L'épuration extrarénale (EER) nécessite une anticoagulation afin de prévenir les risques de coagulation du circuit. Les thromboses répétées du circuit d'EER engendrent une augmentation des coûts, de la charge en soins et des besoins transfusionnels. L'héparine peut induire un risque hémorragique important. Ce risque a motivé le développement de techniques alternatives telles que la réduction des doses d'héparine, l'association héparine–protamine, les héparines de bas poids moléculaire, la prostacycline, et l'anticoagulation régionale au citrate. Le but de cet article est de présenter une revue des différentes possibilités d'anticoagulation en épuration extrarénale.

Renal replacement therapy (RRT) requires anticoagulation in order to prevent clotting of the extracorporeal circuit. Recurrent filter clotting and the need for frequent circuit replacement would be economically undesirable and the source of blood transfusion in critically ill patients. Heparin may be associated with a high-risk of hemorrhagic complications. Various alternative methods have been developed for the anticoagulation of the circuit; including heparin minimization and heparin-free RRT, regional heparin anticoagulation with protamine infusion, low molecular weight heparins, prostacyclin, and regional citrate anticoagulation. This paper reviews our current anticoagulation strategies for RRT, according to the bleeding risk of the patient. © 2005 Publié par Elsevier SAS pour Société de réanimation de langue française. Mots clés : Insuffisance rénale aiguë ; Anticoagulation ; Hémodialyse ; Hémofiltration

To identify the potential impact of novel therapeutic approaches, we studied the early predictive factors of survival at the onset of acute respiratory distress syndrome (ARDS) in a 24-bed medical ICU of an academic tertiary care hospital. Over a 48-mo period, a total of 3,511 adult patients were admitted and 259 mechanically ventilated patients met ARDS criteria, as defined by American-European consensus conference, i.e., bilateral pulmonary infiltrates and PaO2/FIO2 lower than 200 without left atrial hypertension. These patients were randomly included in a developmental sample (177 patients) and a validation sample (82 patients). Demographic variables, hemodynamic and respiratory parameters, underlying diseases, as well as several severity scores (SAPS, SAPS-II, OSF) and Lung Injury Score (LIS) were collected. These variables were compared between survivors and nonsurvivors and entered into a stepwise logistic regression model to evaluate their independent prognostic roles. The overall mortality rate was 65%. SAPS-II, the severity of the underlying medical conditions, the oxygenation index (mean airway pressure x FIO2 x 100/PaO2), the length of mechanical ventilation prior to ARDS, the mechanism of lung injury, cirrhosis, and occurrence of right ventricular dysfunction were independently associated with an elevated risk of death. Model calibration was very good in the developmental and validation samples (p = 0.84 and p = 0.72, respectively), as was model discrimination (area under the ROC curves of 0.95 and 0.92, respectively). Thus, the prognosis of ARDS seems to be related to the triggering risk factor, the severity of the respiratory illness, and the occurrence of a right ventricle dysfunction, after adjustment for a general severity score.

Purpose: The aim of this study was to evaluate the reliability of a new continuous cardiac output (CCO) monitoring device (Qvue/OptiQ system; Abbott Critical Care Systems, Mountain View, CA) based on the pulsed warm thermodilution technique in critically ill medical patients.Methods: Nineteen patients with cardiogenic or septic shock were included in the study. Pairs of CCO and intermittent bolus cardiac output (ICO) were noted at least every 6 hours for determination of bias, precision, and limits of agreement. Simultaneously, blood samples were collected, and arterial-venous oxygen content difference (C[a-V]O-2) was determined. A multiple stepwise logistic regression was used to identify situations associated with a CCO-ICO difference exceeded 20%. A multiple linear regression was performed to analyze the respective accuracy of CCO and ICO to predict the variations of C[a-v]O-2.Results: A total of 203 pairs of cardiac output measurements was obtained, The bias was 0.12 L/min (1.2% of pairs mean) and the precision 1.0 L/min (13%). The 95% limits of agreement were between -1.7 L/min (-25%) and 1.9 L/min (+26%), Low blood temperatures and heart rates above 120 beats/min were significantly associated with a ICO-CCO difference higher than 20%. In a multiple linear regression, CCO was significantly correlated with C[a-v]O-2, an independent reflection of the patient's cardiac output; by contrast, ICO did not.Conclusion: These results suggest that ICO and CCO measurement by the Qvue/OptiQ system are interchangeable, except for temperature or heart rate extreme values. Copyright (C) 1998 by W.B. Saunders Company.

OBJECTIVE The Sometec Dynemo-3000 system allows the permanent measurement of descending aorta diameter by an echographic (A-scan) device and the blood flow velocity by a pulse Doppler velocimeter. The Dynemo-3000 then furnishes a new hemodynamic parameter, i.e., descending aortic blood flow (ABF), which is a fraction of the cardiac output (CO). We evaluate the ability of this system to measure the aortic diameter and to accurately detect ABF changes. DESIGN A case study prospective trial. SETTING A 24-bed medical intensive care unit of a 1,100-bed university hospital. PATIENTS Twenty critically ill patients fully sedated, mechanically ventilated, and monitored by a pulmonary artery catheter. INTERVENTIONS CO values determined by conventional thermodilution method (TD-CO) and ABF were recorded during the study, which included two initial baseline periods, a dobutamine infusion (5 microg/kg/min) interval of 30 mins, and a third baseline period. To assess the accuracy of A-scan, aortic diameter was measured by transesophageal echocardiography. The difference between echocardiography and A-scan was used to determine bias and precision for aortic diameter measurements. TD-CO and ABF variations were analyzed using Kruskal-Wallis and Wilcoxon tests. Association between TD-CO and ABF values was determined by calculating the linear correlation coefficient. The ability of ABF to detect a TD-CO >6.0 L/min and its variations >13% was analyzed by determination of sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values. MEASUREMENTS AND MAIN RESULTS Aortic diameter measurements by A-scan and bidimensional methods were 23.0+/-2.8 mm (SD) and 24.2+/-2.7 mm, respectively. Bias and precision were 1.1 mm and 1.4 mm (95% confidence interval: -1.9 to 3.7), respectively. During the course of dobutamine infusion, we observed a significant increase of TD-CO mean value from 6.65+/-1.53 L/min to 9.30+/-2.5 L/min (p=.0008), and a parallel and significant increase in ABF mean value from 4.34+/-1.18 L/min to 5.70+/-1.63 L/min (p= .0029). Absolute TD-CO and ABF values had a correlation coefficient of 0.80. For detection of an increased TD-CO, PPV and NPV were 87% and 86%, respectively. For detection of TD-CO changes >13%, PPV and NPV were 80% and 94%, respectively. CONCLUSIONS The Dynemo-3000 system is able to display the real aortic diameter, which is one of the most important components of this noninvasive ultrasonic technique. When compared with TD-CO, the ABF determination provided by this ultrasonic device constitutes a reliable noninvasive tool for estimating CO and tracking its changes.