Abstract
To determine the “structure” of alveolar PCO2 (PACO2) and PO2 (PAO2) changes during periodic breathing we studied 13 preterm infants during sleep (B.W. 1430±94 g; G.A. 31±1 wk, PNA 28±3 days). A total of 94 breathing/apneic cycles were analyzed. During apnea (2 to 14 sec) ΔPACO2 increased from 2.8±0.1 to 6±1 and PAO2 from 8±1 to 24±2 mmHg. The regression equation of PAO2 on PACO2 of the breath preceding apnea was PAO2 = -1.48 PACO2 + 166. Combinations of PACO2 and PAO2 were clustered at different levels along this line for different babies. Short and long apneas occurred anywhere along the regression line for individual babies. During periods of regular breathing (130 breaths in 13 babies) the regression was PAO2 = −2.34 PACO2 + 194. Individual infants became apneic by moving their PACO2 and PAO2 coordinates along the regression line towards lower PACO2 and higher PAO2 values. “Structure” analysis showed that apnea occurred at the lowest PACO2 and highest PAO2 levels if allowance was made for circulation time. We suggest: 1) the increase in PACO2 and the decrease in PAO2 during apnea are linear, not logarithmic; 2) for individual infants, apnea occurs at well defined clusters of PACO2 and PAO2 levels along the regression line; and 3) short and long apneas occur randomly along the regression line for individual babies. The data are consistent with the idea that each baby chooses an optimum range of CO2 and O2 in which apnea occurs.
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Rigatto, H., Pereira, M. & Reis, F. 1405 THE “STRUCTURE” OF ALVEOLAR PCO2 AND PO2 DURING PERIODIC BREATHING IN PRETERM INFANTS. Pediatr Res 15 (Suppl 4), 677 (1981). https://doi.org/10.1203/00006450-198104001-01434
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DOI: https://doi.org/10.1203/00006450-198104001-01434