• Moritz Kretzschmar, Alf Kozian, James E Baumgardner, Joao Batista Borges, Göran Hedenstierna, Anders Larsson, Thomas Hachenberg, and Thomas Schilling.
• From the Hedenstierna Laboratory, Department of Surgical Sciences (M.K., A.K., J.B.B., A.L., T.S.), and Clinical Physiology, Department of Medical Sciences (G.H.), Uppsala University, Uppsala, Sweden; Department of Anesthesiology and Intensive Care Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany (M.K., A.K., T.H., T.S.); Oscillogy LLC, Pittsburgh, Pennsylvania (J.E.B.); and Department of Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (J.E.B.).
• Anesthesiology. 2017 Nov 1; 127 (5): 800-812.

BackgroundIncreasing numbers of patients with obstructive lung diseases need anesthesia for surgery. These conditions are associated with pulmonary ventilation/perfusion (VA/Q) mismatch affecting kinetics of volatile anesthetics. Pure shunt might delay uptake of less soluble anesthetic agents but other forms of VA/Q scatter have not yet been examined. Volatile anesthetics with higher blood solubility would be less affected by VA/Q mismatch. We therefore compared uptake and elimination of higher soluble isoflurane and less soluble desflurane in a piglet model.MethodsJuvenile piglets (26.7 ± 1.5 kg) received either isoflurane (n = 7) or desflurane (n = 7). Arterial and mixed venous blood samples were obtained during wash-in and wash-out of volatile anesthetics before and during bronchoconstriction by methacholine inhalation (100 μg/ml). Total uptake and elimination were calculated based on partial pressure measurements by micropore membrane inlet mass spectrometry and literature-derived partition coefficients and assumed end-expired to arterial gradients to be negligible. VA/Q distribution was assessed by the multiple inert gas elimination technique.ResultsBefore methacholine inhalation, isoflurane arterial partial pressures reached 90% of final plateau within 16 min and decreased to 10% after 28 min. By methacholine nebulization, arterial uptake and elimination delayed to 35 and 44 min. Desflurane needed 4 min during wash-in and 6 min during wash-out, but with bronchoconstriction 90% of both uptake and elimination was reached within 15 min.ConclusionsInhaled methacholine induced bronchoconstriction and inhomogeneous VA/Q distribution. Solubility of inhalational anesthetics significantly influenced pharmacokinetics: higher soluble isoflurane is less affected than fairly insoluble desflurane, indicating different uptake and elimination during bronchoconstriction.

36 keywords...

hide…