Creatinine-based definitions: from baseline creatinine to serum creatinine adjustment in intensive care

Urine Neutrophil Gelatinase-associated Lipocalin (NGAL) for Prediction of Persistent AKI and Major Adverse Kidney Events

We aimed to determine whether urinary neutrophil gelatinase-associated lipocalin (uNGAL) can accurately predict persistent AKI, major adverse kidney events at 30 days (MAKE30) and 365 days (MAKE365) in hospitalized AKI patients. This is a retrospective study of adult patients who were admitted at King Chulalongkorn Memorial Hospital. We performed multivariable logistic regression for persistent AKI, MAKE30, and MAKE365. We developed equations for predicting MAKE30 and MAKE365 and divided the dataset into derivation and validation cohorts. uNGAL performance and predictive models were assessed using the area under the receiver operating characteristic curve (AROC). Among 1,322 patients with AKI, 76.9%, 45.1%, and 61.7% had persistent AKI, MAKE30, and MAKE365. The AROC were 0.75 (95% confidence interval[CI] 0.70–0.80), 0.66 (95%CI 0.61–0.71), and 0.64 (95%CI 0.59–0.70) for prediction of persistent AKI, MAKE30, and MAKE365 by uNGAL. The AROC in the validation dataset combining uNGAL with clinical covariates were 0.74 (95%CI 0.69–0.79) and 0.72 (95%CI 0.67–0.77) for MAKE30 and MAKE365. We demonstrated an association between uNGAL and persistent AKI, MAKE30, and MAKE365. Prediction models combining uNGAL can modestly predict MAKE30 and MAKE365. Therefore, uNGAL is a useful tool for improving AKI risk stratification.

Clinical prediction models for acute kidney injury

Objective

To report on the currently available prediction models for the development of acute kidney injury in heterogeneous adult intensive care units.

Methods

A systematic review of clinical prediction models for acute kidney injury in adult intensive care unit populations was carried out. PubMed^® was searched for publications reporting on the development of a novel prediction model, validation of an established model, or impact of an existing prediction model for early acute kidney injury diagnosis in intensive care units.

Results

We screened 583 potentially relevant articles. Among the 32 remaining articles in the first selection, only 5 met the inclusion criteria. The nonstandardized adaptations that were made to define baseline serum creatinine when the preadmission value was missing led to heterogeneous definitions of the outcome. Commonly included predictors were sepsis, age, and serum creatinine level. The final models included between 5 and 19 risk factors. The areas under the Receiver Operating Characteristic curves to predict acute kidney injury development in the internal validation cohorts ranged from 0.78 to 0.88. Only two studies were externally validated.

Conclusion

Clinical prediction models for acute kidney injury can help in applying more timely preventive interventions to the right patients. However, in intensive care unit populations, few models have been externally validated. In addition, heterogeneous definitions for acute kidney injury and evaluation criteria and the lack of impact analysis hamper a thorough comparison of existing models. Future research is needed to validate the established models and to analyze their clinical impact before they can be applied in clinical practice.

Urinary [TIMP-2] × [IGFBP7] and serum procalcitonin to predict and assess the risk for short-term outcomes in septic and non-septic critically ill patients

BACKGROUND

Biomarkers can play a critical role by facilitating diagnosis and stratification of disease, as well as assessment or prediction of disease severity. Urinary tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 product ([TIMP-2] × [IGFBP7]) predict the development and progression of AKI and recently procalcitonin (PCT), a widely used biomarker for sepsis diagnosis and management, has been associated with AKI occurrence in ICU patients. To assess combinations of [TIMP-2] × [IGFBP7] and PCT results for prediction and risk stratification of short-term outcomes in septic and non-septic patients, a retrospective cohort analysis of critically ill patients was performed in a multidisciplinary ICU. ROC curve analysis was used in order to evaluate predictive performance of combined results of [TIMP-2] × [IGFBP7] and PCT at the time of admission for AKI development. To verify the utility of adding [TIMP-2] × [IGFBP7] and PCT results for risk assessment, we evaluated the predictive value of having a single-marker positivity compared to a double-marker positivity using the widely used cut-off of 0.3 (ng/mL)²/1000 for [TIMP-2] × [IGFBP7] and 0.5 μg/L for PCT. Risk assessment for AKI occurrence within 48 h, acute kidney disease (AKD) and mortality at 7 days was performed by logistic/Cox regression analysis.

RESULTS

433 patients were analysed, of whom 168 had AKI within 48 h (93 septic and 65 non-septic patients). Combination of [TIMP-2] × [IGFBP7] and PCT showed a good predictive ability for AKI occurrence (AUC 0.81, 95% CI 0.77-0.86, p < 0.001, Sens 78%, Spec 73%). Combinations of biomarkers increased the odd ratios (OR) considerably. A single-marker positivity showed a fourfold risk increase, while the double-marker positivity a 26-fold risk increase for AKI occurrence. Moreover, the double-marker positivity showed an elevated risk for AKD at 7 days in non-septic patients (OR 15.9, 95% CI 3,21-73,57, p < 0.001) and for mortality within 7 days in septic patients (HR 4.1, 95% CI 1.4-11.8, p = 0.001).

CONCLUSIONS

Although combining the results of [TIMP-2] × [IGFBP7] and PCT may be a useful tool to identify and stratify ICU patients at high risk for septic AKI and short-term adverse outcomes, data should be confirmed in a large prospective study.

The influence of prolonged temperature management on acute kidney injury after out-of-hospital cardiac arrest: A post hoc analysis of the TTH48 trial

BACKGROUND

Acute kidney injury (AKI) is common after cardiac arrest and targeted temperature management (TTM). The impact of different lengths of cooling on the development of AKI has not been well studied. In this study of patients included in a randomised controlled trial of TTM at 33 °C for 24 versus 48 h after cardiac arrest (TTH48 trial), we examined the influence of prolonged TTM on AKI and the incidence and factors associated with the development of AKI. We also examined the impact of AKI on survival.

METHODS

This study was a sub-study of the TTH48 trial, which included patients cooled to 33 ± 1 °C after out-of-hospital cardiac arrest for 24 versus 48 h. AKI was classified according to the KDIGO AKI criteria based on serum creatinine and urine output collected until ICU discharge for a maximum of seven days. Survival was followed for up to six months. The association of admission factors on AKI was analysed with multivariate analysis and the association of AKI on mortality was analysed with Cox regression using the time to AKI as a time-dependent covariate.

RESULTS

Of the 349 patients included in the study, 159 (45.5%) developed AKI. There was no significant difference in the incidence, severity or time to AKI between the 24- and 48-h groups. Serum creatinine values had significantly different trajectories for the two groups with a sharp rise occurring during rewarming. Age, time to return of spontaneous circulation, serum creatinine at admission and body mass index were independent predictors of AKI. Patients with AKI had a higher mortality than patients without AKI (hospital mortality 36.5% vs 12.5%, p < 0.001), but only AKI stages 2 and 3 were independently associated with mortality.

CONCLUSIONS

We did not find any association between prolonged TTM at 33 °C and the risk of AKI during the first seven days in the ICU. AKI is prevalent after cardiac arrest and TTM and occurs in almost half of all ICU admitted patients and more commonly in the elderly, with an increasing BMI and longer arrest duration. AKI after cardiac arrest is an independent predictor of time to death.

Defining pediatric community-acquired acute kidney injury: an observational study

BACKGROUND

Pediatric acute kidney injury (AKI) is associated with long-term morbidity and mortality; however, outcomes improve when AKI is detected earlier. Current definitions of AKI use baseline creatinine; community-acquired AKI (CA-AKI) is difficult to define and detect in the pediatric emergency department (ED) when no baseline creatinine is available. Our objective was to compare age- and gender-based creatinine norms to the traditional baseline (lowest creatinine in previous 3 months) to diagnose CA-AKI.

METHODS

This was a retrospective cross-sectional study conducted in children 1 month-18 years of age seen in the pediatric ED in whom a creatinine was obtained.

RESULTS

Per the Kidney Disease Improving Global Outcomes AKI definition in encounters with baseline creatinine available, 343/2338 (14.7%) had CA-AKI. When the upper limit of the age- and gender-based creatinine norm was applied as a surrogate baseline creatinine, CA-AKI was diagnosed in 1.5% of encounters (239/15,486). Additionally, CA-AKI was diagnosed in 178 cases using the upper limit of age- and gender-based creatinine norms only, as these cases did not have a baseline creatinine.

CONCLUSIONS

Age- and gender-based creatinine norms can be applied as a surrogate baseline to detect CA-AKI in all children regardless of whether baseline creatinine is available, potentially detecting it earlier.

Early diagnosis of acute kidney injury by urinary YKL-40 in critically ill patients in ICU: a pilot study

PURPOSE

In critically ill patients, acute kidney injury (AKI) is a devastating problem often associated with adverse outcomes. Depending on the conventional markers for diagnosis of AKI, an undesirable delay in the diagnosis and initiation of treatment has occurred. Thus, it is challenging to find a biomarker for early diagnosis of AKI. We sought to evaluate urinary YKL-40 as a biomarker for early diagnosis of AKI among critically ill patients compared with conventional markers and to assess its relation to the severity of AKI.

METHODS

Thirty-six patients without AKI at the time of ICU admission who enrolled in this prospective cohort study had the following measured: serum creatinine as well as urine YKL-40 at admission and thereafter at 4 time intervals (0, 12, and 24 ± 48 h) (therefore, we studied 94 urine samples in 36 patients). Urine YKL-40 was quantified by enzyme-linked immunosorbent assay (ELISA). AKI was defined using the Kidney Disease Improving Global Outcomes (KDIGO) criteria, which include three stages (1, 2, and 3) of progressive renal dysfunction.

RESULTS

In this study, 18 (50%) patients developed AKI within 48-72 h. Moreover, urine YKL-40 increased significantly within 12 h in patients who developed AKI (n = 18, 11.75 ± 1.94), but not in non-AKI patients (n = 18, 5.66 ± 3.42) ng/ml (P < 0.001) and, at the same time, we did not find any significant difference in the serum creatinine levels between the two groups. In addition, AKI group showed rising levels with KIDGO classes.

CONCLUSION

In this pilot study we found that urinary YKL-40 can be used as a valuable and noninvasive marker for early diagnosis of AKI among critically ill patients in ICU as compared to conventional markers and its level is increasing with the severity of AKI classes. However, the small sample size is important limitation. Therefore, large multicenter studies may be needed to confirm it.

eResearch in acute kidney injury: a primer for electronic health record research

Acute kidney injury (AKI) has a significant impact on patient morbidity and mortality as well as overall health care costs. eResearch, which integrates information technology and information management to optimize research strategies, provides a perfect platform for necessary ongoing AKI research. With the recent adoption of a widely accepted definition of AKI and near-universal use of electronic health records, eResearch is becoming an important tool in AKI research. Conducting eResearch in AKI should ideally be based on a relatively uniform methodology. This article is the first of its kind to describe a methodology for pursuing eResearch specific to AKI and includes an illustrative database example for critically ill patients. We discuss strategies for using serum creatinine and urine output in large databases to identify and stage AKI and ways to interpolate missing values and validate data. Issues specific to the pediatric population include variation in serum creatinine with growth, varied severity of illness scoring systems and medication dosage based on weight. Many of these same strategies used to optimize AKI eResearch can be applicable to real-time AKI alerts with potential integration of additional clinical variables.

Acute kidney injury

Acute kidney injury (AKI) is defined by a rapid increase in serum creatinine, decrease in urine output, or both. AKI occurs in approximately 10-15% of patients admitted to hospital, while its incidence in intensive care has been reported in more than 50% of patients. Kidney dysfunction or damage can occur over a longer period or follow AKI in a continuum with acute and chronic kidney disease. Biomarkers of kidney injury or stress are new tools for risk assessment and could possibly guide therapy. AKI is not a single disease but rather a loose collection of syndromes as diverse as sepsis, cardiorenal syndrome, and urinary tract obstruction. The approach to a patient with AKI depends on the clinical context and can also vary by resource availability. Although the effectiveness of several widely applied treatments is still controversial, evidence for several interventions, especially when used together, has increased over the past decade.

Renal outcomes of intensive care burn patients in an Asian tertiary centre

INTRODUCTION

Acute kidney injury (AKI) is a frequent complication of severe burn injury and is associated with a high mortality rate of up to 80%. We aimed to establish the incidence, mortality rate, and factors related to mortality in adult patients with severe burn injury and AKI with renal replacement therapy (RRT) in Singapore.

METHODS

We performed a retrospective cohort study of severely burned patients who were admitted to the Burns Intensive Care Unit (BICU) at the Singapore General Hospital (SGH) from January 2008 to December 2016. We compared patients with AKI with RRT who survived with those who did not survive. As there were changes in the protocol for burns management after 2013, we also compared patients with AKI with RRT who survived with non-survivors in each of the 2008-2012 and 2013-2016 cohorts.

RESULTS

Data of 201 patients were studied. The incidence of AKI with RRT use in severe burn injury was 21.9% and their mortality rate was 50.0%. The non-survivors had significantly higher median burned total body surface area (p = 0.043), earlier AKI (p = 0.046), earlier use of RRT (p = 0.035), lower rate of renal recovery (p = <0.0001), higher rates of adult respiratory distress syndrome (ARDS) (p = 0.005) and shock with vasopressors (p = 0.009) compared to the survivors. The survival rate was 36.8% in the 2008-2012 cohort, but improved to 60.0% in the 2013-2016 cohort. In the 2008-2012 cohort, the non-survivors developed AKI earlier (day 0 admission vs. day 3 admission, p = 0.039), and were initiated on RRT at lower serum creatinine level (173.5 μmol/L vs. 254.0 μmol/L, p = 0.042), when compared to the survivors in this same cohort. On the other hand, there were no significant differences in the renal status and fluid balance parameters between the non-survivors and survivors in the 2013-2016 cohort.

CONCLUSIONS

The incidence of AKI with RRT in the Singapore study cohort was high, but their mortality rate was relatively lower compared to other study cohorts. Severity of AKI and use of RRT were associated with poor prognosis. Large scale study is required to further study the risk factors for mortality in this group of patients and establish cause-and-effect relationship.

The utility of neutrophil gelatinase-associated Lipocalin (NGAL) as a marker of acute kidney injury (AKI) in critically ill patients

In current clinical practice, Serum Creatinine (SCr) is a commonly used marker for the diagnosis of acute kidney injury (AKI). Unfortunately, due to a delayed increase in SCr, it is unable to accurately estimate the timing of the injury. The purpose of this study was to assess the ability of plasma neutrophil gelatinase-associated lipocalin (pNGAL) to predict AKI in critically ill adult patients. The study was conducted at the Section of Chemical Pathology, Department of Pathology& Laboratory Medicine in collaboration with Department of Anesthesiology, at Aga Khan University Hospital in Karachi, Pakistan. Subjects in the age groups of18 to 60, that were admitted into the intensive care unit (ICU) with suspected sepsis were enrolled in this study.AKI was labeled by using Risk-Injury-Failure-loss-End Stage (RIFLE) criteria. Forty-eight patients, mean age being 46.5 ± 16.3, were recruited over a nine-month period. Multiple blood samples were collected from each patient at 12 h, 24 h, and 48 h. A total of 52.1% (n = 24) of ICU patients suspected of sepsis had developed AKI. Baseline characteristics of subjects with AKI were compared to those without AKI. Statistically significant difference was noted in gender (p-value< 0.05) and pNGAL (p-value< 0.001). However, no significant differences were seen with respect to age, in patients with and without AKI. The area under the curve (AUC) at12hr was 0.82 (95% CI 0.68-0.96) with a sensitivity of 70.8% and specificity of 90.9%.While AUCs at 24 h was 0.86(95% CI 0.74-0.97) with a sensitivity of 78.5% and specificity of 88.8%. Furthermore, there was a positive correlation between pNGAL and the length of ICU stay (r = 0.98). Non-survivors or expired patients had higher median pNGAL170 (202-117) ng/ml as compared to survivors 123(170-91) ng/ml. In conclusion, pNGAL is an early predictor of AKI in a heterogeneous adult ICU population. Plasma NGAL allows the diagnosis of AKI 48 h prior to a clinical diagnosis based on RIFLE criteria. Early identification of high-risk AKI in patients may allow earlier initiation of therapies and improve patient outcome.

Derivation and validation of plasma endostatin for predicting renal recovery from acute kidney injury: a prospective validation study

BACKGROUND

Acute kidney injury (AKI) is associated with high morbidity and mortality in surgical patients. Nonrecovery from AKI may increase mortality and early risk stratification seems key to improving clinical outcomes. The aim of the current study was to explore and validate the value of endostatin for predicting failure to recover from AKI.

METHODS

We conducted a prospective cohort study of 198 patients without known chronic kidney disease who underwent noncardiac major surgery and developed new-onset AKI in the first 48 h after admission to the ICU. The biomarkers of plasma endostatin, neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C were detected immediately after AKI diagnosis. The primary endpoint was nonrecovery from AKI (within 7 days). Cutoff values of the biomarkers for predicting nonrecovery were determined in a derivation cohort (105 AKI patients). Predictive accuracy was then analyzed in a validation cohort (93 AKI patients).

RESULTS

Seventy-six of 198 (38.4%) patients failed to recover from AKI onset, with 41 in the derivation cohort and 35 in the validation cohort. Compared with NGAL and cystatin C, endostatin showed a better prediction for nonrecovery, with an area under the receiver operating characteristic curve (AUC) of 0.776 (95% confidence interval (CI) 0.654-0.892, p < 0.001) and an optimal cutoff value of 63.7 ng/ml. The predictive ability for nonrecovery was greatly improved by the prediction model combining endostatin with clinical risk factors of Sequential Organ Failure Assessment (SOFA) score and AKI classification, with an AUC of 0.887 (95% CI 0.766-0.958, p < 0.001). The value of the endostatin-clinical risk prediction model was superior to the NGAL-clinical risk and cystatin C-clinical risk prediction models in predicting failure to recover from AKI, which was supported by net reclassification improvement and integrated discrimination improvement. Further, the endostatin-clinical risk prediction model achieved sensitivity and specificity of 94.6% (76.8-99.1) and 72.7% (57.2-85.0), respectively, when validated in the validation cohort.

CONCLUSION

Plasma endostatin shows a useful value for predicting failure to recover from AKI. The predictive ability can be greatly improved when endostatin is combined with the SOFA score and AKI classification.

Methods used to assess the performance of biomarkers for the diagnosis of acute kidney injury: a systematic review and meta-analysis

PURPOSE

Methods used to explore biomarkers for acute kidney injury (AKI) might have a major impact on the results and the use of these biomarkers. We evaluated the methods used to investigate biomarkers of AKI.

MATERIALS AND METHODS

A systematic review and meta-analysis were performed using a computerized search of the MEDLINE and the EMBASE databases (PROSPERO CRD42017059618). Articles reporting biomarker's performance to diagnose AKI were included. The outcome included a description of the methods used to assess the performance of biomarkers to diagnose AKI.

RESULTS

Among the 295 included studies, assessment of biomarkers was the primary endpoint in 284 with sample size calculation in only 8% of cases. Eighty-five percent of the studies summarized the performance of biomarkers with receiver operating characteristic (ROC) curves; however, 74 studies (25%) did not provide the threshold, sensibility or specificity. A total of 176 studies evaluated more than one biomarker, and only 25% combined biomarkers to increase diagnostic performance. We determined that the definition of AKI and study design impacted the diagnostic performance using uNGAL (urinary neutrophil gelatinase-associated lipocalin) as an example. Major publication bias was identified.

CONCLUSIONS

Most articles that reported biomarkers of AKI performance present methodological weaknesses. Basic rules should be provided to increase the quality of reporting in this area.

Is the mean platelet volume a predictive marker of a high in-hospital mortality of acute cardiorenal syndrome patients receiving continuous renal replacement therapy?

A high mean platelet volume (MPV) level has been demonstrated to predict poor clinical outcomes in patients with cardiovascular disease. However, the relationship between MPV and mortality in patients with acute cardiorenal syndrome (ACRS) is unknown. Therefore, we investigated the predictive value of MPV for in-hospital mortality of patients with ACRS who received continuous renal replacement therapy (CRRT) in this study.We retrospectively analyzed the demographics, etiology, severity of illness, prognosis, and risk factors of ACRS patients who underwent CRRT in our hospital from January 2009 to December 2014. Patients were classified into 2 groups based on the prognosis and timing of CRRT. The receiver operating characteristic curve was used to examine the performance of MPV in predicting in-hospital mortality. Baseline characteristics, clinical, and hematological parameters at CRRT initiation were compared between the 2 groups. Factors influencing in-hospital mortality were analyzed by univariate logistic regression analysis.The median age of patients was 74 years. Acute myocardial infarction was the most common cause of ACRS, followed by acute decompensated heart failure. The in-hospital mortality was 51.4%. Age, number of organ failure, APACHE II score, and MPV in the nonsurvivors were significantly higher than those in the survivors (P < .05). However, the cardiac function and mean arterial pressure were significantly lower in the nonsurvivors (P < .05). The prognosis of the early intervention group was better than the late-intervention group, but no significant difference was found (P > .05). The area under the curve (AUC) for in hospital mortality based on MPV was 0.735. Univariate analysis showed that age, cardiac function NYHA class, number of organ failure, APACHE II score, MAP, MPV, and use of vasopressors were associated with the prognosis of patients (P < .05).These findings suggest that the prognosis of patients with ACRS who received CRRT was poor, and MPV might be useful as a marker for predicting the in-hospital mortality of these patients.

Risk, Predictors, and Outcomes of Acute Kidney Injury in Patients Admitted to Intensive Care Units in Egypt

Epidemiology of acute kidney injury (AKI) in developing countries is under-studied. We evaluated the risk and prognosis of AKI in patients admitted to intensive care units (ICUs) in Egypt. We recruited consecutive adults admitted to ICUs in Alexandria Teaching Hospitals over six months. We used the KDIGO criteria for AKI. We followed participants until the earliest of ICU discharge, death, day 30 from entry or study end. Of the 532 participants (median age 45 (Interquartile range [IQR]: 30-62) years, 41.7% male, 23.7% diabetics), 39.6% had AKI at ICU admission and 37.4% developed AKI after 24 hours of ICU admission. Previous need of diuretics, sepsis and low education were associated with AKI at ICU admission; APACHE II score independently predicted AKI after ICU admission. A total of 120 (22.6%) patients died during 30-day follow-up. Compared to patients who remained AKI-free, mortality was significantly higher in patients who had AKI at study entry (Hazard Ratio [HR] 2.14; 95% Confidence Interval [CI] 1.02-4.48) or developed AKI in ICU (HR 2.74; 95% CI 1.45-5.17). The risk of AKI is high in critically ill people and predicts poor outcomes. Further studies are needed to estimate the burden of AKI among patients before ICU admission.

Routine adoption of TIMP2 and IGFBP7 biomarkers in cardiac surgery for early identification of acute kidney injury

Background and purpose

Acute Kidney Injury (AKI) is a severe complication affecting many hospitalized patients after cardiac surgery, with negative impacts on short- and long-term clinical outcomes and on healthcare costs. Recently, clinical interest has been aimed at defining and classifying AKI, identifying risk factors and developing diagnostic strategies to identify patients at risk early on. Achieving an early and accurate diagnosis of AKI is a crucial issue, because prevention and timely detection may help to prevent negative clinical outcomes and avoid AKI-associated costs. In this retrospective study, we evaluate the NephroCheck Test as a diagnostic tool for early detection of AKI in a high-risk population of patients undergoing cardiac surgery at the San Bortolo Hospital of Vicenza.

Methods

We assessed the ability of the NephroCheck Test to predict the probability of developing CSA-AKI (cardiac surgery-associated AKI) and evaluated its accuracy as a diagnostic test, by building a multivariate logistic regression model for CSA-AKI prediction.

Results

Based on our findings, when the results of the NephroCheck Test are included in a multivariate model its performance is substantially improved, as compared to the benchmark model, which only accounts for the other clinical factors. We also define a rule – in terms of a probability cut-off – for discriminating cases that are at higher risk of developing AKI of any stage versus those in which AKI is less likely.

Conclusions

Our study has implications in clinical practice: when a Nephrocheck Test result is >0.3 ng/dL, an automated electronic alert prompts the physician to intervene by following a checklist of preventive measures.

Management of Chronic Kidney Disease Patients in the Intensive Care Unit: Mixing Acute and Chronic Illness

Patients with chronic kidney disease (CKD) are at high risk for developing critical illness and for admission to intensive care units (ICU). 'Critically ill CKD patients' frequently develop an acute worsening of renal function (i.e. acute-on-chronic, AoC) that contributes to long-term kidney dysfunction, potentially leading to end-stage kidney disease (ESKD). An integrated multidisciplinary effort is thus necessary to adequately manage the multi-organ damage of those kidney patients and contemporaneously reduce the progression of kidney dysfunction when they are critically ill. The aim of this review is to describe (1) the pathophysiological mechanisms underlying the development of AoC kidney dysfunction and its role in the progression toward ESKD; (2) the most common clinical presentations of critical illness among CKD/ESKD patients; and (3) the continuum of care for CKD/ESKD patients from maintenance hemodialysis/peritoneal dialysis to acute renal replacement therapy performed in ICU and, vice-versa, for AoC patients who develop ESKD.

Early-phase cumulative hypotension duration and severe-stage progression in oliguric acute kidney injury with and without sepsis: an observational study

BACKGROUND

Managing blood pressure in patients with acute kidney injury (AKI) could effectively prevent severe-stage progression. However, the effect of hypotension duration in the early phase of AKI remains poorly understood. This study investigated the association between early-phase cumulative duration of hypotension below threshold mean arterial pressure (MAP) and severe-stage progression of oliguric AKI in critically ill patients, and assessed the difference in association with presence of sepsis.

METHODS

This was a single-center, observational study conducted in the ICU of a university hospital in Japan. We examined data from adults with oliguric AKI who were admitted to the ICU during 2010-2014 and stayed in the ICU for ≥24 h after diagnosis of stage-1 oliguric AKI defined in the Kidney Disease Improving Global Outcomes (KDIGO) guidelines. The primary outcome was the progression from stage-1 oliguric AKI to stage-3 oliguric AKI (progression to oligoanuria and use of renal replacement therapy) according to the KDIGO criteria. During the first 6 h after oliguric AKI, we analyzed the association between cumulative time the patient had below threshold MAP (65, 70, and 75 mm Hg) and progression to stage-3.

RESULTS

Among 538 patients with oliguric AKI, progression to stage-3 increased as the time spent below any threshold MAP was elongated. In the multivariable analysis of all patients, longer hypotension time (3-6 h) showed significant association with stage-3 progression for the time spent below MAP of 65 mm Hg (adjusted odds ratio (OR) 3.73, 95% confidence interval (CI) 1.53-9.09, p = 0.004), but the association was attenuated for the threshold MAP of 70 mm Hg (adjusted OR 2.35, 95% CI 0.96-5.78, p = 0.063) and 75 mm Hg (adjusted OR 1.92, 95% CI 0.72-5.15, p = 0.200). Longer hypotension time with the thresholds of 65 and 70 mm Hg was significantly associated with the risk of stage-3 progression in patients without sepsis, whereas the association was weak and not significant in patients with sepsis.

CONCLUSIONS

Even in a short time frame (6 h) after oliguric AKI diagnosis, early-phase cumulative hypotension duration was associated with progression to stage-3 oliguric AKI, especially in patients without sepsis.