Acute kidney injury 2016: diagnosis and diagnostic workup

Fluid management in acute kidney injury: from evaluating fluid responsiveness towards assessment of fluid tolerance

Despite the widespread use of intravenous fluids in acute kidney injury (AKI), solid evidence is lacking. Intravenous fluids mainly improve AKI due to true hypovolaemia, which is difficult to discern at the bedside unless it is very pronounced. Empiric fluid resuscitation triggered only by elevated serum creatinine levels or oliguria is frequently misguided, especially in the presence of fluid intolerance syndromes such as increased extravascular lung water, capillary leak, intra-abdominal hypertension, and systemic venous congestion. While fluid responsiveness tests clearly identify patients who will not benefit from fluid administration (i.e. those without an increase in cardiac output), the presence of fluid responsiveness does not guarantee that fluid therapy is indicated or even safe. This review calls for more attention to the concept of fluid tolerance, incorporating it into a practical algorithm with systematic venous Doppler ultrasonography assessment to use at the bedside, thereby lowering the risk of detrimental kidney congestion in AKI.

Postoperative Blood Pressure Deficit and Acute Kidney Injury After Liver Transplant

OBJECTIVES

Acute kidney injury is a common cause of morbidity in liver transplant recipients. In critically ill patients who received an orthotopic liver transplant, we examined whether those with acute kidney injury had a greater deficit between pretransplant and posttransplant hemodynamic pressure-related parameters compared with those without acute kidney injury in the early postoperative period.

MATERIALS AND METHODS

We included patients who underwent an orthotopic liver transplant during the study period. We obtained premorbid and intensive care unit time-weighted average values for hemodynamic pressure-related parameters (systolic, diastolic, and mean arterial pressure; central venous pressure; mean perfusion pressure; and diastolic perfusion pressure) and calculated deficits in those values. We defined acute kidney injury progression as an increase of ≥1 Kidney Disease: Improving Global Outcomes stage.

RESULTS

We included 150 eligible transplantrecipients, with 88 (59%) having acute kidney injury progression. Acute kidney injury was associated with worse clinical outcomes. All achieved pressure-related values were similar between transplant recipients with or without acute kidney injury progression. However, those with acute kidney injury versus those without progression had greater diastolic perfusion pressure deficit at 12 hours (-8.33% vs 1.93%; P = .037) and 24 hours (-7.38% vs 5.11%; P = .002) and increased central venous pressure at 24 hours (46.13% vs 15%; P = .043) and 48 hours (40% vs 20.87%; P = .039).

CONCLUSIONS

Patients with acute kidney injury progression had a greater diastolic perfusion pressure deficit and increased central venous pressure compared with patients without progression. Such deficits might be modifiable risk factors for the prevention of acute kidney injury progression.

Necrotizing Fasciitis Presenting as Generalized Weakness, Malaise, and Acute Kidney Injury

Necrotizing fasciitis (NF) is a surgical emergency that must be diagnosed promptly in order to avoid serious consequences or death. Additionally, symptoms of this condition are similar to less severe skin and soft tissue infections such as cellulitis or erysipelas and can be easily confused. In this case, the patient presented to the emergency department with systemic symptoms, notably malaise and generalized weakness. A cutaneous complaint, a "labial cyst", was only elicited after more specific questioning. Laboratory investigations revealed abnormal renal function tests (RFTs), suggestive of an acute kidney injury. An abdominal/pelvic computed tomography (CT) showed gas in the subcutaneous tissue. These findings led to clinical suspicion of NF, prompting a general surgery consultation. The surgeon proceeded to perform extensive debridement following the discovery of necrotic tissue. The prompt diagnosis and treatment of this condition resulted in patient survival and expected recovery. It is, therefore, critical to keep this condition in mind when diagnosing apparent skin and soft tissue infections presenting with abnormal RFTs due to the possibility of rapid decline and death if the NF is left untreated. Additionally, this is a case of less frequent Fournier's gangrene in a non-diabetic female. Finally, it underlines the importance of eliciting additional symptoms, even those that may seem unrelated, or less concerning, to the patient's initial complaint.

Noninvasive and Invasive Renal Hypoxia Monitoring in a Porcine Model of Hemorrhagic Shock

Up to 50% of patients with trauma develop acute kidney injury (AKI), in part due to poor renal perfusion after severe blood loss. AKI is currently diagnosed based on a change in serum creatinine concentration from baseline or prolonged periods of decreased urine output. Unfortunately, baseline serum creatinine concentration data is unavailable in most patients with trauma, and current estimation methods are inaccurate. In addition, serum creatinine concentration may not change until 24-48 h after the injury. Lastly, oliguria must persist for a minimum of 6 h to diagnose AKI, making it impractical for early diagnosis. AKI diagnostic approaches available today are not useful for predicting risk during the resuscitation of patients with trauma. Studies suggest that urinary partial pressure of oxygen (PuO2) may be useful for assessing renal hypoxia. A monitor that connects the urinary catheter and the urine collection bag was developed to measure PuO2 noninvasively. The device incorporates an optical oxygen sensor that estimates PuO2 based on luminescence quenching principles. In addition, the device measures urinary flow and temperature, the latter to adjust for confounding effects of temperature changes. Urinary flow is measured to compensate for the effects of oxygen ingress during periods of low urine flow. This article describes a porcine model of hemorrhagic shock to study the relationship between noninvasive PuO2, renal hypoxia, and AKI development. A key element of the model is the ultrasound-guided surgical placement in the renal medulla of an oxygen probe, which is based on an unsheathed optical microfiber. PuO2 will also be measured in the bladder and compared to the kidney and noninvasive PuO2 measurements. This model can be used to test PuO2 as an early marker of AKI and assess PuO2 as a resuscitative endpoint after hemorrhage that is indicative of end-organ rather than systemic oxygenation.

Postoperative serum myoglobin as a predictor of early allograft dysfunction after liver transplantation

Background

Early allograft dysfunction (EAD) is a common postliver transplant complication that has been associated with graft failure and risk for poor prognosis. There are many risk factors for the incidence of EAD after liver transplantation (LT). This study investigated whether elevated postoperative myoglobin (Mb) increases the incidence of EAD in liver transplanted recipients.

Methods

A total of 150 adult recipients who measured Mb within 3 days after liver transplantation between June 2019 and June 2021 were evaluated. Then, all patients were divided into two groups: the EAD group and the non-EAD group. Univariate and multivariate logistic regression analyses were performed, and receiver operating characteristic curves (ROCs) were constructed.

Results

The incidence of EAD was 53 out of 150 patients (35.3%) in our study. Based on the multivariate logistic analysis, the risk of EAD increased with elevated postoperative Mb (OR = 1.001, 95% CI 1.000–1.001, P = 0.002). The Mb AUC was 0.657, and it was 0.695 when combined with PCT. When the subgroup analysis was conducted, the AUC of serum Mb prediction was better in patients whose preoperative model for end-stage liver disease score  ≤ 15 or operative time ≥ 10 h (AUC = 0.751, 0.758, respectively, or 0.760, 0.800 when combined with PCT).

Conclusion

Elevated Mb significantly increased the risk of postoperative EAD, suggesting that postoperative Mb may be a novel predictor of EAD after liver transplantation.

The study was registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR2100044257, URL: http://www.chictr.org.cn).

Vancomycin Loading Doses and Nephrotoxicity on Medicine Teaching Services

Background

Infectious Disease Society of America (IDSA) guidelines recommend the usage of a loading dose when using vancomycin for seriously ill patients. While the relationship between vancomycin and nephrotoxicity is the focus of many studies, few studies have examined the relationship between vancomycin loading doses and nephrotoxicity.

Methods

We performed a retrospective cohort study examining vancomycin dosing for internal medicine teaching services' patients over the 2014-15 academic year at one academic medical center. We generated a list of all hospitalized patients aged 18-85 who received vancomycin and were admitted to a teaching service. Nephrotoxicity was determined by 7-day acute kidney injury (AKI) rate. Patients in the loading dose cohort were compared with those in the standard-dose cohort. Primary modeling used multivariable logistic regression with AKI as our outcome of interest.

Results

Four hundred and thirty-eight patients were included for analysis. The loading dose (n = 365, 83%) and standard dosing (n = 73, 17%) cohorts were not significantly different regarding demographics, GFR, nephrotoxic drug exposure, total vancomycin received, trough levels, or comorbidities and were only significantly different regarding body mass index (BMI). The 7-day AKI rate was not significantly different between the two arms (6.3% in the standard dosing arm and 8.2% in the loading dose arm, p = 0.6).

Conclusion

Few studies have examined the relationship between nephrotoxicity and vancomycin loading doses. The results of this study provide evidence that the use of loading doses is not significantly associated with increased 7-day AKI rate.

ISCCM Guidelines on Acute Kidney Injury and Renal Replacement Therapy

Acute kidney injury (AKI) is a complex syndrome with a high incidence and considerable morbidity in critically ill patients. Renal replacement therapy (RRT) remains the mainstay of treatment for AKI. There are at present multiple disparities in uniform definition, diagnosis, and prevention of AKI and timing of initiation, mode, optimal dose, and discontinuation of RRT that need to be addressed. The Indian Society of Critical Care Medicine (ISCCM) AKI and RRT guidelines aim to address the clinical issues pertaining to AKI and practices to be followed for RRT, which will aid the clinicians in their day-to-day management of ICU patients with AKI.

How to cite this article

Mishra RC, Sodhi K, Prakash KC, Tyagi N, Chanchalani G, Annigeri RA, et al. ISCCM Guidelines on Acute Kidney Injury and Renal Replacement Therapy. Indian J Crit Care Med 2022;26(S2):S13-S42.

Urinary Neutrophil Gelatinase-Associated Lipocalin Predicts Intensive Care Unit Admission Diagnosis: A Prospective Cohort Study

Background

Acute kidney injury (AKI) is most commonly caused by tubular injury and is associated with a wide variety of critical illnesses. It is well known that urinary biomarkers can lead to the early identification of AKI. However, the ability of urinary biomarkers to distinguish between different types of critical illness has been less studied.

Methods

In this prospective cohort study, urinary neutrophil gelatinase-associated lipocalin (uNGAL) was measured in 107 patients consecutively admitted to the ICUs in our tertiary medical center. uNGAL samples were collected within 3-6 hours of admission to an ICU and measured by ELISA. All data were analyzed using R statistical software, and univariate analysis was used to determine the correlations of uNGAL levels with AKI stage, admission diagnoses, and ICU course.

Results

uNGAL level increased by a mean of 24-fold (SD 10-59) in ICU patients with AKI and demonstrated a significant correlation with the different AKI stages. uNGAL predicted the need for RRT, with values increased by more than 15-fold (P<0.05) in patients needing RRT, and remained a useful tool to predict AKI in ICU patients with a urinary tract infection. uNGAL level was correlated with certain ICU admitting diagnoses whereby uNGAL levels were lower in ICU patients with cardiogenic shock compared with other admission diagnoses (β=-1.92, P<0.05).

Conclusions

uNGAL can be used as an early predictor of AKI and its severity in patients admitted to the ICU, including the need for RRT. uNGAL may also help in distinguishing patients with cardiogenic shock from those with other critical illnesses and identifying those at risk for poor outcomes irrespective of the presence of AKI.

Measurement of Serum Levels of 5 Amino Acids and Dimethylamine Using Liquid Chromatography-Tandem Mass Spectrometry in Patients without Septic Associated Acute Kidney Injury and with Septic Associated Acute Kidney Injury Requiring Continuous Renal Replacement Therapy

BACKGROUND Acute kidney injury (AKI) is one of the most common organ failures. An early diagnosis of AKI using specific biomarkers is essential for effective treatment. This study determined the serum concentrations of selected amino acids and amines using targeted liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) in patients with AKI during sepsis and septic shock treated in the Intensive Care Unit (ICU). MATERIAL AND METHODS A sample of 41 patients was divided into 2 groups: (1) patients with sepsis and septic shock along required continuous renal replacement therapy (CRRT) due to AKI (n=13), and (2) patients with sepsis and septic shock but without AKI (n=28). LC-MS/MS was used to measure a serum concentration of 6 amino acids and amines: arginine, ornithine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), dimethylamine (DMA), and citrulline. RESULTS There was a statistically significantly higher median DMA level in AKI patients compared to those without AKI (8.1 vs 5.2 umol/L; P=0.022). The results for the remaining molecules showed no significant differences (P>0.05). Patients with DMA ≥14.95 umol/L (n=5; 100%) and treated with CRRT presented DMA level below the cut-off point (n=7; 20%). Subjects with creatinine levels ≥1.19 mg/dL (n=11; 28%) and treated with CRRT presented creatinine levels below the cut-off point (n=1; 3%). CONCLUSIONS In patients with sepsis, increased serum levels of DMA were significantly associated with AKI requiring CRRT. It remains unclear whether increased DMA concentrations are secondary to sepsis-induced AKI or are a cause.

Artificial Intelligence in Acute Kidney Injury Prediction

The use of artificial intelligence (AI) in nephrology and its associated clinical research is growing. Recent years have seen increased interest in utilizing AI to predict the development of hospital-based acute kidney injury (AKI). Several AI techniques have been employed to improve the ability to detect AKI across a variety of hospitalized settings. This review discusses the evolutions of AKI risk prediction discussing the static risk assessment models of yesteryear as well as the more recent trend toward AI and advanced learning techniques. We discuss the relative improvement in AKI detection as well as the relative dearth of data around the clinical implementation and patient outcomes using these models. The use of AI for AKI detection and clinical care is in its infancy, and this review describes how we arrived at our current position and hints at the promise of the future.

Acute kidney injury in critical COVID-19: a multicenter cohort analysis in seven large hospitals in Belgium

BACKGROUND

Acute kidney injury (AKI) has been reported as a frequent complication of critical COVID-19. We aimed to evaluate the occurrence of AKI and use of kidney replacement therapy (KRT) in critical COVID-19, to assess patient and kidney outcomes and risk factors for AKI and differences in outcome when the diagnosis of AKI is based on urine output (UO) or on serum creatinine (sCr).

METHODS

Multicenter, retrospective cohort analysis of patients with critical COVID-19 in seven large hospitals in Belgium. AKI was defined according to KDIGO within 21 days after ICU admission. Multivariable logistic regression analysis was used to explore the risk factors for developing AKI and to assess the association between AKI and ICU mortality.

RESULTS

Of 1286 patients, 85.1% had AKI, and KRT was used in 9.8%. Older age, obesity, a higher APACHE II score and use of mechanical ventilation at day 1 of ICU stay were associated with an increased risk for AKI. After multivariable adjustment, all AKI stages were associated with ICU mortality. AKI was based on sCr in 40.1% and UO in 81.5% of patients. All AKI stages based on sCr and AKI stage 3 based on UO were associated with ICU mortality. Persistent AKI was present in 88.6% and acute kidney disease (AKD) in 87.6%. Rapid reversal of AKI yielded a better prognosis compared to persistent AKI and AKD. Kidney recovery was observed in 47.4% of surviving AKI patients.

CONCLUSIONS

Over 80% of critically ill COVID-19 patients had AKI. This was driven by the high occurrence rate of AKI defined by UO criteria. All AKI stages were associated with mortality (NCT04997915).

Kidney Damage and Stress Biomarkers for Early Identification of Drug-Induced Kidney Injury: A Systematic Review

INTRODUCTION

Acute kidney injury (AKI) resulting from nephrotoxic medication use is prominent in hospitalized patients and is attributable to overall increases in mortality and costs of care. Serum creatinine (SCr), the current standard for identifying drug-induced AKI (DIAKI) is often delayed in its response to kidney insult by 26-36 h.

OBJECTIVE

This systematic review seeks to evaluate the clinical utility of several novel kidney damage and stress biomarkers for the prediction/timely detection of DIAKI, in comparison with traditional methods.

METHODS

A systematic review of the CINAHL, Cochrane Library, Embase, and PubMed databases was conducted per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, for articles analyzing the use of β2-microglobulin (B2M), interleukin (IL)-18, kidney injury molecule-1 (KIM-1), liver-type fatty acid-binding protein (L-FABP), neutrophil gelatinase-associated lipocalin (NGAL), and tissue inhibitor of metalloproteinase-2 * insulin-like growth factor-binding protein 7 [TIMP-1]*[IGFBP-7], for identifying DIAKI. Primary outcomes included time to DIAKI diagnosis using traditional methods and the time to significant difference in biomarker concentrations between DIAKI and non-AKI study subjects. Secondary outcomes included biomarker concentrations at the time of significant difference between the AKI status groups.

RESULTS

Fifteen unique articles were identified from the literature search. Twelve studies consisted of strictly hospitalized patient populations and three studies included hospitalized patients and patients discharged to home treatment. No studies reported values for urine volume output. Seventy-three percent of studies reported earlier times to significant difference of novel biomarker concentrations between the AKI and non-AKI groups than diagnosis of DIAKI by SCr alone. Significant variation was observed for individual urine biomarker concentrations at time of significant difference between the AKI status groups.

CONCLUSIONS

All analyzed biomarkers showed potential for use as early clinical markers of DIAKI, however further consensus on threshold urine concentrations for DIAKI is needed for meaningful implementation of these biomarkers in clinical practice.

Optimization of antimicrobial dosing in patients with acute kidney injury: a single-centre observational study

Background

Acute kidney injury (AKI) is a potential complication of systemic infection. Optimizing antimicrobial dosing in this dynamic state can be challenging with sub- or supra-therapeutic dosing risking treatment failure or toxicity, respectively. Locally, unadjusted renal dosing for the first 48 h of infection is recommended.

Objectives

To determine the outcomes associated with this dosing strategy.

Methods

A retrospective cohort analysis was undertaken in patients treated for Gram-negative bacteraemia with concurrent non-filtration dependent AKI from a single-centre NHS acute hospital (April 2016–March 2020). Patient demographics, microbiology data, antimicrobial treatment and patient outcome (in-hospital mortality and kidney function) were analysed.

Results

In total, 647 episodes of Gram-negative bacteraemia (608 patients) were included; 305/608 (50.2%) were male with median age 71 years (range 18–100). AKI was present in 235/647 (36.3%); 78/647 (12.1%) and 45/647 (7.0%) having Kidney Disease Improving Global Outcomes-defined injury (stage 2) or failure (stage 3), respectively. In-hospital 30 day mortality was 25/352 (7.1%), 14/112 (12.5%), 26/123 (21.1%) and 11/60(18.3%) in patients with normal renal function, AKI stage 1, AKI stage ≥2 and established chronic kidney disease, respectively. Recovery of renal function at Day 21 or discharge was present in 105/106 surviving patients presenting with AKI stage ≥2. Time to recovery of AKI was similar in patients receiving full, low or no aminoglycoside (3 versus 4 versus 3 days, P = 0.612) and those receiving full- and low-dose β-lactam (3 versus 5 days, P = 0.077).

Conclusions

There is a high burden of AKI in patients with Gram-negative bacteraemia. Dose adjustments of β-lactams may not be necessary in the first 48 h of infection-induced AKI and single-dose aminoglycosides may be considered for early empirical coverage.

Plants with Therapeutic Potential for Ischemic Acute Kidney Injury: A Systematic Review

Acute kidney injury (AKI) is a complex condition which has an intricate pathology mostly involving hemodynamic, inflammatory, and direct toxic effects at the cellular level with high morbidity and mortality ratios. Renal ischemic reperfusion injury (RIRI) is the main factor responsible for AKI, most often observed in different types of shock, kidney transplantation, sepsis, and postoperative procedures. The RIRI-induced AKI is accompanied by increased reactive oxygen species generation together with the activation of various inflammatory pathways. In this context, plant-derived medicines have shown encouraging nephroprotective properties. Evidence provided in this systemic review leads to the conclusion that plant-derived extracts and compounds exhibit nephroprotective action against renal ischemic reperfusion induced-AKI by increasing endogenous antioxidants and decreasing anti-inflammatory cytokines. However, there is no defined biomarker or target which can be used for treating AKI completely. These plant-derived extracts and compounds are only tested in selected transgenic animal models. To develop the results obtained into a therapeutic entity, one should apply them in proper vertebrate multitransgenic animal models prior to further validation in humans.

Neutralizing Antibody Titers in Hospitalized Patients with Acute Puumala Orthohantavirus Infection Do Not Associate with Disease Severity

Nephropathia epidemica (NE), a mild form of haemorrhagic fever with renal syndrome (HFRS), is an acute febrile illness caused by Puumala orthohantavirus (PUUV). NE manifests typically with acute kidney injury (AKI), with a case fatality rate of about 0.1%. The treatment and management of hantavirus infections are mainly supportive, although neutralizing monoclonal antibodies and immune sera therapeutics are under investigation. In order to assess the potential use of antibody therapeutics in NE, we sought to determine the relationship between circulating PUUV neutralizing antibodies, PUUV nucleocapsid protein (N) IgG antibodies, and viral loads with markers of disease severity. The study included serum samples of extensively characterized patient cohorts (n = 116) from Tampere University Hospital, Finland. The results showed that upon hospitalization, most patients already had considerable neutralizing and anti-PUUV-N IgG antibody levels. However, contrary to expectations, neutralizing antibody titers from the first day of hospitalization did not appear to protect from AKI or correlate with more favorable disease outcomes. This indicates that further studies are needed to investigate the applicability of neutralizing antibodies as a therapy for hospitalized NE patients.

Variations of urinary N-acetyl-β-D-glucosaminidase levels and its performance in detecting acute kidney injury under different thyroid hormones levels: a prospectively recruited, observational study

OBJECTIVE

Changes in thyroid function will be accompanied by changes in urinary N-acetyl-β-D-glucosaminidase (uNAG) levels. Therefore, whether thyroid hormones interfere the ability of uNAG in detecting acute kidney injury (AKI) has raised concern in patients with critical illness.

DESIGN

A prospectively recruited, observational study was performed.

SETTING

Adults admitted to the intensive care unit of a grade A tertiary hospital in China.

PARTICIPANTS

A total of 1919 critically ill patients were enrolled in the study.

MAIN OUTCOME MEASURES

To investigate the variations of the ability of uNAG to detect AKI in patients with critical illness under different thyroid hormones levels (differences in area under the curve (AUC) for uNAG diagnosis and prediction of AKI with different thyroid hormones levels).

RESULTS

The bivariate correlation analysis revealed that FT3 and TT3 levels were independently associated with uNAG levels (p<0.001). FT3 and uNAG also showed correlation in multivariable linear regression analysis (p<0.001). After stratification according to the levels of FT3 or TT3, significant variation was observed in the uNAG levels with different quartiles (p<0.05). However, in patients with varying FT3 and TT3 levels, no significant difference was found in the AUCs of uNAG to detect AKI (p>0.05).

CONCLUSIONS

Even if uNAG levels varied with FT3 and TT3 levels, these hormones did not interfere with uNAG's ability to detect AKI in patients with critical illness.

Renal Outcomes of Pregnancy-Related Acute Kidney Injury: a Single Centre Experience in India

Objective:This study aimed to investigate the incidence, clinical characteristics, and outcomes of acute kidney injury (AKI) during pregnancy in Indian population. Materials and methods:A prospective observational study was conducted in pregnant patients admitted to Pt. B.D. Sharma PGIMS, Rohtak, Haryana, India. Acute kidney injury was assessed using Risk, Injury, Failure, Loss of function, and End-stage renal disease (RIFLE) criteria. Patients were analyzed on the basis of demographic data, detailed history, clinical examination, and laboratory investigations. The primary outcome was maternal renal outcome, including return to normal renal function and progression to chronic kidney disease (CKD). The secondary outcomes included the mode of delivery, complications of pregnancy, intensive care unit (ICU) admission, and maternal death. Results:A total of 51 patients with an average age of 29.5 years were included in the present study. About 49.9% of subjects had severe anemia and 41.2% were primigravida. The main cause of AKI was pre-eclampsia and postpartum hemorrhage. There was a marked improvement in renal outcome with 33 patients having complete renal recovery and six patients developed CKD was observed during three months follow-up period. The peaked median value of blood urea was 62.0 mg% in patients with normal renal function, 178.5 mg% in those with CKD and 120.0 mg% in expired patients (P=0.001). A statistically significant change in serum potassium (P=0.010) and creatinine levels (P<0.001) was observed during the follow-up period. Liver enzymes, including serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase, were high in all patients at the time of admission, but decreased to normal on follow-up. Conclusion:Our study indicates that pregnancy-related AKI patients present with multiorgan complications and many of them require mechanical ventilation and renal replacement therapy. Most of these patients have poor outcome. Hence, the management of pregnancy-related AKI presents a challenge that requires proper evaluation of causative factors to facilitate appropriate treatment.

Advances in Biosensor Technologies for Acute Kidney Injury

Acute kidney injury (AKI) is one of the most prevalent and complex clinical syndromes with high morbidity and mortality. The traditional diagnosis parameters are insufficient regarding specificity and sensitivity, and therefore, novel biomarkers and their facile and rapid applications are being sought to improve the diagnostic procedures. The biosensors, which are employed on the basis of electrochemistry, plasmonics, molecular probes, and nanoparticles, are the prominent ways of developing point-of-care devices, along with the mutual integration of efficient surface chemistry strategies. In this manner, biosensing platforms hold pivotal significance in detecting and quantifying novel AKI biomarkers to improve diagnostic interventions, potentially accelerating clinical management to control the injury in a timely manner. In this review, novel diagnostic platforms and their manufacturing processes are presented comprehensively. Furthermore, strategies to boost their effectiveness are also indicated with several applications. To maximize these efforts, we also review various biosensing approaches with a number of biorecognition elements (e.g., antibodies, aptamers, and molecular imprinting molecules), as well as benchmark their features such as robustness, stability, and specificity of these platforms.

Serum Creatinine Levels and Nephrocheck® Values With and Without Correction for Urine Dilution-A Multicenter Observational Study

Background

The Nephrocheck® test is a single-use cartridge designed to measure the concentrations of two novel cell-cycle arrest biomarkers of acute kidney injury, namely tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7). Correlations of serum creatine values and TIMP-2 and IGFBP7 with and without correction for urine dilution have not been previously undertaken in patients undergoing major abdominal surgery. We hypothesized that the Nephrocheck® values would be significantly different with and without correction for urine dilution in patients with elevated creatinine values post major abdominal surgery.

Methods

We performed a post hoc analysis of serum and urine specimens sampled preoperatively and postoperatively in 72 patients undergoing major abdominal surgery. Thirty samples were measured from patients with the greatest decrease and the greatest increase in postoperative serum creatinine values. Urine was analyzed with the Nephrocheck to predict the risk of acute kidney injury (AKIRisk™). We then examined the relationship between serum creatinine and the urinary excretion of TIMP-2 and IGFBP7 as measured by the Nephrocheck test. The AKIRisk between the groups with and without correction for urine dilution was assessed.

Results

The median perioperative change in serum creatinine in the two groups was −19% and +57%, respectively. The uncorrected median baseline AKIRisk decreased from 0.70 (25th−75th percentiles, 0.09–1.98) to 0.35 (0.19–0.57) (mg/L)² in the first group and rose from 0.57 (0.22–1.53) to 0.85 (0.67–2.20) (mg/L)² in the second group. However, when corrected for the squared urine dilution, the AKIRisk™ in patients with postoperative increases in serum creatinine was not indicative of kidney injury; the corrected AKIRisk was 8.0 (3.2–11.7) μg²/mmol² before surgery vs.6.9 (5.3–11.0) μg²/mmol² after the surgery (P = 0.69).

Conclusion

In the setting of major abdominal surgery, after correction of TIMP-2 and IGFBP7 for urine dilution, the Nephrocheck AKIRisk scores were significantly different from the uncorrected values. These finding imply that the AKIRisk index is a function of urine flow in addition to an increased release of the biomarkers.

Cell cycle arrest biomarkers for predicting renal recovery from acute kidney injury: a prospective validation study

Background

Acute kidney injury (AKI) is a common disease in the intensive care unit (ICU). AKI patients with nonrecovery of renal function have a markedly increased risk of death compared with patients with recovery. The current study aimed to explore and validate the utility of urinary cell cycle arrest biomarkers for predicting nonrecovery in patients who developed AKI after ICU admission.

Methods

We prospectively and consecutively enrolled 379 critically ill patients who developed AKI after admission to the ICU, which were divided into a derivation cohort (194 AKI patients) and a validation cohort (185 AKI patients). The biomarkers of urinary tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) were detected at inclusion immediately after AKI diagnosis (day 0) and 24 h later (day 1). The optimal cut-off values of these biomarkers for predicting nonrecovery were estimated in the derivation cohort, and their predictive accuracy was assessed in the validation cohort. The primary endpoint was nonrecovery from AKI (within 7 days).

Results

Of 379 patients, 159 (41.9%) patients failed to recover from AKI onset, with 79 in the derivation cohort and 80 in the validation cohort. Urinary [TIMP-2]*[IGFBP7] on day 0 showed a better prediction ability for nonrecovery than TIMP-2 and IGFBP7 alone, with an area under the reciever operating characteristic curve (AUC) of 0.751 [95% confidence interval (CI) 0.701–0.852, p < 0.001] and an optimal cut-off value of 1.05 ((ng/mL)²/1000). When [TIMP-2]*[IGFBP7] was combined with the clinical factors of AKI diagnosed by the urine output (UO) criteria, AKI stage 2–3 and nonrenal SOFA score for predicting nonrecovery, the AUC was significantly improved to 0.852 (95% CI 0.750–0.891, p < 0.001), which achieved a sensitivity and specificity of 88.8% (72.9, 98.7) and 92.6% (80.8, 100.0), respectively. However, urine [TIMP-2]*[IGFBP7], TIMP-2 alone, and IGFBP7 alone on day 1 performed poorly for predicting AKI recovery.

Conclusion

Urinary [TIMP-2]*[IGFBP7] on day 0 showed a fair performance for predicting nonrecovery from AKI. The predictive accuracy can be improved when urinary [TIMP-2]*[IGFBP7] is combined with the clinical factors of AKI diagnosed by the UO criteria, AKI stage 2–3 and nonrenal SOFA score.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-00989-8.

The influence of timing of coronary angiography on acute kidney injury in out-of-hospital cardiac arrest patients: a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) is a frequent complication in cardiac arrest survivors and associated with adverse outcome. It remains unclear whether the incidence of AKI increases after the post-cardiac arrest contrast administration for coronary angiography and whether this depends on timing of angiography. Aim of this study was to investigate whether early angiography is associated with increased development of AKI compared to deferred angiography in out-of-hospital cardiac arrest (OHCA) survivors.

METHODS

In this retrospective multicenter cohort study, we investigated whether early angiography (within 2 h) after OHCA was non-inferior to deferred angiography regarding the development of AKI. We used an absolute difference of 5% as the non-inferiority margin. Primary non-inferiority analysis was done by calculating the risk difference with its 90% confidence interval (CI) using a generalized linear model for a binary outcome. As a sensitivity analysis, we repeated the primary analysis using propensity score matching. A multivariable model was built to identify predictors of acute kidney injury.

RESULTS

A total of 2375 patients were included from 2009 until 2018, of which 1148 patients were treated with early coronary angiography and 1227 patients with delayed or no angiography. In the early angiography group 18.5% of patients developed AKI after OHCA and 24.1% in the deferred angiography group. Risk difference was - 3.7% with 90% CI ranging from - 6.7 to - 0.7%, indicating non-inferiority of early angiography. The sensitivity analysis using propensity score matching showed accordant results, but no longer non-inferiority of early angiography. The factors time to return of spontaneous circulation (odds ratio [OR] 1.12, 95% CI 1.06-1.19, p < 0.001), the (not) use of angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker (OR 0.20, 95% CI 0.04-0.91, p = 0.04) and baseline creatinine (OR 1.05, 95% CI 1.03-1.07, p < 0.001) were found to be independently associated with the development of AKI.

CONCLUSIONS

Although AKI occurred in approximately 20% of OHCA patients, we found that early angiography was not associated with a higher AKI incidence than a deferred angiography strategy. The present results implicate that it is safe to perform early coronary angiography with respect to the risk of developing AKI after OHCA.

Optimal indicator for changing the filter during the continuous renal replacement therapy in intensive care unit patients with acute kidney injury: A crossover randomized trial

BACKGROUND

The study aims to investigate an optimal indicator for changing the filter during the continuous renal replacement therapy (CRRT) in intensive care unit (ICU) patients with acute kidney injury (AKI).

METHODS

Patients with AKI requiring CRRT in an ICU were randomly divided into two groups for crossover trial, i.e., groups A and B. Patients in the group A were firstly treated with continuous veno-venous hemofiltration (CVVH), followed by continuous veno-venous hemodiafiltration (CVVHDF). Patients in the group B were firstly treated with CVVHDF followed by CVVH. Delivered doses of solutes with different molecular weights at the indicated time points between groups were compared. A correlation analysis between the delivered dose and pre-filter pressure (PPRE) and transmembrane pressure (PTM) was performed. Receiver operating characteristic (ROC) curves were constructed to evaluate the accuracy of PTM as an indicator for filter replacement.

RESULTS

A total of 50 cases were analyzed, 27 in the group A and 23 in the group B. Delivered doses of different molecular-weight solutes significantly decreased before changing the filter in both modalities, compared with those at the initiation of treatment (all P<0.05). In the late stage of CRRT, the possible rebound of serum medium-molecular-weight solute concentration was observed. PTM was negatively correlated with the delivered dose of medium-molecular-weight solute in both modalities. The threshold for predicting the rebound of serum concentration of medium-molecular-weight solute by PTM was 146.5 mmHg (1 mmHg=0.133 kPa).

CONCLUSIONS

The filter can be used as long as possible within the manufacturer's safe use time limits to remove small-molecular-weight solutes. PTM of 146.5 mmHg may be an optimal indicator for changing the filter in CRRT therapies to remove medium-molecular-weight solutes.

Drug Interactions Affecting Kidney Function: Beware of Health Threats from Triple Whammy

Triple whammy (TW) is a potentially dangerous drug combination that can lead to acute kidney injury (AKI). This drug interaction (DI) occurs when angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) are used together with diuretics and non-steroidal anti-inflammatory drugs (NSAIDs). One of the most serious consequences of TW DI is an increased risk of developing pre-renal acute kidney injury (pr-AKI). The term TW, in the context of a DI affecting kidney function, is not very widespread. The aim of this article was to gather information on this interaction. Previous knowledge on the mechanism of TW and how to increase patient awareness of this interaction is described. In addition, the specific nature of the acute kidney injury (AKI) caused by triple whammy (AKITW) is presented. On the basis of the current state of knowledge, recommendations on how to manage the TW DI are also demonstrated.

Relationship between creatine kinase and liver enzymes in war wounded with rhabdomyolysis

BACKGROUND

Rhabdomyolysis is a frequent complication in war wounded. Its complex pathophysiology suggests that it not only affects kidneys but also other organs such as the liver. The aim of this study was to evaluate the relationship between creatine kinase (CK) and liver enzymes in war wounded with rhabdomyolysis.

METHODS

War wounded admitted to the intensive care unit of Percy Military Hospital between 2009 and 2017 with a rhabdomyolysis (CK peak >1,000 U/L) were included. They were divided in two groups: mild (CK peak <10,000 U/L) and severe rhabdomyolysis (CK peak ≥10,000 U/L). Demographic characteristics, peaks in transaminases, alkaline phosphatase (ALP), bilirubin, and CK were recorded. Mann Whitney-U test and, Fisher's exact test were used as appropriate. A Pearson's correlation test was used to determine the correlation between CK and liver enzymes after a log-normal transformation of the data.

RESULTS

Fifty-one patients were included (31 in the mild and 20 in the severe rhabdomyolysis group). Patients in the severe rhabdomyolysis group were more likely victims of explosions (85% vs 39%, p = 0.003). The transaminases peak was significantly higher in the severe rhabdomyolysis group (median AST peak 398 (270-944) vs 91 (63-157) U/L, p <0.0001, and median ALT peak 106 (77-235) vs 45 (34-71) U/L, p<0.0001). Bilirubin and ALP were higher in the severe rhabdomyolysis group (39 (25-49) vs 14(11-23) U/L, p = 0.0031 and 84 (55-170) vs 52 (39-85) U/L, p = 0.0063, respectively). We found a significant positive linear correlation between CK and ALT (r = 0.73, p<0.0001), AST (r = 0.89, p<0.0001), ALP (r = 0.41, p = 0.0035), and bilirubin (r = 0.37, p = 0.0083).

CONCLUSION

We found a statistically significant positive correlation between CK and liver enzymes in rhabdomyolysis war wounded, indicating that hepatic damage occurs when rhabdomyolysis is severe and associated with elevated bilirubin and ALP. Further studies are needed to confirm this phenomenon and elucidate the pathophysiological mechanism.

LEVEL OF EVIDENCE

IV STUDY TYPE: Diagnostic.

Assessment of 17 clinically available renal biomarkers to predict acute kidney injury in critically ill patients

Background:

Systematic estimation of renal biomarkers in the intensive care unit (ICU) patients is lacking. Seventeen biomarkers were assessed to predict acute kidney injury (AKI) after admission to ICU.

Materials and methods:

A prospective, observational study was conducted in the general ICU of Guangdong Provincial People’s Hospital. Seventeen serum or urine biomarkers were studied for their abilities alone or in combination for predicting AKI and severe AKI.

Results:

Of 1498 patients, 376 (25.1%) developed AKI. Serum cystatin C (CysC) showed the best performance for predicting both AKI (area under the receiver operator characteristic curve [AUC] = 0.785, mean square error [MSE] = 0.118) and severe AKI (AUC = 0.883, MSE = 0.06). Regarding biomarkers combinations, CysC plus N-acetyl-β-d-glucosaminidase-to-creatinine ratio (NAG/Cr) was the best for predicting AKI (AUC = 0.856, MSE = 0.21). At the same time, CysC plus lactic acid (LAC) performed the best for predicting severe AKI (AUC = 0.907, MSE = 0.058). Regarding combinations of biomarkers and clinical markers, CysC plus Acute Physiology and Chronic Health Evaluation (APACHE) II score showed the best performance for predicting AKI (AUC = 0.868, MSE = 0.407). In contrast, CysC plus Multiple Organ Dysfunction Score (MODS) had the highest predictive ability for severe AKI (AUC = 0.912, MSE = 0.488).

Conclusion:

Apart from CysC, the combination of most clinically available biomarkers or clinical markers does not significantly improve the forecasting ability, and the cost–benefit ratio is not economical.

Definitions of acute renal dysfunction: an evolving clinical and biomarker paradigm

PURPOSE OF REVIEW

The current definition and classification of acute kidney injury (AKI) has limitations and shortcomings, which impact clinical management. The aim of this review is to highlight recent advances in our understanding of the pathophysiology and epidemiology of AKI, which impacts management and offers opportunities.

RECENT FINDINGS

Kidney damage varies according to the type of primary insult, secondary effects and mitigating responses and leads to distinct molecular, cellular and functional changes. Different sub-types of AKI with varying clinical phenotypes, recovery patterns and responses to therapeutic interventions have been identified. New tools to identify and characterize these AKI sub-types are available with the potential opportunity for individualized timely aetiology-based management of AKI.

SUMMARY

The identification of different sub-phenotypes of AKI based on genetic, molecular, cellular and functional pathophysiological changes following potential nephrotoxic exposures is possible with new technologies. This offers opportunities for personalized management of AKI and supports the call for a refinement of the existing AKI criteria.

Cardiac Surgery Associated AKI Prevention Strategies and Medical Treatment for CSA-AKI

Acute kidney injury (AKI) is common after cardiac surgery. To date, there are no specific pharmacological therapies. In this review, we summarise the existing evidence for prevention and management of cardiac surgery-associated AKI and outline areas for future research. Preoperatively, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers should be withheld and nephrotoxins should be avoided to reduce the risk. Intraoperative strategies include goal-directed therapy with individualised blood pressure management and administration of balanced fluids, the use of circuits with biocompatible coatings, application of minimally invasive extracorporeal circulation, and lung protective ventilation. Postoperative management should be in accordance with current KDIGO AKI recommendations.

Emergency angiography for trauma patients and potential association with acute kidney injury

BACKGROUND

Angiography has been conducted as a hemostatic procedure for trauma patients. While several complications, such as tissue necrosis after embolization, have been reported, little is known regarding subsequent acute kidney injury (AKI) due to contrast media. To elucidate whether emergency angiography would introduce kidney dysfunction in trauma victims, we compared the incidence of AKI between patients who underwent emergency angiography and those who did not.

METHODS

A retrospective cohort study was conducted using a nationwide trauma database (2004-2019), and adult trauma patients were included. The indication of emergency angiography was determined by both trauma surgeons and radiologists, and AKI was diagnosed by treating physicians based on a rise in serum creatinine and/or fall in urine output according to any published standard criteria. Incidence of AKI was compared between patients who underwent emergency angiography and those who did not. Propensity score matching was conducted to adjust baseline characteristics including age, comorbidities, mechanism of injury, vital signs on admission, Injury Severity Scale (ISS), degree of traumatic kidney injury, surgical procedures, and surgery on the kidney, such as nephrectomy and nephrorrhaphy.

RESULTS

Among 230,776 patients eligible for the study, 14,180 underwent emergency angiography. The abdomen/pelvis was major site for angiography (10,624 [83.5%]). Embolization was performed in 5,541 (43.5%). Propensity score matching selected 12,724 pairs of severely injured patients (median age, 59; median ISS, 25). While the incidence of AKI was rare, it was higher among patients who underwent emergency angiography than in those who did not (140 [1.1%] vs. 67 [0.5%]; odds ratio = 2.10 [1.57-2.82]; p < 0.01). The association between emergency angiography and subsequent AKI was observed regardless of vasopressor usage or injury severity in subgroup analyses.

CONCLUSIONS

Emergency angiography in trauma patients was probably associated with increased incidence of AKI. The results should be validated in future studies.

Prescribing Continuous Kidney Replacement Therapy in Acute Kidney Injury: A Narrative Review

Severe acute kidney injury is a common complication in critically ill patients, often necessitating support with a modality of kidney replacement therapy. Continuous kidney replacement therapies (CKRTs) have become a mainstay in the management of patients with acute kidney injury in the intensive care unit. Understanding the fundamentals of CKRT is necessary to safely and effectively prescribe treatment. In this narrative review, we summarize critical aspects of CKRT management, including selection of the mode of therapy; choice of hemofilter/hemodialyzer used; determination of the blood flow rate, composition and flow rates of dialysate and/or replacement fluids, and the ultrafiltration rate; and use and methods of anticoagulation. Requirements for vascular access and appropriate monitoring and dose adjustment of medications and a plan for monitoring the delivery of therapy and ensuring appropriate nutritional management are also discussed.

The pathophysiology of sepsis - 2021 update: Part 2, organ dysfunction and assessment

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

This is the second article in a 2-part series discussing the pathophysiology of sepsis. Part 1 of the series reviewed the immunologic response and overlapping pathways of inflammation and coagulation that contribute to the widespread organ dysfunction. In this article (part 2), major organ systems and their dysfunction in sepsis are reviewed, with discussion of scoring systems used to identify patterns and abnormal vital signs and laboratory values associated with sepsis.

SUMMARY

Sepsis is a dysregulated host response to infection that produces significant morbidity, and patients with shock due to sepsis have circulatory and cellular and metabolic abnormalities that lead to a higher mortality. Cardiovascular dysfunction produces vasodilation, reduced cardiac output and hypotension/shock requiring fluids, vasopressors, and advanced hemodynamic monitoring. Respiratory dysfunction may require mechanical ventilation and attention to volume status. Renal dysfunction is a frequent manifestation of sepsis. Hematologic dysfunction produces low platelets and either elevation or reduction of leucocytes, so consideration of the neutrophil:lymphocyte ratio may be useful. Procoagulant and antifibrinolytic activity leads to coagulation that is stimulated by inflammation. Hepatic dysfunction manifest as elevated bilirubin is often a late finding in sepsis and may cause reductions in production of essential proteins. Neurologic dysfunction may result from local endothelial injury and systemic inflammation through activity of the vagus nerve.

CONCLUSION

Timely recognition and team response with efficient use of therapies can improve patient outcome, and pharmacists with a complete understanding of the pathophysiologic mechanisms and treatments are valuable members of that team.

Early kidney injury in immunoglobulin A vasculitis: Role of renal biomarkers

BACKGROUND

We aimed to determine whether urine kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) can be used as early noninvasive biomarkers of kidney injury in immunoglobulin A vasculitis.

METHODS

Patients who were diagnosed with immunoglobulin A vasculitis were included in the study. Urine samples were collected for determination of urine KIM-1 and NGAL levels. The control group consisted of age-matched healthy children.

RESULTS

Sixty-one patients who were diagnosed with immunoglobulin A vasculitis were included in the study; 37.7% of these patients were determined to have renal involvement. Median KIM-1 was found to be significantly higher in the patient group (69.59 pg/mL) than the control group (40.84 pg/mL) (P = 0.001). Median NGAL was determined to be statistically significantly higher in the patient group (59.87 ng/mL) compared with the control group (44.87 ng/mL) (P = 0.013). In 23.6% of the patients without renal involvement at admission renal involvement developed within the following 6 months. When median KIM-1 and NGAL at admission of these patients were compared with the control group, they were determined to be statistically significantly higher (P = 0.001, P = 0.003).

CONCLUSIONS

The fact that our patients with late-term nephropathy had no hematuria and / or proteinuria and that KIM-1 and NGAL levels were determined to be high indicates that these biomarkers might be potentially reliable, noninvasive and early determinants of kidney injury.

Next-Day Discharge vs Early Discharge After Transcatheter Aortic Valve Replacement: Systematic Review and Meta-Analysis

With the growing utilization of transcatheter aortic valve replacement (TAVR) as an alternative option to surgical valve replacement (SAVR) in patients considered to be suboptimal for surgery, there is a need to explore the possibility of next day discharge (NDD) and its potential outcomes. The aim of our study is to compare outcomes and complications following NDD vs the standard early discharge (ED) (less than 3 days). A comprehensive literature search was performed in PubMed, Embase, and Cochrane to identify relevant trials. Summary effects were calculated using a DerSimonian and Laird random effects model as odds ratio with 95% confidence intervals for all the clinical endpoints. Studies comparing same-day or next-day discharge vs discharge within the next three days were included in our analysis. 6 studies with 2,672 patients were identified. The risk of bleeding and vascular complications was significantly lower in patients with NDD compared to ED (OR 0.10, P < 0.00001 and OR 0.22, P = 0.002 respectively). The incidence of permanent pacemaker (PPM) implants was significantly lower in patients who had NDD compared to ED (OR 0.21, P = 0.0005). The incidence of 30 day mortality, stroke, AKI and readmission rates was not different between the two groups. NDD after TAVR allows for reduction in hospital stay and can mitigate hospital costs without an increased risk of complications. Our analysis shows that complication rate is comparable to ED, NDD is a reasonable option for certain patients with severe aortic stenosis who undergo TAVR. Further studies are needed to elucidate whether higher risk patients who would benefit from an extended inpatient monitoring post TAVR.

Utility of suPAR and NGAL for AKI Risk Stratification and Early Optimization of Renal Risk Medications among Older Patients in the Emergency Department

Diagnosis of acute kidney injury (AKI) based on plasma creatinine often lags behind actual changes in renal function. Here, we investigated early detection of AKI using the plasma soluble urokinase plasminogen activator receptor (suPAR) and neutrophil gelatinase-sssociated lipocalin (NGAL) and observed the impact of early detection on prescribing recommendations for renally-eliminated medications. This study is a secondary analysis of data from the DISABLMENT cohort on acutely admitted older (≥65 years) medical patients (n = 339). Presence of AKI according to kidney disease: improving global outcomes (KDIGO) criteria was identified from inclusion to 48 h after inclusion. Discriminatory power of suPAR and NGAL was determined by receiver-operating characteristic (ROC). Selected medications that are contraindicated in AKI were identified in Renbase®. A total of 33 (9.7%) patients developed AKI. Discriminatory power for suPAR and NGAL was 0.69 and 0.78, respectively, at a cutoff of 4.26 ng/mL and 139.5 ng/mL, respectively. The interaction of suPAR and NGAL yielded a discriminatory power of 0.80, which was significantly higher than for suPAR alone (p = 0.0059). Among patients with AKI, 22 (60.6%) used at least one medication that should be avoided in AKI. Overall, suPAR and NGAL levels were independently associated with incident AKI and their combination yielded excellent discriminatory power for risk determination of AKI.

Defining Acute Kidney Injury

Acute kidney injury (AKI) is a syndrome of impaired kidney function associated with reduced survival and increased morbidity. International consensus criteria were developed based on changes in serum creatinine and urine output. Based on these definitions, epidemiologic studies have shown strong associations with clinical outcomes including death and dialysis. However, numerous limitations exist for creatinine and urine volume as markers of AKI and novel biomarkers have been developed to detect cellular stress or damage. Persistent AKI and acute kidney disease are relatively new concepts that explore the idea of AKI as a continuum with chronic kidney disease.

Admission creatinine is associated with poor outcomes in burn patients

INTRODUCTION

Renal failure is the most common organ failure in severely burned patients. However, defining acute kidney injury and renal failure is very challenging. This study was designed to determine the relationship between a biomarker commonly measured on admission, serum creatinine, and outcomes in burn patients.

METHODS

We conducted a retrospective cohort study of adult patients (≥ 18 years) with a burn ≥ 5% total body surface area (TBSA) and a serum creatinine level measured within the first 72 h after injury. Patients were admitted over an 11-year period and divided into two groups based on creatinine levels measured within the first 72 h after injury. Patients were categorized in the high creatinine group if they had a measured creatinine ≥107 μmol/L (≥1.21 mg/dL); this value was chosen as the threshold for creatinine based on our institution's reference range. Clinical outcomes included morbidities, hospital length of stay, and mortality. Multivariable logistic regression was used to model the association between high admission creatinine and each outcome, adjusting for patient and injury characteristics.

RESULTS

We studied 923 patients, mean age 47 ± 18 years and median 13% (IQR 8-24) TBSA burned. There were 718 patients categorized with low admission creatinine and 205 patients with high admission creatinine. After adjustment for patient and injury characteristics, high admission creatinine was associated with a significantly higher rate of sepsis (OR 3.44; 95% CI 2.11-5.59), pneumonia (OR 4.56; 95% CI 1.8-11.53), and mortality (OR 3.59; 95% CI 1.91-6.75).

CONCLUSIONS

Elevated creatinine on admission is associated with an increased risk of morbidity and mortality. We suggest that admission creatinine can be used as a "red flag" to identify patients at a higher risk for poor outcomes.

Clinical Profile and Short-Term Outcomes of Acute Kidney Injury in Patients Admitted to a Teaching Hospital in Ethiopia: A Prospective Study

Background

Acute kidney injury (AKI) is a common complication in hospitalized patients and a marker for poor patient outcomes. It is associated with a high risk of mortality and other short- and long-term adverse outcomes. We aim to assess the clinical profile and short-term outcomes of acute kidney injury in adult patients admitted to the medical ward.

Methods

A hospital-based prospective observational study was conducted from October 2019 to January 2020. All adult patients diagnosed as AKI using kidney disease improving global outcomes (KIDGO) criteria were included in the study and prospectively followed to document the short-term outcomes. Outcomes and their predictors were determined using multivariate logistic regression. P-value less than 0.05 was taken as statistically significant.

Results

A total of 160 patients were included in the study. Out of this, 96 (60%) were males, 118 (74%) had community-acquired AKI, and 51 (32%) had stage 3 AKI. Common causes of AKI were hypovolemia 62 (39%) and sepsis 35 (22%). Hypertension 69 (43%) and heart failure 50 (31%) were common underlying comorbidities. Fifty-six (35%) patients developed systemic complications, 98 (61.2%) had persistent AKI, 136 (85%) had prolonged length of hospital stay, and 18 (11%) were readmitted to the hospital. The presence of AKI-related complication (AOR=2.7, 95% CI: 1.14–6.58, p=0.024), and duration of AKI (AOR=9.7, 95% CI: 2.56–36.98, p=0.001) were factors associated with prolonged length of hospital stay. Preexisting CKD (AOR=3.6, 95% CI: 1.02–13.14, p=0.035) and stage 3 AKI (AOR=2.1, 95% CI: 1.6–3.57, p=0.04) were factors associated with 30-day hospital readmission.

Conclusion

Hypovolemia and infections were the primary causes of AKI. Complications, prolonged length of hospital stay, persistent AKI, and rehospitalization were poor short-term outcomes of AKI. Early diagnosis and timely management of AKI particularly in high-risk hospitalized patients, and post-AKI care including management of comorbidities for AKI survivors should improve these poor short-term outcomes.

The case for precision dosing: medical conservatism does not justify inaction

The need for precision dosing has been challenged on the basis of insufficient evidence. Herein, we argue that adequate evidence exists to conduct therapeutic drug monitoring (TDM) and precisely target antibiotic exposures. While achievement of any antibiotic concentration does not guarantee efficacy sans toxicity for any single patient, stochastic control optimizes the probability of achieving favourable responses across patients. We argue that variability in targets (such as the organism's MIC) can be considered with models. That is, complexity alone does not relegate the decision-making framework to 'clinician intuition'. We acknowledge the exposure-response relationships are modified by patient-specific factors (other drugs, baseline organ functional status etc.) and describe how precision dosing can inform clinical decision making rather than protocolize it. Finally, we call for randomized, controlled trials; however, we suggest that these trials are not necessary to make TDM standard of care for multiple classes of antibiotics.

Evidence for SARS-CoV-2 Spike Protein in the Urine of COVID-19 Patients

Background

SARS-CoV-2 infection has, as of April 2021, affected >133 million people worldwide, causing >2.5 million deaths. Because the large majority of individuals infected with SARS-CoV-2 are asymptomatic, major concerns have been raised about possible long-term consequences of the infection.

Methods

Wedeveloped an antigen capture assay to detect SARS-CoV-2 spike protein in urine samples from patients with COVID-19whose diagnosis was confirmed by positive PCR results from nasopharyngeal swabs (NP-PCR+) forSARS-CoV-2. We used a collection of 233 urine samples from 132 participants from Yale New Haven Hospital and the Children's Hospital of Philadelphia that were obtained during the pandemic (106 NP-PCR+ and 26 NP-PCR-), and a collection of 20 urine samples from 20 individuals collected before the pandemic.

Results

Our analysis identified 23 out of 91 (25%) NP-PCR+ adult participants with SARS-CoV-2 spike S1 protein in urine (Ur-S+). Interestingly, although all NP-PCR+ children were Ur-S-, one child who was NP-PCR- was found to be positive for spike protein in their urine. Of the 23 adults who were Ur-S+, only one individual showed detectable viral RNA in urine. Our analysis further showed that 24% and 21% of adults who were NP-PCR+ had high levels of albumin and cystatin C, respectively, in their urine. Among individuals with albuminuria (>0.3 mg/mg of creatinine), statistical correlation could be found between albumin and spike protein in urine.

Conclusions

Together, our data showed that one of four individuals infected with SARS-CoV-2 develop renal abnormalities, such as albuminuria. Awareness about the long-term effect of these findings is warranted.

Effect of National Early Warning Scoring System Implementation on Cardiopulmonary Arrest, Unplanned ICU Admission, Emergency Surgery, and Acute Kidney Injury in an Emergency Hospital, Egypt

Purpose

To evaluate the effect of national early warning scoring system (NEWS) implementation in identifying patients at risk of clinical deterioration at an emergency hospital.

Background

Early warning score has been developed to facilitate early detection of deterioration by categorizing a patients’ severity of illness and prompting nursing staff to request a medical review at specific trigger points.

Patients and Methods

A prospective, control/intervention groups’, quasi-experimental design was utilized. A sample of 364 adult patients were admitted to the inpatient unit at an emergency hospital for six months. The patients were divided into a study group (174 patients) and a control group (190 patients). All study patients were followed up to either death or hospital discharge before and after implementing a new observation chart. The patients’ outcomes were compared and analyzed between both groups.

Results

In the intervention period, compared to the control period, a significant reduction was seen in the number of cardiopulmonary arrest (4.7% vs 1.1%, p = 0.046), unplanned ICU admission (5.3% vs 1.7%, p = 0.049), emergency surgery (6.3% vs 0%, p = 0.001), acute kidney injury (6.8% vs 1.1%, p = 0.006). As well, there was a significant increase in the number of patients receiving medical reviews following clinical deterioration in terms of escalation plan (3.2% vs 26.4%, p = <0.001).

Conclusion

The implementation of NEWS was associated with a significant improvement in patients’ outcomes in hospital wards, increases in the frequency of vital signs measurements, and an increase in the number of medical reviews following clinical instability.

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Fiber scaffold bioartificial liver therapy relieves acute liver failure and extrahepatic organ injury in pigs

Rationale: Acute liver failure (ALF) causes severe liver injury and a systemic inflammatory response, leading to multiorgan failure with a high short-term mortality. Bioartificial liver (BAL) therapy is a promising approach that is hampered by the lack of appropriate bioreactors and carriers to retain hepatic cell function and poor understanding of BAL treatment mechanisms in ALF and extrahepatic organ injury. Recently, we used a fiber scaffold bioreactor (FSB) for the high-density, three-dimensional (3D) culture of primary porcine hepatocytes (PPHs) combined with an absorption component to construct a BAL and verified its function in a D-galactosamine (D-gal)-induced ALF porcine model to evaluate its protective effects on the liver and extrahepatic organs. Methods: Male pigs were randomized into standard/supportive therapy (ST), ST+no-cell BAL (ST+Sham BAL) and ST+BAL groups and received treatment 48 h after receiving a D-gal injection. Changes in blood chemistry and clinical symptoms were monitored for 120 h. Tissues and plasma were collected for analysis by pathological examination, immunoblotting, quantitative PCR and immunoassays. Results: PPHs cultured in the FSB obtained sufficient aeration and nutrition for high-density, 3D culture and maintained superior viability and functionality (biosynthesis and detoxification) compared with those cultured in flasks. All the animals developed ALF, acute kidney injury (AKI) and hepatic encephalopathy (HE) 48 h after D-gal infusion and received corresponding therapies. Animals in the BAL group showed markedly improved survival (4/5; 80%) compared with those in the ST+Sham BAL (0/5; p < 0.001) and ST (0/5; p < 0.001) groups. The levels of blood ammonia and biochemical and inflammatory indices were alleviated after BAL treatment. Increased liver regeneration and attenuations in the occurrence and severity of ALF, AKI and HE were observed in the ST+BAL group compared with the ST (p = 0.0009; p = 0.038) and ST+Sham BAL (p = 0.011; p = 0.031) groups. Gut leakage, the plasma endotoxin level, bacterial translocation, and peripheral and neuroinflammation were alleviated in the ST+BAL group compared with those in the other groups. Conclusions: BAL treatment enhanced liver regeneration and alleviated the systemic inflammatory response and extrahepatic organ injury to prolong survival in the ALF model and has potential as a therapeutic approach for ALF patients.

Importance of KIM-1 and MCP-1 in Determining the Leptospirosis-Associated AKI: A Sri Lankan Study

BACKGROUND

Acute kidney injury (AKI) is one of most prevalent and serious complications of leptospirosis, a prevalent zoonotic disease in tropical countries. Prompt diagnosis of the leptospirosis-associated AKI is a challenge as there are no proper diagnostic tools that can identify patients in the early stage. Kidney injury molecule-1 (KIM-1) and monocyte chemoattractant protein-1 (MCP-1) are widely used novel AKI biomarkers that are studied in various disease conditions with AKI, but not in leptospirosis. Thus, this study is aimed at seeking the importance of KIM-1 and MCP-1 in determining the leptospirosis-associated AKI.

METHODS

Leptospirosis-suspected patients who were admitted to medical wards of two selected hospitals in the Western province of Sri Lanka were recruited. Leptospirosis was confirmed by three diagnostic tests: PCR, MAT, and culture, and the status of AKI was determined by Kidney Disease Improving Global Outcomes (KDIGO) criteria.

RESULTS

Of 170 leptospirosis-suspected patients, 79 were leptospirosis confirmed, and among them, 24.05% of patients were diagnosed to have AKI according to KDIGO criteria. Median serum KIM-1 (p < 0.0001), urine KIM-1 (0.0053), serum MCP-1 (0.0080), and urine MCP-1 (0.0019) levels in those developing AKI were significantly higher than in patients not developing AKI. The biomarker levels associated with leptospirosis AKI had AUC-ROC of 0.8565, 0.7292, 0.7024, and 0.7282 for serum KIM-1, urine KIM-1, serum MCP-1, and urine MCP-1, respectively.

CONCLUSION

This study revealed serum KIM-1 as a promising marker for leptospirosis-associated AKI among the tested biomarkers. Thus, further validation is recommended with a larger study group.

Acute kidney injury among medical and surgical in-patients in the Cape Coast Teaching Hospital, Cape Coast, Ghana: a prospective cross-sectional study

Background

Acute kidney injury (AKI) is a syndrome associated with high morbidity, mortality and high hospital costs. Despite its adverse clinical and economic effects, only a few studies have reported reliable estimates on the incidence of AKI in sub-Sahara Africa. We assessed the incidence and associated factors of AKI among medical and surgical patients admitted to a tertiary hospital in Ghana.

Methods

A prospective cross-sectional study was conducted among one hundred and forty-five (145) consecutive patients admitted to the medical and the surgical wards at the Cape Coast Teaching Hospital (CCTH), Cape Coast, Ghana from April 2017 to April 2018. Socio-demographic and clinical information were collected using structured questionnaires. AKI was diagnosed and staged with the KDIGO guideline, using admission serum creatinine as baseline kidney function.

Results

The mean age of the study participants was 46.6±17.7 years, whilst the male:female ratio was 68:77. The overall incidence of AKI among the participants was 15.9% (95% CI: 10.33 – 22.84%). Stage 1 AKI occurred in 56.5% of the participants, whilst stages 2 and 3 AKI respectively occurred among 4.1% and 2.8% of respondents. About 20% of the participants in the medical ward developed AKI (n= 15) whilst 12% of those in surgical ward developed AKI (n= 8). Among the participants admitted to the medical ward, 60.0%, 26.7% and 13.3% had stages 1, 2 and 3 AKI respectively. Whilst 50.0%, 25.0% and 25.0% respectively developed stages 1, 2 and 3 AKI in the surgical ward. Medical patients with AKI had hypertension (40%), followed by liver disease (33.3%); 37.5% of surgical inpatients had gastrointestinal (GI) disorders.

Conclusion

The incidence of AKI is high among medical and surgical patients in-patients in the CCTH, Ghana, with hypertension and liver disease as major comorbidities.

A nomogram incorporating functional and tubular damage biomarkers to predict the risk of acute kidney injury for septic patients

Background

Combining tubular damage and functional biomarkers may improve prediction precision of acute kidney injury (AKI). Serum cystatin C (sCysC) represents functional damage of kidney, while urinary N-acetyl-β-D-glucosaminidase (uNAG) is considered as a tubular damage biomarker. So far, there is no nomogram containing this combination to predict AKI in septic cohort. We aimed to compare the performance of AKI prediction models with or without incorporating these two biomarkers and develop an effective nomogram for septic patients in intensive care unit (ICU).

Methods

This was a prospective study conducted in the mixed medical-surgical ICU of a tertiary care hospital. Adults with sepsis were enrolled. The patients were divided into development and validation cohorts in chronological order of ICU admission. A logistic regression model for AKI prediction was first constructed in the development cohort. The contribution of the biomarkers (sCysC, uNAG) to this model for AKI prediction was assessed with the area under the receiver operator characteristic curve (AUC), continuous net reclassification index (cNRI), and incremental discrimination improvement (IDI). Then nomogram was established based on the model with the best performance. This nomogram was validated in the validation cohort in terms of discrimination and calibration. The decision curve analysis (DCA) was performed to evaluate the nomogram’s clinical utility.

Results

Of 358 enrolled patients, 232 were in the development cohort (69 AKI), while 126 in the validation cohort (52 AKI). The first clinical model included the APACHE II score, serum creatinine, and vasopressor used at ICU admission. Adding sCysC and uNAG to this model improved the AUC to 0.831. Furthermore, incorporating them significantly improved risk reclassification over the predictive model alone, with cNRI (0.575) and IDI (0.085). A nomogram was then established based on the new model including sCysC and uNAG. Application of this nomogram in the validation cohort yielded fair discrimination with an AUC of 0.784 and good calibration. The DCA revealed good clinical utility of this nomogram.

Conclusions

A nomogram that incorporates functional marker (sCysC) and tubular damage marker (uNAG), together with routine clinical factors may be a useful prognostic tool for individualized prediction of AKI in septic patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02388-w.

Predictors and Outcomes of Dengue-Associated Acute Kidney Injury

Dengue viral infections present with a wide clinical spectrum ranging from asymptomatic to severe manifestations with organ involvement. The term "expanded dengue syndrome" has been commonly used to illustrate the unusual or atypical manifestations; acute kidney injury (AKI) is one of the atypical manifestations of this syndrome. The use of heterogeneous criteria to determine the presence of AKI in dengue patients due to the vast diversity in populations led to difficulties in assessing the true incidence of dengue-associated AKI. This review presents a variable, but often high, frequency of dengue-associated AKI among vastly diverse populations with various disease severities. Dengue-associated AKI is not an uncommon complication, and its importance has often been neglected during the management of dengue patients. The risk factors and certain clinical and laboratory findings commonly reported among dengue patients with AKI should be considered to support a timely diagnosis and case management. This review highlights the need for clinicians to be aware of dengue-associated AKI to reduce the morbidity and mortality associated with this common and important tropical disease.

Convolutional Neural Network Model for Intensive Care Unit Acute Kidney Injury Prediction

INTRODUCTION

Acute kidney injury (AKI) is common among hospitalized patients and has a significant impact on morbidity and mortality. Although early prediction of AKI has the potential to reduce adverse patient outcomes, it remains a difficult condition to predict and diagnose. The purpose of this study was to evaluate the ability of a machine learning algorithm to predict for AKI as defined by Kidney Disease: Improving Global Outcomes (KDIGO) stage 2 or 3 up to 48 hours in advance of onset using convolutional neural networks (CNNs) and patient electronic health record (EHR) data.

METHODS

A CNN prediction system was developed to use EHR data gathered during patients' stays to predict AKI up to 48 hours before onset. A total of 12,347 patient encounters were retrospectively analyzed from the Medical Information Mart for Intensive Care III (MIMIC-III) database. An XGBoost AKI prediction model and the sequential organ failure assessment (SOFA) scoring system were used as comparators. The outcome was AKI onset. The model was trained on routinely collected patient EHR data. Measurements included area under the receiver operating characteristic (AUROC) curve, positive predictive value (PPV), and a battery of additional performance metrics for advance prediction of AKI onset.

RESULTS

On a hold-out test set, the algorithm attained an AUROC of 0.86 and PPV of 0.24, relative to a cohort AKI prevalence of 7.62%, for long-horizon AKI prediction at a 48-hour window before onset.

CONCLUSION

A CNN machine learning-based AKI prediction model outperforms XGBoost and the SOFA scoring system, revealing superior performance in predicting AKI 48 hours before onset, without reliance on serum creatinine (SCr) measurements.

Endothelial glycocalyx degradation is associated with early organ impairment in polytrauma patients

BACKGROUND

Endothelial glycocalyx (EG) abnormal degradation were widely found in critical illness. However, data of EG degradation in multiple traumas is limited. We performed a study to assess the EG degradation and the correlation between the degradation and organ functions in polytrauma patients.

METHODS

A prospective observational study was conducted to enroll health participants (control group) and polytrauma patients (trauma group) at a University affiliated hospital between Feb 2020 and Oct 2020. Syndecan1 (SDC1) and heparin sulfate (HS) were detected in serum sample of both groups. In trauma group, injury severity scores (ISS) and sequential organ failure assessments (SOFA) were calculated. Occurrences of acute kidney injury (AKI), trauma-induced coagulopathy (TIC) within 48 h and 28-day all-cause mortality in trauma group were recorded. Serum SDC1 and HS levels were compared between two groups. Correlations between SDC1/HS and the indicators of organ systems in the trauma group were analyzed. ROC analyses were performed to assess the predictive value of SDC1 and HS for AKI, TIC within 48 h, and 28-day mortality in trauma group.

RESULTS

There were 45 polytrauma patients and 15 healthy participants were collected, totally. SDC1 and HS were significantly higher in trauma group than in control group (69.39 [54.18-130.80] vs. 24.15 [13.89-32.36], 38.92 [30.47-67.96] vs. 15.55 [11.89-23.24], P <  0.001, respectively). Trauma group was divided into high degradation group and low degradation group according to SDC1 median. High degradation group had more severe ISS, SOFA scores, worse organ functions (respiratory, kidney, coagulation and metabolic system), and higher incidence of hypothermia, acidosis and shock. The area under the receiver operator characteristic curves (AUC) of SDC1 to predict AKI, TIC occurrence within 48 h and 28-day mortality were 0.838 (95%CI: 0.720-0.957), 0.700 (95%CI: 0.514-0.885) and 0.764 (95%CI: 0.543-0.984), respectively.

CONCLUSIONS

EG degradation was elevated significantly in polytrauma patients, and the degradation was correlated with impaired respiratory, kidney, coagulation and metabolic systems in early stage. Serum SDC1 is a valuable predictive indicator of early onset of AKI, TIC, and 28-day mortality in polytrauma patients.

Enhancing Military Burn- and Trauma-Related Acute Kidney Injury Prediction Through an Automated Machine Learning Platform and Point-of-Care Testing

CONTEXT.—

Delayed recognition of acute kidney injury (AKI) results in poor outcomes in military and civilian burn-trauma care. Poor predictive ability of urine output (UOP) and creatinine contribute to the delayed recognition of AKI.

OBJECTIVE.—

To determine the impact of point-of-care (POC) AKI biomarker enhanced by machine learning (ML) algorithms in burn-injured and trauma patients.

DESIGN.—

We conducted a 2-phased study to develop and validate a novel POC device for measuring neutrophil gelatinase-associated lipocalin (NGAL) and creatinine from blood samples. In phase I, 40 remnant plasma samples were used to evaluate the analytic performance of the POC device. Next, phase II enrolled 125 adults with either burns that were 20% or greater of total body surface area or nonburn trauma with suspicion of AKI for clinical validation. We applied an automated ML approach to develop models predicting AKI, using a combination of NGAL, creatinine, and/or UOP as features.

RESULTS.—

Point-of-care NGAL (mean [SD] bias: 9.8 [38.5] ng/mL, P = .10) and creatinine results (mean [SD] bias: 0.28 [0.30] mg/dL, P = .18) were comparable to the reference method. NGAL was an independent predictor of AKI (odds ratio, 1.6; 95% CI, 0.08-5.20; P = .01). The optimal ML model achieved an accuracy, sensitivity, and specificity of 96%, 92.3%, and 97.7%, respectively, with NGAL, creatinine, and UOP as features. Area under the receiver operator curve was 0.96.

CONCLUSIONS.—

Point-of-care NGAL testing is feasible and produces results comparable to reference methods. Machine learning enhanced the predictive performance of AKI biomarkers including NGAL and was superior to the current techniques.