TY - JOUR
T1 - Effects of cardiac output on 18O2 lung diffusion in normal resting man
AU - Gong, Henry
AU - Kurpershoek, Cornelis J.
AU - Meyer, Delbert H.
AU - Cross, Carroll E
PY - 1972
Y1 - 1972
N2 - Single-breath resting diffusing capacities for CO (DlCO) and 18O2 (DlO2
) were measured simultaneously with pulmonary capillary blood flow (Q̇c) in nine normal males at hypoxic alveolar O2 tensions (PO2
42 torr). DlCO (54 ± 5 ml stpd . min-1 . torr-1) was significantly higher than DlO2
(33 ± 11 ml stpd ± min-1 . torr-1). Extrapolation of the linear regressions between DlCO and DlO2
and cardiac output (range 4860 to 12,270 ml . min-1) suggest that DlO2
approximates DlCO at cardiac outputs of 18 L . min-1 in our subjects. No significant differences between the previously measured diffusing capacity for 18O16O (Hyde et al., 1966) and the present value for 18O18O was found. The discrepancy between the measured DlO2
and the predicted DlO2
calculated indirectly from the DlCO is confirmed. Inhomogeneity of pulmonary capillary diffusing surface area to capillary blood flow (Dl/Q̇c) probably accounts for this discrepancy. DL/Q̇c inhomogeneity, along with right-to-left shunts and V̇a/Qc inhomogeneities, must be taken into account when arterial-alveolar O2 gradients are evaluated.
AB - Single-breath resting diffusing capacities for CO (DlCO) and 18O2 (DlO2
) were measured simultaneously with pulmonary capillary blood flow (Q̇c) in nine normal males at hypoxic alveolar O2 tensions (PO2
42 torr). DlCO (54 ± 5 ml stpd . min-1 . torr-1) was significantly higher than DlO2
(33 ± 11 ml stpd ± min-1 . torr-1). Extrapolation of the linear regressions between DlCO and DlO2
and cardiac output (range 4860 to 12,270 ml . min-1) suggest that DlO2
approximates DlCO at cardiac outputs of 18 L . min-1 in our subjects. No significant differences between the previously measured diffusing capacity for 18O16O (Hyde et al., 1966) and the present value for 18O18O was found. The discrepancy between the measured DlO2
and the predicted DlO2
calculated indirectly from the DlCO is confirmed. Inhomogeneity of pulmonary capillary diffusing surface area to capillary blood flow (Dl/Q̇c) probably accounts for this discrepancy. DL/Q̇c inhomogeneity, along with right-to-left shunts and V̇a/Qc inhomogeneities, must be taken into account when arterial-alveolar O2 gradients are evaluated.
KW - Diffusion/perfusion ratio
KW - Pulmonary capillary blood flow
KW - Pulmonary capillary blood volume
KW - Pulmonary diffusing capacity
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U2 - 10.1016/0034-5687(72)90061-8
DO - 10.1016/0034-5687(72)90061-8
M3 - Article
C2 - 4644058
AN - SCOPUS:0015458693
VL - 16
SP - 313
EP - 326
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
SN - 1569-9048
IS - 3
ER -