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R C Gosselin

Publications and source records attributed to R C Gosselin.

9 recordsLinked to original sources
PubMed2002

Evaluation of a new automated quantitative d-dimer, Advanced D-Dimer, in patients suspected of venous thromboembolism.

The objective of our study was to evaluate the performance characteristics of a new automated d-dimer, the Advanced D-Dimer (Dade Behring Inc., Deerfield, IL) for use in the diagnosis of venous thromboembolism (VTE). To do this we compared the Advanced D-Dimer to existing d-dimer methods using established target cut-off values in patients suspected of VTE who were to undergo definitive radiographic studies for VTE. We studied hospitalized patients and outpatients who were suspected of having VTE and who had whole blood d-dimer performed. The patients who underwent a diagnostic study for VTE had their D-dimer results used to determine sensitivity, specificity and negative predictive values. There was relatively poor correlation between the Advanced D-Dimer and D-Dimer Gold (r = 0.63; t-test: P < 0.005) and Asserachrome D-Di (r = 0.58; t-test: P < 0.005). The Advanced D-Dimer target cutoff values for excluding VTE in hospitalized and outpatients were < or = 1800 microg/L and < or = 1500 microg/l respectively. There were 139 patients suspected with pulmonary embolism (PE) and 328 evaluated for deep vein thrombosis (DVT). There were 24 patients with PE, and 43 with DVT. The Advanced D-Dimer had comparable sensitivity, specificity and negative predictive values (96, 43, 98% for PE and 96, 48, 99% for DVT respectively) to other d-dimer methods used for that purpose. We conclude that the Advanced D-Dimer correlates relatively poorly with enzyme-linked immunosorbent assay methods. This poor correlation is likely due to incorrect reporting units and concentration. When these factors are corrected correlations improved. Compared to existing d-dimer methods used for VTE exclusion, the high sensitivity and negative predictive value would suggest that this method can be used as part of a diagnostic algorithm for the exclusion of PE and DVT.

Algorithms↗
PubMed2001

Practical utility of the D-dimer assay for excluding thromboembolism in severely injured trauma patients.

BACKGROUND: We have advocated the use of a D-dimer assay to exclude the diagnosis of pulmonary embolism (PE) and deep venous thrombosis (DVT) in surgical and trauma patients suspected of having these diagnoses. Injury is known to increase D-dimer levels independent of thromboembolism. The purpose of this study was to assess the period after injury over which the D-dimer assay remains positive because of injury exclusive of thromboembolism. METHODS: We prospectively sampled the plasma of severely injured patients for D-dimer using an enzyme-linked immunosorbent assay method at admission; at hours 8, 16, 24, and 48; and at days 3, 4, 5, and 6. Patients were then screened for DVT with a routine duplex Doppler at day 7. Patients were followed for PE, adult respiratory distress syndrome, and disseminated intravascular coagulation. RESULTS: One hundred fifty-four patients (mean Injury Severity Score of 23) underwent a total of 1,230 D-dimer assays. Twenty-six (17%) had thromboembolism. Nine (6%) patients developed DVT, 2 (1%) developed PE, 13 (8%) developed disseminated intravascular coagulation, and 11 (7%) developed severe adult respiratory distress syndrome. None of the trauma patients with thromboembolism had a (false) negative D-dimer at or after the time of their thromboembolic complication. True-negative D-dimer results as a function of time from injury are: 0 hours, 18%; 8 hours, 16%; 16 hours, 17%; 24 hours, 22%; 48 hours, 37%; day 3, 34%; day 4, 32%; day 5, 30%; and day 6, 30%. The negative predictive value of the assay was 100%. D-dimer levels were significantly higher in those who developed a thromboembolic complication than in those who did not (independent of Injury Severity Score). CONCLUSION: These data serve to validate D-dimer as a means of excluding thromboembolism, specifically in patients with severe injury (100% negative predictive value). Before 48 hours after injury, however, the vast majority of these patients without thromboembolism had positive D-dimer assays. Because of the high false-positive rate early after severe injury, the D-dimer assay may be of little value before postinjury hour 48.

Adult↗
PubMed2001

Platelet activation and function after trauma.

BACKGROUND: Abnormal hemostasis is associated with many of the complications of trauma-associated morbidity and mortality. Platelets are integral in the maintenance of hemostasis. METHODS: Samples were obtained from 100 trauma patients on arrival at the emergency room (initial time) and at 24, 48, and 72 hours later. Samples were also obtained from 10 healthy controls at the same time intervals. Using flow cytometry, three parameters were used to measure platelet activation: platelet microparticles, expression of P-selectin (CD62P), and expression of the activated conformation of glycoprotein IIb-IIIa (PAC-1 binding). Platelet function was measured using a platelet function analyzer (PFA-100, Dade International Inc., Miami, FL). RESULTS: One hundred trauma patients were enrolled. The average age was 40 years, 75% were men, and 84% had blunt injuries. The mean Injury Severity Score was 22.3 +/- 10.9 (mean +/- SD) and the average Glasgow Coma Scale score was 11 +/- 4. All three platelet activation parameters were increased in trauma patients versus controls for all time periods (p < 0.001). Trauma patients had a trend toward a shorter initial collagen/epinephrine closure time versus controls (p = 0.096). Compared with the 24-, 48-, and 72-hour time intervals, initial collagen/epinephrine closure times were shortened (p < 0.001, p < 0.001, and p < 0.001). Platelet function returned to normal reference ranges within 24 hours but platelet activation parameters remained elevated at least 72 hours after initial trauma. In contrast, when trauma patients with and without brain injury were compared, brain injury patients had increased platelet activation but decreased platelet function (increased collagen/epinephrine closure times). In addition, there was a significant prolongation in collagen/epinephrine closure times for the 24-, 48-, and 72-hour time points in nonsurviving patients versus survivors. There was no association between platelet activation and function and other adverse outcomes including pulmonary embolism, deep venous thrombosis, and disseminated intravascular coagulation. CONCLUSION: Severe injury usually results in increased platelet activation and function. However, the combination of increased platelet activation with decreased function was associated with increased mortality.

Adult↗
PubMed2000

Anticoagulation of children undergoing cardiopulmonary bypass is overestimated by current monitoring techniques.

HYPOTHESIS: Children who undergo cardiopulmonary bypass (CPB) are proportionally more hemodiluted than adults who undergo CPB. Current methods of monitoring high-dose heparin sulfate anticoagulation are dependent on fibrinogen level. Because of the decreased fibrinogen levels in children, current methods of monitoring heparin anticoagulation overestimate their level of anticoagulation. DESIGN: Prospective controlled trial. MAIN OUTCOME MEASURE: Production of thrombin (adequacy of anticoagulation). METHODS: Children and adults undergoing cardiac surgery who received CPB were anticoagulated in the standard fashion as directed by activated clotting time (ACT) results. Each subject had blood sampled at baseline; heparinization; start of the CPB; CPB at 30, 60, and 90 minutes; and at termination of CPB. Samples were used to assess anticoagulation with the Heparin Management Test (less dependent on fibrinogen level than ACT). We also assessed 2 subclinical markers of thrombosis, thrombin-antithrombin complexes and prothrombin fragment F1.2; a marker of procoagulant reserve, fibrinogen; the natural antithrombotic, antithrombin; and heparin concentration. RESULTS: Ten children and 10 adults completed the study. Children had lower fibrinogen levels than adults throughout CPB (P<.05). All adults had both therapeutic ACT and Heparin Management Test levels measured throughout CPB. Although children had therapeutic ACT levels, their Heparin Management Test levels were subtherapeutic while undergoing CPB. The children had significantly higher thrombin-antithrombin complexes and prothrombin fragment F1.2 than adults, indicating ongoing thrombin production (P<.01). The increases in thrombin-antithrombin complexes and prothrombin fragment F1.2 in children were inversely proportional to their weight. CONCLUSIONS: Children undergoing CPB with heparin dosing adjusted to optimize the ACT manifest inadequate anticoagulation (ongoing thrombin formation). High-dose heparin anticoagulation therapy in children undergoing CPB should be directed by tests (like the Heparin Management Test) that are less dependent on fibrinogen level than ACT.

Anticoagulants↗
PubMed2000

A new method for measuring D-dimer using immunoturbidometry: a study of 255 patients with suspected pulmonary embolism and deep vein thrombosis.

D-Dimer testing has been suggested as a non-invasive method for the exclusion of pulmonary embolism (PE) and deep vein thrombosis (DVT). In this study, we compared a new method, the Miniquant D-dimer (Biopool International, Ventura, California, USA) to other previously validated D-dimer methods used for the purpose. Patients who were undergoing a definitive diagnostic study for thromboembolism had a blood sample drawn at that time. A whole-blood D-dimer (SimpliRed; Agen Biomedical Ltd, Brisbane, Australia) test was performed, and residual plasma was frozen and later analyzed using two enzyme-linked immunosorbent assay (ELISA) methods (D-dimer Gold; Agen, and Asserachrome D-Di; Stago International, Parsippany, New Jersey, USA) and the Miniquant D-dimer. Once all samples were analyzed, the correlation and accuracy of the Miniquant was compared with the ELISA method using Spearman's regression and Dunn's multiple paired comparison. All D-dimer methods were compared with radiographic studies. The data was analyzed collectively and segregated into in-patient (n = 112) and out-patient (n = 143) populations. The Miniquant D-dimer sensitivity, specificity and negative predictive value (NPV) for all patients were 95, 21, and 94% for DVT, and 100, 26, and 100% for PE. This new D-dimer method demonstrates acceptable sensitivity in patients with PE and DVT and, based on the high NPV of this method, it can be used for the exclusion of thromboembolism.

Adult↗
PubMed2000

Whole blood D-dimer assay: an effective noninvasive method to rule out pulmonary embolism.

BACKGROUND: The whole blood D-dimer assay has gained recognition as a noninvasive test to rule out pulmonary embolism (PE) in medical patients. METHODS: We performed a whole blood D-dimer assay in medical and surgical patients undergoing either pulmonary angiogram or pulmonary ventilation perfusion scan for suspected PE or duplex Doppler or venogram for suspected deep venous thrombosis (DVT). RESULTS: A total of 483 patients were enrolled; 16 were excluded because of an equivocal pulmonary ventilation perfusion scan. The 467 remaining patients had a mean age of 56 +/- 27 years. There were 258 women and 209 men. A total of 353 patients were admitted to a medical service and 114 to surgery/ trauma. A total of 82 patients (18%) developed thromboembolism: 20 had PE, and 62 had DVT. CONCLUSION: No surgical patient with PE or DVT (n = 27) had a negative D-dimer. A negative D-dimer result in a stable surgical patient should be considered conclusive evidence to rule out thromboembolism and, thus, negate the need for further diagnostic studies. In our surgical patients suspected of DVT or PE, had D-dimer been used, one third of the patients would have avoided an expensive or invasive diagnostic test.

Aged↗