PubMed Health⌕ Search

Biomedical subjects

K Sarier

Publications and source records attributed to K Sarier.

4 recordsLinked to original sources
PubMed1999

Platelet-activated clotting time does not measure platelet reactivity during cardiac surgery.

BACKGROUND: Platelet dysfunction is a major contributor to bleeding after cardiopulmonary bypass (CPB), yet it remains difficult to diagnose. A point-of-care monitor, the platelet-activated clotting time (PACT), measures accelerated shortening of the kaolin-activated clotting time by addition of platelet activating factor. The authors sought to evaluate the clinical utility of the PACT by conducting serial measurements of PACT during cardiac surgery and correlating postoperative measurements with blood loss. METHODS: In 50 cardiac surgical patients, blood was sampled at 10 time points to measure PACT. Simultaneously, platelet reactivity was measured by the thrombin receptor agonist peptide-induced expression of P-selectin, using flow cytometry. These tests were temporally analyzed. PACT values, P-selectin expression, and other coagulation tests were analyzed for correlation with postoperative chest tube drainage. RESULTS: PACT and P-selectin expression were maximally reduced after protamine administration. Changes in PACT did not correlate with changes in P-selectin expression at any time interval. Total 8-h chest tube drainage did not correlate with any coagulation test at any time point except with P-selectin expression after protamine administration (r = -0.4; P = 0.03). CONCLUSIONS: The platelet dysfunction associated with CPB may be a result of depressed platelet reactivity, as shown by thrombin receptor activating peptide-induced P-selectin expression. Changes in PACT did not correlate with blood loss or with changes in P-selectin expression suggesting that PACT is not a specific measure of platelet reactivity.

Adult↗
PubMed1997

An algorithm for assessing intraoperative mean arterial pressure lability.

BACKGROUND: Intraoperative blood pressure lability may be related to risk factors, hypovolemia, light anesthesia, and morbid outcomes, but the measurements of lability in previous studies have been limited by imprecise and infrequent data collection methods. Computerized intraoperative data acquisition systems have provided an opportunity to readdress the issue of intraoperative blood pressure lability with more abundant and precise data. This study sought to derive and validate an algorithm (expert system) to measure mean arterial pressure (MAP) lability. METHODS: Two hundred thirty-nine computerized anesthesis records were reviewed retrospectively. Three anesthesiologists separately rated MAP as very stable, average, or very labile. The parameters of a computer algorithm that measured the change of median MAP between consecutive 2-min epochs were optimized to achieve the best possible agreement among the anesthesiologists. The algorithm was then validated on 229 additional anesthesia records. RESULTS: The proportion of consecutive 2-min epochs in which the absolute value of the fractional change of median MAP exceeded 0.06 (i.e., 6%) correlated strongly with the anesthesiologists' ratings (r = 0.78; P < 0.0001). The optimal sensitivity and specificity of the algorithm for detecting MAP lability were 98% and 59%, respectively. CONCLUSIONS: One potential application of expert systems to anesthesia practice is a "smart alarm" to detect blood pressure lability. It may also provide a better tool to assess the relation between lability and outcome than has been available previously.

Algorithms↗
PubMed1996

The effects of thrombocytopenia on the activated coagulation time.

The activated coagulation (clotting) time (ACT) is widely used to monitor heparin therapy during cardiopulmonary bypass (CPB). Since thrombocytopenia occurs during and for some time after CPB, we considered the possibility that thrombocytopenia may affect the ACT. Blood samples were obtained from 12 healthy volunteers. Thrombocytopenic samples were created by a differential centrifugation technique. Blood samples from five thrombocytopenic patients were also studied. The platelet counts of the control citrated whole blood samples were 254,000 +/- 35,000/microL (mean +/- SD), whereas the platelet counts of the thrombocytopenic citrated samples were 49,000 +/- 8000/microL. There were no significant differences in the ACTs between these two groups (143 +/- 8 vs 145 +/- 9 s, respectively, P = 0.16). There were also no significant differences in the ACTs of the heparinized control samples compared with the ACTs of the heparinized thrombocytopenic samples. The platelet counts of the five thrombocytopenic patients were 43,000, 18,000, 16,000, 8000, and 7000/microL, and the ACTs of the unanticoagulated samples were 162, 240, 191, 210, and 215s, respectively. We conclude that the ACT is not affected by moderate thrombocytopenia and therefore this test may be used in patients who are moderately thrombocytopenic.

Anticoagulants↗