Evaluation of a new point-of-care test that measures PAF-mediated acceleration of coagulation in cardiac surgical patients.
BACKGROUND
This study was designed to evaluate a new point-of-care test (HemoSTATUS) that assesses acceleration of kaolin-activated clotting time (ACT) by platelet activating factor (PAF) in patients undergoing cardiac surgery. Our specific objectives were to determine whether HemoSTATUS-derived measurements correlate with postoperative blood loss and identify patients at risk for excessive blood loss and to characterize the effect of desmopressin acetate (DDAVP) and/or platelet transfusion on these measurements.


METHODS
Demographic, operative, blood loss and hematologic data were recorded in 150 patients. Two Hepcon instruments were used to analyze ACT values in the absence (channels 1 and 2: Ch1 and Ch2) and in the presence of increasing doses of PAF (1.25, 6.25, 12.5, and 150 nM) in channels 3-6 (Ch3-Ch6). Clot ratio (CR) values were calculated with the following formula for each respective PAF concentration: clot ratio = 1-(ACT/control ACT). These values also were expressed as percent of maximal (%M = clot ratio/0.51 x 100) using the mean CRCh6 (0.51) obtained in a reference population.


RESULTS
When compared with baseline clot ratios before anesthetic induction, a marked reduction in clot ratios was observed in both Ch5 and Ch6 after protamine administration, despite average platelet counts greater than 100 K/microliter. There was a high degree of correlation between clot ratio values and postoperative blood loss (cumulative chest tube drainage in the first 4 postoperative hours) with higher concentrations of PAF: CRCh6 (r = -0.80), %M of CRCh6 (r = -0.82), CRCh5 (r = -0.70), and %M of CRCh5 (r = -0.85). A significant (P < 0.01) improvement in clot ratios was observed with time after arrival in the intensive care unit in both Ch5 and Ch6, particularly in patients receiving DDAVP and/or platelets.


CONCLUSIONS
Activated clotting time-based clot ratio values correlate significantly with postoperative blood loss and detect recovery of PAF-accelerated coagulation after administration of DDAVP or platelet therapy. The HemoSTATUS assay may be useful in the identification of patients at risk for excessive blood loss and who could benefit from administration of DDAVP and/or platelet transfusion.
Despotis
G J
GJ
Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA.
Levine
V
V
Filos
K S
KS
Santoro
S A
SA
Joist
J H
JH
Spitznagel
E
E
Goodnough
L T
LT
D000368:Aged; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D006348:Cardiac Surgical Procedures; D003894:Deamino Arginine Vasopressin / Q000627:therapeutic use*; D005069:Evaluation Studies as Topic; D005260:Female; D006487:Hemostasis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010972:Platelet Activating Factor / Q000627:therapeutic use*; D017713:Platelet Transfusion; D011183:Postoperative Complications / Q000517:prevention & control*; D011300:Preoperative Care; D012076:Renal Agents / Q000627:therapeutic use*; D014914:Whole Blood Coagulation Time
D010972:Platelet Activating Factor; D012076:Renal Agents; D003894:Deamino Arginine Vasopressin