Acute renal failure: time for consensus

RIFLE criteria for acute kidney injury are associated with hospital mortality in critically ill patients: a cohort analysis

Introduction

The lack of a standard definition for acute kidney injury has resulted in a large variation in the reported incidence and associated mortality. RIFLE, a newly developed international consensus classification for acute kidney injury, defines three grades of severity – risk (class R), injury (class I) and failure (class F) – but has not yet been evaluated in a clinical series.

Methods

We performed a retrospective cohort study, in seven intensive care units in a single tertiary care academic center, on 5,383 patients admitted during a one year period (1 July 2000–30 June 2001).

Results

Acute kidney injury occurred in 67% of intensive care unit admissions, with maximum RIFLE class R, class I and class F in 12%, 27% and 28%, respectively. Of the 1,510 patients (28%) that reached a level of risk, 840 (56%) progressed. Patients with maximum RIFLE class R, class I and class F had hospital mortality rates of 8.8%, 11.4% and 26.3%, respectively, compared with 5.5% for patients without acute kidney injury. Additionally, acute kidney injury (hazard ratio, 1.7; 95% confidence interval, 1.28–2.13; P < 0.001) and maximum RIFLE class I (hazard ratio, 1.4; 95% confidence interval, 1.02–1.88; P = 0.037) and class F (hazard ratio, 2.7; 95% confidence interval, 2.03–3.55; P < 0.001) were associated with hospital mortality after adjusting for multiple covariates.

Conclusion

In this general intensive care unit population, acute kidney 'risk, injury, failure', as defined by the newly developed RIFLE classification, is associated with increased hospital mortality and resource use. Patients with RIFLE class R are indeed at high risk of progression to class I or class F. Patients with RIFLE class I or class F incur a significantly increased length of stay and an increased risk of inhospital mortality compared with those who do not progress past class R or those who never develop acute kidney injury, even after adjusting for baseline severity of illness, case mix, race, gender and age.

Consensus development in acute renal failure: The Acute Dialysis Quality Initiative

PURPOSE OF REVIEW

Although acute renal failure is both common and highly lethal in the intensive care unit, our understanding of the epidemiology and pathophysiology of acute renal failure is limited, and treatment for acute renal failure is extremely variable around the world. The general lack of consensus with regard to definitions, prevention, and treatment of acute renal failure has limited progress in this field.

RECENT FINDINGS

Consensus in acute renal failure requires establishing a framework in which intensivists, nephrologists, pharmacologists, and others who care for critically ill patients with or at risk for acute renal failure can reach consensus and develop evidence-based practice guidelines. The Acute Dialysis Quality Initiative seeks to provide an objective, dispassionate distillation of the literature and description of the current state of practice of dialysis and related therapies as they are applied to acutely ill patients. The purposes of Acute Dialysis Quality Initiative are first, to develop a consensus of opinion, with evidence where possible, on best practice; and second, to articulate a research agenda to focus on important unanswered questions.

SUMMARY

Broad consensus in the diagnosis and management of acute renal failure and in the use of blood purification in nonrenal critical illness is achievable. Standardization of definitions, practice, and research methodology is urgently needed, and specific proposals have been made by an international, interdisciplinary group.

Emergency endovascular stent graft repair for acute blunt thoracic aortic injury: a retrospective case control study

OBJECTIVE

To compare surgical and endovascular stent graft (ESG) treatment of blunt thoracic aortic injury (BAI) in the emergency setting.

DESIGN AND SETTING

Retrospective case control study in two surgical intensive care units of a university hospital.

PATIENTS

30 patients who presented with BAI between 1995 and 2005: 17 treated surgically and 13 by ESG. The two groups were comparable for the severity of trauma and mean delay before treatment; the mean age was higher in the ESG group (46+/-18 vs. 35+/-15 years).

RESULTS

In the surgical group time spent in the operating theater was longer (310+/-130 vs. 140+/-48 min) and blood losses higher (2000+/-1300 vs. no significant bleeding); aortic clamping time was 48+/-20 min. The mortality rate was 15% with ESG (n=2) and 23% with surgery (n=4). Complications of the procedure were more frequent in the surgical group (1 vs. 7). In the ESG group there was one pulmonary embolism. In the surgical group there were three neurological complications, one acute aortic dissection, one perioperative rupture, one periprosthetic leak, and one septic shock. Two complications (postoperative aortic dissection and paraplegia) appeared in the same patient in the surgical group. Intensive care unit length of stay, duration of mechanical ventilation, and catecholamine support were similar in the two groups.

CONCLUSIONS

Stent graft for emergency treatment of BAI is efficient and is associated with fewer complications than surgical treatment.

A comparison between fenoldopam and low-dose dopamine in early renal dysfunction of critically ill patients*

OBJECTIVE

Fenoldopam mesylate is a selective dopamine-1 agonist, with no effect on dopamine-2 and alpha1 receptors, producing a selective renal vasodilation. This may favor the kidney oxygen supply/demand ratio and prevent acute renal failure. The aim of the study was to investigate if fenoldopam can provide greater benefit than low-dose dopamine in early renal dysfunction of critically ill patients.

DESIGN

Prospective, multiple-center, randomized, controlled trial.

SETTING

University and city hospital intensive care units.

PATIENTS

One hundred adult critically ill patients with early renal dysfunction (intensive care unit stay<1 wk, hemodynamic stability, and urine output<or=0.5 mL/kg over a 6-hr period and/or serum creatinine concentration>or=1.5 mg/dL and<or= 3.5 mg/dL).

INTERVENTIONS

Patients were randomized to receive 2 microg/kg/min dopamine (group D) or 0.1 microg/kg/min fenoldopam mesylate (group F). Drugs were administered as continuous infusion over a 4-day period.

MEASUREMENTS AND MAIN RESULTS

Systemic hemodynamic and renal function variables were recorded daily. The two groups were well matched at enrollment for illness severity and hemodynamic and renal dysfunction. No differences in heart rate or systolic, diastolic, or mean arterial pressure were observed between groups. Fenoldopam produced a more significant reduction in creatinine values compared with dopamine after 2, 3, and 4 days of infusion (change from baseline at time 2, -0.32 vs. -0.03 mg/dL, p=.047; at time 3, -0.45 vs. -0.09 mg/dL, p=.047; and at time 4, -.041 vs. -0.09 mg/dL, p=.02, in groups F and D, respectively). The maximum decrease in creatinine compared with baseline was significantly greater in group F than group D (-0.53+/-0.47 vs. -0.34+/-0.38 mg/dL, p=.027). Moreover, 66% of patients in group F had a creatinine decrease>10% of the baseline value at the end of infusion, compared with only 46% in dopamine group (chi-square=4.06, p=.04). Total urinary output during drug infusion was not significantly different between groups. After 1 day, urinary output was lower in group F compared with group D (p<.05).

CONCLUSIONS

In critically ill patients, a continuous infusion of fenoldopam at 0.1 microg/kg/min does not cause any clinically significant hemodynamic impairment and improves renal function compared with renal dose dopamine. In the setting of acute early renal dysfunction, before severe renal failure has occurred, the attempt to reverse renal hypoperfusion with fenoldopam is more effective than with low-dose dopamine.

The outcome of acute renal failure in the intensive care unit according to RIFLE: model application, sensitivity, and predictability

BACKGROUND

The definition, classification, and choice of management of acute renal failure (ARF) in the setting of the intensive care unit (ICU) remain subjects of debate. To improve our approach to ARF in the ICU setting, we retrospectively applied the new classification of ARF put forward by the Acute Dialysis Quality Initiative group, RIFLE (acronym indicating Risk of renal failure, Injury to the kidney, Failure of kidney function, Loss of kidney function, and End-stage renal failure), to evaluate its sensitivity and specificity to predict renal and patient outcomes.

METHODS

RIFLE classification was applied to 183 patients with ARF admitted to the ICU (2002 to 2003) at the Northern General Hospital, Sheffield, UK. Patients were divided into 4 groups according to percentage of decrease in glomerular filtration rate from baseline. The risk group included 60 patients; injury group, 56 patients; failure group, 43 patients; and control group, 24 patients. Demographic, biochemical, hematologic, clinical, and long-term health status were studied and compared in the 4 groups. An attempt was made to evaluate, by means of logistic regression analysis and receiver operator characteristic curve analysis, the predictive value of RIFLE classification for mortality in the ICU.

RESULTS

The failure group showed the worst parameters with regard to Acute Physiology and Chronic Health Evaluation (APACHE) II score, pH, lowest and highest mean arterial pressures, and Glasgow Coma Scale (P < 0.001). Mortality rate in the ICU (1 month) was significantly greater in the failure group compared with all groups (32 of 43 patients [74.4%]; P < 0.001) and, again, 6-month mortality rate (37 of 43 patients [86%]; P < 0.001). Receiver operator characteristic curve analysis showed that Simplified Acute Physiology Score (SAPS) II was more sensitive than APACHE II score for prediction of patient death in the risk and injury groups compared with the failure and control groups (risk group: SAPS II, 0.8 +/- 0.06; P < 0.001; APACHE II, 0.63 +/- 0.07; P = 0.14; injury group: SAPS II, 0.76 +/- 0.08; P < 0.001; APACHE II, 0.72 +/- 0.07; P = 0.006).

CONCLUSION

RIFLE classification can improve the ability of such older and established ICU scoring systems as APACHE II and SAPS II in predicting outcome of ICU patients with ARF.

Atrial fibrillation in trauma patients requiring intensive care

OBJECTIVES

To evaluate the incidence and risk factors of atrial fibrillation (AF) in trauma patients.

DESIGN AND SETTING

Prospective observational study in a surgical intensive care unit (ICU).

PATIENTS

All trauma patients admitted in the surgical ICU except those who had AF at admission.

MEASUREMENTS AND RESULTS

AF occurred in 16/293 patients (5.5%). AF patients were older, had a higher number of regions traumatized, and received more fluid therapy, transfusion products, and catecholamines. They more frequently experienced systemic inflammatory response syndrome, sepsis, shock, and acute renal failure and had higher scores of severity (Simplified Acute Physiology Score, SAPS II; Injury Severity Score). ICU length of stay and resources use were also increased. ICU and hospital mortality rates were twice higher in AF patients whereas standardized mortality ratio (observed/expected mortality by SAPS II) was similar in the two groups. We found five independent risk factors of developing AF: catecholamine use (OR = 5.7, 95% CI 1.7-19.1), SAPS II of 30 or higher (OR = 11.6, 95% CI 1.3-103.0), three or more regions traumatized (OR = 6.2, 95% CI 1.8-21.4), age 40 years or higher (OR = 6.3, CI 1.4-28.7), and systemic inflammatory response syndrome (OR = 4.4, 95% CI 1.2-16.1).

CONCLUSIONS

In addition to age and catecholamine use, inflammation and severity of injury may be involved in the development of AF in trauma patients. Our results suggest that AF could rather be a marker of a higher severity of illness without major effect on mortality.

Early isovolaemic haemofiltration in oliguric patients with septic shock

OBJECTIVE

To evaluate the effects of early short-term, isovolaemic haemofiltration at 45 ml/kg/h on physiological and clinical outcomes in patients with septic shock.

DESIGN

Retrospective study before and after a change of unit protocol (study period 8 years).

SETTING

Intensive care unit of metropolitan hospital.

PATIENTS

Eighty patients with septic shock.

INTERVENTIONS

Introduction of a new septic shock protocol based on early isovolaemic haemofiltration (EIHF). In the pre-EIHF period (before), 40 patients received conventional supportive therapy. In the post-EIHF period (after), 40 patients received EIHF at 45 ml/kg/h of plasma-water exchange over 6 h followed by conventional continuous venovenous haemofiltration (CVVH). Anticoagulation policy remained unchanged.

MEASUREMENTS AND MAIN RESULTS

The two groups were comparable for age, gender and baseline APACHE II score. Delivered haemofiltration dose was above 85% of prescription in all patients. PaO2/FiO2 ratio increased from 117+/-59 to 240+/-50 in EIHF, while it changed from 125+/-55 to 160+/-50 in the control group (p<0.05). In EIHF patients, mean arterial pressure increased (95+/-10 vs 60+/-12 mmHg; p<0.05), and norepinephrine dose decreased (0.20+/-2 vs 0.02+/-0.2 microg/kg/min; p<0.05). Among EIHF patients, 28 (70%) were successfully weaned from the ventilator compared with 15 (37%) in the control group (p<0.01). Similarly, 28-day survival was 55% compared with 27.5% (p<0.05). Length of stay in the ICU was 9+/-5 days compared with 16+/-4 days (p<0.002).

CONCLUSIONS

In patients with septic shock, EIHF was associated with improved gas exchange, haemodynamics, greater likelihood of successful weaning and greater 28-day survival compared with conventional therapy.

Early veno-venous haemodiafiltration for sepsis-related multiple organ failure

Introduction

We conducted a prospective observational study from January 1995 to December 2004 to evaluate the impact on recovery of a major advance in renal replacement therapy, namely continuous veno-venous haemodiafiltration (CVVHDF), in patients with refractory septic shock.

Method

CVVHDF was implemented after 6–12 hours of maximal haemodynamic support, and base excess monitoring was used to evaluate the improvement achieved. Of the 60 patients studied, 40 had improved metabolic acidosis after 12 hours of CVVHDF, with a progressive improvement in all failing organs; the final mortality rate in this subgroup was 30%. In contrast, metabolic acidosis did not improve in the remaining 20 patients after 12 hours of CVVHDF, and the mortality rate in this subgroup was 100%. The crude mortality rate for the whole group was 53%, which is significantly lower than the predicted mortality using Simplified Acute Physiology Score II (79%).

Conclusion

Early CVVHDF may improve the prognosis of sepsis-related multiple organ failure. Failure to correct metabolic acidosis rapidly during the procedure was a strong predictor of mortality.

Prognostic value, kinetics and effect of CVVHDF on serum of the myoglobin and creatine kinase in critically ill patients with rhabdomyolysis

BACKGROUND

(I) To investigate the kinetics of the myoglobin and creatine kinase (CK) in rhabdomyolysis. Especially to describe those patients in whom an isolated increase in the myoglobin or the CK occurred at a later stage. (II) To evaluate the sensitivity of the myoglobin and the CK as prognostic tools for the development of Acute renal failure (ARF). (III) To investigate the effect of continuous venovenous haemodiafiltration (CVVHDF) on the myoglobin elimination in ARF.

PATIENTS AND METHODS

Prospective and retrospective cohort study carried out in an ICU of a university hospital. A total of 47 critically ill patients with rhabdomyolysis and a plasma myoglobin > 5000 microg l(-1) were admitted between July 1998 and July 2003.

RESULTS

(I) The myoglobin peaked 0.66 +/- 0.6 days before the CK. The elimination kinetics of the myoglobin was faster than for the CK. (II) Fifty percent developed ARF. Mortality in the ARF patients was 52% compared to 14% in the non-ARF patients. The sensitivity and specificity of developing ARF were higher with the myoglobin in comparison to the CK. (III) In non-ARF, t(1/2) CK was 25.5 h and t(1/2) myoglobin was 17 h (13-23). In those with ARF treated with CVVHDF, t(1/2) CK was 24.8 and t(1/2) myoglobin was 21 h (17-29).

CONCLUSION

(I) The myoglobin peaked earlier than the CK. (II) The myoglobin was a better prognostic tool than the CK. However, the myoglobin also has a wide interindividual range. (III) Though the myoglobin is eliminated in ultrafiltration t(1/2) myoglobin, it was not faster in patients with ARF treated with CVVHDF compared to non-ARF patients.

Acute renal failure after lung transplantation: incidence, predictors and impact on perioperative morbidity and mortality

The incidence, predictors and clinical significance of acute renal failure (ARF) after lung transplantation are not well described. We retrospectively collected data on 296 patients transplanted at our center between April 1992 and December 2000; follow-up was extended until December 2002. Patients were initially divided into two groups: ARF (doubling of baseline creatinine within 2 weeks after surgery) and NoARF. The ARF group was subdivided into ARFD (dialyzed) and ARFnD (not dialyzed). The incidence of ARF was 56% (166/296), but most cases were ARFnD (n = 143). Independent predictors of ARFD (n = 23) were: baseline GFR (OR 0.98, CI 0.96-0.99, p = 0.012), pulmonary diagnosis other than COPD (OR 6.80, CI 1.5-30.89, p = 0.013), mechanical ventilation > 1 d (OR 6.16, CI 1.70-22.24, p = 0.006) and parenteral amphotericin B use (OR 3.04, CI 1.03-8.98, p = 0.045). Both ARFnD and ARFD were associated with longer duration of mechanical ventilation, increased hospital stay and increased early mortality. One-year patient survival was 92.3%, 81.8% and 21.7% in the NoARF, ARFnD and ARFD groups, respectively (p < 0.0001). After controlling for important covariates, ARFD remained associated with an increased hazard of dying (HR 6.77, CI 4.00-11.44, p < 0.0001). In conclusion, ARF occurs commonly after lung transplantation and affects important clinical outcomes, especially when dialysis is required.

Does urinalysis predict acute renal failure after heart surgery?

Acute renal failure (ARF) usually develops in 5% to 30% of patients undergoing heart surgery and is associated with a more complicated clinical evolution course and with an excessive mortality of up to 80%. The objective of this study was to verify the frequency of ARF in postoperative coronary artery bypass surgery with and without cardiopulmonary bypass, by the evaluation of renal function markers' performance [plasma creatinine, plasma urea, urinalysis, fractional excretion of sodium, creatinine clearance and Alpha-glutathione S-transferase (alpha-GST)], besides to verify possible relations between clinical variables involved in postoperative heart surgery and the occurrence of renal insufficiency.

Defining, Quantifying, and Classifying Acute Renal Failure

The syndrome of acute renal failure (ARF) is a common complication of critical illness. Like every other syndrome in the intensive care unit, it requires a consensus definition to progress with a research agenda that is dedicated to preventing and treating it. A consensus definition has been proposed and is being validated. ARF also requires quantification of severity because severity of functional loss is likely to determine the way in which ARF affects outcome. The new consensus definition also offers a quantification of severity. Finally, classification according to pathogenesis would be desirable but remains elusive. Important steps are being taken toward improving the outcome of these patients. Critical care physicians need to understand and participate in this process.

Assessment of renal function in recently admitted critically ill patients with normal serum creatinine

BACKGROUND

Detection of renal dysfunction is important in critically ill patients, and in daily practice, serum creatinine is used most often. Other tools allowing the evaluation of renal function are the Cockcroft-Gault and MDRD (Modification of Diet in Renal Disease) equations. These parameters may, however, not be optimal for critically ill patients. The present study evaluated the value of a single serum creatinine measurement, within normal limits, and three commonly used prediction equations for assessment of glomerular function (Cockcroft-Gault, MDRD and the simplified MDRD formula), compared with creatinine clearance (Ccr) measured on a 1 h urine collection in an intensive care unit (ICU) population.

METHODS

This was a prospective observational study. A total of 28 adult patients with a serum creatinine <1.5 mg/dl, within the first week of ICU admission, were included in the study. Renal function was assessed with serum creatinine, timed 1 h urinary Ccr, and the Cockcroft-Gault, MDRD and simplified MDRD equations.

RESULTS

Serum creatinine was in the normal range in all patients. Despite this, measured urinary Ccr was <80 ml/min/1.73 m2 in 13 patients (46.4%), and <60 ml/min/1.73 m2 in seven patients (25%). Urinary creatinine levels were low, especially in patients with low Ccr, suggesting a depressed production of creatinine caused by pronounced muscle loss. Regression analysis and Bland-Altman plots revealed that neither the Cockcroft-Gault formula nor the MDRD equations were specific enough for assessment of renal function.

CONCLUSIONS

In recently admitted critically ill patients with normal serum creatinine, serum creatinine had a low sensitivity for detection of renal dysfunction. Furthermore, the Cockcroft-Gault and MDRD equations were not adequate in assessing renal function.

Prognosis of acute renal failure: an evaluation of proposed consensus criteria

OBJECTIVES

To validate the recently proposed criteria for acute renal injury (ARI), acute renal failure syndrome (ARFS) and severe acute renal failure syndrome (SARFS) and to evaluate the significance of other prognostic factors.

DESIGN AND SETTING

Retrospective analysis of the Riyadh ICU Program database of patients admitted to 22 ICUs in UK and Germany between 1989 and 1998.

PATIENTS

Included in the study were 41,972 patients, of whom 7,522 (17.9%) had ARI, 2,641 (6.3%) had ARFS and 1,747 (4.2%) had SARFS.

RESULTS

Patients with ARI, ARFS or SARFS had a hospital mortality of 29.5%, 49.2% or 63.0%, respectively, compared to 10.3% among patients without acute renal failure. In the presence of contemporaneous failure of any other organs on the day of acute renal failure, hospital mortality increased to 73.3%, 76.2%, 72.1% and 18%, respectively. Multivariate analysis showed that non-surgical admission, need for emergency surgery, development of acute renal failure during stay in ICU, need for mechanical ventilation and the number of other failed organ systems had a greater impact on prognosis than the need for renal replacement therapy.

CONCLUSIONS

The proposed criteria for ARI, ARFS and SARFS correlated with mortality, but other factors had a greater impact on prognosis. Renal replacement therapy did not increase the risk of hospital mortality among patients with acute renal failure.

Fenoldopam mesylate and renal function in patients undergoing liver transplantation: a randomized, controlled pilot trial

To test the relative effects on serum creatinine (CRE), blood urea nitrogen (BUN), and urine output of small-dose dopamine and fenoldopam in patients undergoing liver transplantation, we randomized 43 patients to 1 of 2 continuous infusions over 48 h, starting with anesthesia induction: fenoldopam, 0.1 microg . kg(-1) . min(-1) or dopamine, 2 microg . kg(-1) . min(-1). We used predetermined hemodynamic and intravascular volume goals (intrathoracic blood volume index 800-1000 mL/m(2), extravascular lung water index <7 mL/kg) to manage patients with an algorithm for use of mannitol and furosemide to maintain urine output >1 mL . kg(-1) . h(-1). At postoperative day 3, the median CRE increase was 0.2 mg/dL (interquartile range [IQR] -0.2-0.5) with fenoldopam and 0.5 mg/dL (IQR 0.3-0.9, P = 0.004) in the dopamine group. The BUN increase was median 2 mg/dL (IQR -2-8) versus 8.5 mg/dL (IQR 5-12, P = 0.01), respectively, with fenoldopam versus dopamine. Urine output was similar; however, significantly fewer fenoldopam patients required furosemide compared with dopamine patients (median 1 [IQR 0-3] versus 3 [IQR 2-4], respectively, P = 0.003). The hemodynamic effects of dopamine and fenoldopam were similar. Compared with dopamine, in the setting of liver transplantation, fenoldopam is associated with better CRE and BUN values.

Immediate Postoperative Renal Function Deterioration in Cardiac Surgical Patients Predicts In-Hospital Mortality and Long-Term Survival

Postoperative renal function deterioration is a serious complication after cardiac surgery with cardiopulmonary bypass and is associated with increased in-hospital mortality. However, the long-term prognosis of patients with postoperative renal deterioration is not fully determined yet. Therefore, both in-hospital mortality and long-term survival were studied in patients with postoperative renal function deterioration. Included were 843 patients who underwent cardiac surgery with cardiopulmonary bypass in 1991. Postoperative renal function deterioration (increase in serum creatinine in the first postoperative week of at least 25%) occurred in 145 (17.2%) patients. In these patients, in-hospital mortality was 14.5%, versus 1.1% in patients without renal function deterioration (P < 0.001). Multivariate analysis significantly associated in-hospital mortality with postoperative renal function deterioration, re-exploration, postoperative cerebral stroke, duration of operation, age, and diabetes. In patients who were discharged alive, during long-term follow-up (100 mo), mortality was significantly increased in the patients with renal function deterioration (n = 124) as compared with those without renal function deterioration (hazard ratio 1.83; 95% confidence interval 1.38 to 3.20). Also after adjustment for other independently associated factors, the risk for mortality in patients with postoperative renal function deterioration remained elevated (hazard ratio 1.63; 95% confidence interval 1.15 to 2.32). The elevated risk for long-term mortality was independent of whether renal function had recovered at discharge from hospital. It is concluded that postoperative renal function deterioration in cardiac surgical patients not only results in increased in-hospital mortality but also adversely affects long-term survival.

Complicaciones postoperatorias en el trasplante hepático. Relación con la mortalidad

BACKGROUND AND OBJECTIVE

Liver transplant is an effective procedure for fulminant hepatitis or chronic liver disease and offers an adequate quality of life. However, even though it is a consolidated treatment, patients can develop serious complications in the immediate postoperative course.

PATIENTS AND METHOD

Prospective observational study of 131 patients admitted in our intensive care unit after liver transplant surgery. We studied variables related with the development of complications and their relation to outcome.

RESULTS

Intensive care unit mortality was 11.5%. Median stay was 4 days. 90% of patients presented 2 or more complications. Hyperglycemia, thrombocytopenia and hypothermia were the most frequent complications but they were not related with mortality. Less frequent but related to outcome complications were acute renal failure (23.6% mortality vs. 1.3%; p < 0.01), ADRS (63.6% vs 6.7%; p < 0,01), low cardiac output (71.4% vs 4.3%; p < 0.01), > or = 2 vasoactive drugs (61.9% vs 1.8%; p < 0.01), encephalopathy (37.5% vs 9.8%; p < 0.05), pneumonia (80% vs 8%; p < 0.01) and hemorrhage (29.4% vs 8.8%; p < 0.05). Graph ischemia, coagulopathy, reperfusion syndrome and use of blood derivatives during surgery were factors related with the development of complications and mortality. Multivariate analysis showed a relationship with mortality and low cardiac output, number of vasoactive drugs and total time of graft ischemia.

CONCLUSIONS

Complications during the postoperative course of liver transplant are frequent but most of them have no effect on prognosis. The negative effect of severe complications should be limited by optimizing the hemodynamic support in these patients and minimizing ischemia of transplanted organs.

Acute renal failure - definition, outcome measures, animal models, fluid therapy and information technology needs: the Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group

INTRODUCTION

There is no consensus definition of acute renal failure (ARF) in critically ill patients. More than 30 different definitions have been used in the literature, creating much confusion and making comparisons difficult. Similarly, strong debate exists on the validity and clinical relevance of animal models of ARF; on choices of fluid management and of end-points for trials of new interventions in this field; and on how information technology can be used to assist this process. Accordingly, we sought to review the available evidence, make recommendations and delineate key questions for future studies.

METHODS

We undertook a systematic review of the literature using Medline and PubMed searches. We determined a list of key questions and convened a 2-day consensus conference to develop summary statements via a series of alternating breakout and plenary sessions. In these sessions, we identified supporting evidence and generated recommendations and/or directions for future research.

RESULTS

We found sufficient consensus on 47 questions to allow the development of recommendations. Importantly, we were able to develop a consensus definition for ARF. In some cases it was also possible to issue useful consensus recommendations for future investigations. We present a summary of the findings. (Full versions of the six workgroups' findings are available on the internet at http://www.ADQI.net)

CONCLUSION

Despite limited data, broad areas of consensus exist for the physiological and clinical principles needed to guide the development of consensus recommendations for defining ARF, selection of animal models, methods of monitoring fluid therapy, choice of physiological and clinical end-points for trials, and the possible role of information technology.

Acute renal failure - definition, outcome measures, animal models, fluid therapy and information technology needs: the Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group

INTRODUCTION

There is no consensus definition of acute renal failure (ARF) in critically ill patients. More than 30 different definitions have been used in the literature, creating much confusion and making comparisons difficult. Similarly, strong debate exists on the validity and clinical relevance of animal models of ARF; on choices of fluid management and of end-points for trials of new interventions in this field; and on how information technology can be used to assist this process. Accordingly, we sought to review the available evidence, make recommendations and delineate key questions for future studies.

METHODS

We undertook a systematic review of the literature using Medline and PubMed searches. We determined a list of key questions and convened a 2-day consensus conference to develop summary statements via a series of alternating breakout and plenary sessions. In these sessions, we identified supporting evidence and generated recommendations and/or directions for future research.

RESULTS

We found sufficient consensus on 47 questions to allow the development of recommendations. Importantly, we were able to develop a consensus definition for ARF. In some cases it was also possible to issue useful consensus recommendations for future investigations. We present a summary of the findings. (Full versions of the six workgroups' findings are available on the internet at http://www.ADQI.net)

CONCLUSION

Despite limited data, broad areas of consensus exist for the physiological and clinical principles needed to guide the development of consensus recommendations for defining ARF, selection of animal models, methods of monitoring fluid therapy, choice of physiological and clinical end-points for trials, and the possible role of information technology.

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.

Monitoring Renal Oxygen Supply in Critically-Ill Patients Using Urinary Oxygen Tension

Critically-ill patients are at risk of developing renal disorders as a consequence of systemic hypoperfusion. Ischemic acute tubular necrosis and resulting acute renal failure are caused by hypotension or therapeutic management. In this study, we tested the change of O(2) availability induced by fenoldopam mesylate using the continuous measurement of urinary oxygen tension (PuO(2)), a relatively noninvasive technique that could provide potentially important real-time data regarding renal oxygenation in intensive care unit patients. Fenoldopam was administered at different doses (0.03, 0.06, and 0.09 microg x kg(-1) x min(-1)) to 50 stable critically-ill patients. Urine output was collected every hour to assess volume and urinary electrolytes. Heart rate, mean arterial blood pressure, cardiac output, pulmonary artery occlusion pressure, arterial oxygen delivery index, and oxygen consumption index were analyzed after fenoldopam dose modifications and at infusion end. PaO(2) and PuO(2) continuous measurements were obtained through two sensors inserted in the radial artery and in the bladder. After a fenoldopam dose increase, PuO(2) significantly increased (P < 0.05), whereas PaO(2) remained unchanged. During the study, heart rate, mean arterial blood pressure, cardiac output, central venous pressure, pulmonary artery occlusion pressure, arterial oxygen delivery index, and oxygen consumption remained unchanged. Dose-dependent PuO(2) increases, unrelated to indexes of systemic perfusion and cardiac function, demonstrate that fenoldopam affects the balance between renal oxygen supply and demand in stable critically-ill patients.

IMPLICATIONS

Acute renal failure in critically-ill patients is associated with frequent mortality. Prolonged renal hypoperfusion cannot be detected by current systemic hemodynamic indexes. Using continuous measurement of urinary oxygen tension, which could indirectly provide real-time data regarding renal oxygenation, our study showed that fenoldopam increases the ratio between oxygen supply and demand.

Incidence and circumstances of serum creatinine increase after abdominal aortic surgery

OBJECTIVE

To evaluate the incidence and the circumstances of a moderate increase in serum creatinine early after elective abdominal aortic surgery.

DESIGN

Prospective clinical observational study.

SETTING

Surgical intensive care unit in a university hospital.

PATIENTS

Two hundred and fifteen consecutive adult patients operated on for infra-renal abdominal aortic surgery during 1 year.

INTERVENTIONS

A moderate increase in plasma creatinine of 20% from preoperative value (renal dysfunction, RD) was systematically recorded during the first 3 days following surgery. Organ dysfunctions (cardiac, pulmonary, haematological, and neurological) were assessed.

MEASUREMENTS AND RESULTS

Forty-three patients (20%) experienced a postoperative RD; six of these required dialysis. RD was associated with other organ dysfunctions in 60.5% patients. Mortality rate was significantly higher for patients who had a RD, than patients without RD (9.3% vs 1.2%, P<0.02). Mean ICU stay of patients with RD was significantly longer (7.9+/-5.6 days vs 5.0+/-1.8 days, P<0.01). However, patients with RD but without other organ dysfunctions had a mortality rate of 0% and did not have a significantly longer stay in ICU than patients without any organ dysfunctions (5.2+/-2.1 days vs 4.6+/-1.2 days, P=0.09).

CONCLUSION

Our results suggest that a postoperative 20%-increase in plasma creatinine after abdominal aortic surgery is not rare and occurs frequently with other organ dysfunction.

Renal dysfunction after cardiac surgery with normothermic cardiopulmonary bypass: incidence, risk factors, and effect on clinical outcome

Renal dysfunction is a frequent and severe complication after conventional hypothermic cardiac surgery. Little is known about this complication when cardiopulmonary bypass (CPB) is performed under normothermic conditions (e.g., more than 36 degrees C). Thus, we prospectively studied 649 consecutive patients undergoing coronary artery bypass surgery or valve surgery with normothermic CPB. The association between renal dysfunction (defined as a > or =30% preoperative-to-maximum postoperative increase in serum creatinine level) and perioperative variables was studied by univariate and multivariate analysis. Renal dysfunction occurred in 17% of the patients. Twenty-one (3.2%) patients required dialysis. Independent preoperative predictors of this complication were: advanced age, ASA class >3, active infective endocarditis, radiocontrast agent administration <48 h before surgery, and combined surgery. When all the variables were entered, active infective endocarditis, radiocontrast agent administration, postoperative low cardiac output, and postoperative bleeding were independently associated with renal dysfunction. The in-hospital mortality rate was 27.5% when this complication occurred (versus 1.6%; P < 0.0001). Furthermore, postoperative renal dysfunction was independently associated with in-hospital mortality (odds ratio, 4.1 [95% confidence interval, 1.3-12.8]). We conclude that advanced age, active endocarditis, and recent (within 48 h) radiocontrast agent administration, as well as postoperative hemodynamic dysfunction, are more consistently predictive of postoperative renal dysfunction than CPB factors.

IMPLICATIONS

We found that postoperative renal dysfunction was a frequent and severe complication after normothermic cardiac surgery, independently associated with poor outcome. Independent predictors of this complication were advanced age, active endocarditis, and recent (within 48 h) radiocontrast agent administration (the only preoperative modifiable factor), as well as postoperative hemodynamic dysfunction.

Application of the sequential organ failure assessment score to cardiac surgical patients

OBJECTIVE

To assess the applicability of the sequential organ failure assessment (SOFA) score to cardiac surgical patients.

DESIGN

Observational cohort study.

SETTING

Adult cardiac surgical ICU.

PATIENTS

Two hundred eighteen patients requiring ICU stay > 96 h.

MEASUREMENTS AND RESULTS

The SOFA score was calculated daily until ICU discharge. Derived SOFA variables-total maximum SOFA (TMS), DeltaSOFA, maximum SOFA (maxSOFA), and DeltamaxSOFA-were considered. Length of ICU stay was 8.9 +/- 6.7 days (mean +/- SD). The mortality rate was 11.0% in the ICU and 15.6% in the hospital. Nonsurvivors had higher TMS, DeltaSOFA, single-organ system, and mean total scores on day 1 (9.8 +/- 2.5 vs 7.8 +/- 2.3, p < 0.05) and thereafter until day 10. The total SOFA score on the first 10 days of ICU stay, time, survival status, and their interaction were all significant (p < 0.001), with higher SOFA scores for nonsurvivors, and lower scores for survivors that decreased as the number of days from operation increased. Cardiovascular score on day 1 carried the highest relative risk of mortality among other systems (risk ratio [RR], 2.12; 95% confidence interval [CI], 1.31 to 3.45; p < 0.01), as did maximum cardiovascular score (RR, 2.81; 95% CI, 1.62 to 4.85; p < 0.001). A growing number of failing organs was associated with mortality, from the first to the sixth postoperative day (p < 0.05). Total score on day 1, TMS, DeltaSOFA, maxSOFA, and DeltamaxSOFA were reliable predictors of mortality with area under receiver operating characteristic curve of 0.71 (SE, 0.08), 0.89 (SE, 0.05), 0.86 (SE, 0.06), 0.88 (SE, 0.05), and 0.88 (SE, 0.06), respectively. Length of hospital stay was significantly associated (p = 0.05) to TMS and DeltaSOFA and not to other SOFA scores, age, or sex.

CONCLUSIONS

The SOFA score may be used to grade the severity of postoperative morbidity in cardiac surgical patients without specific adaptations. The model identifies patients at increased risk for postoperative mortality.

Special issues in the patient with renal failure

Renal failure commonly occurs in an ICU as part of the evolution of an underlying disease process. Appropriate and rapid resuscitation and treatment prevents or reverses prerenal insults. Patients usually make a complete recovery if the disease process is reversible and the renal injury mild or moderate. More severe degrees of renal injury initially require conservative management with attention to maintaining a diuresis, preventing fluid, electrolyte, and acid-base imbalances, and ensuring adequate nutrition. Renal replacement therapy is required for the more severe forms of renal failure. Continuous forms of RRT are gaining favor as they are associated with less hemodynamic instability, though current evidence does not demonstrate any clear outcome benefit. Mortality is high when the severe form of ARF is established. ARF may have some attributable mortality, but the poor outcome is usually related more to the underlying medical problems and concurrent multisystem derangements.

Prevention of acute renal failure in the critically ill

Acute renal failure (ARF) is a common and important complication of critical illness and many interventions have been proposed to prevent it. The pathogenesis of acute renal failure during critical illness is poorly understood. Animal models are based on the induction of renal ischemia and do not reflect the dominance of sepsis as a cause of ARF in the clinical arena. Although biological rationale exists for several interventions, none have been shown to be effective in large randomized double-blind multicentre trials. The only interventions with close to level I evidence are confined to the attenuation of radiocontrast nephropathy. The effect on such interventions is, however, of limited clinical relevance to critically ill patients. The maintenance of adequate intravascular filling, cardiac output and renal perfusion pressure and the avoidance of hypoxemia, marked anemia and nephrotoxins remain the only justifiable interventions at this time.

The first international consensus conference on continuous renal replacement therapy

BACKGROUND

Management of acute renal failure (ARF) in the critically ill is extremely variable and there are no published standards for the provision of renal replacement therapy in this population. We sought to review the available evidence, make evidence-based practice recommendations, and delineate key questions for future study.

METHODS

We undertook an evidence-based review of the literature on continuous renal replacement therapy (CRRT) using MEDLINE searches. We determined a list of key questions and convened a 2-day consensus conference to develop summary statements via a series of alternating breakout and plenary sessions. In these sessions, we identified supporting evidence and generated practice guidelines and/or directions for future research.

RESULTS

Of the 46 questions considered, we found consensus for 20. We found inadequate evidence for 21 questions and for the remaining five we found data but no consensus. Full versions of workgroup findings are available on the Internet at http://www.ADQI.net.

CONCLUSIONS

Despite limited data, broad areas of consensus exist for use of CRRT and guideline development appears feasible. Equally broad areas of disagreement also exist and additional basic and applied research in acute renal failure is needed.

Effect of acute renal failure requiring renal replacement therapy on outcome in critically ill patients

OBJECTIVES

Acute renal failure is a complication in critically ill patients that has been associated with an excess risk of hospital mortality. Whether this reflects the severity of the disease or whether acute renal failure is an independent risk factor is unknown. The aim of this study was to analyze severity of illness and mortality in a group of critically ill patients with acute renal failure requiring renal replacement therapy in a number of Austrian intensive care units.

DESIGN

Prospective, multicenter cohort study.

PATIENTS AND SETTING

A total of 17,126 patients admitted consecutively to 30 medical, surgical, and mixed intensive care units in Austria over a period of 2 yrs.

MEASUREMENTS AND MAIN RESULTS

Analyzed data included admission data, Simplified Acute Physiology Score, Logistic Organ Dysfunction system, Simplified Therapeutic Intervention Scoring System, length of intensive care unit stay, intensive care unit mortality, and hospital mortality. Of the admitted patients, 4.9% (n = 839) underwent renal replacement therapy because of acute renal failure (renal replacement therapy patients). These patients had a significantly higher hospital mortality (62.8% vs. 15.6%, p<.001), which remained significantly higher even when renal replacement therapy patients were matched with control subjects for age, severity of illness, and treatment center. Since univariate analysis demonstrated further intensity of treatment to be an additional predictor for outcome, a multivariate model including therapeutic interventions was developed. Five interventions were associated with nonsurvival (mechanical ventilation, single vasoactive medication, multiple vasoactive medication, cardiopulmonary resuscitation, and treatment of complicated metabolic acidosis/alkalosis). In contrast, the use of enteral nutrition predicted a favorable outcome.

CONCLUSIONS

The results of our study suggest that acute renal failure in patients undergoing renal replacement therapy presents an excess risk of in-hospital death. This increased risk cannot be explained solely by a more pronounced severity of illness. Our results provide strong evidence that acute renal failure presents a specific and independent risk factor for poor prognosis.

Acute renal failure in hospitalized patients: part I

BACKGROUND

Acute renal failure (ARF) is a common condition in hospitalized patients. Morbidity, mortality, and health resource use are considerable, but the true magnitude of the problem is not well described in the literature.

OBJECTIVE

To provide a detailed discussion of the epidemiology, economic costs, and classification of ARF.

DATA SOURCES

A MEDLINE search (1996-December 2001) was conducted using the search terms kidney and acute kidney failure: epidemiology, etiology, and drug therapy/drug effects. Bibliographies of selected articles were also examined to include all relevant investigations. Economic data were identified using the terms costs and cost analysis and cost of illness.

STUDY SELECTION AND DATA EXTRACTION

Review articles, meta-analyses, and clinical trials describing epidemiology and classification of hospital-acquired ARF were identified. Results from prospective, controlled trials were given priority when available.

CONCLUSIONS

ARF occurs in up to 25% of critically ill patients, resulting in significant morbidity and high mortality. Characterization of ARF is difficult due to multiple etiologic factors and variable definitions. Limited cost data describe the extensive economic burden associated with the disorder, although further pharmacoeconomic research is needed. Epidemiology and classification of ARF allow prospective management of at-risk patients.