End-tidal to Arterial Gradients and Alveolar Deadspace for Anesthetic Agents

ConclusionsAlveolar deadspace for anesthetic agents is much larger than for carbon dioxide and related to blood solubility. Unlike the three-compartment model, multicompartment scatter models explain this from physiologically realistic gas uptake distributions, but suggest a residual factor other than solubility, potentially diffusion limitation, contributes to deadspace.Editor ’s PerspectiveWhat We Already Know about This TopicGeneral anesthesia increases the inhomogeneity (scatter) of the distribution of ventilation-perfusion ratios in the lung, widening alveolar to arterial partial pressure gradients for respired gasesThis inhomogeneity is reflected in increased alveolar deadspace fraction in the traditional three-compartment model of ventilation-perfusion scatterThe alveolar to arterial partial pressure difference for isoflurane is inconsistent with that measured simultaneously using end-tidal and arterial carbon dioxide partial pressuresWhat This Article Tells Us That Is NewAlveolar deadspace fraction calculated for volatile anesthetic agents is much larger than that calculated simultaneously for carbon dioxide, and its magnitude increases as blood solubility decreasesPhysiologically realistic multicompartment modeling of ventilation-perfusion scatter explains the relative differences between inhalational agents in alveolar to arterial partial pressure gradients and alveolar deadspace
Source: Anesthesiology - Category: Anesthesiology Source Type: research