Continuous vs. intermittent forms of haemofiltration and/or dialysis in the management of acute renal failure in patients with defective cerebral autoregulation at risk of cerebral oedema. Influencing hemostasis during continuous venovenous hemofiltration after acute renal failure: comparison with intermittent hemodialysis. A randomized controlled trial comparing intermittent with continuous dialysis in patients with ARF. Continuous venovenous haemodiafiltration versus intermittent haemodialysis for acute renal failure in patients with multiple-organ dysfunction syndrome: a multicentre randomised trial. Effects of continuous haemofiltration vs intermittent haemodialysis on systemic haemodynamics and splanchnic regional perfusion in septic shock patients: a prospective, randomized clinical trial. Hemodynamic response to fluid withdrawal in overhydrated patients treated with intermittent ultrafiltration and slow continuous ultrafiltration: role of blood volume monitoring. Continuous renal replacement therapy (CRRT) or intermittent hemodialysis (IHD)--what is the procedure of choice in critically ill patients? Efficacy and cardiovascular tolerability of extended dialysis in critically ill patients: a randomized controlled study. A randomized clinical trial of continuous versus intermittent dialysis for acute renal failure. Comparison of continuous and intermittent renal replacement therapy for acute renal failure. A randomized cross-over comparison of the hemodynamic response to intermittent hemodialysis and continuous hemofiltration in ICU patients with acute renal failure. Long-term quality of life and hospital mortality in patients treated with intermittent or continuous hemodialysis for acute renal and respiratory failure.
nan nan Despite the widespread use of continuous renal replacement therapy in critically ill patients with acute renal failure (ARF), there are few data supporting its benefits over conventional intermittent hemodialysis (IHD). We sought to analyze differences in survival between modalities in a study that compared continuous venovenous hemodialysis (CVVHD) with IHD.
                Eighty critically ill patients with ARF requiring dialysis were randomized after stratification by severity of illness to treatment with CVVHD or IHD.
                There were no differences in survival or renal recovery between groups. In patients who died, mean survival time was 10.7 +/- 11.2 days for the IHD group versus 14.3 +/- 16.1 days for the CVVHD group (P = not significant). There was greater net volume removal in the CVVHD group during 72 hours. Declines in urine output during 72 hours were similar between groups. Mean arterial pressure off and on dialysis therapy was analyzed retrospectively. There was a significant decrease in mean arterial pressure for patients on IHD therapy not seen in those on CVVHD therapy, but this did not lead to a survival advantage.
                Despite greater volume control, CVVHD did not lead to an improvement in survival, preservation of urine output, or renal recovery compared with IHD in patients with ARF. Whether continuous renal replacement therapy is better than intermittent haemodialysis for the treatment of acute renal failure in critically ill patients is controversial. In this study, we compare the effect of intermittent haemodialysis and continuous venovenous haemodiafiltration on survival rates in critically ill patients with acute renal failure as part of multiple-organ dysfunction syndrome.
                Our prospective, randomised, multicentre study took place between Oct 1, 1999, and March 3, 2003, in 21 medical or multidisciplinary intensive-care units from university or community hospitals in France. Guidelines were provided to achieve optimum haemodynamic tolerance and effectiveness of solute removal in both groups. The two groups were treated with the same polymer membrane and bicarbonate-based buffer. 360 patients were randomised, and the primary endpoint was 60-day survival based on an intention-to-treat analysis.
                Rate of survival at 60-days did not differ between the groups (32% in the intermittent haemodialysis group versus 33% in the continuous renal replacement therapy group [95 % CI -8.8 to 11.1,]), or at any other time.
                These data suggest that, provided strict guidelines to improve tolerance and metabolic control are used, almost all patients with acute renal failure as part of multiple-organ dysfunction syndrome can be treated with intermittent haemodialysis. Parameters of splanchnic regional perfusion, like intramucosal pH (pHi) and pCO(2) (pCO(2)i), may predict outcome in septic shock patients. Continuous venovenous haemofiltration (CVVH) has been considered beneficial in haemodynamically unstable septic shock patients. In a prospective, randomized, clinical study, we investigated whether CVVH, in comparison to intermittent haemodialysis (IHD), is able to improve splanchnic regional perfusion in critically ill patients.
                Thirty septic shock patients with acute renal failure were randomized to either CVVH (n=20) or IHD (n=10) groups for renal replacement therapy. Patient characteristics at baseline were not different in terms of severity of illness (APACHE II scores), haemodynamics, and pHi/pCO(2)i values. Systemic haemodynamics, oxygen transport variables, and splanchnic regional perfusion parameters were measured at 0.5, 2, 4 and 24 h after initiation of renal replacement therapy. There were no major changes in vasopressor support throughout the 24-h study period.
                In contrast to IHD, CVVH caused a decrease in heart rate (-3+/-11 vs +9+/-8/min, P<0.01) and an increase in systolic blood pressure (+12+/-1 vs -5+/-17 mmHg, P<0.05) after 2 h. After 24 h, increased systemic vascular resistance was found in the CVVH group in comparison with the IHD group (+312+/-755 vs -29+/-89 dyne/cm(5), P<0.05) and was accompanied by a decrease in cardiac output (-1.54+/-1.4 vs -0.25+/-0.9 l/min, P<0.01). However pHi values remained constant throughout the 24-h study period in both groups and were not different between the groups (CVVH 7.19+/-0.1 vs IHD 7.19+/-0.1, n.s.) as did the pCO(2)i values (CVVH +7+/-17 vs IHD 0+/-15 mmHg, n.s.) and pCO(2) gap values (CVVH +6+/-15 vs IHD +5+/-12 mmHg, n.s.).
                Despite different changes of systemic haemodynamics between CVVH and IHD, CVVH did not improve parameters of splanchnic regional perfusion like pHi, pCO(2)i or pCO(2) gap in septic shock patients. Fluid overload may occur in patients with congestive heart failure, especially when there is associated acute renal failure. When the pharmacological approach is not sufficient to maintain the patient's fluid balance, extracorporeal therapies must be instituted. However, since the ultrafiltration rate may be faster than fluid refilling from the interstitial space, remarkable changes in the circulating blood volume may occur. This may finally result in further worsening of peripheral perfusion due to a significant drop in cardiac output. In order to prevent a fall in the circulating blood volume, slow continuous ultrafiltration (SCUF) should be employed instead of acute intermittent ultrafiltration (UF). To further improve the tolerance to extracorporeal ultrafiltration, the session can be driven by the relative blood volume change monitored on-line with adequate sensors and devices. We utilized one of these systems (Crit-Line, Hemametrics, USA) to compare the relative changes in blood volume during UF and SCUF in 22 patients with fluid overload. Variations in blood pressure were significantly greater with UF than with SCUF even in the presence of similar levels of fluid removal. The variations in blood pressure were paralleled by variations in blood volume, which were greater with UF than with SCUF. In conclusion, extracorporeal ultrafiltration can be used to control the fluid balance in congestive heart failure, but it is advisable to prescribe low ultrafiltration rates over an extended period of time. The use of on-line blood volume monitors can be of further help in improving tolerance and the hemodynamic response.
                Copyright 2002 S. Karger AG, Basel Although at present there is no prospective randomized study which could show significantly better survival of patients on continuous procedures, the majority of intensivists advocate this technique of renal function replacement due to generally accepted opinion that it has less effect on circulation of already hemodynamically unstable patients. In our prospective randomized study with 104 patients, we also did not observe any difference in 28 days survival, in total survival, as well as in circulatory instability between two treatment modalities. Even in subgroup of 80 patients with sepsis and septic shock there were no difference in survival. Sepsis was the underlying disorder in 52 and septic shock in 28 patients out of 104 patients analyzed in this study. Our prospective randomized study did not show a statistically significant difference between the two methods of renal replacement therapy. Survival rates were not affected and neither was the occurrence of hemodynamic instability. We believe that both methods are complementary; IHD for faster elimination of electrolytes and waste products elimination, CRRT for regulation of higher calories requirements and for hemodynamically unstable patients. The expectations that one method is superior to the other in the term of better survival have not been corroborated by the current data available in the literature. The choice of the method should be individualized. ARF, which is an integral part of MOF, is a problem frequently encountered in critically ill patient treated in the ICU, but outcome of these patients depends closely on the control of basic event. Evaluation of each of the supportive procedures is therefore hindered by the fact that the underlying disease has the crucial effect on survival and the type of supportive procedure less so. Extended dialysis is an increasingly used modality of renal replacement therapy that theoretically offers advantages of both intermittent and continuous therapies in the intensive care unit (ICU).
                We randomly treated 39 ventilated critically ill patients with oliguric acute renal failure with either continuous venovenous hemofiltration (CVVH; n = 19; age, 50.1 +/- 3.2 years; Acute Physiology and Chronic Health Assessment II [APACHE II] score, 32.3 +/- 1.2; 79% sepsis) and a substitution fluid rate of at least 30 mL/kg/h for 24 hours or with extended dialysis for 12 hours (n = 20; age, 50.8 +/- 3.6 years; APACHE II score, 33.6 +/- 1.0; 85% sepsis). The latter was performed using an easy-to-handle, single-pass, batch dialysis system. All hemodynamic parameters were monitored invasively by means of an indwelling arterial catheter.
                Average mean arterial blood pressure, heart rate, cardiac output, systemic vascular resistance, and catecholamine dose were not significantly different in both therapies. Urea reduction rate was similar with extended dialysis compared with CVVH therapy (53% +/- 2% versus 52% +/- 3%; P = not significant) despite an average rate of substitution fluid with the latter of 3.2 +/- 0.1 L/h. This was corroborated by the finding of similar amounts of urea eliminated in the collected spent total hemofiltration and dialysis fluid. Correction of acidosis was accomplished faster with extended dialysis than CVVH, and the amount of heparin used was significantly lower with extended dialysis (P < 0.01).
                Extended dialysis combines excellent detoxification with cardiovascular tolerability, even in severely ill patients in the ICU. The technically simple dialysis system used offers flexibility of treatment time. Acute renal failure (ARF) requiring dialysis in critically ill patients is associated with an in-hospital mortality rate of 50 to 80%. The worldwide standard for renal replacement therapy is intermittent hemodialysis (IHD). Continuous hemodialysis and hemofiltration techniques have recently emerged as alternative modalities. These two therapies have not been directly compared.
                A multicenter, randomized, controlled trial was conducted comparing two dialysis modalities (IHD vs. continuous hemodiafiltration) for the treatment of ARF in the intensive care unit (ICU). One hundred sixty-six patients were randomized. Principal outcome measures were ICU and hospital mortality, length of stay, and recovery of renal function.
                Using intention-to-treat analysis, the overall ICU and in-hospital mortalities were 50.6 and 56.6%, respectively. Continuous therapy was associated with an increase in ICU (59.5 vs. 41.5%, P < 0.02) and in-hospital (65.5 vs. 47.6%, P < 0.02) mortality relative to intermittent dialysis. Median ICU length of stay from the time of nephrology consultation was 16.5 days, and complete recovery of renal function was observed in 34.9% of patients, with no significant group differences. Despite randomization, there were significant differences between the groups in several covariates independently associated with mortality, including gender, hepatic failure, APACHE II and III scores, and the number of failed organ systems, in each instance biased in favor of the intermittent dialysis group. Using logistic regression to adjust for the imbalances in group assignment, the odds of death associated with continuous therapy was 1.3 (95% CI, 0.6 to 2.7, P = NS). A detailed investigation of the randomization process failed to explain the marked differences in patient assignment.
                A randomized controlled trial of alternative dialysis modalities in ARF is feasible. Despite the potential advantages of continuous techniques, this study provides no evidence of a survival benefit of continuous hemodiafiltration compared with IHD. This study did not control for other major clinical decisions or other supportive management strategies that are widely variable (for example, nutrition support, hemodynamic support, timing of initiation, and dose of dialysis) and might materially influence outcomes in ARF. Standardization of several aspects of care or extremely large sample sizes will be required to answer optimally the questions originally posed by this investigation. Mortality rates of critically ill patients with acute renal failure (ARF) requiring renal replacement therapy (RRT) are high. Intermittent and continuous RRT are available for these patients on the intensive care units (ICUs). It is unknown which technique is superior with respect to patient outcome.
                We randomized 125 patients to treatment with either continuous venovenous haemodiafiltration (CVVHDF) or intermittent haemodialysis (IHD) from a total of 191 patients with ARF in a tertiary-care university hospital ICU. The primary end-point was ICU and in-hospital mortality, while recovery of renal function and hospital length of stay were secondary end-points.
                During 30 months, no patient escaped randomization for medical reasons. Sixty-six patients were not randomized for non-medical reasons. Of the 125 randomized patients, 70 were treated with CVVHDF and 55 with IHD. The two groups were comparable at the start of RRT with respect to age (62+/-15 vs 62+/-15 years, CVVHDF vs IHD), gender (66 vs 73% male sex), number of failed organ systems (2.4+/-1.5 vs 2.5+/-1.6), Simplified Acute Physiology Scores (57+/-17 vs 58+/-23), septicaemia (43 vs 51%), shock (59 vs 58%) or previous surgery (53 vs 45%). Mortality rates in the hospital (47 vs 51%, CVVHDF vs IHD, P = 0.72) or in the ICU (34 vs 38%, P = 0.71) were independent of the technique of RRT applied. Hospital length of stay in the survivors was comparable in patients on CVVHDF [median (range) 20 (6-71) days, n = 36] and in those on IHD [30 (2-89) days, n = 27, P = 0.25]. The duration of RRT required was the same in both groups.
                The present investigation provides no evidence for a survival benefit of continuous vs intermittent RRT in ICU patients with ARF. To compare the hemodynamic response of ICU patients with acute renal failure of a 24-h continuous arteriovenous hemofiltration (CAVH) and that of patients with a 4-h intermittent hemodialysis (HD).
                Cross-over randomized clinical trial. The two periods to be compared were a 24-h CAVH and the 24-h encompassing a 4-h HD. These two periods were separated by a 24-h wash-out period.
                Ten bed medicosurgical ICU of a tertiary care center in Paris, France.
                Inclusion criterion was the requirement of replacement therapy for acute renal failure in patients already submitted to mechanical ventilation.
                CAVH was performed with Ringers' lactate used for restitution and infused before the hemofilter. The ultrafiltrate output was maintained at around 15 ml/min. HD was performed with a bicarbonate-buffered dialysate.
                Mean arterial pressure (MAP), use of adrenergic drugs, and change in body weight during each period.
                Twenty-seven consecutive patients were included, 15 CAVH-HD and 12HD-CAVH. CAVH and HD allowed the same metabolic efficacy. No hemodynamic parameter (MAP, amount of adrenergic drugs, change in body weight) differed between the two methods.
                CAVH is equivalent to HD in terms of MAP and the use of vasopressive drugs and fluids. Establishing the superiority of CAVH would require carefully controlled studies assessing either outcome or changes in tissue oxygenation. To describe long-term quality of life, intensive care, and hospital mortality in patients with acute renal and respiratory failure treated with one of two methods of renal replacement therapy (RRT).
                Cross-sectional survey of long-term survivors from a prospective observational study of two methods of RRT.
                A combined surgical and medical intensive care unit in a university hospital.
                One hundred and twenty-six patients with acute renal and respiratory failure who required treatment with RRT and mechanical ventilation. Interventions. (1) RRT for acute renal failure was with either continuous hemodialysis with ultrafiltration using biocompatible membranes and prostacyclin and heparin anticoagulation (CHDF) or intermittent hemodialysis using cuprophane membranes and heparin anticoagulation (IHD); (2) Health-related quality of life in long-term survivors was assessed with the SF-36 (HRQL) questionnaire.
                (1) There was no difference in ICU mortality (73.5% [39/53] IHD vs. 71.8% [46/64] CHDF, P = NS) or hospital mortality (83% [44/53] IHD vs. 76.5% [49/64] CHDF, P = NS) between the two RRT treatment groups. By 1999, there were 16 surviving patients; (2) Twelve of these survivors completed SF-36 forms (10 CHDF vs. 2 IHD). The overall physical health summary score and scores for seven of the health domains were significantly reduced. The mental health summary score and the domain mental health score did not differ from the general population.
                (1) The method of RRT used in ICU patients with ARF had no influence on survival; (2) The long-term survivors of multi-organ failure have poor physical health.
In patients who are haemodynamically stable, the RRT modality does not appear to influence important patient outcomes, and therefore the preference for CRRT over IRRT in such patients does not appear justified in the light of available evidence. CRRT was shown to achieve better haemodynamic parameters such as MAP. Future research should focus on factors such as the dose of dialysis and evaluation of newer promising hybrid technologies such as SLED. Triallists should follow the recommendations regarding clinical endpoints assessment in RCTs in ARF made by the Working Group of the Acute Dialysis Quality Initiative Working Group.