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The hyperoxic test in infants reinvestigated
B Bouferrache1, S Filtchev, A Leke
1URAPC (EA 2088), School of Medicine, Amiens, and Department of Physiology, INSERM-CRI 9701, Robert Debré Hospital, Paris, France.
American Journal of Respiratory and Critical Care Medicine
|January 5, 2000
Summary
The hyperoxic test (HT) can better assess infant peripheral chemoreceptor function (PCF) by measuring the ventilatory response (VR) at the response time (RT). This method improves accuracy and reproducibility compared to using the mean response.
Area of Science:
- Neonatal physiology
- Respiratory control
- Cardiorespiratory function
Background:
- The hyperoxic test (HT) assesses peripheral chemoreceptor function (PCF) by measuring ventilation (VE) changes during 100% oxygen inhalation.
- Current methods using mean VE change over 30 seconds may underestimate PCF strength and reproducibility due to secondary VE rises.
Purpose of the Study:
- To investigate if calculating ventilatory response (VR) at the response time (RT) during HT improves PCF assessment in infants.
- To evaluate the reproducibility of VR calculation at RT compared to mean VR.
Main Methods:
- Eighteen infants underwent two 30-second HTs during quiet sleep.
- Breath-by-breath analysis calculated VR at RT (time to first significant VE change) and mean VE change.
- Measurements included VE, tidal volume (VT), and VT/inspiratory time (VT/TI).
Main Results:
- Decreases in VE, VT, and VT/TI at RT were significantly greater than mean decreases.
- VR calculation at RT showed significantly smaller intra-individual variation for VE, VT, and VT/TI compared to mean values.
- This indicates improved reproducibility when using RT.
Conclusions:
- Calculating VR at RT during HT provides a more accurate assessment of PCF in infants.
- This refined method enhances the reproducibility of the HT, making it a more reliable diagnostic tool.