Prognosis for long-term survival and renal recovery in critically ill patients with severe acute renal failure: a population-based study

INTRODUCTION: Severe acute renal failure (sARF) is associated with considerable morbidity, mortality and use of healthcare resources; however, its precise epidemiology and long-term outcomes have not been well described in a non-specified population. METHODS: Population-based surveillance was conducted among all adult residents of the Calgary Health Region (population 1 million) admitted to multidisciplinary and cardiovascular surgical intensive care units between May 1 1999 and April 30 2002. Clinical records were reviewed and outcome at 1 year was assessed. RESULTS: sARF occurred in 240 patients (11.0 per 100,000 population/year). Rates were highest in males and older patients (≥65 years of age). Risk factors for development of sARF included previous heart disease, stroke, pulmonary disease, diabetes mellitus, cancer, connective tissue disease, chronic renal dysfunction, and alcoholism. The annual mortality rate was 7.3 per 100,000 population with rates highest in males and those ≥65 years. The 28-day, 90-day, and 1-year case-fatality rates were 51%, 60%, and 64%, respectively. Increased Charlson co-morbidity index, presence of liver disease, higher APACHE II score, septic shock, and need for continuous renal replacement therapy were independently associated with death at 1 year. Renal recovery occurred in 78% (68/87) of survivors at 1 year. CONCLUSION: sARF is common and males, older patients, and those with underlying medical conditions are at greatest risk. Although the majority of patients with sARF will die, most survivors will become independent from renal replacement therapy within a year

Is regional citrate superior to systemic heparin anticoagulation for continuous renal replacement therapy? A prospective observational study in an adult regional critical care system

Purpose: Continuous renal replacement therapy (CRRT) is commonly used in the care of critically ill patients although the optimal means of anticoagulation is not well defined. We report our regional CRRT protocol that was developed using the principles of quality improvement and compare the effect of regional citrate with systemic heparin anticoagulation on filter life span. Materials and Methods: Prospective observational cohort study in a Canadian adult regional critical care system. A standardized protocol for CRRT has been implemented at all adult intensive care units in the Calgary Health Region since August 1999. All patients with acute renal failure treated with CRRT during October 1, 2002, to September 30, 2003, were identified and followed up prospectively until hospital discharge or death. Results: Eighty-seven patients with acute renal failure requiring CRRT were identified, 54 were initially treated with citrate, 29 with heparin, and 4 with saline flushes. Citrate and heparin were used in 212 (66%) and 97 (30%) of filters for 8776 and 2651 hours of CRRT, respectively. Overall median (interquartile range) filter life span with citrate was significantly greater than heparin (40 [14-72] vs 20 [5-44] hours, P 72 vs 33 hours, P .001). Citrate anticoagulation was well tolerated with no patient requiring elective discontinuation for hypernatremia, metabolic alkalosis, or hypocalcemia. Conclusions: Regional citrate anticoagulation was associated with prolonged filter survival and increased completion of scheduled filter life span compared with heparin. These data support small studies suggesting that citrate is a superior anticoagulant for CRRT and suggest the need for a future definitive randomized controlled trial.</p

One-Year Mortality in Critically Ill Patients by Severity of Kidney Dysfunction: A Population-Based Assessment

Background: Kidney dysfunction in the intensive care unit (ICU) results in increased morbidity, mortality, and health care costs; however, long-term mortality has not been described across strata of severity in kidney dysfunction. Methods: The primary objective is to describe and assess factors associated with 1-year mortality in critically ill patients stratified by severity of kidney dysfunction during admission to the ICU. Kidney dysfunction is defined by peak serum creatinine values and stratified by: (1) no dysfunction (creatinine < 1.7 mg/dL [<150 μmol/L]), (2) mild dysfunction (creatinine, 1.7 to 3.4 mg/dL [150 to 299 μmol/L]), (3) moderate dysfunction (creatinine ≥ 3.4 mg/dL [≥ 300 μmol/L]), (4) severe acute dysfunction requiring renal replacement therapy (acute renal failure), or (5) preexisting end-stage kidney disease. Population-based surveillance was of adult residents of the Calgary Health Region (population, 1 million) admitted to any multidisciplinary ICU and a cardiovascular surgery ICU from May 1, 1999, to April 30, 2002. Results: Of 5,693 admissions, 62% were men, median age was 64.9 years (interquartile range, 50.6 to 74.5 years), and mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 24.9 ± 8.7 (SD). Case fatality rates stratified by renal dysfunction were 17% (763 of 4,411), 47% (370 of 790), 48% (77 of 160), 64% (153 of 240), and 40% (37 of 92) for no, mild, and moderate dysfunction; severe acute renal failure; and end-stage kidney disease, respectively. By means of multivariate analysis, 1-year mortality was associated independently with advancing age, medical diagnosis, higher APACHE II score, and presence and severity of kidney dysfunction, although no difference was evident comparing those with mild to moderate dysfunction. End-stage kidney disease was not associated independently with 1-year mortality. Conclusion: Severity of kidney dysfunction in patients in the ICU is associated with an incremental increase in long-term mortality. Although patients classified with either mild or moderate kidney dysfunction had an increased risk for death, use of serum creatinine level alone was poor at discriminating long-term outcome, suggesting this measure alone should not be used for defining long-term prognosis.</p