Christophe Ridel

Cardiac filling pressures are not appropriate to predict hemodynamic response to volume challenge.

Objective: Values of central venous pressure of 8–12 mm Hg and of pulmonary artery occlusion pressure of 12–15 mm Hg have been proposed as volume resuscitation targets in recent international guidelines on management of severe sepsis. By analyzing a large number of volume challenges, our aim was to test the significance of the recommended target values in terms of prediction of volume responsiveness. Design: Retrospective study. Setting: A 24‐bed medical intensive care unit. Patients: All consecutive septic patients monitored with a pulmonary artery catheter who underwent a volume challenge between 2001 and 2004. Intervention: None. Measurements and Main Results: A total of 150 volume challenges in 96 patients were reviewed. In 65 instances, the volume challenge resulted in an increase in cardiac index of ≥15% (responders). The pre‐infusion central venous pressure was similar in responders and nonresponders (8 ± 4 vs. 9 ± 4 mm Hg). The pre‐infusion pulmonary artery occlusion pressure was slightly lower in responders (10 ± 4 vs. 11 ± 4 mm Hg, p < .05). However, the significance of pulmonary artery occlusion pressure to predict fluid responsiveness was poor and similar to that of central venous pressure, as indicated by low values of areas under the receiver operating characteristic curves (0.58 and 0.63, respectively). A central venous pressure of <8 mm Hg and a pulmonary artery occlusion pressure of <12 mm Hg predicted volume responsiveness with a positive predictive value of only 47% and 54%, respectively. With the knowledge of a low stroke volume index (<30 mL·m−2), their positive predictive values were still unsatisfactory: 61% and 69%, respectively. When the combination of central venous pressure and pulmonary artery occlusion pressure was considered instead of either pressure alone, the degree of prediction of volume responsiveness was not improved. Conclusion: Our study demonstrates that cardiac filling pressures are poor predictors of fluid responsiveness in septic patients. Therefore, their use as targets for volume resuscitation must be discouraged, at least after the early phase of sepsis has concluded.

Predicting volume responsiveness by using the end-expiratory occlusion in mechanically ventilated intensive care unit patients

Objective:During mechanical ventilation, inspiration cyclically decreases the left cardiac preload. Thus, an end-expiratory occlusion may prevent the cyclic impediment in left cardiac preload and may act like a fluid challenge. We tested whether this could serve as a functional test for fluid responsiveness in patients with circulatory failure. Design:Prospective study. Setting:Medical intensive care unit. Patients:Thirty-four mechanically ventilated patients with shock in whom volume expansion was planned. Intervention:A 15-second end-expiratory occlusion followed by a 500 mL saline infusion. Measurements:Arterial pressure and pulse contour-derived cardiac index (PiCCOplus) at baseline, during passive leg raising (PLR), during the 5-last seconds of the end-expiratory occlusion, and after volume expansion. Main Results:Volume expansion increased cardiac index by >15% (2.4 ± 1.0 to 3.3 ± 1.2 L/min/m2, p < 0.05) in 23 patients (“responders”). Before volume expansion, the end-expiratory occlusion significantly increased arterial pulse pressure by 15% ± 15% and cardiac index by 12% ± 11% in responders whereas arterial pulse pressure and cardiac index did not change significantly in nonresponders. Fluid responsiveness was predicted by an increase in pulse pressure ≥5% during the end-expiratory occlusion with a sensitivity and a specificity of 87% and 100%, respectively, and by an increase in cardiac index ≥5% during the end-expiratory occlusion with a sensitivity and a specificity of 91% and 100%, respectively. The response of pulse pressure and cardiac index to the end-expiratory occlusion predicted fluid responsiveness with an accuracy that was similar to the response of cardiac index to PLR and that was significantly better than the response of pulse pressure to PLR (receiver operating characteristic curves area 0.957 [95% confidence interval {CI:} 0.825–0.994], 0.972 [95% CI: 0.849–0.995], 0.937 [95% CI: 0.797–0.990], and 0.675 [95% CI: 0.497–0.829], respectively). Conclusions:The hemodynamic response to an end-expiratory occlusion can predict volume responsiveness in mechanically ventilated patients.

Renal replacement therapy in adult and pediatric intensive care : Recommendations by an expert panel from the French Intensive Care Society (SRLF) with the French Society of Anesthesia Intensive Care (SFAR) French Group for Pediatric Intensive Care Emergencies (GFRUP) the French Dialysis Society (SFD).

Acute renal failure (ARF) in critically ill patients is currently very frequent and requires renal replacement therapy (RRT) in many patients. During the last 15xa0years, several studies have considered important issues regarding the use of RRT in ARF, like the time to initiate the therapy, the dialysis dose, the types of catheter, the choice of technique, and anticoagulation. However, despite an abundant literature, conflicting results do not provide evidence on RRT implementation. We present herein recommendations for the use of RRT in adult and pediatric intensive care developed with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system by an expert group of French Intensive Care Society (SRLF), with the participation of the French Society of Anesthesia and Intensive Care (SFAR), the French Group for Pediatric Intensive Care and Emergencies (GFRUP), and the French Dialysis Society (SFD). The recommendations cover 4 fields: criteria for RRT initiation, technical aspects (access routes, membranes, anticoagulation, reverse osmosis water), practical aspects (choice of the method, peritoneal dialysis, dialysis dose, adjustments), and safety (procedures and training, dialysis catheter management, extracorporeal circuit set-up). These recommendations have been designed on a practical point of view to provide guidance for intensivists in their daily practice.

Ionic dialysance: principle and review of its clinical relevance for quantification of hemodialysis efficiency.

Ionic dialysance (D) is an online measured variable now available on several dialysis monitors to evaluate small‐solute clearance. Based on conductivity measurements in the inlet and outlet dialysate, the principle of the measurement and the different measurement methods are described. Studies that have evaluated the reliability of ionic dialysance to assess dialysis efficiency are discussed. These studies are divided into two groups: the first comparing ionic dialysance to urea clearance and the second comparing Dt/V to Kt/Vurea, in which the uncertainties of the measurement of Vurea could have misrepresented the relationship between Dt/V and Kt/Vurea. When Kt/Vurea via the Daugirdas second‐generation equation taking the rebound into account is considered, slight—even nonsignificant—differences are evidenced between Kt/Vurea and Dt/V. Therefore, ionic dialysance should be considered as a valid measure in future guidelines for dialysis efficiency.

Ionic dialysance: a new valid parameter for quantification of dialysis efficiency in acute renal failure?

ObjectiveSeveral studies have reported axa0close relationship between an increased dose of dialysis and survival in patients treated for acute renal failure. Unfortunately, the quantification of dialysis in critically ill patients based on the urea nitrogen formula Kt/V is not applicable. Ionic dialysance is axa0new parameter calculated in real time from the dialysate conductivity and correlated with the effective urea clearance in chronic hemodialysis patients. The aim of our study was to evaluate ionic dialysance in the quantification of dialysis in critically ill patients with acute renal failure.DesignProspective open-label study.SettingAn 18-bed medical intensive care unit.PatientsThirty-one patients with multiple organ dysfunction syndrome and acute renal failure requiring intermittenthemodialysis were included.MeasurementsUsing the first dialysis session of each patient, we compared the delivered dose of dialysis based on ionic dialysance measurement (KtID) with the well-accepted gold standard method based on fractional dialysate sampling (Ktdialysate). The data were analyzed using linear regression and Bland–Altman analysis.ResultsThirty-one intermittent hemodialysis sessions were performed in 31 critically ill patients (mean age 58u202f±u202f12xa0years, SAPSxa0II score 56u202f±u202f10). We found axa0close correlation between Ktdialysate and KtID (Ktdialysateu202f=u202f36.3u202f±u202f11.4u202fl; KtIDu202f=u202f38.4u202f±u202f11.8; ru202f=u202f0.96) with excellent limits of agreement (–2.2u202fl; 6.4u202fl).ConclusionThe feasibility of dialysis quantification based on ionic dialysance in the critically ill patient is good. This method is axa0simple and accurate tool for the determination of dialysis dose in critically ill patients.

Regional citrate anticoagulation during hemodialysis: a simplified procedure using Duocart biofiltration.

Background: Regional citrate anticoagulation during hemodialysis is promising, but its clinical implementation is routinely cumbersome because a continuous adjustment of calcium infusion at the dialyzer outlet is needed. Duocart biofiltration (DCB) is a new hemodialysis method using a calcium and magnesium-free dialysate containing only sodium chloride and bicarbonate combined with the infusion into the venous line of a solution containing the ionic complement (K, Ca, Mg) and glucose. Since the dialysate is calcium- and magnesium-free and infusion rate of the solution containing calcium is automatically determined by the dialysis delivery system according to the on-line measured value of ionic dialysance, DCB seems a technique especially suitable for citrate anticoagulation procedure. Methods: Thirty DCB sessions were performed in 10 patients with increased risk of bleeding. A commercially available mixture of trisodium citrate, citric acid and glucose was infused into the arterial line at a rate equal to 3% of dialyzer blood flow. The ionic complement (K: 48 mM, Ca: 42 mM, Mg: 14 mM, glucose: 110 mM) was infused at a rate equal to 1/24 ionic dialysance value automatically determined each 15 min by the dialysis monitor. DCB sessions were compared to 21 conventional bicarbonate hemodialysis (BHD) sessions with low-molecular-weight heparin anticoagulation. Results: Whole blood activated clotting time (WBACT) measured in the venous line (before infusion of ionic complement) was 200% of the WBACT value in the arterial line. Clotting and citrate-related adverse events were not observed. Postdialysis compression time of the arteriovenous access is significantly (p < 0.001) shorter after DCB sessions (3.9 ± 1.1 min) compared with BHD sessions (8.7 ± 4.6 min). Conclusion: Citrate anticoagulation during Duocart biofiltration is effective, safe and suitable for routine use because calcium infusion rate is automatically adjusted without the need of monitoring degree of anticoagulation and level of ionized calcium.

A simple and novel technique for regional citrate anticoagulation during intermittent hemodialysis may obviate the need for calcium monitoring

Introduction We performed a safety and feasibility study to evaluate a simplified regional citrate anticoagulation (RCA) technique for intermittent hemodialysis (iHD) with calciumand magnesium-free citrate-containing dialysate and calcium/magnesium re-injection in the venous line of the extracorporeal circuit (ECC). Generators for iHD automatically perform an on-line measurement of ionic dialysance (ID). This measurement can be useful to optimize the rate of calcium and magnesium infusion during hemodialysis using a calciumand magnesium-free dialysate [see Electronic Supplementary Material (ESM) Methods] [1]. The primary endpoint of the present prospective study was to determine the incidence rate of ECC clotting during hemodialysis sessions. The secondary endpoint was to validate the kinetic model for calcium infusion. This RCA approach, which obviates the need for a citrate infusion and plasma ionized calcium monitoring, has not been previously investigated. We analyzed 29 dialysis sessions with RCA in 17 patients with contraindications for anticoagulation (see ESM Table 1). Efficacy Twenty-five sessions were finished at the expected time (240 min) without clotting. We stopped four dialysis sessions for the following reasons: one patient pulled out the arterial line, one patient had a deficient arteriovenous fistula, and two patients each had an initial RCA session of 3 h. At +30 min, all measurements of ionized calcium concentration from the dialyzer outlet (iCaout) were below 0.4 mmol/L (mean 0.21 ± 0.07 mmol/L). At +240 min, iCaout had increased significantly (0.35 ± 0.19 mmol/L, p = 0.0019), but remained below 0.4 mmol/L in 89.6% of sessions (ESM Fig. 1). After rinsing of the dialyzer we found only minor clots with a low global thrombosis index (ESM Table 2).

Functional EPO-Hepcidin axis in Recombinant human EPO independent hemodialysis patients: Hepcidin status in rHU-EPO free patients

Relatively few haemodialysis (HD) patients remain independent of recombinant human erythropoietin (‘rHU‐EPO free patients’). We investigated the role of EPO and hepcidin, two key hormones involved in anaemia.

An unusual cause of gastrointestinal bleeding in a hemodialysis patient: Lower Gastrointestinal Bleeding

Iron deficiency caused by gastrointestinal (GI) bleeding is a common cause of anemia in hemodialysis patient. Herein, we report the case of an 89‐year‐old hemodialysis patient who presented with acute anemia and melena. Endoscopy found gastritis and diverticulosis without active bleeding. A capsule endoscopy (CE) was then performed and revealed multiple vascular lesions that lead to the diagnosis of Blue Rubber Bleb Nevus syndrome (BRBNS). This rare disease is associated with multiple venous malformations in the skin and the GI tract, usually observed in children. The patient developed 4 months latter 2 skin lesions compatible with BRBNS. Treatment included blood transfusion and intravenous iron supplementation. We reported an unusual presentation of venous malformation BRBS which differs from angioectasia, in an adult hemodialysis patient. Overall prognosis is good

Insuffisance rénale aiguë par atteinte rénale autre que la nécrose tubulaire aiguë

Il s’agit le plus souvent de glomerulonephrites proliferatives extracapillaires caracterisees par une insuffisance renale rapidement progressive qui justifie parfois le passage en reanimation.