A randomized clinical trial of continuous versus intermittent dialysis for acute renal failure

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.     

Outcome and predictive factors of acute renal failure in the intensive care unit

The development of acute renal failure (ARF) in the ICU setting carries a high morbidity and mortality. To assess the outcomes and its predictive factors in our ICU, we analyzed the data of patients with ARF treated during 18 months. The 33 patients included 21 men and 12 women of mean age 51 +/- 21.7 years (13 to 87). Sepsis with multi-organ dysfunction (MOD) was the leading cause of ARF (58%). Comorbid conditions were malignancy in 30% of patients, diabetes mellitus in 24%, hypertension in 21%, ischemic heart disease in 21%, liver disease in 15%, and chronic renal failure in 15%. Predisposing factors were hypotension in 67% of cases, dehydration in 36%, drug related in 33%, congestive heart failure in 24%, and liver cirrhosis in 6%. Twenty-five (76%) patients needed mechanical ventilation, 22 (67%) were anuric, 18 (55%) had MODS, and 15 (45%) needed inotropic support. Length of stay in hospital was 27.2 +/- 28.0 days (2 to 94). Nineteen patients (58%) were managed conservatively and 14 (42%) by renal replacement therapy. Patient mortality was 67% and renal mortality 52%. The impact of the following factor: was assessed on patient and renal outcome was assessed ventilation support, presence of oliguria, need for inotropes, and presence of MOD. Patient mortality was significantly influenced by an elevated odds ratios (OR) (95% CI): mechanical ventilation [OR = 34 (95% CI 1.95 to 538)], and presence of MODS [OR = 12.3 (95% CI 2 to 75)]. Renal mortality was influenced by mechanical ventilation [OR = 12.3 (95% CI 1.6 to 119)], oliguria [OR = 12 (95% CI 2 to 72)], inotrope support [OR = 10 (95% CI 2 to 52), and MOD [OR = 35 (95% CI 3.5 to 35.0)]. This study confirms the high patient and renal mortality of ARF among patients to ICU. The four parameters were excellent predictors of renal outcome, while only the need for mechanical ventilation and the presence of MOD were predictors for patient survival.     

Benefit of continuous renal replacement therapy in subgroups of acutely ill patients: a retrospective analysis

AIMS: Acute renal failure in the intensive care setting is common and impacts on patient's outcome. Continuous hemodialysis or hemofiltration offers theoretical benefit for patients with acute renal failure, but the clinical benefit has not been demonstrated in randomized trials. ICU patients with acute renal failure are a heterogeneous population and we hypothesize that patients with increased illness severity would benefit from continuous renal replacement therapy. METHODS: From a comprehensive ICU database, we identified patients with acute renal failure exposed to continuous or intermittent renal replacement therapy. We a priori identified a subgroup of patients with multiple organ dysfunction syndrome, then used survival analysis to assess the effect of dialysis modality in the overall acute renal failure population and in the subgroup with increased illness severity. RESULTS: We identified 66 patients treated with intermittent and 36 patients treated with continuous renal replacement therapy. Patients with severe illness were preferentially selected for treatment with continuous dialysis (p = 0.01). Overall, there was no significant difference in survival between patients treated with intermittent or continuous dialysis. The relative risk of in-hospital mortality was significantly decreased in patients with multiple organ dysfunction syndrome (relative risk = 0.42+/-0.22, p = 0.027) treated with continuous therapy as compared with intermittent therapy. Among the survivors, continuous dialysis did not appear to hasten the return of renal function. CONCLUSIONS: This retrospective study suggests that continuous dialysis may be beneficial in a subgroup of ICU patients with multiple organ dysfunction syndrome or severe sepsis. Further randomized trials of dialysis modality should, if possible, concentrate on this population.     

连续性肾脏替代治疗剂量对急性肾衰竭患者预后影响的荟萃分析

目的 通过荟萃分析评价连续性肾脏替代治疗（CRRT）剂量对急性肾衰竭（ARF）患者预后的影响。 方法 制定原始文献的纳入标准和检索策略,在Medline、EMBASE及Cochrane 图书馆内进行相关的检索。比较标准剂量和低剂量CRRT对ARF患者预后影响的随机对照试验（RCT）纳入分析。应用随机或固定效应模型处理预后指标的相对危险度（RR）。 结果 6项研究符合纳入标准。与低剂量比较,标准剂量CRRT未能降低病死率（RR 0.87,95%CI 0.70~1.07,P = 0.19）和联合终点事件（死亡和依赖透析）的发生率（RR 0.87,95%CI 0.69~1.09,P = 0.21）,但有增加依赖透析率的趋势（RR 1.43,95%CI 0.94~2.18,P = 0.09）。由于研究间存在异质性,亚组分析显示,实际治疗剂量达标（标准剂量>35 ml&#8226;kg-1&#8226;min-1）、治疗模式以连续性静脉-静脉血液滤过（CVVH）为主（置换液量大于透析液量）、非脓毒症为ARF主要原因（脓毒血症发病率<50%）的研究中,经标准剂量CRRT后病死率显著下降（P < 0.01）。 结论 尽管标准剂量CRRT未能降低ARF患者的病死率、依赖透析率和联合终点事件的发生率,但可改善实际治疗剂量达标、治疗模式以CVVH为主及非脓毒症ARF患者的存活率。     

Adding a dialysis dose to continuous hemofiltration increases survival in patients with acute renal failure

Acute renal failure (ARF) in critically ill patients is associated with high mortality. Optimal method and dose of continuous renal replacement therapy could improve survival in these patients. We studied the hypothesis that an increase in dialysis dose obtained by continuous veno-venous hemodiafiltration (CVVHDF) is associated with a better survival than continuous veno-venous hemofiltration (CVVH) among critically ill patients with ARF. In a prospective randomized trial, these two methods were compared in patients undergoing renal replacement therapy in two intensive care units (ICUs). The patients had either CVVH (1-2.5 l/h replacement fluid) or continuous CVVHDF (1-2.5 l/h replacement fluid+1-1.5 l/h dialysate) according to their body weight. 28- and 90-day mortalities, renal recovery, and duration of ICU stay were the main outcome measures. Two hundred and six patients were randomized from October 2000 to December 2003. Twenty-eight-day survivals (%) were, respectively, 39 and 59 (P=0.03) in the CVVH and CVVHDF groups. Three months survivals (%) were, respectively, 34 and 59 (P=0.0005) in the CVVH and CVVHDF groups. Apache II score, age, baseline blood urea nitrogen, and hemodiafiltration (hazard ratio 0.59, 95% confidence interval 0.40-0.87; P=0.008) were independent predictors of survival at 90 days. Renal recovery rate among survivors (71 versus 78% in the CVVH and CVVHDF groups respectively, P=0.62) was not affected by the type of renal replacement therapy. These results suggest that increasing the dialysis dose especially for low molecular weight solutes confers a better survival in severely ill patients with ARF.     

Initiation time of renal replacement therapy on patients with acute kidney injury: A systematic review and meta‐analysis of 8179 participants

The early initiation of renal replacement therapy has been recommended for patients with acute renal failure by some studies, but its effects on mortality and renal recovery are unknown. We conducted an updated meta‐analysis to provide quantitative evaluations of the association between the early initiation of renal replacement therapy and mortality for patients with acute kidney injury. After applying inclusion/exclusion criteria, 51 studies, including 10 randomized controlled trials, with a total of 8179 patients were analyzed. Analysis of the included trials showed that patients receiving early renal replacement therapy had a 25% reduction in all‐cause mortality compared to those receiving late renal replacement therapy (risk ratio [RR] 0.75, 95% CI [0.69, 0.82]). We also noted a 30% increase in renal recovery (RR 1.30, 95% CI [1.07, 1.56]), a reduction in hospitalization of 5.84 days (mean difference [MD], 95% CI [–10.27, –1.41]) and a reduction in the duration of mechanical ventilation of 2.33 days (MD, 95% CI [–3.40, –1.26]) in patients assigned to early renal replacement therapy. The early initiation of renal replacement therapy was associated with a decreased risk of all‐cause mortality compared with the late initiation of RRT in patients with acute kidney injury. These findings should be interpreted with caution given the heterogeneity between studies. Further studies are needed to identify the causes of mortality and to assess whether mortality differs by dialysis dose.     

Continuous arteriovenous hemofiltration in acute renal failure

This extensive review describes the settings for continuous arteriovenous hemofiltration (CAVH) and attempts to compare it to traditional dialysis therapies for acute renal failure. In addition hemodynamic stability, membrane biocompatibility, nutrition, fluid and solute removal, operational characteristics, anticoagulation, replacement solutions, drug removal, complications, and trouble shooting during CAVH are all discussed in detail. The cost of CAVH v dialysis is equal. CAVH is probably the renal replacement therapy of choice for hemodynamically unstable patients with acute renal failure and contraindications to peritoneal dialysis.     

Evaluation of continuous veno-venous hemofiltration for the treatment of cardiogenic shock in conjunction with acute renal failure after cardiac surgery

Background: Cardiogenic dysfunction with acute renal failure (ARF) and diuretic drug resistance increases mortality after cardiac surgery with cardiopulmonary bypass (CPB) in adults. Until few years ago, intermittent renal replacement therapy (IRRT) was the only therapeutical strategy proposed to such patients. Few data are available in the literature regarding the use of continuous veno-venous haemofiltration (CVVH) in this clinical context. The aim of our observational study was to evaluate the impact of CVVH strategy on ARF in conjunction with cardiogenic shock after cardiac surgery and on its well-known associated poor outcome. Methods: During the period 2005–2006, we prospectively collected data from our database as we controlled the renal replacement therapy using CVVH (n = 73). We also retrospectively collected data from our computerised database on patients who were treated with IRRT (n = 68, period 2002–2003). Among CVVH-treated patients, a multivariate analysis of the data aimed to identify risk factors associated with 30-day mortality. Results: In patients who presented with ARF in conjunction with cardiogenic shock after cardiac surgery, 30-day mortality rate was 59% for the IRRT group and 42% for the CVVH group. Within the CVVH group, the logistic regression and multivariate analyses reported that some variables were associated with higher mortality risk: a score F concerning the urinary output criteria of the RIFLE (risk, injury, failure, loss, end-stage kidney disease) classification (for scores R or I: odds ratio (OR): 0.01, 95% confidence interval (95% CI): 0.02–0.59; p = 0.01), plasma bilirubin (OR: 1.44, 95% CI: 1.12–1.84; p = 0.04), total CVVH duration <50 h over 72 h (>50 h; OR: 0.009, 95% CI: 0.04–0.93; p = 0.01), the need of catecholamine support (OR: 12.88, 95% CI: 1.95–84.96; p = 0.01), tachycardia in the intensive care unit (ICU; OR: 1.64, 95% CI: 1.02–2.65; p = 0.04), surgery duration (<300 min; OR: 0.11, 95% CI: 0.02–0.71; p = 0.02) and combined cardiac surgery (OR: 7.00, 95% CI: 1.29–37.88; p = 0.02). Conclusion: In patients with ARF in conjunction with cardiogenic shock after cardiac surgery, renal replacement therapeutic strategy based on long-lasting CVVH could improve patients’ outcome. The identification of risk factors associated with a poor outcome would help to better manage such patients in the ICU. Low total duration of CVVH within the first 72 h was one criteria related to poor outcome. This suggests that CVVH must be initiated as soon as possible when ARF with diuretic resistance occurs in patients after cardiac surgery and continued as long as possible for the first 3 days.     

Development of renal failure during the initial 24 h of intensive care unit stay correlates with hospital mortality in trauma patients

BACKGROUND: Although multiple organ failure is the leading late cause of death, there is controversy about the impact of acute organ dysfunction and failure on trauma survival. METHODS: Consecutive adult trauma admissions between January 2000 and June 2003, excluding isolated head traumas and burns, were analysed for parameters of organ function during the first 24 h following intensive care unit (ICU) admission using the Sequential Organ Failure Assessment (SOFA) scoring system. A national prospectively collected ICU data registry was used for analysis, including data from 22 ICUs in university and central hospitals in Finland. RESULTS: The study population consisted of 1044 eligible trauma admissions; 32% of the cases were treated at university hospital level, the rest being secondary referral central hospital admissions. The mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 15 (SD8), ICU mortality was 5.6% and a further 1.6% of patients died during their post-ICU hospital stay. Forty-five per cent of the patients were categorized as having multiple traumas. In univariate analysis, APACHE II > or = 25 [odds ratio (OR), 35; 95% confidence interval (CI), 18-66] and renal failure (OR, 29.5; 95% CI, 14-63) produced the highest ORs for ICU mortality. In the APACHE II-, sex- and age-adjusted logistic regression model, renal failure was a significant risk factor for both ICU and hospital mortality (OR, 11.8; 95% CI, 3.9-35.4; OR, 8.2; 95% CI, 2.9-23.2, respectively). CONCLUSION: The development of renal failure during the initial 24 h of ICU stay remained an independent risk factor for mortality in trauma patients requiring intensive care treatment even after adjusting for the APACHE II score, age and sex.     

Continuous renal replacement therapy in acute renal failure

The management of acute renal failure in the critically ill patient is extremely variable and there are no published standards for the provision of renal replacement therapy in this population. Continuous renal replacement therapy seems to be the treatment of choice because of its superior metabolic and hemodynamic control. There is better organ protection by continuous treatment but no evidence for better survival or renal recovery due to continuous treatment. The debate about optimal membrane as well as about optimal dialysis dose is ongoing. An effluent flow rate of at least 35 ml/kg/h as well as lower BUN level at treatment initiation seem to be necessary to provide better survival rate. Peritoneal dialysis is a less suitable option in continuous renal replacement of the adult intensive care patient but hybrid methods such as extended daily dialysis and sustained low efficient daily dialysis need consideration with respect to continuous hemofiltration/dialysis.     

Acute renal failure early after heart transplantation: risk factors and clinical consequences

Gude E, Andreassen AK, Arora S, Gullestad L, Grov I, Hartmann A, Leivestad T, Fiane AE, Geiran OR, Vardal M, Simonsen S. Acute renal failure early after heart transplantation: risk factors and clinical consequences.
Clin Transplant 2010: 24: E207–E213. © 2010 John Wiley & Sons A/S. Abstract: Limited information exists about acute renal failure (ARF) early after heart transplantation (HTx). We correlated pre‐, per‐, and post‐operative patient and donor parameters to the risk of developing ARF. We also analyzed the consequences of ARF on kidney function after HTx, risk of later need for chronic dialysis or kidney transplantation, and mortality. In a retrospective study from 1983 to 2007, 145 (25%) of 585 HTx recipients developed ARF, defined as ≥26.4 micromol/L or ≥50% increase in serum creatinine from pre‐operatively to the seventh day post‐HTx and/or the need of early post‐operative dialysis. Independent risk factors for ARF were intravenous cyclosporine immediately post‐operatively (odds ratio [OR] 2.16, 95% CI 1.34–3.50, p = 0.02), donor age (OR 1.02, 95% CI 1.00–1.04, p = 0.02), and pre‐operative cardiac output (OR 1.38, 95% CI 1.12–1.71, p = 0.003). The development of ARF was a predictor for short‐term survival (≤3 months) ranging from 98% for patients who improved their creatinine after HTx vs. 79% for those in need of dialysis (p < 0.001). However, ARF did not predict subsequent end stage renal disease in need of dialysis or renal transplantation. ARF is a common complication post‐HTx. As ARF is associated with short‐term survival, post‐operative strategies of preserving renal function have the potential of reducing mortality. Of avoidable risk factors, the use of intravenous CsA should be discouraged.     

Prevalence and clinical outcome associated with preexisting malnutrition in acute renal failure: a prospective cohort study

Malnutrition is a frequent finding in hospitalized patients and is associated with an increased risk of subsequent in-hospital morbidity and mortality. Both prevalence and prognostic relevance of preexisting malnutrition in patients referred to nephrology wards for acute renal failure (ARF) are still unknown. This study tests the hypothesis that malnutrition is frequent in such clinical setting, and is associated with excess in-hospital morbidity and mortality. A prospective cohort of 309 patients admitted to a renal intermediate care unit during a 42-mo period with ARF diagnosis was studied. Patients with malnutrition were identified at admission by the Subjective Global Assessment of nutritional status method (SGA); nutritional status was also evaluated by anthropometric, biochemical, and immunologic parameters. Outcome measures included in-hospital mortality and morbidity, and use of health care resources. In-hospital mortality was 39% (120 of 309); renal replacement therapies (hemodialysis or continuous hemofiltration) were performed in 67% of patients (206 of 309); APACHE II score was 23.1+/-8.2 (range, 10 to 52). Severe malnutrition by SGA was found in 42% of patients with ARF; anthropometric, biochemical, and immunologic nutritional indexes were significantly reduced in this group compared with patients with normal nutritional status. Severely malnourished patients, as compared to patients with normal nutritional status, had significantly increased morbidity for sepsis (odds ratio [OR] 2.88; 95% confidence interval [CI], 1.53 to 5.42, P < 0.001), septic shock (OR 4.05; 95% CI, 1.46 to 11.28, P < 0.01), hemorrhage (OR 2.98; 95% CI, 1.45 to 6.13, P < 0.01), intestinal occlusion (OR 5.57; 95% CI, 1.57 to 19.74, P < 0.01), cardiac dysrhythmia (OR 2.29; 95% CI, 1.36 to 3.85, P < 0.01), cardiogenic shock (OR 4.39; 95% CI, 1.83 to 10.55, P < .001), and acute respiratory failure with mechanical ventilation need (OR 3.35; 95% CI, 3.35 to 8.74, P < 0.05). Hospital length of stay was significantly increased (P < 0.01), and the presence of severe malnutrition was associated with a significant increase of in-hospital mortality (OR 7.21; 95% CI, 4.08 to 12.73, P < 0.001). Preexisting malnutrition was a statistically significant, independent predictor of in-hospital mortality at multivariable logistic regression analysis both with comorbidities (OR 2.02; 95% CI, 1.50 to 2.71, P < 0.001), and with comorbidities and complications (OR 2.12; 95% CI, 1.61 to 2.89, P < 0.001). Malnutrition is highly prevalent among ARF patients and increases the likelihood of in-hospital death, complications, and use of health care resources.     

Outcome in critically ill medical patients treated with renal replacement therapy for acute renal failure: comparison between patients with and those without haematological malignancies.

BACKGROUND: Starting renal replacement therapy (RRT) for acute renal failure in critically ill patients with haematological malignancies is controversial because of the poor outcome and high costs. The aim of this study was to compare the outcome between critically ill medical patients with and without haematological malignancies who received RRT for acute renal failure. METHODS: We retrospectively collected data on all consecutive patients who received RRT for acute renal failure at the Medical Intensive Care Unit (ICU) of a University Hospital between 1997 and 2002, and assessed the impact of the presence of a haematological malignancy on the survival within 6 months after ICU admission by Cox proportional hazard models. RESULTS: Fifty of the 222 (22.5%) consecutive patients with haematological malignancies admitted to the ICU over the study period received RRT for acute renal failure compared with 248 of the 4293 (5.8%) patients without haematological malignancies (P<0.001). Among patients who received RRT, those with haematological malignancies had higher crude ICU (79.6 vs 55.7%, P=0.002) and in-hospital (83.7 vs 66.1%, P=0.016) mortality rates, and a higher mortality at 6 months (86 vs 72%, P=0.018) by Kaplan-Meier estimates compared with those without haematological malignancies. However, after adjustment for the severity of illness and the duration of hospitalization before ICU admission, haematological malignancy by itself was no longer associated with a higher risk of death (hazard ratio 1.04; 95% confidence interval, 0.73-1.54, P=0.78). CONCLUSIONS: Medical ICU patients with haematological malignancies have a higher rate of occurrence of acute renal failure treated with RRT and a higher mortality, compared with those without haematological malignancies. However, the presence of a haematological malignancy by itself is not a reason to withhold RRT in medical ICU patients with acute renal failure.     

The burden of acute renal failure in nonrenal solid organ transplantation

BACKGROUND: Recipients of nonrenal solid organ transplants are at risk for acute renal failure resulting from cardiac or hepatic failure, prolonged surgery, and nephrotoxic effects of immunosuppression. Single-center studies have suggested a variable incidence of acute renal failure in this population, with an associated increase in mortality. This study examines the incidence of acute renal failure and its associated mortality and morbidity in a modern multicenter cohort. METHODS: All adult liver, heart, and lung transplant recipients from 2002 were identified from the New York Statewide Planning and Research Cooperative System database. The impact of acute renal failure on mortality, length of stay, and charges was analyzed using multivariate regression models. RESULTS: Among 519 liver, heart, and lung transplant recipients, the incidence of acute renal failure was 25%, with 8% of patients requiring renal replacement therapy. Acute renal failure requiring renal replacement therapy was associated with increased mortality among both heart (odds ratio, 9.0; 95% confidence interval, 1.8-45.8) and liver transplant recipients (odds ratio, 12.1; 95% confidence interval, 3.9-37.3). This degree of acute renal failure also increased length of stay by nearly 3 weeks and charges by more than $115,000. Even among patients who did not require renal replacement, acute renal failure was strongly associated with increased mortality, length of stay, and charges. CONCLUSIONS: Acute renal failure remains a common complication of nonrenal solid organ transplantation and is associated with increased mortality, prolonged hospitalization, and significant financial costs.     

Acute kidney injury with renal replacement therapy in trauma patients

Background: Acute kidney injury (AKI) with renal replacement therapy (RRT) is rare in trauma patients. The primary aim of the study was to assess incidence, mortality and chronic RRT dependency in this patient group. Methods: Adult trauma patients with AKI receiving RRT at a regional trauma referral center over a 12‐year period were retrospectively reviewed. Results: Population‐based incidence of post‐traumatic AKI with RRT was 1.8 persons per million inhabitants per year (p.p.m./year) [95% confidence the interval (CI) 1.5–2.1 p.p.m./year]. In trauma patients admitted to hospital, incidence was 0.5‰ (95% CI 0.3–0.7‰) of those treated in intensive care unit (ICU), it was 8.3% (95% CI 5.9–10.8%). The median age was 46 years. Odds ratio (OR) for post‐traumatic AKI requiring RRT was higher in males than in females in general population (OR 5.6, 95% CI 2.2–14.0), and in trauma patients admitted to hospital (OR 4.4, 95% CI 1.9–10.3) and ICU (OR 4.5, 95% CI 1.9–10.7). The in‐hospital mortality rate was 24% (95% CI 11–37%), 3‐month mortality 36% (95% CI 21–51%) and 1‐year mortality 40% (95% CI 25–55%). Age was a risk factor for death after 1 year, with 57% (95% CI 7–109%) increased risk for each 10 years added. None of the survivors was dialysis‐dependent 3 months or 1 year after trauma. Conclusion: AKI in trauma patients requiring RRT was rare in this single‐center study. More males than females were affected. Mortality was modest, and renal recovery was excellent as none of the survivors became dependent on chronic RRT.     

The effect of aprotinin on risk of acute renal failure requiring dialysis after on-pump cardiac surgery

The use of aprotinin in cardiac surgery to reduce perioperative bleeding and transfusion is controversial. We assessed the effect of aprotinin on the risk of acute renal failure in 423 patients who underwent on-pump cardiac surgery between January 1, 2005 and December 31, 2006. Of these 423 patients, 318 (75.2%) received aprotinin (median dose=3.0 million KIU, standard deviation=2.8 million KIU; interquartile range: 2 million KIU to 4 million KIU). Aprotinin was more likely to be used in patients who did not cease aspirin before surgery, in urgent or emergency surgery, who had impaired left ventricular function, a longer period of bypass and aortic cross-clamp time, and with both coronary artery bypass graft and valvular surgery performed. The overall incidence of acute renal failure requiring dialysis was 2.8%. The use of aprotinin was not associated with a reduction in transfusion nor an increased risk of renal failure requiring dialysis, atrial fibrillation, cerebrovascular accident or mortality in the univarate analyses. In the multivariate analysis, only preoperative serum creatinine concentration (odds ratio [OR] 1.06 per 10 micromol/l increment in creatinine, 95% confidence interval [CI]: 1.01 to 1.14, P=0.029) and urgency of the surgery (urgent vs. scheduled surgery: OR 12.8, CI: 2.3 to 70.8, P=0.004; emergency vs. scheduled surgery: OR 23.1, CI: 3.0 to 180.2, P=0.003) were significantly associated with an increased risk of acute renal failure requiring dialysis. The use of low-dose aprotinin did not significantly reduce perioperative transfusion requirements and was not a significant risk factor for acute renal failure requiring dialysis in our patients.     

Dialysis adequacy in patients with acute renal failure

Measurement of dialysis adequacy in patients with end-stage renal disease involves the use of urea kinetic modeling, which is a reflection of both dietary protein intake and efficiency of small solute clearance. Different dialytic modalities are available for patients in acute renal failure, including intermittent hemodialysis, continuous renal replacement therapies and peritoneal dialysis. In recent years, there has been a growing effort to measure dialysis adequacy in patients with acute renal failure using urea kinetic modeling. This initiative has been driven by the persistently high mortality rates in patients with dialysis-requiring acute renal failure, which may partly be related to inadequate dialysis dosing. In the setting of acute renal failure, dialysis adequacy has been measured using both single-pool and double-pool urea kinetics, as well as blood-based and dialysate-based urea kinetic modeling. Unfortunately, current goals and methods of measuring dialysis adequacy have been extrapolated from the end-stage renal disease patient population. These extrapolations are problematic because of differences in total body water, protein catabolic rate, and vascular access. Continuous renal replacement therapy has theoretical advantages over intermittent hemodialysis, including a decreased tendency to induce hypotension, and improved solute clearance and fluid removal, while allowing intensive nutritional support, and a better clearance of medium- to large-size molecules. The latter may play a significant role in patients with sepsis-associated acute renal failure. To date, comparative studies are scant and equivocal in establishing the superiority of a particular dialysis dose or modality.     

Patients supported by extracorporeal membrane oxygenation and acute dialysis: acute physiology and chronic health evaluation score in predicting hospital mortality

Extracorporeal membrane oxygenation (ECMO) can provide short-term cardiopulmonary support to critically ill patients. Among ECMO patients, acute renal failure requiring dialysis has an ominous prognosis. However, a prognostic scoring system and risk factors adjustment for hospital mortality in these patients have not been elucidated previously. A multicenter observational cohort study was conducted from January 2002 to December 2006. Information obtained included demographics, biochemical variables, Acute Physiology and Chronic Health Evaluation (APACHE) II, III, and IV scores at ICU admission and initial acute dialysis, and hospital mortality in 102 non-coronary artery bypass graft (CABG) patients receiving ECMO support with acute dialysis. This retrospective cohort study included 70 men and 32 women with a mean age of 47.9 ± 15.7 years. Seventy-two patients (70.6%) had hospital mortality. The area under the receiver operating characteristic curve showed APACHE IV (0.653) had a better discriminative power to predict hospital mortality than APACHE II (0.584) and APACHE III (0.634) at initializing dialysis. Hosmer-Lemeshow statistics showed good calibration for all three scores to predict hospital mortality at initializing dialysis (APACHE IV, P = 0.392; APACHE III, P = 0.094; and APACHE II, P = 0.673). Independent predictors for hospital mortality by multivariate logistic regression analysis were higher central venous pressure (odds ratio [OR], 1.11; confidence interval [CI] 95%, 1.02-1.20; P = 0.016), higher APACHE IV score at initializing dialysis (OR, 1.03; CI 95%, 1.01-1.05; P = 0.003), and latency from hospital admission to dialysis (OR, 1.04; CI 95%, 1.00-1.08; P = 0.033). High mortality rate was noted in non-CABG patients receiving ECMO and acute dialysis. Predialysis APACHE IV scores had good calibration and moderate discrimination in predicting hospital mortality in these patients. Because ECMO support could stabilize cardiopulmonary status, APACHE IV scores would likewise underestimate disease severity at lower score ranges in these patients.     

Race and mortality after acute renal failure

Black patients receiving dialysis for end-stage renal disease in the United States have lower mortality rates than white patients. Whether racial differences exist in mortality after acute renal failure is not known. We studied acute renal failure in patients hospitalized between 2000 and 2003 using the Nationwide Inpatient Sample and found that black patients had an 18% (95% confidence interval [CI] 16 to 21%) lower odds of death than white patients after adjusting for age, sex, comorbidity, and the need for mechanical ventilation. Similarly, among those with acute renal failure requiring dialysis, black patients had a 16% (95% CI 10 to 22%) lower odds of death than white patients. In stratified analyses of patients with acute renal failure, black patients had significantly lower adjusted odds of death than white patients in settings of coronary artery bypass grafting, cardiac catheterization, acute myocardial infarction, congestive heart failure, pneumonia, sepsis, and gastrointestinal hemorrhage. Black patients were more likely than white patients to be treated in hospitals that care for a larger number of patients with acute renal failure, and black patients had lower in-hospital mortality than white patients in all four quartiles of hospital volume. In conclusion, in-hospital mortality is lower for black patients with acute renal failure than white patients. Future studies should assess the reasons for this difference.     

Withholding and withdrawal of therapy in patients with acute renal injury: a retrospective cohort study

The incidence of withholding and withdrawal of therapy in the setting of multi-organ failure in critically ill patients has increased. Epidemiological data on the decision-making process of withholding or withdrawal of therapy from Australian and New Zealand intensive care units is sparse. We examined the clinical and electronic records of 179 consecutive patients, admitted to the ICU between 1st January 2000 and 31st December 2001, who had acute renal injury. Acute renal replacement therapy was offered in 11.2% of patients. Therapy was withheld or withdrawn in 21.2% of patients. The levels of supportive care were comparable between those who had therapy withheld or withdrawn and those who had full intensive care therapy until such a decision was made. Predicted mortality (OR 1.04, 95% CI: 1.01-1.08, P = 0.03) and age (OR 1.04, 95% CI: 1.00-1.08, P = 0.03) were independently associated with the decision to withhold or withdraw therapy. The mean ICU stay of those with withdrawal or withholding of therapy was much shorter than those with full therapy (2.5 vs 5.7 days). This was likely to be due to an older age of our cohort, rapid progressive nature of the acute disease, a different clinical approach to treating critically ill elderly patients, or a combination of these factors. This pattern of practice was quite different from those reported from ICUs in other parts of the world. A prospective multi-centre observational study will clarify the pattern of practice in this important area of intensive care practice in Australasia.