Profile of alveolar gases during periodic and regular breathing in preterm XXXX .

@entity1 @entity4095 @entity386
To determine the changes in alveolar PCO2 (PACO2) and @entity4095 (PAO2) during periodic and regular breathing epochs in the same @entity1 , we studied 11 preterm @entity1 during quiet sleep (birth weight 1,630 +/- 94 g; gestational age 31 +/- 1 weeks; postnatal age 32 +/- 3 days). A total of 94 breathing/apneic cycles were analyzed and compared with regular periods. During periodic and regular breathing epochs, there were negative correlations of PAO2 on PACO2. Short (< or = 5 s) and long (> 5 s) apneas for individual @entity1 occurred along the regression line for that @entity1 . There was not a single overall critical PACO2 below which @entity386 occurred, but for individual @entity1 the PACO2 and the PAO2 of the breath preceding @entity386 varied within a limited range. @entity386 occurred in clusters of PACO2 and PAO2 along the average regression line of PAO2 on PACO2. Analysis of the data showed that @entity386 occurred at the lowest PACO2 and highest PAO2 levels if allowance was made for circulation time. During @entity386 , 'the best fit' for the increase in PACO2 and the decrease in PAO2 was linear, rather than logarithmic. The findings suggest the following. (1) There is not a single overall critical level of PACO2 for @entity386 to occur, but in a given @entity1 this level varies within a limited range. This indicates that these @entity1 are likely breathing near the @entity386 threshold. (2) Short and long apneas appear to occur randomly along the regression of PAO2 on PACO2 for a particular @entity1 . (3) The changes in alveolar gases are linear during @entity386 .(ABSTRACT TRUNCATED AT 250 WORDS)
