005
Comparative StudyMonitoring 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 5min episodes of normoxia, hypoxia and hyperoxia. Correlation between the two oximeters for both SpO(2) and heart rate was very good, regardless of oxygenation conditions. ⋯ According to the plethysmographic pulse waveform, reliable SpO(2) values were obtained in more than 85% of recording time. Multiple decreases in SpO(2) 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 SpO(2) variations in lambs, and offers new perspectives for researchers interested in continuous monitoring of oxygenation throughout sleep stages and wakefulness.
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Respir Physiol Neurobiol · May 2005
Comparative StudyDoxapram stimulates the carotid body via a different mechanism than hypoxic chemotransduction.
To determine if doxapram stimulates the carotid body through the same mechanism as hypoxia, we compared the effects of doxapram and hypoxia on isolated-perfused carotid bodies in rabbits. Doxapram stimulated the carotid body in a dose-dependent manner. In Ca(2+)-free solution, neither doxapram nor hypoxia stimulated the carotid body. ⋯ Interestingly, the effect of doxapram was partially inhibited by NS-1619. Neither pinacidil nor levcromakalim affected the stimulatory effect of doxapram. We conclude that doxapram stimulates the carotid body via a different mechanism than hypoxic chemotransduction.