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NSAID's IN-VITRO DO NOT AFFECT HEMOCHRON-SALINE AND LEE-WHITE WHOLE BLOOD CLOTTING TIMES

Inchiosa, MA Jr, PhD; Pothula, S MD; Chang, G. BS; Sanchala, VT MD

doi: 10.1097/00000539-199802001-00070
Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Cardiovascular Anesthesia
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Depts. of Anesthesiology and Pharmacology, New York Medical College, Valhalla, New York.

Abstract S70

INTRODUCTION: There is need for a rapid on-site assay of hemostasis when there is history of nonsteroidal antiinflammatory (NSAID) use. The Hemochron-Saline (H-S) whole blood coagulation assay has been noted to have high sensitivity and specificity for detection of low levels of heparin in patients stabilized prior to cardiac surgery. [1] We tested the response of this assay to acetylsalicylic acid (ASA) and ibuprofen (IBU) that was added in-vitro. The H-S assay is automated, but contains no activators or buffers, as such, it appears to be sensitive to subtle changes in hemostasis. Lee-White clotting times (LWCT) were also evaluated for NSAID effects.

METHODS: With IRB approval, 20 ml of blood was drawn from 13 cardiac surgery patients, pre-induction, into sodium citrate tubes. Blood was incubated (37[degree sign]C) for 60 min with either ASA(13-390 [micro sign]g/ml) or IBU(5-50 [micro sign]g/ml); antiinflammatory blood levels of ASA are 195-390 [micro sign]g/ml and IBU is antipyretic at 10 [micro sign]g/ml. [2] (Controls showed stable clotting times after incubation at 37[degree sign]C for 2-60 min). Assay tubes were reconstituted with 6.8-7.5 [micro sign]moles CaCl2/ml blood, 2.0ml for H-S and 1.0ml for LWCT. LWCT tubes (13mm x 75mm), incubated at 37[degree sign]C, were inverted every 30 sec until the clot adhered, even with tube inversion.

RESULTS: ASA and IBU did not affect clotting time in the H-S assay (Table 1). ASA also had no apparent effect on LWCT, although experimental error was high in LWCT assays, ASA at 13, 52, 210 and 390 [micro sign]g/ml showed average clotting times that were 87%, 120%, 96% and 98% of controls, respectively. In a single experiment, ASA additions were made directly to H-S tubes in the operating room before addition of fresh, uncitrated blood, 66, 130 and 390 [micro sign]g/ml of ASA had clotting times that were 94%, 101% and 102% of control, respectively.

Table 1

Table 1

DISCUSSION: ASA and IBU, added in-vitro to blood at therapeutic levels, did not influence clotting times. Expected effects of these NSAID's on platelet function may not have been detectable by the tests employed; or, the drugs did not influence platelet function under the test conditions.

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REFERENCES

1. Anesth Analg 84: SCA 39, 1997.
2. Goodman and Gilman's, The Pharmacological Basis of Therapeutics, 9th Ed., 1996, pp. 1749, 1780.
© 1998 International Anesthesia Research Society