Acute Kidney Injury and Renal Replacement Therapy: A Review and Update for the Perioperative Physician

Post-operative acute kidney injury is a devastating complication with significant morbidity and mortality associated with it. The perioperative anesthesiologist is in a unique position to potentially mitigate the risk of postoperative AKI, however, understanding the pathophysiology, risk factors and preventative strategies is paramount. There are also certain clinical scenarios, where renal replacement therapy may be indicated intraoperatively including severe electrolyte abnormalities, metabolic acidosis and massive volume overload. A multidisciplinary approach including the nephrologist, critical care physician, surgeon and anesthesiologist is necessary to determine the optimal management of these critically ill patients.

The incidence and outcome of AKI in patients with sepsis in the emergency department applying different definitions of AKI and sepsis

BACKGROUND

Sepsis is often accompanied with acute kidney injury (AKI). The incidence of AKI in patients visiting the emergency department (ED) with sepsis according to the new SOFA criteria is not exactly known, because the definition of sepsis has changed and many definitions of AKI exist. Given the important consequences of early recognition of AKI in sepsis, our aim was to assess the epidemiology of sepsis-associated AKI using different AKI definitions (RIFLE, AKIN, AKIB, delta check, and KDIGO) for the different sepsis classifications (SIRS, qSOFA, and SOFA).

METHODS

We retrospectively enrolled patients with sepsis in the ED in three hospitals and applied different AKI definitions to determine the incidence of sepsis-associated AKI. In addition, the association between the different AKI definitions and persistent kidney injury, hospital length of stay, and 30-day mortality were evaluated.

RESULTS

In total, 2065 patients were included. The incidence of AKI was 17.7-51.1%, depending on sepsis and AKI definition. The highest incidence of AKI was found in qSOFA patients when the AKIN and KDIGO definitions were applied (51.1%). Applying the AKIN and KDIGO definitions in patients with sepsis according to the SOFA criteria, AKI was present in 37.3% of patients, and using the SIRS criteria, AKI was present in 25.4% of patients. Crude 30-day mortality, prolonged length of stay, and persistent kidney injury were comparable for patients diagnosed with AKI, regardless of the definition used.

CONCLUSION

The incidence of AKI in patients with sepsis is highly dependent on how patients with sepsis are categorised and how AKI is defined. When AKI (any definition) was already present at the ED, 30-day mortality was high (22.2%). The diagnosis of AKI in sepsis can be considered as a sign of severe disease and helps to identify patients at high risk of adverse outcome at an early stage.

The Effect of Different Colistin Dosing Regimens on Nephrotoxicity: A Cohort Study

(1) Background: It is not known whether different daily dosing schemes have different effects on colistin nephrotoxicity. We examined the effect of once- versus twice- or thrice-daily doses of colistin on renal function. (2) Methods: We performed a multicenter retrospective cohort study of hospitalized patients with a baseline glomerular filtration rate ≥ 50 mL/min who received intravenously the same colistin dose once (regimen A), twice (regimen B) or thrice daily (regimen C). The primary endpoint was acute kidney injury (AKI), defined as fulfilment of any of the RIFLE (Risk-Injury-Failure-Loss-End stage renal disease) criteria. (3) Results: We included 306 patients; 132 (43.1%) received regimen A, 151 (49.3%) regimen B, and 23 (7.5%) regimen C. Ninety-nine (32.4%) patients developed AKI; there was no difference between regimen A vs. B and C [45 (34.1%) vs. 54 (31.0%), p = 0.57]. In a propensity score−matched cohort, AKI was similar in patients receiving Regimen A, Regimen B, and Regimen C (31.6% vs. 33.3%, p = 0.78). On logistic regression analysis, diabetes was an independent predictor of AKI (OR = 4.59, 95% CI 2.03−10.39, p = 0.001) while eGFR > 80 mL/min (OR = 0.50, 95% CI 0.25−0.99, p = 0.048) was inversely associated with AKI. (4) Conclusions: Colistin once daily is not more nephrotoxic than the standard colistin regimens. The only independent predictor of nephrotoxicity was diabetes mellitus, while eGFR > 80 mL/min had a protective effect.

Insights into early postoperative acute kidney injury following lung transplantation

BACKGROUND

Acute kidney injury (AKI) is a common complication after lung transplantation (LT) and is associated with higher cost and mortality. We sought to evaluate the incidence of postoperative AKI, defined as AKI within 14 days of transplant, and identify associated perioperative factors.

METHODS

We conducted a single-center, retrospective review of 153 lung transplant recipients. Postoperative AKI was determined using the RIFLE (Risk, Injury, Failure, Loss, End Stage) criteria. Perioperative covariates and their association with postoperative AKI were analyzed using Cox proportional hazards. Kaplan-Meier survival curves were constructed to evaluate patient survival at one year and data finalization. A subanalysis was performed evaluating factors associated with early AKI (within 48 hours of transplant) and late AKI.

RESULTS

Postoperative AKI occurred in 36.6% of patients with 51.8% of cases occurring within 48 hours of LT. Recipient race, transplant type, cardiopulmonary support, and red blood cell administration were associated with postoperative AKI. Survival was significantly lower in patients with postoperative AKI following LT.

CONCLUSIONS

Postoperative AKI within 2 weeks of lung transplant is associated with lower short- and long-term survival. Perioperative factors associated with postoperative AKI may be potential points of intervention to minimize AKI development in the future. This article is protected by copyright. All rights reserved.

Rifle Criteria For Acute Kidney Injury In Burn Patients: Prevalence And Risk Factors

Acute kidney injury is one of the severe complications after burns. The purpose of this study was to identify prevalence, risk factors to the development of acute kidney injury (AKI) in burn patients and mortality, using RIFLE classification: risk (R), injury (I), failure (F), loss (L), and end-stage kidney disease (E). This 3-year retrospective study was conducted in burn patients admitted to the Dr. Soetomo Hospital Burn Center between January 2018 and September 2020. Burn patients aged >18 years old and diagnosed with acute kidney injury during hospitalization were enrolled in this study. Factors influencing AKI and its mortality were assessed using bivariate and multivariate logistic regression analysis. Eighty-nine burn patients were available for analysis, and 18 (20%) of them developed AKI according to the RIFLE classification: risk in 6 (33%), injury in 7 (39%) and failure in 5 (28%). Patients with AKI had a significantly higher age and % of TBSA than those without AKI (p-value <0.05). Age more than 60 years old was significantly associated as a risk factor to develop AKI (OR=25.553, p value=0.014). The mortality rate of patients with AKI was 83% (15 deaths from 18 patients), with the overall mortality of patients 16.8%. Chi-square analysis indicated inhalation injury, % of TBSA, and age as risk factors for mortality (p-value < 0.05). The conclusion of our study was that the incidence of AKI in burn patients was relatively high. Older age as a risk factor to develop AKI and inhalation injury, TBSA, and age were associated with mortality.

Evaluation of renal effects of liposomal amphotericin B in children with malignancies with KDIGO and RIFLE criteria

BACKGROUND

Amphotericin B is a broad-spectrum antifungal agent and is the backbone of the treatment for medically important opportunistic fungal pathogens in children. This study aimed to compare the nephrotoxicity associated with L-AmB in children with acute lymphoblastic leukemia and acute myeloid leukemia.

MATERIALS AND METHODS

A total of 112 pediatric acute lymphoblastic leukemia or acute myeloid leukemia patients who received treatment with L-AmB (Ambisome®) at the University of Health Sciences Dr Behcet Uz Children's Hospital over 7 years were included. The incidence of hypokalemia, decreased estimated glomerular filtration rate and presence of acute kidney injury was recorded.

RESULTS

The average L-AmB treatment duration was 17.1±15.0 days. Five patients (4.4%) of the patients had grade I acute renal injury according to KDIGO criteria and 16 patients (14.2%) had increased risk for kidney injury according to RIFLE criteria. There were no patients with eGFR decrease above 50% and no renal injury and failure were observed during L-AmB treatment. The rate of patients with hypokalemia in the pre-treatment was 17.9% and the post-L-AmB group was 50.0%. The rate of hypokalemia was higher in the post-treatment group (P=0.0015). Among the 112 patients, only two patients (1.7%) required cessation of L-AmB treatment due to resistant hypokalemia despite supplementation.

CONCLUSIONS

Hypokalemia was more common compared to glomerulotoxicity and acute renal injury (according to KDIGO and RIFLE criteria) in pediatric leukemia patients treated with L-AmB. Hypokalemia developed in nearly half of the patients and the study shows the need for randomized controlled trials and strategies for hypokalemia associated with L-AmB treatment.

Acute renal disease in patients with ovarian peritoneal carcinomatosis treated with cytoreduction and HIPEC: the influence of surgery and the cytostatic agent used

BACKGROUND

The main objective of this study was to evaluate the differences between cisplatin and paclitaxel in the development of postoperative renal toxicity, using as a reference the RIFLE (Risk, Injury, Insufficiency, Loss, and End-stage renal function) and AKIN (Acute Kidney Injury Network) criteria in patients with primary or recurrent ovarian cancer with peritoneal dissemination treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

One hundred fifty-two patients who were treated between December 2007 and June 2017 were analyzed.

RESULTS

Patients who received previous platinum-based chemotherapy had higher baseline creatinine levels than those who had not (p = 0.05). A total of 11 (7.2%) and 4 (2.6%) patients developed an acute renal dysfunction (ARD) during the postoperative period of cytoreduction and HIPEC according to the RIFLE and AKI criteria respectively. RIFLE detects a higher rate of ARD due to different parameters such as GFR (7.2% versus 2.6%, p = 0.016). Performing ostomy (p = 0.007; OR: 39.320; 95% CI = 2.74-56.13) and using of cisplatin during HIPEC treatment (p = 0.017; OR = 13.619; 95% IC = 1.600-25.95) were factors independently related to a higher rate of ARD.

CONCLUSION

ARD has a multifactorial origin. Cisplatin was associated with the development of a higher rate of ARD than paclitaxel. Diagnosis of ARD did not correlate with worse survival figures.

Relationship between acute kidney injury and mortality in poisoning - a systematic review and metanalysis

RATIONALE

Three consensus classifications of acute kidney injury have been published. These are RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease published by the Acute Dialysis Quality Initiative workgroup), AKIN (published by the Acute Kidney Injury Network) and KDIGO (published by the Kidney Disease Improving Global Outcome workgroup). Acute kidney injury has been reported consistently as associated with worsened outcomes. However, toxicant-related acute kidney injury has been excluded from the studies used to validate the classifications of acute kidney injury.

OBJECTIVE

To study whether poisoned patients who develop acute kidney injury, as defined by consensus definitions/classifications, have higher mortality compared to those who did not.

METHODS

Databases were searched from 2004 to 2019 using the following keywords (KDIGO OR "Kidney Disease: Improving Global Outcomes" OR "Kidney Disease Improving Global Outcomes" OR AKIN OR "AKI network" OR "Acute kidney Injury Network" OR ADQI OR RIFLE OR "Acute dialysis quality initiative") AND (intoxication OR poisoning OR overdose OR ingestion) AND (AKI OR kidney OR renal OR ARF). If data were available, we used a random-effects meta-analysis model and Fisher's exact test to compare mortality in patients according to kidney function definitions (acute kidney injury vs not) and stages (stages vs no acute kidney injury), respectively. If data were available, we assessed the correlation between mortality and renal function (no acute kidney injury, risk/stage 1, injury/stage 2 and failure/stage 3) using the Spearman correlation. If available, we collected the results of statistical analyses in studies that have used acute kidney injury to predict mortality.

RESULTS

Study selection. Thirty-three relevant studies were found, 22/33 retrospective studies (67%) and 11/33 prospective studies (33%). Paraquat was the most frequent toxicant involved (13/33, 39%). We found a disparity between studies regarding the timeframe during which mortality was assessed, the temporality of the renal function considered to predict mortality (initial/worst) and the criteria used to define/grade acute kidney injury across studies. Univariate association between acute kidney injury definitions/stages and mortality. Consensus definitions/staging of acute kidney injury were associated with higher mortality, using univariate analyses, in twenty-eight (RIFLE = 7; AKIN = 12; KDIGO = 9) studies included but not in five (AKIN = 4, KDIGO = 1). When available data were pooled, RIFLE (5 studies), AKIN (16 studies) and KDIGO definitions (8 studies) of acute kidney injury were associated with a higher mortality (Log unadjusted Odds ratios [95%-confidence interval], 2.60 [2.23; 2.97], 2.02 [1.48; 2,52] and 3.22 [2,65; 3.78], respectively). However, we found high heterogeneity (I²=54,7%) and publication bias among studies using AKIN. In ten studies with available data, the correlation between renal function (no acute kidney injury, risk/stage 1, injury/stage 2, failure/stage 3) and mortality was significant in 5 studies (RIFLE = 2; AKIN = 3), but not in five studies (RIFLE = 1; AKIN = 3; KDIGO = 1).Multivariate association between acute kidney injury definitions/stages and mortality. The definitions of acute kidney injury were associated with higher mortality in two studies (RIFLE = 2), but not in four studies (AKIN = 1 and KDIGO = 3. The stages of acute kidney injury (including one or more stages) were associated with higher mortality in four (RIFLE = 1, AKIN = 1 and KDIGO = 2).

CONCLUSIONS

All three consensus definitions/classifications were associated independently with increased mortality in poisoning but with disparity between studies reporting acute kidney injury.

Association between acute kidney injury and mortality after successful cardiopulmonary resuscitation: a retrospective observational study

BACKGROUND AND OBJECTIVES

Acute Kidney Injury (AKI) affect mortality and morbidity in critically ill patients. There have been few studies examining the prevalence of AKI and mortality after successful cardiopulmonary resuscitation. In the present study, we investigated the association between AKI and mortality in post-cardiac arrest patients admitted to the Intensive Care Unit (ICU).

METHODS

Our retrospective analysis included 109 patients, admitted to the ICU following successful cardiopulmonary resuscitation between 2014 and 2016. We compared two scoring systems to estimate mortality.

RESULTS AND DISCUSSION

AKI were diagnosed in 46.7% (n = 51) of the patients based on the RIFLE criteria and 66.1% (n = 72) using the KDIGO. Mortality rate was significantly higher among patients with AKI diagnosed according to the RIFLE criteria (p = 0.012) and those with AKI diagnosed using KDIGO criteria (p = 0.003). Receiver Operating Characteristic (ROC) analysis showed that both scoring systems were able to successfully detect mortality (Area under the ROC curve = 0.693 for RIFLE and 0.731 for KDIGO).

CONCLUSION

AKI increases mortality and morbidity rates after cardiac arrest. Although more renal injury and mortality were detected with KDIGO, the sensitivity and specificity of both scoring systems were similar in predicting mortality in patients with Return of Spontaneous Circulation (ROSC).

Polymyxin-induced nephrotoxicity and its predictors: a systematic review and meta-analysis of studies conducted using RIFLE criteria of acute kidney injury

Polymyxins are last-resort antibiotics re-emerged to treat infections caused by multidrug resistant (MDR) and extensively drug-resistant (XDR) Gram-negative bacterial infections. However, polymyxin-associated nephrotoxicity has become the main safety concern. Therefore, we conducted this systematic review and meta-analysis on polymyxin-induced nephrotoxicity and its predictors using studies conducted based on the validated RIFLE (Risk, Injury, Failure, Loss of Function and End-stage renal disease) criteria of acute kidney damage. Literature search was carried out through visiting legitimate databases and indexing services including PubMed, MEDLINE (Ovid®), EMBASE (Ovid®), and Scopus to retrieve relevant studies. Following screening and eligibility evaluation, relevant data were extracted from included studies and analyzed using STATA 15.0 and Rev-Man 5.3. Inverse variance method with random effects pooling model was used for the analysis of outcome measures at 95% confidence interval. Besides, meta-regression, meta-influence, and publication bias analyses were conducted. A total of 48 studies involving 6,199 adult patients aged ≥ 18 years were included for systematic review and meta-analysis. The pooled incidence of polymyxin-induced nephrotoxicity was found to be 45% (95% CI: 41- 49%; I² = 92.52%). Stratifying with RIFLE severity scales, pooled estimates of polymyxin-treated patients identified as 'risk', 'injury' and 'failure' were 17% (95% CI: 14-20%), 13% (95% CI: 11-15%), and 10% (95% CI: 9-11%), respectively. Besides, the pooled incidence of colistin-induced nephrotoxicity was about 48% (95% CI: 42-54%), whereas that of polymyxin B was 38% (95% CI: 32-44%). Likewise, colistin had 37% increased risk of developing nephrotoxicity compared to the polymyxin B treated cohorts (RR = 1.37, 95% CI: 1.13-1.67; I² = 57%). Older age (AOR = 1.03, 95% CI: 1.01-1.05), daily dose (AOR = 1.46, 95% CI: 1.09-1.96), underlying diabetes mellitus (AOR = 1.81, 95% CI: 1.25-2.63), and concomitant nephrotoxic drugs (AOR = 2.31, 95% CI: 1.79-3.00) were independent risk factors for polymyxin-induced nephrotoxicity. Patients with high serum albumin level were less likely (AOR = 0.69, 95% CI: 0.56-0.85] to experience nephrotoxicity compared to those with low albumin level. Despite the resurgence of these antibiotics for the chemotherapy of MDR/XDR-Gram-negative superbugs, the high incidence of nephrotoxicity has become a contemporary clinical concern. Being elderly, high daily dose, having underlying diseases such as diabetes, and use of concomitant nephrotoxic drugs were independent predictors of nephrotoxicity. Therefore, therapeutic drug monitoring should be done to these patients to outweigh the potential benefits of polymyxin therapy from its risk.

Utilizing the Patient Care Process to Minimize the Risk of Vancomycin-Associated Nephrotoxicity

Vancomycin-associated acute kidney injury (AKI) is a popular topic in the medical literature with few clear answers. While many studies evaluate the risk of AKI associated with vancomycin, few data are high quality and/or long in duration of follow-up. This review takes the clinician through an approach to evaluate a patient for risk of AKI. This evaluation should include patient assessment, antibiotic prescription, duration, and monitoring. Patient assessment involves evaluating severity of illness, baseline renal function, hypotension/vasopressor use, and concomitant nephrotoxins. Evaluation of antibiotic prescription includes evaluating the need for methicillin-resistant Staphylococcus aureus (MRSA) coverage and/or vancomycin use. Duration of therapy has been shown to increase the risk of AKI. Efforts to de-escalate vancomycin from the antimicrobial regimen, including MRSA nasal swabs and rapid diagnostics, should be used to lessen the likelihood of AKI. Adequate monitoring includes therapeutic drug monitoring, ongoing fluid status evaluations, and a continual reassessment of AKI risk. The issues with serum creatinine make the timely evaluation of renal function and diagnosis of the cause of AKI problematic. Most notably, concomitant piperacillin-tazobactam can increase serum creatinine via tubular secretion, resulting in higher rates of AKI being reported. The few studies evaluating the long-term prognosis of AKI in patients receiving vancomycin have found that few patients require renal replacement therapy and that the long-term risk of death is unaffected for patients surviving after the initial 28-day period.

The impact of comorbidities, sex and age on the occurrence of acute kidney injury among patients undergoing nephron-sparing surgery

Background

The aim of this study was to report the impact of patients' baseline characteristics on the incidence of acute kidney injury (AKI) after nephron-sparing surgery (NSS) for localized kidney cancer.

Patients and methods

Data from our kidney cancer database were retrospectively extracted to include 402 patients who underwent NSS between March 2000 and June 2016, and had sufficient data. Definition of AKI was based on the postoperative serum creatinine levels and estimated glomerular filtration rate (eGFR) magnitude, which were measured during the 72 h after surgery.

Results

Based on RIFLE and AKIN criteria, the overall rate of postoperative AKI was 35%. The average decrease in eGFR among patients who developed AKI was 20% as compared with the non-AKI subgroup (2%). In univariate analysis, variables that were associated with AKI included right-sided tumors (p = 0.014), male sex (p = 0.01), hypertension (p = 0.003), baseline eGFR (p = 0.009) and history of nephrolithiasis (p = 0.039). However, multivariate analysis revealed that the only independent predictors of postoperative AKI were hypertension (p = 0.009) and cigarette smoking (p = 0.024).

Conclusion

AKI is a common complication of NSS affecting about one-third of the patients. The most important risk factors are hypertension and smoking.

Comparison of RIFLE, AKIN, and KDIGO classifications for assessing prognosis of patients on extracorporeal membrane oxygenation

BACKGROUND/PURPOSE

Acute kidney injury (AKI) developing during extracorporeal membrane oxygenation (ECMO) is associated with very poor outcome. The Kidney Disease: Improving Global Outcomes (KDIGO) group published a new AKI definition in 2012. This study analyzed the outcomes of patients treated with ECMO and identified the relationship between the prognosis and the KDIGO classification.

METHODS

This study examined total 312 patients initially, and finally reviewed the medical records of 167 patients on ECMO support at a tertiary care university hospital between March 2002 and November 2011. Demographic, clinical, and laboratory variables were retrospectively collected as survival predicators.

RESULTS

The overall mortality rate was 55.7%. In the analysis of the areas under the receiver operating characteristic curves, the KDIGO classification showed relatively higher discriminatory power (0.840 ± 0.032) than the Risk of renal failure, Injury to the kidney, Failure of kidney function, Loss of kidney function, and End-stage renal failure (RIFLE) (0.826 ± 0.033) and Acute Kidney Injury Network (AKIN) (0.836 ± 0.032) criteria in predicting in-hospital mortality. Furthermore, multiple logistic regression analysis showed that KDIGO, hemoglobin, and Glasgow Coma Scale score on the first day of patients on ECMO were independent predictors for in-hospital mortality. Finally, cumulative survival rates at 6-month follow-up after hospital discharge differed significantly for KDIGO stage 3 versus KDIGO stage 0, 1, and 2 (p < 0.001); and KDIGO stage 2 versus KDIGO stage 0 (p < 0.05).

CONCLUSION

For those patients with ECMO support, the KDIGO classification proved to be a more reproducible evaluation tool with excellent prognostic abilities than RIFLE or AKIN classification.

Retrospective Cohort Analysis of Liposomal Amphotericin B Nephrotoxicity in Patients with Hematological Malignancies

We retrospectively examined the incidence, onset, risk factors, and outcomes of renal injury during 103 treatment courses of liposomal amphotericin B (L-AMB) in 97 adult patients with hematological malignancies. All the patients were analyzed before, during, and after the administration of L-AMB, and renal injury was graded according to the RIFLE criteria (risk, injury, failure, loss of function, end-stage renal disease). Most patients (87.3%) received L-AMB at 3 mg/kg of body weight/day. Nearly two-thirds (61.7%) of the treatment courses did not meet any RIFLE category for renal injury, while 19.4% of patients were classified at risk, 13.6% met an injury classification, and 5.8% were categorized as developing renal failure. However, 15% of the patients developed renal injury within 48 h of the onset of multiorgan failure associated with sepsis, bleeding, or progressing malignancy. When these patients were analyzed as a competing risk for L-AMB-associated renal injury (RIFLE category I or above) in a multivariate Cox regression model, receipt of cyclosporine (subhazard ratio [SHR], 2.62; 95% confidence interval [CI], 1.10 to 6.27; P = 0.03), cyclosporine plus furosemide at ≥40 mg/day (SHR, 5.46; 95% CI, 1.89 to 15.74; P = 0.002), or cyclosporine plus foscarnet (SHR, 9.03; 95% CI, 3.68 to 22.14; P < 0.0001) were the only comedications significantly associated with increased rates of renal injury. The cumulative incidence of L-AMB renal injury during the first 10 days of therapy was 7% overall but only 3% in patients who were not receiving cyclosporine. Hence, the renal risk of L-AMB therapy may be lessened if patients are switched to alternative agents after 7 to 10 days or if aggressive diuresis and/or foscarnet is avoided, especially among patients receiving calcineurin inhibitors.

Evaluation of acute kidney injury (AKI) with RIFLE, AKIN, CK, and KDIGO in critically ill trauma patients

PURPOSE

The aim of our study was to evaluate the effects of AKI development on mortality with four different classification systems (RIFLE, AKIN, CK, KDIGO) in critically ill trauma patients followed in the intensive care unit.

METHODS

A retrospective review of 2034 patients in our intensive care unit was conducted between July 2010 and August 2013. A total of 198 patients with primary trauma were included in the study to evaluate the development of AKI.

RESULTS

When the presence of AKI was investigated according to the four criteria (RIFLE, AKIN, CK, and KDIGO), the highest incidence of AKI was found according to the KDIGO classification (74.2%), followed by AKIN (72.2%), RIFLE (69.7%), and CK (59.1%). It was observed that more AKI developed according to KDIGO in patients with multiple trauma and thoracic trauma (p = 0.031, p = 0.029). Sixty-two (31%) of the 198 trauma patients monitored in the intensive care unit died; mortality was frequently found high in AKI stage 2 and 3 patients. According to the CK classification, there was a significant increase in mortality in patients with AKI on the first day (p = 0.045). AKI classifications by RIFLE, AKIN, CK, and KDIGO were independently associated with the risk of in-hospital death.

CONCLUSION

In this study, the presence of AKI was found to be an independent risk factor in the development of in-hospital mortality according to all classification systems (RIFLE, AKIN, CK, and KDIGO) in critically traumatic patients followed in ICU, and the compatibility between RIFLE, AKIN, and KDIGO was the highest among the classification systems.

Good tolerability of high dose colistin-based therapy in patients with haematological malignancies

PURPOSE

Colistin is usually the only drug fully active against multi-drug resistant Gram-negative bacteria, but its nephrotoxicity might limit its use. Recent pharmacokinetic/pharmacodynamic data suggest that high dose of colistin, preceded by a loading dose, are needed to maximize its antibacterial effect. The aim of this study was to determine the safety of high doses colistin, in haematology population.

METHODS

A retrospective review of haematology patients who received high dose colistin-based therapy in years 2011-2016 was performed. Nephrotoxicity was assessed using RIFLE criteria.

RESULTS

Thirty patients who received 38 courses of colistin were included in the study. Colistin was always administered together with other antibiotics. Colistin was well tolerated, with one case of neurological toxicity and one of cutaneous reaction. There were 22 (58%) treatment cycles without any nephrotoxicity, even though during 16 of these cycles other nephrotoxic drugs were administered. Severe (injury or failure) renal toxicity occurred during 6 (16%) treatment courses, requiring colistin discontinuation in 2 patients and colistin dose reduction in 1. Poorer renal function at baseline and younger age were the only variables associated with increased renal toxicity (p = 0.011 and p = 0.031, respectively). Overall mortality was 18% (7/38) and 29% (11/38) at 7 and 30 days after the treatment onset.

CONCLUSIONS

In adult haematology population, high dose colistin therapy is safe and efficacious, despite high frequency of concomitant nephrotoxic treatment.

Incidence, risk factors and clinical outcomes of acute kidney injury associated with scrub typhus: a retrospective study of 510 consecutive patients in South Korea (2001-2013)

OBJECTIVES

Renal involvement in scrub typhus ranges from simple urinary abnormalities to acute kidney injury (AKI) leading to death. This study evaluated the incidence, predictors and prognosis of AKI associated with scrub typhus according to the RIFLE (risk, injury, failure, loss, end-stage kidney disease) criteria.

METHODS

We retrospectively evaluated the medical records of patients diagnosed with scrub typhus from January 2001 to November 2013 in Gyeongsang National University Hospital.

RESULTS

During the study period, 510 patients were diagnosed with scrub typhus and the incidence of AKI was 35.9%. There were 132 (25.9%) patients at risk, 37 (7.3%) with injury and 14 (2.7%) with failure. In comparison with the non-AKI group, the AKI group was older (73.9 vs 63.4 years, p<0.001) and had more comorbidities such as hypertension, diabetes mellitus and chronic kidney disease (CKD). AKI frequently occurs in hypertensive patients taking angiotensin receptor blockers or ACE inhibitors (p=0.002), and in patients with diabetes with higher glycated haemoglobin levels (p=0.033). Haematuria and proteinuria were more frequent in the AKI group. There was no relationship between the severity of proteinuria and occurrence of AKI. Intensive care unit admission and death were more frequent in the AKI group. The renal function of most patients with AKI recovered without sequelae, except for 1 patient who had underlying CKD. Multivariate analysis showed that age, presence of CKD, serum albumin level and time to hospital presentation after symptom onset were independent predictors of AKI in patients with scrub typhus.

CONCLUSIONS

Our current results suggest that the presence of underlying CKD, older age, lower serum albumin level and time to hospital presentation after symptom onset were important risk factors to determine occurrence of AKI. Whether earlier diagnosis and treatment in patients with the above risk factors reduce the incidence and severity of AKI deserves to be investigated.

Pregnancy-related acute kidney injury: An analysis of 165 cases

Pregnancy-related acute kidney injury (PRAKI) contributes to 3–7% of overall acute kidney injury (AKI) cases in Indian subcontinent. The aim of this study was to determine the outcomes of PRAKI and risk factors associated with renal injury and maternal mortality. One hundred and sixty-five patients with PRAKI, seen at M. S. Ramaiah Medical College between 2005 and 2014, were included in this, observational study. AKI was analyzed in terms of maximal stage of renal injury attained as per Risk, Injury, Failure, Loss of function, and End-stage renal disease (RIFLE) criteria. Outcomes included requirement for renal replacement therapy (RRT), maternal, and fetal mortality. Incidence of PRAKI was 1.56%, and the mean age of the study population was 25 years. Fifty percent of the patients were diagnosed with PRAKI during their first pregnancy. PRAKI was observed most commonly in the postpartum period (60%), followed by third trimester (32%); as per RIFLE criteria, failure was seen in 36% and injury in 34%. Thirty percent of cases required RRT. Sepsis (59%), pre-eclampsia, and eclampsia (56%) were the leading causes of PRAKI, while sepsis was the leading cause of maternal mortality. Maternal and fetal mortality were 20% and 22%, respectively. In univariate analysis, shock, hemorrhage requiring transfusion of >5 units packed red blood cells, oliguria, and “Loss” category of RIFLE were significantly associated with mortality. Majority of the patients (57%) required Intensive Care Unit care with a mean duration of admission at 7.3 days, and 75% was diagnosed with AKI at the time of admission. We report the lowest incidence of PRAKI in contemporary Indian literature. PRAKI was associated with high maternal and fetal mortality, with sepsis being the leading cause. No association was noted between mortality and initial stages of RIFLE criteria.

Predictive value of the RIFLE urine output criteria on contrast-induced nephropathy in critically ill patients

Background

To investigate the predictive value of decreased urine output based on the Risk of renal dysfunction, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal disease (RIFLE) classification on contrast- induced acute kidney injury (CA-AKI) in intensive care (ICU) patients.

Methods

All patients who received contrast media (CM) injection for CT scan or coronary angiography during a 3-year period in a 24 bed medico-surgical ICU were reviewed.

Results

Daily serum creatinine concentrations and diuresis were measured for 3 days after CM injection. We identified 23 cases of CA-AKI in the 149 patients included (15.4 %). Patients who developed CA-AKI were more likely to require renal replacement therapy and had higher ICU mortality rates. At least one RIFLE urine output criteria was observed in 45 patients (30.2 %) and 14 of these 45 patients (31.1 %) developed CA-AKI based on creatinine concentrations. In 30 % of these cases, urine output decreased or didn’t change after the increase in creatinine concentrations. The RIFLE urine output criteria had low sensitivity (39.1 %) and specificity (67.9 %) for prediction of CA-AKI, a low positive predictive value of 50 % and a negative predictive value of 87.2 %. The maximal dose of vasopressors before CM was the only independent predictive factor for CA-AKI.

Conclusions

CA-AKI is a frequent pathology observed in ICU patients and is associated with increased need for renal replacement therapy and increased mortality. The predictive value of RIFLE urine output criteria for the development of CA-AKI based on creatinine concentrations was low, which limits its use for assessing the effects of therapeutic interventions on the development and progression of AKI.

"Assessment of RIFLE and AKIN criteria to define acute renal dysfunction for HIPEC procedures for ovarian and non ovarian peritoneal malignances"

BACKGROUND

The acute renal dysfunction (ARD) is a common complication in cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). Our aim is evaluate the ARD post-HIPEC procedures using the RIFLE and AKIN criteria. Evaluate the risk factors and analyze ARD's impact on postoperative course.

METHODS

From 2011 to 2014, in a retrospective way using a prospective database were operated by HIPEC procedure. The ARD was analyzed by RIFLE and AKIN criteria. The perioperative features were analyzed and a multivariate analysis was performed to define the risk factors to develop the ARD.

RESULTS

141 patients were treated and analyzed. The ARD was detected in 30.5% (Injury 18.4% and Failure 12.1%) when RIFLE criteria were applied. The multivariate analysis detected that decrease of pH during HIPEC [OR = 29.39 (5.09-169.76)], PCI [OR = 1.07 (1.01-1.15)] and ureteral catheters [OR = 12.71 (1.44-111.85)] were associated to the development of acute renal injury (ARI) post-HIPEC. Decrease of Na during HIPEC [OR = 1.15 (1.01-1.30)], intraoperative inotrope use [OR = 3.83 (1.12-13.09)] and PCI [OR = 1.06 (1.0-1.14)] were associated to acute renal failure (ARF) post-HIPEC. The ARD was related to a higher length of stay hospital (17.2 ± 11 vs. 13.8 ± 8 days) (p = 0.05) but no impact in early survival was observed in ARD group.

CONCLUSIONS

The widespread use of RIFLE criteria for ARD would have major benefits in terms of accurately diagnosing patients undergone HIPEC procedures. The ARD has a detrimental impact in length of stay hospital. The knowledge of risk factors helps us to prevent the ARD post-HIPEC by means of an aggressive and multidisciplinary perioperative management.

The Risk Factors and Outcomes of Acute Kidney Injury after Thoracic Endovascular Aortic Repair

Background

We aimed to evaluate the incidence, predictive factors, and impact of acute kidney injury (AKI) after thoracic endovascular aortic repair (TEVAR).

Methods

A total of 53 patients who underwent 57 TEVAR operations between 2008 and 2015 were reviewed for the incidence of AKI as defined by the RIFLE (risk, injury, failure, loss, and end-stage kidney disease risk) consensus criteria. The estimated glomerular filtration rate was determined in the perioperative period. Comorbidities and postoperative outcomes were retrospectively reviewed.

Results

Underlying aortic pathologies included 21 degenerative aortic aneurysms, 20 blunt traumatic aortic injuries, six type B aortic dissections, five type B intramural hematomas, three endoleaks and two miscellaneous diseases. The mean age of the patients was 61.2±17.5 years (range, 15 to 85 years). AKI was identified in 13 (22.8%) of 57 patients. There was an association of preoperative stroke and postoperative paraparesis and paraplegia with AKI. The average intensive care unit (ICU) stay in patients with AKI was significantly longer than in patients without AKI (5.3 vs. 12.7 days, p=0.017). The 30-day mortality rate in patients with AKI was significantly higher than patients without AKI (23.1% vs. 4.5%, p=0.038); however, AKI did not impact long-term survival.

Conclusion

Preoperative stroke and postoperative paraparesis and paraplegia were identified as predictors for AKI. Patients with AKI experienced longer average ICU stays and greater 30-day mortality than those without AKI. Perioperative identification of high-risk patients, as well as nephroprotective strategies to reduce the incidence of AKI, should be considered as important aspects of a successful TEVAR procedure.

Diagnostic and short-term prognostic utility of plasma pro-enkephalin (pro-ENK) for acute kidney injury in patients admitted with sepsis in the emergency department

BACKGROUND

Acute kidney injury (AKI) aggravates the prognosis of patients with sepsis. Reliable biomarkers for early detection of AKI in this setting are lacking. Enkephalins influence kidney function, and may have a role in AKI from sepsis. We utilized a novel immunoassay for plasma proenkephalin (pro-ENK), a stable surrogate marker for endogenous enkephalins, in patients hospitalized with sepsis, in order to assess its clinical utility.

METHODS

In an observational retrospective study we enrolled 101 consecutive patients admitted to the emergency department (ED) with suspected sepsis. Plasma levels of pro-ENK and neutrophil gelatinase-associated lipocalin (NGAL) were evaluated at ED arrival for their association with presence and severity of AKI and 7-day mortality.

RESULTS

pro-ENK was inversely correlated to creatinine clearance (r = -0.72) and increased with severity of AKI as determined by RIFLE (risk, injury, failure, loss of function, end-stage renal disease) stages (p < 0.0001; pro-ENK median [interquartile range, IQR]) pmol/l: no AKI: 71 [41-97]; risk: 72 [51-120]; injury: 200 [104-259]; failure: 230 [104-670]; loss of function: 947 [273-811]. The majority of septic patients without AKI or at risk had pro-ENK concentrations within the normal range. While NGAL was similarly associated with AKI severity, it was strongly elevated already in septic patients without AKI. pro-ENK added predictive information to NGAL for detecting kidney dysfunction (added χ (2) 10.0, p = 0.0016). Admission pro-ENK outperformed creatinine clearance in predicting 7-day mortality (pro-ENK: χ (2) 13.4, p < 0.001, area under curve, AUC 0.69; creatinine clearance: χ (2) 4, p = 0.045, AUC: 0.61), and serial measurement improved prediction.

CONCLUSIONS

Use of pro-ENK in septic patients can detect the presence and severity of AKI. Moreover, pro-ENK is highly predictive of short-term mortality and could enable early identification of patients at risk of death.

Sepsis and Acute Kidney Injury

Acute kindney injury (AKI) is a clinical syndrome which is generally defined as an abrupt decline in glomerular filtration rate, causing accumulation of nitrogenous products and rapid development of fluid, electrolyte and acid base disorders. In intensive care unit sepsis and septic shock are leading causes of AKI. Sepsis-induced AKI literally acts as a biologic indicator of clinical deterioration. AKI triggers variety of immune, inflammatory, metabolic and humoral patways; ultimately leading distant organ dysfunction and increases morbidity and mortality. Serial mesurements of creatinine and urine volume do not make it possible to diagnose AKI at early stages. Serum creatinine influenced by age, weight, hydration status and become apparent only when the kidneys have lost 50% of their function. For that reason we need new markers, and many biomarkers in the diagnosis of early AKI activity is assessed. Historically "Risk-Injury-Failure-Loss-Endstage" (RIFLE), "Acute Kidney Injury Netwok" (AKIN) and "The Kidney Disease/ Improving Global Outcomes" (KDIGO) classification systems are used for diagnosing easily in clinical practice and research and grading disease. Classifications including diagnostic criteria are formed for the identification of AKI. Neutrophil gelatinase associated lipocalin (NGAL), cystatin-C (Cys-C), kidney injury molecule-1 (KIM-1) and also "cell cycle arrest" molecules has been concerned for clinical use. In this review the pathophysiology of AKI, with the relationship of sepsis and the importance of early diagnosis of AKI is evaluated.

The incidence of cisplatin nephrotoxicity post hyperthermic intraperitoneal chemotherapy (HIPEC) and cytoreductive surgery

BACKGROUND

Cisplatin is commonly used in hyperthermic intraperitoneal chemotherapy (HIPEC) for the management of peritoneal carcinomatosis. Little is known about the nephrotoxic effects of cisplatin use in HIPEC.

OBJECTIVES

To report the incidence of nephrotoxicity post-HIPEC using cisplatin 50 mg/m(2) plus doxorubicin 15 mg/m(2). The incidence of hypomagnesemia was investigated as a secondary endpoint.

METHODS

This is a retrospective study evaluating patients who received cisplatin with doxorubicin during HIPEC. RIFLE classification was used to assess the development of nephrotoxicity. Variables, such as comorbidities and nephrotoxic medications were obtained. Renal function parameters were also collected, including serum creatinine levels and serum magnesium levels at baseline and at days 3, 7 and 30 after HIPEC. Perioperative urine output (UO) was also recorded.

RESULTS

Fifty-three patients were identified. Based on the RIFLE classification, two patients (3.7%) developed acute kidney injury (AKI) following HIPEC with cisplatin. One patient met criteria for renal failure and progressed to chronic renal failure. The other patient had renal injury. Comparable mean creatinine levels were observed at baseline and on day 30 following HIPEC (p > 0.05). The incidence of hypomagnesemia increased to 24.5% by day 7 (p = 0.041) and 30.1% by day 30 (p < 0.001) following HIPEC. Low intraoperative UO, angiotensin II receptor antagonist use and hypertension were associated with development of AKI (p < 0.05).

CONCLUSION

Nephrotoxicity can complicate HIPEC with cisplatin therapy and that permanent renal dysfunction may rarely occur. More attention to be directed toward monitoring magnesium levels after cisplatin use with HIPEC.

Colistin- and Polymyxin-Induced Nephrotoxicity

With the reintroduction of colistimethate and polymyxin B into clinical practice, a review of their individual and comparative nephrotoxicity attributes as reported in contemporary literature was undertaken. Given variability in definitions used for acute kidney injury, a particular focus was placed on studies utilizing the Risk-Injury-Failure-Loss-End Stage Kidney Disease (RIFLE) criteria of assessment to provide for standardized comparison. Primary risk factors examined included the influence of dosing and the receipt of concomitant nephrotoxins. The typical severity and time course of renal injury that develops were also analyzed. Nephrotoxicity rates with colistimethate appear to approach 50%, and could be of lower frequency and severity with polymyxin B based on limited literature. Acute kidney injury generally appears to be mild to moderate in magnitude and reversible in nature, though as many as 20% of patients experiencing it may require renal replacement therapy of some duration. The majority of studies showed some relationship with dosing- variably reported as being associated with daily dose or cumulative exposure. Traditional nephrotoxic agents did not appear to confer additional risk individually in the majority of investigations, though receipt of multiple concurrent nephrotoxins did yield a relationship in several. Further studies will be required to better characterize the renal adverse effect profile of these agents, particularly in the case of polymyxin B.

Acute renal failure according to the RIFLE and AKIN criteria: a multicenter study

OBJECTIVE

To determine the incidence of acute renal failure (ARF) in critically ill patients using the RIFLE and AKIN criteria.

DESIGN

A prospective, multicenter observational study with a duration of one year from February 2010 was carried out. RIFLE and AKIN were employed using the urinary (UC) and creatinine criteria (CC) jointly and separately.

SCOPE

Nine polyvalent Critical Care Units (CCUs) in Argentina.

PATIENTS

A total of 627 critical patients over 18 years of age were admitted to the CCU for more than 48h.

EXCLUSION CRITERIA

inability to quantify diuresis, surgical instrumentation of the urinary tract, and need for renal support therapy (RST).

VARIABLES OF INTEREST

Calculated hourly diuresis (CHD) was used to apply the UC.

RESULTS

The incidence of ARF was 69.4% and 51.8% according to RIFLE and AKIN, respectively. UC detected ARF in 59.5% of cases, while CC identified ARF in 34.7% (RIFLE) and 25.3% (AKIN). The mortality rate was 40.9% and 44.6% according to RIFLE and AKIN respectively, was significantly higher than in patients without ARF, and increased with disease severity (Data processing: Excel, SQL and SPSS. Levene test, comparison of means with Student t and chi-squared, with 95% confidence interval).

CONCLUSIONS

RIFLE identified more cases of ARF. UC proved more effective than CC. The presence of ARF and severity levels were correlated to mortality but not to days of stay in the CCU. Implementation of the unified CHD was useful for implementing UC and achieving comparable results.

A real-time electronic alert to improve detection of acute kidney injury in a large teaching hospital

BACKGROUND

Acute kidney injury (AKI) is a common and serious problem in hospitalized patients. Early detection is critical for optimal management but in practice is currently inadequate. To improve outcomes in AKI, development of early detection tools is essential.

METHODS

We developed an automated real-time electronic alert system employing algorithms which combined internationally recognized criteria for AKI [Risk, Injury, Failure, Loss, End-stage kidney disease (RIFLE) and Acute Kidney Injury Network (AKIN)]. All adult patients admitted to Nottingham University Hospitals were included. Where a patient's serum creatinine increased sufficiently to define AKI, an electronic alert was issued, with referral to an intranet-based AKI guideline. Incidence of AKI Stages 1-3, in-hospital mortality, length of stay and distribution between specialties is reported.

RESULTS

Between May 2011 and April 2013, 59,921 alerts resulted from 22,754 admission episodes, associated with 15,550 different patients. Overall incidence of AKI for inpatients was 10.7%. Highest AKI stage reached was: Stage 1 in 7.2%, Stage 2 in 2.2% and Stage 3 in 1.3%. In-hospital mortality for all AKI stages was 18.5% and increased with AKI stage (12.5, 28.4, 35.7% for Stages 1, 2 and 3 AKI, respectively). Median length of stay was 9 days for all AKI.

CONCLUSIONS

This is the first fully automated real time AKI e-alert system, using AKIN and RIFLE criteria, to be introduced to a large National Health Service hospital. It has provided one of the biggest single-centre AKI datasets in the UK revealing mortality rates which increase with AKI stage. It is likely to have improved detection and management of AKI. The methodology is transferable to other acute hospitals.

Epidemiology, outcomes and validation of RIFLE and AKIN criteria in acute kidney injury (AKI) in critically ill patients: Indian perspective

Although the epidemiology and the impact of Acute Kidney Injury on outcomes are well-known in the Western literature, good data is lacking from India. Most studies published from India have not evaluated epidemiology of Acute Kidney Injury in the Intensive Care Unit setting and/or have not used validated criteria. In our observational study of 250 patients, admitted to a tertiary level ICU, we have explored the epidemiology of Acute Kidney Injury using both RIFLE and AKIN criteria and have validated them. We have also demonstrated that the severity of AKI is an independent predictor of mortality in critically ill patients. Our results are very much comparable to other studies and we feel that this study will remain as an epidemiological reference point for Indian clinicians dealing with AKI.

Urine and serum neutrophil gelatinase-associated lipocalin cut-off point for the prediction of acute kidney injury

Background:

The aim of the present study was to determine the optimum cut-off point of urine and serum neutrophil gelatinase-associated lipocalin (NGAL) for the predictive diagnosis of acute kidney injury (AKI).

Materials and Methods:

This study was a prospective observational study which was performed at Alzahra hospital and Emam Hussein Hospital, Isfahan, Iran. During a period of 4 months, from February 2012 to May 2012, consecutive patients admitted to pediatric intensive care unit (PICU) aged between 1 month and 15 years with glomerular filtration rate (GFR) more than 90 ml/min were enrolled in the study. In all the patients who were enrolled in the study, blood and urine samples were attained on the first, third, and fifth day of admission. Serum and urine NGAL were assessed and compared between patients who developed AKI and who didn’t.

Results:

Of 25 patients who enrolled in the study, 13 developed AKI. For the serum NGAL, the most accurate cut-off point was the fifth day cut-off point which was 163 375 pg/ml (sensitivity: 61.5%, specificity: 94.6%, AUC: 0.76) and urine NGAL cut-off point was 86 040 pg/ml (sensitivity: 50%, specificity: 92.5%, AUC: 0.73).

Conclusions:

In conclusion, we deduced that serum NGAL level significantly elevates in critically ill patients admitted in PICU who develop AKI. Serum and urine NGAL on the fifth day are the best predictors for the AKI with cut-off points 163 375 and 86 040.

Clinical characteristics of acute kidney injury in patients with scrub typhus--RIFLE criteria validation

There are limited data available on the validity of the RIFLE classification for AKI in patients with scrub typhus. We investigated the incidence and clinical characteristics of scrub typhus associated AKI using the RIFLE criteria. From 2010 to 2012, 238 patients were diagnosed with scrub typhus. Of these, we included 223 patients who were followed up until renal recovery or for at least three months. We evaluated the incidence, clinical characteristics, and severity of AKI based on the RIFLE classification. Of the 223 patients, 47 (21%) had scrub typhus-associated AKI. The incidence of AKI was 21.1%; of which, 10.7%, 9.4% and 1% were classified as Risk, Injury and Failure, respectively. In comparison with patients in the non-AKI group, the patients in the AKI group were older (70 ± 9 vs 61 ± 14 year, P = 0.01) and had one or more comorbidities such as hypertension, diabetes, and chronic kidney disease (77% vs 22%, p = 0.01). In the AKI group, forty-four patients had AKI prior to admission, and three patients experienced AKI during their hospitalization. By multivariate logistic regression analysis, age and comorbidity were significant predictors of AKI. All patients recovered baseline renal function without renal replacement therapy following antibiotics therapy and supportive care. The incidence of AKI in patient with scrub typhus is 21%. Age and co-morbidity are significant predictors of AKI in scrub typhus. In cases of scrub typhus-associated AKI, anti-rickettsia agent and supportive care are very important.

Incidence, dynamics, and prognostic value of acute kidney injury for death after cardiac surgery

OBJECTIVE

This study relates long-term mortality after cardiac surgery to different methods of measuring postoperative renal function, classified according to the Risk, Injury, Failure, Loss, and End-stage (RIFLE) criteria. The dynamics of acute kidney injury during hospital stay were studied by comparing renal function preoperatively, at its poorest measurement, and at discharge.

METHODS

A total of 5746 patients undergoing coronary artery bypass grafting were studied in a Cox analysis, over a median follow-up time of 6.0 years (range, 2.5-9.5 years). Renal function was determined using the highest and discharge levels of plasma creatinine by Cockroft-Gault and Modification of Diet in Renal Disease formulae. Acute kidney injury was classified according to the RIFLE criteria. Renal recovery was studied in a 2-dimensional matrix, and the impact of renal function at different time points was related to survival.

RESULTS

Although the p-creatinine classified most patients in the nonacute kidney injury and Risk class; the Cockroft-Gault and Modification of Diet in Renal Disease formulae classified more patients in Injury and Failure classes; and higher Risk, Injury, and Failure classes were associated with increased long-term mortality. The effect of renal recovery on long-term survival was only in part associated with improved outcome. In addition, the poorest renal function was a stronger predictor of mortality compared with preoperative and discharge levels.

CONCLUSIONS

Classification using RIFLE criteria seems to be useful because it detects patients with renal impairment that affects long-term survival. The Modification of Diet in Renal Disease method seems to be the most robust method when predicting outcome, and the poorest renal function was the best predictor of outcome. Renal recovery was generally associated with better outcome.

Urinary biomarkers and renal near-infrared spectroscopy predict intensive care unit outcomes after cardiac surgery in infants younger than 6 months of age

OBJECTIVE

To assess the ability of urinary acute kidney injury biomarkers and renal near-infrared spectroscopy (NIRS) to predict outcomes in infants after surgery for congenital heart disease.

METHODS

Urinary levels of neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), kidney injury molecule-1 (KIM-1), and cystatin C were measured preoperatively and postoperatively in 49 infants younger than 6 months of age. Renal NIRS was monitored for the first 24 hours after surgery. A composite poor outcome was defined as death, the need for renal replacement therapy, prolonged time to first extubation, or prolonged intensive care unit length of stay.

RESULTS

Forty-two (86%) patients had acute kidney injury as indicated by at least Acute Kidney Injury Network/Kidney Disease: Improving Global Outcomes (AKIN/KDIGO) stage 1 criteria, and 17 (35%) patients had poor outcomes, including 3 deaths. With the exception of KIM-1, all biomarkers demonstrated significant increases within 24 hours postoperatively among patients with poor outcomes. Low levels of NGAL and IL-18 demonstrated high negative predictive values (91%) within 2 hours postoperatively. Poor outcome infants had greater cumulative time with NIRS saturations less than 50% (60 vs 1.5 minutes; P = .02) in the first 24 hours.

CONCLUSIONS

Within the first 24 hours after cardiopulmonary bypass, infants at increased risk for poor outcomes demonstrated elevated urinary NGAL, IL-18, and cystatin C and increased time with low NIRS saturations. These findings suggest that urinary biomarkers and renal NIRS may differentiate patients with good versus poor outcomes in the early postoperative period, which could assist clinicians when counseling families and inform the development of future clinical trials.

Incidence of postoperative acute kidney injury in patients with chronic kidney disease undergoing minimally invasive valve surgery

BACKGROUND

We hypothesize that minimally invasive valve surgery in patients with chronic kidney disease (CKD) is superior to a conventional median sternotomy.

METHODS

We retrospectively analyzed 1945 consecutive patients who underwent isolated valve surgery. Included were patients with CKD stages 2 to 5. In-hospital mortality, composite complication rates, and intensive care unit and total hospital lengths of stay of those who underwent a minimally invasive approach were compared with those who underwent a standard median sternotomy. Resource use was approximated based on intensive care unit and total hospital lengths of stay.

RESULTS

There were 688 patients identified; 510 (74%) underwent minimally invasive surgery, and 178 (26%) underwent a median sternotomy. There was no significant difference in mortality. Minimally invasive surgery was associated with fewer composite complications (33.1% vs 49.4%; odds ratio, 0.5; P ≤ .001), shorter intensive care unit (48 [interquartile range {IQR}, 33-74] hours vs 71 [IQR, 42-96] hours; P < .01), and hospital (8 [IQR, 6-9] days vs 10 [IQR, 8-15] days; P < .001) lengths of stay, and a lower incidence of acute kidney injury (8% vs 14.7%; odds ratio, 0.5; P = .01), compared with median sternotomy. In a multivariable analysis, minimally invasive surgery was associated with a 60% reduction in the risk of development of postoperative acute kidney injury.

CONCLUSIONS

In patients with CKD undergoing isolated valve surgery, minimally invasive valve surgery is associated with reduced postoperative complications and lower resource use.

Stewart analysis of apparently normal acid-base state in the critically ill

PURPOSE

This study aimed to describe Stewart parameters in critically ill patients with an apparently normal acid-base state and to determine the incidence of mixed metabolic acid-base disorders in these patients.

MATERIALS AND METHODS

We conducted a prospective, observational multicenter study of 312 consecutive Dutch intensive care unit patients with normal pH (7.35 ≤ pH ≤ 7.45) on days 3 to 5. Apparent (SIDa) and effective strong ion difference (SIDe) and strong ion gap (SIG) were calculated from 3 consecutive arterial blood samples. Multivariate linear regression analysis was performed to analyze factors potentially associated with levels of SIDa and SIG.

RESULTS

A total of 137 patients (44%) were identified with an apparently normal acid-base state (normal pH and -2 < base excess < 2 and 35 < PaCO2 < 45 mm Hg). In this group, SIDa values were 36.6 ± 3.6 mEq/L, resulting from hyperchloremia (109 ± 4.6 mEq/L, sodium-chloride difference 30.0 ± 3.6 mEq/L); SIDe values were 33.5 ± 2.3 mEq/L, resulting from hypoalbuminemia (24.0 ± 6.2 g/L); and SIG values were 3.1 ± 3.1 mEq/L. During admission, base excess increased secondary to a decrease in SIG levels and, subsequently, an increase in SIDa levels. Levels of SIDa were associated with positive cation load, chloride load, and admission SIDa (multivariate r(2) = 0.40, P < .001). Levels of SIG were associated with kidney function, sepsis, and SIG levels at intensive care unit admission (multivariate r(2) = 0.28, P < .001).

CONCLUSIONS

Intensive care unit patients with an apparently normal acid-base state have an underlying mixed metabolic acid-base disorder characterized by acidifying effects of a low SIDa (caused by hyperchloremia) and high SIG combined with the alkalinizing effect of hypoalbuminemia.

Risks associated with the transfusion of various blood products in aortic valve replacement

BACKGROUND

Patients undergoing cardiac operations often require transfusions of red blood cells, plasma, and platelets. From a statistical point of view, there is a significant collinearity between the components, but they differ in indications for use and composition. This study explores the relationship between the transfusion of different blood components and long-term mortality in patients undergoing aortic valve replacement alone or combined with revascularization.

METHODS

A retrospective single-center study was performed including 1,311 patients undergoing aortic valve replacement. Patients who received more than 7 units of red blood cells, those who died early (7 days), and emergency cases were excluded. Patients were monitored for up to 9.5 years. A broad selection of potential risk factors were analyzed using Cox proportional hazards regression, where transfusion of red blood cells, plasma, and platelets were forced to remain in the model.

RESULTS

The transfusion of red blood cells was not associated with decreased long-term survival (hazard ratio [HR], 1.01; p = 0.520) nor was the transfusion of platelets (HR, 0.946; p = 0.124); however, the transfusion of plasma was (HR, 1.041; p < 0.001). All HRs are per unit of blood product transfused. No increased risk was found for patients undergoing a combined procedure.

CONCLUSIONS

No significant risk for long-term mortality was associated with transfusion of red blood cells during the study period. However, the transfusion of plasma was associated with increased mortality.

A Comparison of Traditional and Novel Definitions (RIFLE, AKIN, and KDIGO) of Acute Kidney Injury for the Prediction of Outcomes in Acute Decompensated Heart Failure

AIMS

To determine if newer criteria for diagnosing and staging acute kidney injury (AKI) during heart failure (HF) admission are more predictive of clinical outcomes at 30 days and 1 year than the traditional worsening renal function (WRF) definition.

METHODS

We analyzed prospectively collected clinical data on 637 HF admissions with 30-day and 1-year follow-up. The incidence, stages, and outcomes of AKI were determined using the following four definitions: KDIGO, RIFLE, AKIN, and WRF (serum creatinine rise ≥0.3 mg/dl). Receiver operating curves were used to compare the predictive ability of each AKI definition for the occurrence of adverse outcomes (death, rehospitalization, dialysis).

RESULTS

AKI by any definition occurred in 38.3% (244/637) of cases and was associated with an increased incidence of 30-day (32.3 vs. 6.9%, χ(2) = 70.1; p < 0.001) and 1-year adverse outcomes (67.5 vs. 31.0%, χ(2) = 81.4; p < 0.001). Most importantly, there was a stepwise increase in primary outcome with increasing stages of AKI severity using RIFLE, KDIGO, or AKIN (p < 0.001). In direct comparison, there were only small differences in predictive abilities between RIFLE and KDIGO and WRF concerning clinical outcomes at 30 days (AUC 0.76 and 0.74 vs. 0.72, χ(2) = 5.6; p = 0.02) as well as for KDIGO and WRF at 1 year (AUC 0.67 vs. 0.65, χ(2) = 4.8; p = 0.03).

CONCLUSION

During admission for HF, the benefits of using newer AKI classification systems (RIFLE, AKIN, KDIGO) lie with the ability to identify those patients with more severe degrees of AKI who will go on to experience adverse events at 30 days and 1 year. The differences in terms of predictive abilities were only marginal.

The RIFLE and AKIN classifications for acute kidney injury: a critical and comprehensive review

In May 2004, a new classification, the RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease) classification, was proposed in order to define and stratify the severity of acute kidney injury (AKI). This system relies on changes in the serum creatinine (SCr) or glomerular filtration rates and/or urine output, and it has been largely demonstrated that the RIFLE criteria allows the identification of a significant proportion of AKI patients hospitalized in numerous settings, enables monitoring of AKI severity, and is a good predictor of patient outcome. Three years later (March 2007), the Acute Kidney Injury Network (AKIN) classification, a modified version of the RIFLE, was released in order to increase the sensitivity and specificity of AKI diagnosis. Until now, the benefit of these modifications for clinical practice has not been clearly demonstrated.

Here we provide a critical and comprehensive discussion of the two classifications for AKI, focusing on the main differences, advantages and limitations.