Comparison of lung diffusing capacity during rebreathing and during slow exhalation

Recruitment of Lung Diffusing Capacity

“…Measured Dlco should be interpreted not only with respect to lung volume and hemoglobin concentration, but also with respect to Q . Established methods that simultaneously measure Dl, Q , and lung volume using multiple tracer gases such as slow exhalation [81][82][83] and rebreathing 14,84 techniques offer distinct advantage over the routine breathholding method for Dlco alone. The former tech- Figure 5.…”

Comparison of carbon monoxide (CO) single breath pulmonary diffusing capacity with non‐rebreathing, open‐circuit CO pulmonary diffusing capacity in healthy children

“…Bland-Altman analyses (Figs. [5][6][7] show that all but one subject falls within two SD values of the mean. This shows the good agreement between both techniques.…”

“…The method requires matching bag volume to subject breathing, and it typically results in dyspnea from CO 2 build up and drop in oxygenation during the maneuver. [5][6][7] Precise analysis during exercise would require measurement of changes in two insoluble tracer gases to compensate for the change in the lung rebreath bag volume due to a changing respiratory quotient during the maneuver. 6 All of these techniques have significant limitations for use in children due to either requirements for unusual breathing patterns, or CO 2 retention and O 2 depletion.…”

A rebreathing method to determine carbon monoxide diffusing capacity in children: Reference values for six 18-year-olds and validation in adult volunteers

“…In general the rebreathing method is performed during hyperventilation, assuming lungs and rebreathing system to approximate one compartment. [4][5][6][7][8][9][10][11][12][13][14] The conventional rebreathing method during hyperventilation was modified in such a way that rebreathing volume and gas concentrations were kept constant by CO 2 absorption and O 2 supplementation. During spontaneous tidal breathing, the transfer of CO from the rebreathing system into the blood depends on two successive mechanisms: the transfer of CO from the rebreathing system into the alveolar compartment and the CO uptake from the alveolar compartment into the capillary blood.…”

“…2,3 To study the diffusion variables in patients who cannot generate a 1.5 L VC rebreathing methods have been developed. [4][5][6][7][8][9][10][11] In these methods CO 2 is normally not absorbed and O 2 not supplied. Sølvsteen described a system applicable during increased ventilation in which O 2 was supplied, but CO 2 was not absorbed.…”