Incidence, timing and outcome of AKI in critically ill patients varies with the definition used and the addition of urine output criteria (original) (raw)
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Bangladesh Critical Care Journal, 2020
Background: Approximately 7% of all hospitalized patients and 20% of acutely ill patients develop signs of AKI. AKI incidence is very high worldwide among intensive care unit patients. Previously long known term, acute renal failure (ARF) is largely replaced by acute kidney injury (AKI), reflecting the recognition that smaller decrements in kidney function that do not result in overt organ failure are of substantial clinical relevance and are associated with increased morbidity and mortality. Objectives: We designed this study to diagnose even mild renal dysfunction earlier than usual time frame with the combined effect of both serum creatinine and urine output criteria, when compared with serum creatinine criterion alone. To establish this objective we used RIFLE serum creatinine and urine output (UO) criteria combined (Scr+UO) and compared with RIFLE serum creatinine (Scr) alone to diagnose AKI early (in days). Design: Prospective observational cohort study. Duration of the study ...
Clinical journal of the American Society of Nephrology : CJASN, 2014
To promote early detection of AKI, recently proposed pretest probability models combine sub-Kidney Disease Improving Global Outcomes (KDIGO) AKI criteria with baseline AKI risk. The primary objective of this study was to determine sub-KDIGO thresholds that identify patients with septic shock at highest risk for AKI. This was a retrospective analysis of 390 adult patients admitted to the medical intensive care unit (ICU) of a tertiary, academic medical center with septic shock between January 2008 and December 2010. Hourly urine output was collected from the time of septic shock recognition (hour 0) to hour 96, urine catheter removal, or ICU discharge (whichever occurred first). All available serum creatinine (SCr) measurements were collected until hour 96. The AKI pretest probability model was assessed during the first 12 hours of resuscitation and included the initial episode of oliguria, increase from baseline to peak SCr level, and Acute Physiology and Chronic Health Evaluation (...
Defining urine output criterion for acute kidney injury in critically ill patients
Nephrology Dialysis Transplantation, 2011
Background. The widespread use of RIFLE and AKIN classification systems for acute kidney injury (AKI) diagnosis and staging has established the association between AKI severity and adverse outcomes. However, as a result of the difficulties in measuring and recording the urine output every hour, a few prospective studies have validated the urine output criterion as stated in these classification systems. We assessed hourly urine output in ICU patients using an automated and accurate device to determine if changes in urine flow and volume could be a sensitive marker of AKI. Additionally, we assessed various definitions of oliguria to determine whether measurement of urine output using a fixed 6-h interval that matches nurses' shifts would be equivalent to the current standard for AKI diagnosis and staging. Methods. Hourly urine output was recorded continuously using a digital monitor in a medical ICU. Serum creatinine measurements were done at least once per 24 h. We assessed changes in urine output by four different definitions of oliguria. Patients with no AKI by either criterion were compared with patients diagnosed exclusively by the urine output criterion, exclusively by serum creatinine criterion and by both criteria. Results. Fifty-five percent of patients had an episode of oliguria during the ICU stay. There was no significant difference assessing urine output every hour or the total urine volume in a 6-h period for the detection of episodes of oliguria. Twenty-one patients (28%) were diagnosed as AKI using the serum creatinine criterion, whereas additional 24 (32%) were identified by the urine output criterion. Conclusions. Episodes of oliguria occur frequently in ICU patients and identify a higher percentage of AKI patients compared to serum creatinine criterion. Alterations in urine flow may be a sensitive marker of renal dysfunction and need to be validated in larger cohorts.
Clinical Journal of the American Society of Nephrology, 2014
Background and objectives Disease biomarkers require appropriate clinical context to be used effectively. Combining clinical risk factors, in addition to small changes in serum creatinine, has been proposed to improve the assessment of AKI. This notion was developed in order to identify the risk of AKI early in a patient's clinical course. We set out to assess the performance of this combination approach. Design, setting, participants, & measurements A secondary analysis of data from a prospective multicenter intensive care unit cohort study (September 2009 to April 2010) was performed. Patients at high risk using this combination approach were defined as an early increase in serum creatinine of 0.1-0.4 mg/dl, depending on number of clinical factors predisposing to AKI. AKI was defined and staged using the Acute Kidney Injury Network criteria. The primary outcome was evolution to severe AKI (Acute Kidney Injury Network stages 2 and 3) within 7 days in the intensive care unit. Results Of 506 patients, 214 (42.2%) patients had early creatinine elevation and were deemed at high risk for AKI. This group was more likely to subsequently develop the primary endpoint (16.4% versus 1.0% [not at high risk], P,0.001). The sensitivity of this grouping for severe AKI was 92%, the specificity was 62%, the positive predictive value was 16%, and the negative predictive value was 99%. After adjustment for Sequential Organ Failure Assessment score, serum creatinine, and hazard tier for AKI, early creatinine elevation remained an independent predictor for severe AKI (adjusted relative risk, 12.86; 95% confidence interval, 3.52 to 46.97). Addition of early creatinine elevation to the best clinical model improved prediction of the primary outcome (area under the receiver operating characteristic curve increased from 0.75 to 0.83, P,0.001). Conclusion Critically ill patients at high AKI risk, based on the combination of clinical factors and early creatinine elevation, are significantly more likely to develop severe AKI. As initially hypothesized, the high-risk combination group methodology can be used to identify patients at low risk for severe AKI in whom AKI biomarker testing may be expected to have low yield. The high risk combination group methodology could potentially allow clinicians to optimize biomarker use.
Critical Care, 2013
Introduction: Urinary indices have limited effectiveness in separating transient acute kidney injury (AKI) from persistent AKI in ICU patients. Their time-course may vary with the mechanism of AKI. The primary objective of this study was to evaluate the diagnostic value of changes over time of the usual urinary indices in separating transient AKI from persistent AKI. Methods: An observational prospective multicenter study was performed in six ICUs involving 244 consecutive patients, including 97 without AKI, 54 with transient AKI, and 93 with persistent AKI. Urinary sodium, urea and creatinine were measured at ICU admission (H0) and on 6-hour urine samples during the first 24 ICU hours (H6, H12, H18, and H24). Transient AKI was defined as AKI with a cause for renal hypoperfusion and reversal within 3 days.
The fallacy of the BUN:creatinine ratio in critically ill patients
Nephrology Dialysis Transplantation, 2012
Background and objectives. Acute kidney injury (AKI) is common in critically ill patients and is associated with a high mortality rate. Pre-renal azotemia, suggested by a high blood urea nitrogen to serum creatinine (BUN:Cr) ratio (BCR), has traditionally been associated with a better prognosis than other forms of AKI. Whether this pertains to critically ill patients is unknown. Methods. We conducted a retrospective observational study of two cohorts of critically ill patients admitted to a single center: a derivation cohort, in which AKI was diagnosed, and a larger validation cohort. We analyzed associations between BCR and clinical outcomes: mortality and renal replacement therapy (RRT). Results. Patients in the derivation cohort (N ¼ 1010) with BCR >20 were older, predominantly female and white, and more severely ill. A BCR >20 was significantly associated with increased mortality and a lower likelihood of RRT in all patients, patients with AKI and patients at risk for AKI. Patients in the validation cohort (N ¼ 10 228) with a BCR >20 were older, predominantly female and white, and more severely ill. A BCR >20 was associated with increased mortality and a lower likelihood of RRT in all patients and in those at risk for AKI, BUN correlated with age and severity of illness. Conclusions. A BCR >20 is associated with increased mortality in critically ill patients. It is also associated with a lower likelihood of RRT, perhaps because of misinterpretation of the BCR. Clinicians should not use a BCR >20 to classify AKI in critically ill patients.
BMC Anesthesiology, 2013
Background: Sequential physicochemical alterations in blood and urine in the course of acute kidney injury (AKI) development have not been previously described. We aimed to describe these alterations in parallel to traditional renal and acid-base parameters. Methods: One hundred and sixty eight consecutive critically ill patients with no previous kidney disease, who had an indwelling urinary catheter at ICU admission and who remained with the catheter for at least two days without dialysis were included. A sample of blood and spot urine were collected simultaneously, once daily, until catheter removal or dialysis requirement. Traditional acid-base and renal parameters were sequentially evaluated in parallel to blood and urinary physicochemical parameters. Patients were classified during this period as having or not AKI and, for patients with AKI, duration (transient or persistent) and severity (creatinine-based AKIN stage) were evaluated.
Classifying AKI by Urine Output versus Serum Creatinine Level
Journal of the American Society of Nephrology, 2015
Severity of AKI is determined by the magnitude of increase in serum creatinine level or decrease in urine output. However, patients manifesting both oliguria and azotemia and those in which these impairments are persistent are more likely to have worse disease. Thus, we investigated the relationship of AKI severity and duration across creatinine and urine output domains with the risk for RRT and likelihood of renal recovery and survival using a large, academic medical center database of critically ill patients. We analyzed electronic records from 32,045 patients treated between 2000 and 2008, of which 23,866 (74.5%) developed AKI. We classified patients by levels of serum creatinine and/or urine output according to Kidney Disease Improving Global Outcomes staging criteria for AKI. In-hospital mortality and RRT rates increased from 4.3% and 0%, respectively, for no AKI to 51.1% and 55.3%, respectively, when serum creatinine level and urine output both indicated stage 3 AKI. Both short-and long-term outcomes were worse when patients had any stage of AKI defined by both criteria. Duration of AKI was also a significant predictor of long-term outcomes irrespective of severity. We conclude that short-and long-term risk of death or RRT is greatest when patients meet both the serum creatinine level and urine output criteria for AKI and when these abnormalities persist.