When should renal replacement therapy for acute kidney injury be initiated and discontinued?

BACKGROUND: Critically ill patients with acute kidney injury (AKI) are at high risk for death and frequently require initiation of renal replacement therapy (RRT). There is wide variation in clinical practice on the indications for and timing of initiation and discontinuation of RRT. Numerous clinical and biochemical factors (i.e. uremic, metabolic, fluid balance) have been used; however, at present there is no consensus to guide clinicians on the most favorable time to initiate and/or discontinue RRT to optimize patient outcomes. METHODS: In this review, we appraise the available clinical studies that have assessed timing of initiation and/or discontinuation of RRT for critically ill patients with AKI. 'Timing' of initiation has been variably defined including use of conventional biomarkers (i.e. serum urea and creatinine), urine output, fluid balance, and time relative to intensive care unit admission. CONCLUSIONS: Numerous studies consistently point toward a survival benefit to early initiation of RRT; however, there is a paucity of high-quality randomized trials. If early RRT is associated with clinical benefit, it remains uncertain whether this is attributable to more rapid metabolic/uremic control, management of fluid balance or a combination of clinical factors. In addition, timing of RRT initiation is likely context-specific and varies by clinical factors and/or etiology of AKI. There is also little data to accurately distinguish in advance between the injured kidney that will need extracorporeal renal support and one that retains capacity for early recovery. Fewer studies have evaluated the process of weaning of RRT or ideal methods to predict sufficient recovery to avoid re-initiation. Longer duration of RRT support, higher illness severity and lower urine output (independent of diuretic therapy) have all predicted need for re-initiation. Additional investigations on these issues are clearly warranted and urgently needed.

Regional citrate anticoagulation in continuous venovenous hemodiafiltration.

Over the past several years, continuous venovenous hemodiafiltration (CVVHDF) using pump-driven devices has gained wide acceptance as a form of renal replacement therapy for critically ill patients with acute renal failure. More recently, regional citrate anticoagulation has proven useful as a method of anticoagulating CVVHDF circuits, particularly in those patients at high risk for bleeding. However, an easy and convenient method for guiding the dose of citrate infusion has not previously been described. We describe the use of an algorithm using posthemofilter levels of ionized calcium to guide the dose of administered regional citrate on the survival time and urea and creatinine clearances of 24 Hospal AN69HF hemofilters. Nine patients with acute and chronic renal failure requiring CVVHDF were studied. The median filter survival time when using the postfilter ionized calcium algorithm was 3.4 days, with a survival probability of 46% (95% confidence interval [CI], 17 to 71). Random-effects linear regression analysis did not show a significant decline in blood-side urea clearance (P = 0.041) or creatinine clearance (P = 0. 308). Moreover, definite bleeding complications occurred with an incidence rate of 0.045/person-day on citrate anticoagulation (95% CI, 0.006 to 0.16), and occult bleeding occurred with an incidence rate of 0.091/person-day on citrate anticoagulation (95% CI, 0.03 to 0.23). Guiding regional citrate anticoagulation through the use of posthemofilter ionized calcium levels is a safe and effective method of prolonging filter life during CVVHDF.

A multiple center study of multiple chemical sensitivity syndrome.

The lack of widely accepted, standardized, clinical and epidemiologic criteria for Multiple Chemical Sensitivity syndrome has led to confusion about the identification of the condition and has slowed pertinent research. In this article, the authors evaluated the psychometric properties of 2 sets of clinical/epidemiologic criteria for Multiple Chemical Sensitivity syndrome. In this cross-sectional survey of 1,166 patients who visited outpatient occupational, otolaryngology, allergy, and clinical ecological clinics, the authors used the aforementioned sets of criteria to (a) estimate the prevalence of the syndrome in these varied samples and (b) compare the current diagnostic practices of traditional physician specialists with those of clinical ecologists. The authors used a patient-completed questionnaire to assess the medical, psychosocial, and psychological status of patients who reported multiple chemical sensitivities. This approach enabled the formulation of 6 domains, which represented commonly observed characteristics of the syndrome. The authors used a physician-completed questionnaire to collect diagnoses of Multiple Chemical Sensitivity syndrome and other medical conditions. Domains, which were operationalized by the questionnaire and comprised the 2 sets of criteria for identification of the Multiple Chemical Sensitivity syndrome, had test-retest reliabilities that exceeded .75 and estimates of internal consistency that ranged between .59 and .94. Evidence of construct and face validity was considered acceptable. The overall clinic-based prevalences of Multiple Chemical Sensitivity syndrome, based on 6 and 4 domains, were 7% and 23%, respectively. Regardless of the identifying set of criteria used, physicians' diagnoses had relatively low sensitivities (range = 6-50%) and relatively high specificities (range = 82-99%). The study data suggested that the domains operationalized by the questionnaire had reasonable psychometric characteristics. Study data also support the fact that Multiple Chemical Sensitivity syndrome is often overlooked--even by those physicians who treat it most frequently--and that use of both sets of objective criteria for identifying the syndrome would greatly improve the sensitivity of physician diagnoses.

The organizational structure of intensive care units and its influence on patient outcomes.

Despite the growing body of knowledge on the theory of organization, the application of such theory to the organization of intensive care units is in its infancy. Our knowledge about the influence of ICU organization on patient outcomes is limited. Development of instruments to measure ICU organization, and their implementation in studies of new therapies and technologies, will assist in demonstrating the effect of various models of ICU organization on the provision of clinical care.

Successful kidney and liver transplantation from a donor with immune thrombocytopenia.

Antibodies directed against platelet-surface antigen cause immune thrombocytopenia. Transplantation from a donor with immune thrombocytopenia has rarely been reported in the literature and never with a platelet count of 1 × 10(9)/L. We report one liver transplant recipient and one kidney transplant recipient who received organs from a donor with immune thrombocytopenia dying from intracranial hemorrhage. The kidney recipient showed no evidence of thrombocytopenia after transplantation. However, in the liver recipient, the platelet count nadired at 4 × 10(9)/L and normalized within 3 months. Transplantation of a liver from a donor suffering from immune thrombocytopenia must be considered with great caution. Other organs are suitable for transplantation; however, recipients of these organs must be followed carefully for evidence of immune thrombocytopenia and treatment offered accordingly.