The error arising from unmeasured alveolar–arterial differences for the two volatile agents is likely to be small and will effectively only scale the uptake calculations but will not substantially alter the results. Because the arterial partial pressure might have been lower than indicated by the end-expired partial pressure, the data presented in figure 5 may slightly overestimate uptake and elimination. These are abnormal communications between right and left heart, shunting. Second, we did not measure blood–gas partition coefficients but retrieved them from the literature 4 and assumed they would match this in the animals used in this study. + ventilation, no perfusion high V/Q, dead space ventilation o Inspired gas. It is much lower in PCO2 because the CO2-free gas from anatomical dead space dilutes even more. We believe this to be the case because the pigs’ lungs were healthy with minimal V A/Q abnormality, as evidenced by the absence of a significant alveolar–arterial partial pressure difference for carbon dioxide before methacholine administration. First, the calculation of the uptake of inhaled agent across the alveolocapillary membrane was based on a calibration factor that assumed that the end-tidal anesthetic partial pressure approximated the arterial anesthetic partial pressure. what does the shunt fraction and the A-a gradient represent a guide as to the efficiency of the lung for the.

Two assumptions were made that allow us to derive uptake from the partial pressures and cardiac output measurements.

Dead space vs shunt infinity