Perfusion
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Randomized Controlled Trial Clinical Trial
The effects of leucodepletion in patients who develop the systemic inflammatory response syndrome following cardiopulmonary bypass.
The development of the systemic inflammatory response syndrome (SIRS) is associated with increased morbidity and mortality. Numerous anticytokine trials have failed to demonstrate any outcome benefit and there has been little evidence of improvement in the prognosis of this condition over the past 20 years. This study examines the effect of using a white cell filter designed to remove polymorphonuclear cells (PMNs) in patients who developed SIRS 36 h after cardiopulmonary bypass (CPB). ⋯ Leucofiltration safely and effectively removes circulating PMNs from patients with SIRS following CPB. This may result in improved pulmonary and renal function in these patients. Further studies are required of the kinetics and phenotypic characteristics of PMN removal by leucofiltration and a larger multicentre study will be necessary to determine whether this novel therapy has a significant outcome benefit in critically ill patients with SIRS.
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Randomized Controlled Trial Clinical Trial
Systemic leukocyte filtration during cardiopulmonary bypass.
Cardiopulmonary bypass (CPB) induces a whole body inflammatory response leading to postoperative lung dysfunction. Activated leukocytes may play a role in the pathogenesis of pulmonary dysfunction. We evaluated postoperative lung function after the use of leukocyte-depleting filters incorporated in the extracorporeal circuit during CPB. ⋯ There was no difference in intubation time between the two groups (16.4 h for group C vs 11.2 h for group F). Pulmonary function tested by pulmonary respiratory index [RI = partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2 x 100)] did not show significant difference between the two groups, either arriving in the ICU (group C RI 265 vs group F RI 322), or after 3 h (group RI 304 vs group F RI 305) or after 6 h (group C RI 292 vs group F RI 319). Leukocyte-depleting filters reduce with blood cells count during CPB, but, in this study, WBC depletion did not significantly improve clinical conditions or laboratory finding.
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Comparative Study
Evaluation of a new point of care heparin test for cardiopulmonary bypass: the TAS heparin management test.
Patients undergoing cardiopulmonary bypass (CPB) require anticoagulation with heparin to avoid thrombosis within the bypass circuit. The common method used to monitor the degree of anticoagulation is the activated clotting time (ACT). We evaluated a novel point of care device, the TAS (Pharmanetics, Raleigh, NC, USA) heparin management test (HMT), for its suitability in monitoring anticoagulation during CPB. ⋯ Preheparin clotting times for these patients were 143+/-32 s for the HMT and 146+/-18 s for the ACT; 435+/-60 s HMT and 438+/-39 s ACT during CPB; 145+/-50 s HMT and 128+/-14 s ACT post-protamine (r2=0.797). epsilon-Aminocaproic acid treatment for inhibition of fibrinolysis did not affect the HMT. We conclude that the HMT correlates well with the ACT and may be useful for monitoring heparin during CPB. Advantages of the HMT are small sample volume and good sensitivity to heparin.
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Air microbubbles mostly occur unnoticed during cardiopulmonary bypass and are predominantly responsible for serious postoperative psychoneurological dysfunction. A dynamic bubble trap (DBT), which removes air microbubbles from the arterial blood, was tested in a clinical study. The aim was to evaluate the efficiency of microbubble removal under clinical conditions. ⋯ The bubbles are directed to the centre of the blood flow and are collected in the distal end of the DBT, from where they are returned to the cardiotomy reservoir. Doppler ultrasonography was used to detect the microbubbles before and after the DBT, and also the number of high-intensity transient signals (HITS) in the right and left middle cerebral artery during extracorporeal circulation. A significant reduction of microbubbles in the arterial line (3,990 before DBT, 537 after, p < 0.001) and HITS in the brain (51 in the DBT group, 77 in the placebo group, p = 0.04) was measured.
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Comparative Study
Inflammo-coagulatory response, extrinsic pathway thrombin generation and a new theory of activated clotting time interpretation.
When blood is subjected to contact with foreign surfaces, as during cardiopulmonary bypass (CPB), the whole body inflammatory response is initiated, resulting in the expression of procoagulant molecules on the vascular endothelium and white blood cells. These surface bound procoagulants participate in the extrinsic coagulation pathway. It appears that the primary source of thrombin generation during CPB is due to extrinsic pathway activation. ⋯ Anti-inflammatory agents which suppress or inhibit the extrinsic pathway, such as aprotinin, result in decreased thrombin generation. As thrombin generation decreases, the ACT-heparin dose response curve is warped, resulting in a dose response curve resembling a PTT-heparin dose response curve. We can no longer assume that the disproportionate rise in the ACT relative to the [HEP - ATIII] when aprotinin is used as indicative of failure of the ACT to provide a credible indication of anticoagulation.