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Correspondence  |   October 1997
Platelet Aggregation Inhibited by Sevoflurane, or by Ethanol? 
Author Notes
  • Department of Anesthesia; Kyoto University Hospital; Kyoto 606–01, Japan; Email: H-Hirakata@msn.com.
  • (Accepted for publication June 19, 1997.)
Article Information
Correspondence
Correspondence   |   October 1997
Platelet Aggregation Inhibited by Sevoflurane, or by Ethanol? 
Anesthesiology 10 1997, Vol.87, 1016-1017. doi:
Anesthesiology 10 1997, Vol.87, 1016-1017. doi:
In Reply:-We appreciate the interest shown by Drs. Aoki and Mizobe in our manuscript. [1 ] However, we believe that the effect of ethanol used to dilute the anesthetics can not explain our finding with sevoflurane. We used the same range of ethanol to dilute all the concentrated anesthetics (including halothane, sevoflurane and isoflurane) and isoflurane with ethanol did not affect platelet aggregation (Figure 1). The concentration of ethanol stated in the manuscript (less than 0.5%) was the possible maximal concentration, and was calculated basing on the total volume of ethanol divided by the volume of platelet-containing solution in the test tubes. Because of the presence of a gas space in the parafilm-sealed tube, the concentration of ethanol in the liquid phase could have been lowered as that in the gas phase increased during incubation at 37 [degree sign] Celsius. In contrast, the concentration of volatile anesthetics mentioned was, of course, that in the liquid phase, confirmed by gas chromatography. This may explain why ethanol did not affect platelet aggregation during our experimental conditions.
Figure 1. Effects of sevoflurane and isoflurane on platelet aggregation. (A) Sevoflurane (0.13 mM), with 0.225% ethanol, completely suppressed epinephrine (4 micro Meter)-induced secondary aggregation. (B) Isoflurane (0.56 mM), with 0.5% ethanol, did not affect epinephrine (3 micro Meter)-induced platelet aggregation.
Figure 1. Effects of sevoflurane and isoflurane on platelet aggregation. (A) Sevoflurane (0.13 mM), with 0.225% ethanol, completely suppressed epinephrine (4 micro Meter)-induced secondary aggregation. (B) Isoflurane (0.56 mM), with 0.5% ethanol, did not affect epinephrine (3 micro Meter)-induced platelet aggregation.
Figure 1. Effects of sevoflurane and isoflurane on platelet aggregation. (A) Sevoflurane (0.13 mM), with 0.225% ethanol, completely suppressed epinephrine (4 micro Meter)-induced secondary aggregation. (B) Isoflurane (0.56 mM), with 0.5% ethanol, did not affect epinephrine (3 micro Meter)-induced platelet aggregation.
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As Drs. Aoki and Mizobe pointed out, no clinical report has ever suggested increased blood loss or blood transfusion during general anesthesia with sevoflurane. This situation can also be extended to halothane anesthesia, although many investigators have reported suppressive effects of halothane on platelet aggregation. [2–4 ] The fact that the amount of hemorrhage during surgery depends on the surgical technique or skill of the surgeon probably makes clinical studies in this field difficult.
Hideo Hirakata, M.D.
Kumi Nakamura, M.D.
Department of Anesthesia; Kyoto University Hospital; Kyoto 606–01, Japan
Email: H-Hirakata@msn.com
References 
References 
Hirakata H, Ushikubi F, Toda H, Nakamura K, Sai S, Urabe N, Hatano Y, Narumiya S, Mori K: Sevoflurane inhibits human platelet aggregation and thromboxane A sub 2 formation, possibly by suppression of cyclooxygenase activity. Anesthesiology 1996; 85:1447-53.
Ueda I: The effects of volatile general anesthetics on adenocine diphosphate-induced platelet aggregation. Anesthesiology 1971; 34:405-8.
Dalsgaard-Nielsen J, Gromsen J: Effect of halothane on platelet function. Thromb Haemost 1980; 44:143-5.
Weber A, Hohlfeld T, Schror K: ADP-induced second wave aggregation in platelet rich plasma from hypercholesterolemic rabbits. Thromb Res 1991; 64:703-12.
Figure 1. Effects of sevoflurane and isoflurane on platelet aggregation. (A) Sevoflurane (0.13 mM), with 0.225% ethanol, completely suppressed epinephrine (4 micro Meter)-induced secondary aggregation. (B) Isoflurane (0.56 mM), with 0.5% ethanol, did not affect epinephrine (3 micro Meter)-induced platelet aggregation.
Figure 1. Effects of sevoflurane and isoflurane on platelet aggregation. (A) Sevoflurane (0.13 mM), with 0.225% ethanol, completely suppressed epinephrine (4 micro Meter)-induced secondary aggregation. (B) Isoflurane (0.56 mM), with 0.5% ethanol, did not affect epinephrine (3 micro Meter)-induced platelet aggregation.
Figure 1. Effects of sevoflurane and isoflurane on platelet aggregation. (A) Sevoflurane (0.13 mM), with 0.225% ethanol, completely suppressed epinephrine (4 micro Meter)-induced secondary aggregation. (B) Isoflurane (0.56 mM), with 0.5% ethanol, did not affect epinephrine (3 micro Meter)-induced platelet aggregation.
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