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From the *Institute of Anesthesiology,
Department of Trauma Surgery, and
Cardiovascular Anesthesia Research Laboratory, Institute of Anesthesiology, University Hospital Zurich, Zurich, Switzerland.
Address correspondence to Privatdozent Dr. Michael Zaugg, Institute of Anesthesiology, E-HOF, University Hospital Zurich and Zurich Center for Integrative Human Physiology ZIHP, University of Zurich, Rämistrasse 100, CH-8091 Zurich, Switzerland. Address e-mail to michael.zaugg{at}usz.ch.
BACKGROUND: Sevoflurane can be used as sedative-analgesic drug with endothelial protective properties. We tested whether low-dose sevoflurane inhalation provides sustained inhibition of detrimental granulocyte-platelet aggregation in humans.
METHODS: Ten healthy male volunteers were enrolled in this crossover study. Each subject inhaled sevoflurane for 1 h at 0.5–1 vol % end-tidal concentration in oxygen (50 vol %). Inhaling oxygen (50 vol %) alone served as control. Venous blood samples were collected at baseline before inhalation, immediately after inhalation, and 24 h thereafter, and were used for flow cytometry to determine platelet surface marker (CD41, CD42b, CD62P/P-selectin, and PAC-1) on platelets and granulocytes and for kaolin-induced clot formation, as assessed by thromboelastography. In flow cytometry experiments, platelets were stimulated with arachidonic acid (AA, 30 µM), adenosine diphosphate (ADP, 1 µM), and thrombin receptor agonist peptide-6 (TRAP-6, 6 µM).
RESULTS: AA, ADP, and TRAP-6 markedly increased the expression of CD62P on platelets, whereas CD42b (shedding) and PAC-1 (heterotypic conjugates) expression decreased. The amount of granulocyte-platelet aggregates increased upon agonist stimulation. Low-dose sevoflurane inhalation reduced ADP-induced CD62P expression on platelets 24 h after inhalation, and inhibited the formation of granulocyte-platelet aggregates under stimulation with AA and ADP after 1 and 24 h, and with TRAP-6 after 24 h compared with control. Inhibition of granulocyte-platelet aggregates was accompanied by reduced clot firmness 24 h after sevoflurane inhalation compared with control.
CONCLUSIONS: We demonstrated for the first time that inhaling low-dose sevoflurane (<1 vol % end-tidal) inhibits agonist-induced granulocyte-platelet interactions 24 h after administration and thus counteracts thromboinflammatory processes.
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