A Model Analysis of Arterial Oxygen Desaturation during Apnea in Preterm Infants
Figure 7
Impact of hemoglobin content (Hb) and O2 affinity (P50) on .
(A) Effect of three levels of Hb, (i) 12 g dl−1, (ii) 8 g dl−1 and (iii) 4 g dl−1, on arterial () and mixed venous (
) O2 desaturation during apnea. Note the fall in
at the inflection point (shown by short black lines). Note also that the reduced Hb has little impact on desaturation above
. (B) Sensitivity of
to changes in Hb. (C) Effect of three levels of P50, (iv) 18 mmHg, (v) 24 mmHg, and (vi) 36 mmHg, on
. (D) Sensitivity of
to changes in P50. n = ‘normal’ values; S1, stage 1 slope; S2, stage 2 slope.