Norepinephrine Administration Is Associated with Higher Mortality in Dialysis Requiring Acute Kidney Injury Patients with Septic Shock

Unsupervised clustering identifies sub-phenotypes and reveals novel outcome predictors in patients with dialysis-requiring sepsis-associated acute kidney injury

INTRODUCTION

Heterogeneity exists in sepsis-associated acute kidney injury (SA-AKI). This study aimed to perform unsupervised consensus clustering in critically ill patients with dialysis-requiring SA-AKI.

PATIENTS AND METHODS

This prospective observational cohort study included all septic patients, defined by the Sepsis-3 criteria, with dialysis-requiring SA-AKI in surgical intensive care units in Taiwan between 2009 and 2018. We employed unsupervised consensus clustering based on 23 clinical variables upon initializing renal replacement therapy. Multivariate-adjusted Cox regression models and Fine-Gray sub-distribution hazard models were built to test associations between cluster memberships with mortality and being free of dialysis at 90 days after hospital discharge, respectively.

RESULTS

Consensus clustering among 999 enrolled patients identified three sub-phenotypes characterized with distinct clinical manifestations upon renal replacement therapy initiation (n = 352, 396 and 251 in cluster 1, 2 and 3, respectively). They were followed for a median of 48 (interquartile range 9.5-128.5) days. Phenotypic cluster 1, featured by younger age, lower Charlson Comorbidity Index, higher baseline estimated glomerular filtration rate but with higher severity of acute illness was associated with an increased risk of death (adjusted hazard ratio of 3.05 [95% CI, 2.35-3.97]) and less probability to become free of dialysis (adjusted sub-distribution hazard ratio of 0.55 [95% CI, 0.38-0.8]) than cluster 3. By examining distinct features of the sub-phenotypes, we discovered that pre-dialysis hyperlactatemia ≥3.3 mmol/L was an independent outcome predictor. A clinical model developed to determine high-risk sub-phenotype 1 in this cohort (C-static 0.99) can identify a sub-phenotype with high in-hospital mortality risk (adjusted hazard ratio of 1.48 [95% CI, 1.25-1.74]) in another independent multi-centre SA-AKI cohort.

CONCLUSIONS

Our data-driven approach suggests sub-phenotypes with clinical relevance in dialysis-requiring SA-AKI and serves an outcome predictor. This strategy represents further development toward precision medicine in the definition of high-risk sub-phenotype in patients with SA-AKI.Key messagesUnsupervised consensus clustering can identify sub-phenotypes of patients with SA-AKI and provide a risk prediction.Examining the features of patient heterogeneity contributes to the discovery of serum lactate levels ≥ 3.3 mmol/L upon initializing RRT as an independent outcome predictor.This data-driven approach can be useful for prognostication and lead to a better understanding of therapeutic strategies in heterogeneous clinical syndromes.

Distinct Subtyping of Successful Weaning from Acute Kidney Injury Requiring Renal Replacement Therapy by Consensus Clustering in Critically Ill Patients

Background: Clinical decisions regarding the appropriate timing of weaning off renal replacement therapy (RRT) in critically ill patients are complex and multifactorial. The aim of the current study was to identify which critical patients with acute kidney injury (AKI) may be more likely to be successfully weaned off RRT using consensus cluster analysis. Methods: In this study, critically ill patients who received RRT at three multicenter referral hospitals at several timepoints from August 2016 to July 2018 were enrolled. An unsupervised consensus clustering algorithm was used to identify distinct phenotypes. The outcomes of interest were the ability to wean off RTT and 90-day mortality. Results: A total of 124 patients with AKI requiring RRT (AKI-RRT) were enrolled. The 90-day mortality rate was 30.7% (38/124), and 49.2% (61/124) of the patients were successfully weaned off RRT for over 90 days. The consensus clustering algorithm identified three clusters from a total of 45 features. The three clusters had distinct features and could be separated according to the combination of urinary neutrophil gelatinase-associated lipocalin to creatinine ratio (uNGAL/Cr), Sequential Organ Failure Assessment (SOFA) score, and estimated glomerular filtration rate at the time of weaning off RRT. uNGAL/Cr (hazard ratio [HR] 2.43, 95% confidence interval [CI]: 1.36–4.33) and clustering phenotype (cluster 1 vs. 3, HR 2.7, 95% CI: 1.11–6.57; cluster 2 vs. 3, HR 44.5, 95% CI: 11.92–166.39) could predict 90-day mortality or re-dialysis. Conclusions: Almost half of the critical patients with AKI-RRT could wean off dialysis for over 90 days. Urinary NGAL/Cr and distinct clustering phenotypes could predict 90-day mortality or re-dialysis.

The prognosis and risk factors for acute kidney injury in high-risk patients after surgery for type A aortic dissection in the ICU

Background

Acute kidney injury (AKI) is a major complication of cardiac surgery, with high rates of morbidity and mortality. The aim of this study was to identify risk factors for the incidence and prognosis of AKI in high-risk patients before and after surgery for acute type A aortic dissection (TAAD) in the intensive care unit (ICU).

Methods

We performed a retrospective cohort study from April 2018 to April 2019. The primary end points of this study were morbidity due to AKI and risk factors for incidence, and the secondary end points were mortality at 28 days and risk factors for death.

Results

We enrolled 60 patients, 52 (86.67%) patients developed postoperative AKI, 28 (53.84%) patients died. Preoperative lactic acid level (P=0.022) and cardiopulmonary bypass (CPB) duration (P=0.009) were identified as independent risk factors for postoperative AKI. The 28-day mortality for postoperative patients with TAAD was 46.67%, 53.84% for those with TAAD and AKI, 67.5% for those who required continue renal replacement therapy (CRRT). The risk factors for 28-day mortality due to postoperative AKI for patients requiring CRRT were CPB duration (P=0.019) and norepinephrine dose upon diagnosis of AKI (P=0.037).

Conclusions

Morbidity due to AKI in postoperative patients with TAAD was 86.67%, and preoperative lactic acid level and CPB duration were independent risk factors. The 28-day mortality of postoperative patients with TAAD was 46.67%, 53.84% for those with TAAD and AKI, and 67.5% for those requiring CRRT. CPB duration and norepinephrine dose upon diagnosis of AKI may influence patients’ short-term prognosis.

Blind spot in sepsis management - Tissue level changes in microcirculation

In sepsis cytokine-mediated inflammation, clotting cascade activation and glycocalyx shedding impair both function and structure of the microcirculation, compromising adequate tissue oxygenation/perfusion. Such mismatch results in "dysoxia", an imbalance in mitochondrial respiration.Microvessel injuries can be grouped into four types: cytotoxic oedema, micro-vessel heterogeneity, sluggish/absent flow, and focal anaemia. Recognition of such diversity in microcirculatory pathology, alongside with the implementation of novel biomarkers might reveal previously unobserved heterogeneity in adults diagnosed with sepsis. Early identification of distinct subtypes may help not only to better stratify disease severity but may also provide explanation to the often seen insufficient/absent response to resuscitative treatment. Experimental evidence suggests that impaired microcirculatory flow may correlate with organ dysfunction and mortality. Therefore, reliable/reproducible diagnostic tools, that provide real-time information about the dynamic state of the microcirculation, might be practice changers in managing the critically ill.The sublingual mucosa and the nailfolds provide easy access to microcirculation via hand-held, point-of-care devices. Accessing these windows, clinicians may recognise, understand and potentially correct the underlying tissue oxygenation/perfusion mismatch. This new clinical information might facilitate an individualised approach vs protocolised care aiming to administer the right balance of intravenous fluids/vasopressors, time/dose auxiliary treatment modalities and, most importantly, might also guide determining the optimal duration of resuscitation to avoid/minimise harm and maximise benefits in sepsis management. However, before every-day clinical use of such point-of-care microcameras, validation studies are needed to establish not only feasibility but reliability and reproducibility as well.

Determinants of Outcomes of Acute Kidney Injury: Clinical Predictors and Beyond

Acute kidney injury (AKI) is a common clinical syndrome characterized by rapid impairment of kidney function. The incidence of AKI and its severe form AKI requiring dialysis (AKI-D) has been increasing over the years. AKI etiology may be multifactorial and is substantially associated with increased morbidity and mortality. The outcome of AKI-D can vary from partial or complete recovery to transitioning to chronic kidney disease, end stage kidney disease, or even death. Predicting outcomes of patients with AKI is crucial as it may allow clinicians to guide policy regarding adequate management of this problem and offer the best long-term options to their patients in advance. In this manuscript, we will review the current evidence regarding the determinants of AKI outcomes, focusing on AKI-D.

Impact of Intraoperative Norepinephrine Support on Living Donor Liver Transplantation Outcomes: A Retrospective Cohort Study of 430 Children

Norepinephrine (NE) is often administered during the perioperative period of liver transplantation to address hemodynamic instability and to improve organ perfusion and oxygen supply. However, its role and safety profile have yet to be evaluated in pediatric living donor liver transplantation (LDLT). We hypothesized that intraoperative NE infusion might affect pediatric LDLT outcomes. A retrospective study of 430 pediatric patients (median [interquartile range] age, 7 [6.10] months; 189 [43.9%] female) receiving LDLT between 2014 and 2016 at Renji Hospital was conducted. We evaluated patient survival among recipients who received intraoperative NE infusion (NE group, 85 recipients) and those that did not (non-NE group, 345 recipients). The number of children aged over 24 months and weighing more than 10 kg in NE group was more than that in non-NE group. And children in NE group had longer operative time, longer anhepatic phase time and more fluid infusion. After multivariate regression analysis and propensity score regression adjusting for confounding factors to determine the influence of intraoperative NE infusion on patient survival, the NE group had a 169% more probability of dying. Although there was no difference in mean arterial pressure changes relative to the baseline between the two groups, we did observe increased heart rates in NE group compared with those of the non-NE group at anhepatic phase (P=0.025), neohepatic phase (P=0.012) and operation end phase (P=0.017) of the operation. In conclusion, intraoperative NE infusion was associated with a poorer prognosis for pediatric LDLT recipients. Therefore, we recommend the application of NE during pediatric LDLT should be carefully re-considered.

Association between regional economic status and renal recovery of dialysis-requiring acute kidney injury among critically ill patients

The association between regional economic status and the probability of renal recovery among patients with dialysis-requiring AKI (AKI-D) is unknown. The nationwide prospective multicenter study enrolled critically ill adult patients with AKI-D in four sampled months (October 2014, along with January, April, and July 2015) in Taiwan. The regional economic status was defined by annual disposable income per capita (ADIPC) of the cities the hospitals located. Among the 1,322 enrolled patients (67.1 ± 15.5 years, 36.2% female), 833 patients (63.1%) died, and 306 (23.1%) experienced renal recovery within 90 days following discharge. We categorized all patients into high (n = 992) and low economic status groups (n = 330) by the best cut-point of ADIPC determined by the generalized additive model plot. By using the Fine and Gray competing risk regression model with mortality as a competing risk factor, we found that the independent association between regional economic status and renal recovery persisted from model 1 (no adjustment), model 2 (adjustment to basic variables), to model 3 (adjustment to basic and clinical variables; subdistribution hazard ratio, 1.422; 95% confidence interval, 1.022–1.977; p = 0.037). In conclusion, high regional economic status was an independent factor for renal recovery among critically ill patients with AKI-D.

Markers of Poor Prognosis in Patients Requiring Continuous Renal Replacement Therapy After Cardiac Surgery

OBJECTIVE

Acute kidney injury requiring renal replacement therapy after cardiac surgery has an incidence of 2% to 15%, and mortality in affected patients approximates 50%. The authors aimed to study the determinants of poor prognosis in patients receiving continuous renal replacement therapy (CRRT) after cardiac surgery.

DESIGN

Retrospective, observational single-center study.

SETTING

Tertiary care, university hospital.

PARTICIPANTS

Cardiac surgery patients admitted to the intensive care unit (ICU) needing postoperative CRRT between January 1, 2010, and September 31, 2019.

INTERVENTIONS

Predictors of mortality were examined using groupwide comparisons between ICU survivors versus nonsurvivors and univariate and multivariate Cox proportional hazards models.

RESULTS

During the study period, 67 cardiac surgery patients without prior maintenance dialysis required CRRT postoperatively. ICU mortality was 47.7% and 90-day mortality was 58.2%. Only 37.3% of patients were alive at 1 year after surgery. Blood lactate at the start of dialysis was the most significant predictor of ICU and overall mortality. Eighty-seven percent of patients with lactate >3 mmol/L died in the ICU compared with 27.3% of patients with lactate ≤3 mmol/L (p < 0.0001). In patients with lactate exceeding 5.3 mmol/L, ICU mortality was 100%. In a stepwise multivariate Cox proportional hazards model, the association with mortality remained significant for lactate at the start of CRRT (per 1 mmol/L, hazard ratio [HR] 1.19 [95% confidence interval {CI} 1.11-1.28], p < 0.0001), troponin T on the first postoperative morning (per 0.1 µg/L, HR 1.004 [95% CI 1.001-1.008], p = 0.01), and 72-hour fluid balance (per 1000 mL, HR 1.12 [95% CI 1.04-1.21], p = 0.005).

CONCLUSION

Blood lactate at the start of dialysis was the most significant predictor of ICU and overall mortality in patients with CRRT after cardiac surgery.

Diagnostics, Risk Factors, Treatment and Outcomes of Acute Kidney Injury in a New Paradigm

Acute kidney injury (AKI) is a common clinical condition among patients admitted in the hospitals. The condition is associated with both increased short-term and long-term mortality. With the development of a standardized definition for AKI and the acknowledgment of the impact of AKI on patient outcomes, there has been increased recognition of AKI. Two advances from past decades, the usage of computer decision support and the discovery of AKI biomarkers, have the ability to advance the diagnostic method to and further management of AKI. The increasingly widespread use of electronic health records across hospitals has substantially increased the amount of data available to investigators and has shown promise in advancing AKI research. In addition, progress in the finding and validation of different forms of biomarkers of AKI within diversified clinical environments and has provided information and insight on testing, etiology and further prognosis of AKI, leading to future of precision and personalized approach to AKI management. In this this article, we discussed the changing paradigms in AKI: from mechanisms to diagnostics, risk factors, and management of AKI.

Acute Kidney Injury and Septic Shock-Defined by Updated Sepsis-3 Criteria in Critically Ill Patients

Sepsis is commonly associated with acute kidney injury (AKI), particularly in those requiring dialysis (AKI-D). To date, Sepsis-3 criteria have not been applied to AKI-D patients. We investigated sepsis prevalence defined by Sepsis-3 criteria and evaluated the outcomes of septic-associated AKI-D among critically ill patients. Using the data collected from a prospective multi-center observational study, we applied the Sepsis-3 criteria to critically ill AKI-D patients treated in intensive care units (ICUs) in 30 hospitals between September 2014 and December 2015. We described the prevalence, outcomes, and characteristics of sepsis as defined by the screening Sepsis-3 criteria among AKI-D patients, and compared the outcomes of AKI-D patients with or without sepsis using the Sepsis-3 criteria. A total of 1078 patients (median 70 years; 673 (62.4%) men) with AKI-D were analyzed. The main etiology of AKI was sepsis (71.43%) and the most frequent indication for acute dialysis was oliguria (64.4%). A total of 577 (53.3% of 1078 patients) met the Sepsis-3 criteria, and 206 among the 577 patients (19.1%) had septic shock. Having sepsis and septic shock were independently associated with 90-day mortality among these ICU AKI-D patients (hazard ratio (HR) 1.23 (p = 0.027) and 1.39 (p = 0.004), respectively). Taking mortality as a competing risk factor, AKI-D patients with septic shock had a significantly reduced chance of weaning from dialysis at 90 days than those without sepsis (HR 0.65, p = 0.026). The combination of the Sepsis-3 criteria with the AKI risk score led to better performance in forecasting 90-day mortality. Sepsis affects more than 50% of ICU AKI patients requiring dialysis, and one-fifth of these patients had septic shock. In AKI-D patients, coexistent with or induced by sepsis (as screened by the Sepsis-3 criteria), there is a significantly higher mortality and reduced chance of recovering sufficient renal function, when compared to those without sepsis.

Intraoperative Oliguria with Decreased SvO₂ Predicts Acute Kidney Injury after Living Donor Liver Transplantation

Acute kidney injury (AKI) is a frequent complication after living donor liver transplantation (LDLT), and is associated with increased mortality. However, the association between intraoperative oliguria and the risk of AKI remains uncertain for LDLT. We sought to determine the association between intraoperative oliguria alone and oliguria coupled with hemodynamic derangement and the risk of AKI after LDLT. We evaluated the hemodynamic variables, including mean arterial pressure, cardiac index, and mixed venous oxygen saturation (SvO₂). We reviewed 583 adult patients without baseline renal dysfunction and who did not receive hydroxyethyl starch during surgery. AKI was defined using the Kidney Disease Improving Global Outcomes criteria according to the serum creatinine criteria. Multivariable logistic regression analysis was performed with and without oliguria and oliguria coupled with a decrease in SvO₂. The performance was compared with respect to the area under the receiver operating characteristic curve (AUC). Intraoperative oliguria <0.5 and <0.3 mL/kg/h were significantly associated with the risk of AKI; however, their performance in predicting AKI was poor. The AUC of single predictors increased significantly when oliguria was combined with decreased SvO₂ (AUC 0.72; 95% confidence interval (CI) 0.68–0.75 vs. AUC of oliguria alone 0.61; 95% CI 0.56–0.61; p < 0.0001; vs. AUC of SvO₂ alone 0.66; 95% CI 0.61–0.70; p < 0.0001). Addition of oliguria coupled with SvO₂ reduction also increased the AUC of multivariable prediction (AUC 0.87; 95% CI 0.84–0.90 vs. AUC with oliguria 0.73; 95% CI 0.69–0.77; p < 0.0001; vs. AUC with neither oliguria nor SvO₂ reduction 0.68; 95% CI 0.64–0.72; p < 0.0001). Intraoperative oliguria coupled with a decrease in SvO₂ may suggest the risk of AKI after LDLT more reliably than oliguria alone or decrease in SvO₂ alone. Intraoperative oliguria should be interpreted in conjunction with SvO₂ to predict AKI in patients with normal preoperative renal function and who did not receive hydroxyethyl starch during surgery.