Renal dysfunction in trauma: even a little costs a lot

Selection of appropriate reference creatinine estimate for acute kidney injury diagnosis in patients with severe trauma

BACKGROUND

In patients with severe trauma, the diagnosis of acute kidney injury (AKI) is important because it is a predictive factor for poor prognosis and can affect patient care. The diagnosis and staging of AKI are based on change in serum creatinine (SCr) levels from baseline. However, baseline creatinine levels in patients with traumatic injuries are often unknown, making the diagnosis of AKI in trauma patients difficult. This study aimed to enhance the accuracy of AKI diagnosis in trauma patients by presenting an appropriate reference creatinine estimate (RCE).

METHODS

We reviewed adult patients with severe trauma requiring intensive care unit admission between 2015 and 2019 (n=3,228) at a single regional trauma center in South Korea. AKI was diagnosed based on the current guideline published by the Kidney Disease: Improving Global Outcomes organization. AKI was determined using the following RCEs: estimated SCr75-modification of diet in renal disease (MDRD), trauma MDRD (TMDRD), admission creatinine level, and first-day creatinine nadir. We assessed inclusivity, prognostic ability, and incrementality using the different RCEs.

RESULTS

The incidence of AKI varied from 15% to 46% according to the RCE used. The receiver operating characteristic curve of TMDRD used to predict mortality and the need for renal replacement therapy (RRT) had the highest value and was statistically significant (0.797, P<0.001; 0.890, P=0.002, respectively). In addition, the use of TMDRD resulted in a mortality prognostic ability and the need for RRT was incremental with AKI stage.

CONCLUSIONS

In this study, TMDRD was feasible as a RCE, resulting in optimal post-traumatic AKI diagnosis and prognosis.

Risk Factors and Outcomes of Post-traumatic Acute Kidney Injury Requiring Renal Replacement Therapy: A Case-Control Study

Background

Acute kidney injury (AKI) following severe trauma is common. However, the requirement of renal replacement therapy (RRT) in these patients is rare and is associated with high morbidity and mortality. The primary objective of this study was to identify odds of risk factors, in particular, hypotension at presentation, for the requirement of RRT in patients with AKI following trauma.

Methods

We performed a case-control study involving patients who were admitted to the intensive care unit (ICU) at a level I trauma center for at least 24 hours. The primary outcome measure was a study of the odds of risk factors associated with the requirement of RRT in such patients. Univariate comparisons and multiple logistic regression analyses were done to identify other risk factors.

Results

The presence of crush injury, sepsis, and elevated serum creatinine (sCr) on arrival were identified to be independent risk factors for RRT requirement. Hypotension and exposure to radiocontrast or nephrotoxic antimicrobials were not found to be associated with the need for RRT. Acute kidney injury requiring RRT was associated with significantly increased ICU length of stay (15 days vs 5 days; p < 0.001) and higher mortality (83% vs 35%; p < 0.001).

Conclusion

The presence of crush injury, sepsis, and elevated sCr on presentation were identified to be independent risk factors while hypotension association was insignificant for AKI requiring RRT in our investigation.

How to cite this article

Soni KD, Singh A, Tyagi A, Singh Y, Aggarwal R, Trikha A. Risk Factors and Outcomes of Post-traumatic Acute Kidney Injury Requiring Renal Replacement Therapy: A Case-Control Study. Indian J Crit Care Med 2023;27(1):22-25.

The Clinical Impact of Platelets on Post-Injury Serum Creatinine Concentration in Multiple Trauma Patients: A Retrospective Cohort Study

Background and objective: Platelets contribute to the immunological response after multiple trauma. To determine the clinical impact, this study analyzes the association between platelets and creatinine concentration as an indicator of kidney function in polytraumatized patients. Methods: We investigated all patients presenting an Injury Severity Score (ISS) ≥16 for a 2-year period at our trauma center. Platelet counts and creatinine concentrations were analyzed, and correlation analysis was performed within 10 days after multiple trauma. Results: 83 patients with a median ISS of 22 were included. Platelet count was decreased on day 3 (p ≤ 0.001) and increased on day 10 (p ≤ 0.001). Platelet count was elevated on day 10 in younger patients and diminished in severely injured patients (ISS ≥35) on day 1 (p = 0.012) and day 3 (p = 0.011). Creatinine concentration was decreased on day 1 (p = 0.003) and day 10 (p ≤ 0.001) in female patients. Age (p = 0.01), male sex (p = 0.004), and injury severity (p = 0.014) were identified as factors for increased creatinine concentration on day 1, whereas platelets (p = 0.046) were associated with decreased creatinine concentrations on day 5 after multiple trauma. Conclusions: Kinetics of platelet count and creatinine concentration are influenced by age, gender, and trauma severity. There was no clear correlation between platelet counts and creatinine concentration. However, platelets seem to have a modulating effect on creatinine concentrations in the vulnerable phase after trauma.

Neutrophil Gelatinase-associated Lipocalin Predicts Post-traumatic Acute Kidney Injury in Severely Injured Patients

BACKGROUND

Early detection of acute kidney injury (AKI) is crucial in the management of multiple-organ dysfunction syndrome in severely injured patients. Standard laboratory parameters usually increase with temporal delay. Therefore, we evaluated neutrophil gelatinase-associated lipocalin (NGAL) as an early marker for acute kidney injury.

PATIENTS AND METHODS

We retrospectively evaluated patients admitted to a level 1 trauma center. We collected clinicodemographic data and measured kidney-related factors and plasma cytokines.

RESULTS

A total of 39 patients were included. Patients with AKI had significantly higher levels not only of serum creatinine and urea, but also of NGAL (all p<0.001) than patients without AKI. The optimal NGAL cut-off value was determined to be 177 ng/ml, showing significant correlation with imminent or manifest AKI (p<0.001). Other independent markers correlated with AKI included pre-existing chronic kidney disease, use of catecholamines, and severe injury (p<0.001).

CONCLUSION

The serum level of NGAL is feasible early predictor of AKI.

Importance of duration of acute kidney injury after severe trauma: a cohort study

Background

Acute kidney injury (AKI) is common after severe trauma. AKI incidence and AKI stage have previously been shown to be associated with poor outcomes after trauma. However, AKI duration may also be important for outcomes after trauma, given that it is associated with long-term morbidity and mortality in general intensive care unit (ICU) and hospitalized patients. We hypothesized that duration of AKI is independently associated with poor outcomes after trauma.

Methods

A cohort study was conducted at a single, level 1 trauma center. Patients admitted to the ICU between 2009 and 2018 were included. Data were extracted from the trauma registry and electronic medical records. AKI within 7 days from presentation was defined according to the Kidney Disease Improving Global Outcomes guidelines. Multivariable analyses were performed to assess the association between AKI incidence, AKI stage, and AKI duration with outcomes including prolonged ICU and hospital length of stay, discharge to home, and mortality.

Results

Of 7049 patients included, 72% were male, the median age was 41 years (IQR 27–58), and 10% died. The AKI incidence was 45%, with 69% of these patients presenting with AKI on arrival. The majority (73%) of patients who suffered AKI recovered within 2 days. After adjustment in separate models, AKI incidence, AKI stage and AKI duration were each associated with prolonged hospitalization, an unfavorable discharge disposition, and mortality. AKI stage and duration were not used in the same model due to collinearity.

Conclusions

Post-traumatic AKI was common on arrival and frequently short lasting. Duration correlated with highest AKI stage, and both were separately associated with prolonged hospitalization, discharge destination other than home, and mortality on adjusted analyses. Given the high incidence of AKI on arrival, stage or duration may be better targets for future interventions and quality improvement initiatives to improve outcomes after post-traumatic AKI.

Level of evidence

III. Prognostic.

Association between Urinary Potassium Excretion and Acute Kidney Injury in Critically Ill Patients

Introduction

Acute kidney injury (AKI) is defined in terms of serum creatinine (SrCrt) and urine output (UO). AKI occurs in 25% of critically ill patients, which increases the risk of morbidity and mortality. Early diagnosis of AKI is challenging, as utility of biomarkers is limited. This study is the first of its kind to estimate urinary potassium (UrK) excretion and its association with AKI in an Indian intensive care unit (ICU).

Aims and objectives

To study the association between UrK excretion and its ability to predict AKI in ICU patients.

Material and methods

During this prospective observational study, the patient's urinary indices and renal function tests were measured on day 1 of the ICU admission. UrK excretion and creatinine clearance (CrCl) were calculated from a 2-hour morning urine sample. Association between 2-hour UrK excretion and calculated CrCl and their ability to predict AKI in the subsequent 7 days was evaluated by Kidney Disease Improving Global Outcome (KDIGO)-AKI grading.

Results

Hundred patients admitted to ICU with a mean age of 53.59 ± 15.8 years were studied. The mean UrK excretion of 4.39 ± 2.52 was correlated linearly with CrCl and has a better prediction to AKI with the area under the receiver-operating characteristic curve value of 0.809 (CI 0.719-0.899), with a significant p-value (p <0.05). UrK excretion value of 3.49 on day 1 of ICU admission had 87% sensitivity and 74% specificity in predicting AKI. Thirty-one (31%) developed AKI, of which seven (22.58%) required renal replacement therapy (RRT), with 19% of all-cause mortality.

Conclusion

Diagnosis of AKI with traditional methods is not promising. UrK excretion correlates well with CrCl, which can be considered as the simplest accessible marker for predicting AKI in ICUs.

How to cite this article

Kumar NS, Kumar GN, Misra KC, Rao M, Chitithoti S, Prakash SY. Association between Urinary Potassium Excretion and Acute Kidney Injury in Critically Ill Patients. Indian J Crit Care Med 2021;25(7):768-772.

Influence of patients’ clinical features at intensive care unit admission on performance of cell cycle arrest biomarkers in predicting acute kidney injury

Objectives

Identification of acute kidney injury (AKI) can be challenging in patients with a variety of clinical features at intensive care unit (ICU) admission, and the capacity of biomarkers in this subpopulation has been poorly studied. In our study we examined the influence that patients’ clinical features at ICU admission have over the predicting ability of the combination of urinary tissue inhibitor of metalloproteinase-2 (TIMP2) and insulin-like growth factor binding protein 7 (IGFBP7).

Methods

Urinary [TIMP2]•[IGFBP7] were measured for all patients upon admission to ICU. We calculated the receiver operating characteristics (ROC) curves for AKI prediction in the overall cohort and for subgroups of patients according to etiology of ICU admission, which included: sepsis, trauma, neurological conditions, cardiovascular diseases, respiratory diseases, and non-classifiable causes.

Results

In the overall cohort of 719 patients, 239 (33.2%) developed AKI in the first seven days. [TIMP2]•[IGFBP7] at ICU admission were significantly higher in AKI patients than in non-AKI patients. This is true not only for the overall cohort but also in the other subgroups. The area under the ROC curve (AUC) for [TIMP2]•[IGFBP7] in predicting AKI in the first seven days was 0.633 (95% CI 0.588–0.678), for the overall cohort, with sensitivity and specificity of 66.1 and 51.9% respectively. When we considered patients with combined sepsis, trauma, and respiratory disease we found a higher AUC than patients without these conditions (0.711 vs. 0.575; p=0.002).

Conclusions

The accuracy of [TIMP2]•[IGFBP7] in predicting the risk of AKI in the first seven days after ICU admission has significant variability when the reason for ICU admission is considered.

Incidence and Risk Factors for Acute Kidney Injury in Severely Injured Patients Using Current Kidney Disease: Improving Global Outcomes Definitions

BACKGROUND

Acute kidney injury (AKI) is a significant cause of morbidity and mortality for critically injured trauma patients. The Kidney Disease: Improving Global Outcomes (KDIGO) practice guideline is the most up-to-date classification for AKI. The aims of this study were to determine the incidence and risk factors for AKI in critically injured trauma patients using the current KDIGO definitions.

STUDY DESIGN

A prospective cohort study was performed at our academic, level 1 trauma center, from September 2017 to August 2018. All adult trauma patients admitted to the surgical ICU were included. The primary outcome was the development of AKI, as defined by KDIGO. Secondary outcomes included hospital and ICU length of stay, ventilator days, and mortality.

RESULTS

There were 466 patients included and 314 (67%) developed AKI. Those who developed AKI were more often hypotensive on admission (7% vs 2%), had higher Injury Severity Scores (ISS) (19 vs 13), were more likely to have severe injuries to the chest (40% vs 24%) and extremities (20% vs 6%), received transfusion (41% vs 21%), sustained crush injuries (8% vs 1%), received radiocontrast (75% vs 47%), nephrotoxic medication (74% vs 60%), or vasopressors (15% vs 3%). After multivariate analysis, risk factors independently associated with AKI include age, Injury Severity Score (ISS), severe extremity injuries, radiocontrast, and vasopressors. Those who developed AKI had higher mortality (9% vs 2%).

CONCLUSIONS

Using current KDIGO criteria, the incidence of AKI in critically injured trauma patients was higher than previously reported. Older patients, with more severe injuries to their extremities and chest and who have suffered crush injuries, appear to be the most a risk. AKI in the critically injured patient results in an almost 5-fold increase in mortality.

The incidence and associations of acute kidney injury in trauma patients admitted to critical care: A systematic review and meta-analysis

BACKGROUND

As more patients are surviving the initial effects of traumatic injury clinicians are faced with managing the systemic complications of severe tissue injury. Of these, acute kidney injury (AKI) may be a sentinel complication contributing to adverse outcomes.

OBJECTIVE

To establish the incidence of AKI in patients admitted to critical care after major trauma, to explore any risk factors and to evaluate the association of AKI with outcomes.

DATA SOURCES

Systematic search of MEDLINE, Excerpta Medica database and Cochrane library from January 2004 to April 2018.

STUDY SELECTION

Studies of adult major trauma patients admitted to critical care that applied consensus AKI criteria (risk injury failure loss end stage [RIFLE], AKI network, or kidney disease improving global outcomes) and reported clinical outcomes were assessed (PROSPERO Registration: CRD42017056781). Of the 35 full-text articles selected from the screening, 17 (48.6%) studies were included.

DATA EXTRACTION AND SYNTHESIS

We followed the PRISMA guidelines and study quality was assessed using the Newcastle-Ottawa score. The pooled incidence of AKI and relative risk of death were estimated using random-effects models.

MAIN OUTCOMES AND MEASURES

Incidence of AKI was the primary outcome. The secondary outcome was study-defined mortality.

RESULTS

We included 17 articles describing AKI outcomes in 24,267 trauma patients. The pooled incidence of AKI was 20.4% (95% confidence interval [CI], 16.5-24.9). Twelve studies reported the breakdown of stages of AKI with 55.7% of patients classified as RIFLE-R or stage 1, 30.3% as RIFLE-I or stage 2, and 14.0% as RIFLE-F or stage 3. The pooled relative risk of death with AKI compared was 3.6 (95% CI, 2.4-5.3). In addition, there was a concordant increase in odds of death among six studies that adjusted for multiple variables (adjusted odds ratio, 2.7; 95% CI, 1.9-3.8; p = <0.01).

CONCLUSION

Acute kidney injury is common after major trauma and associated with increased mortality. Future research is warranted to reduce the potential for harm associated with this subtype of AKI.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level III.

Review of the Literature on the Costs Associated With Acute Kidney Injury

Acute kidney injury (AKI) develops in 8% to 16% of hospital admissions. These patients exhibit a 4- to 10-fold increase in mortality and prolonged hospital stays. There is a dearth of information on the economics of AKI, especially in critically ill patients whose health-care costs are already high. It is important that pharmacists understand the economic impact of AKI to optimally prevent and treat AKI occurrence, thus reducing total hospital costs. Authors used MEDLINE, PubMed, and Google Scholar searches up to April 2019. Inpatient AKI affects an estimated 498 000 patients in the United States with its annual cost from $4.7 to $24.0 billion. Average patient costs of AKI in the intensive care unit are generally double than those of non-AKI patients. High AKI severity portends a higher cost. Total hospital costs in patients with AKI ranged from $29 700 in cardiac surgery patients to $80 400 in cardiogenic shock. Incremental increases of cost range from $9400 in major surgery patients and up to $81 000 in nonsurviving dialysis patients. The enormity of the clinical and economic impact of AKI should be a call to action by pharmacists to expeditiously select patient-specific therapies to prevent and treat AKI, and thus reduce its economic burden on an already fragile health-care system.

Acute kidney injury following hip fracture

BACKGROUND

Hip fracture causes disability and excess mortality in the aging population. Acute kidney injury (AKI), is known to diminish survival of critically ill and trauma patients. AKI is also a common perioperative complication among surgical patients. We examined the effect of AKI on the survival of hip fracture patients in a Finnish hip fracture population and the risk factors for AKI in a prospective study.

METHODS

The study cohort constituted of 486 consecutive low-energy trauma hip fracture patients referred to Satakunta Central Hospital (Pori, Finland) and Turku University Hospital (Turku, Finland). The patients underwent standard diagnostics and treatment in the emergency department (ER) and were operated according to the local treatment protocol. Serum creatinine (sCr) was analyzed daily pre- and post-operatively during the hospital stay. Patients were divided into groups; AKI and non-AKI based on Kidney Disease: Improving Global Outcomes (KDIGO) criteria.

RESULTS

The incidence of AKI in the study cohort was 8.4% (40/475). Eleven patients were excluded due to missing sCr data. The baseline characteristics of AKI and non-AKI groups differed significantly concerning baseline sCr but were otherwise similar. At 90-day follow-up, the overall mortality was 14.4%. Patients with AKI had a significantly higher mortality (35.0%) than those with no AKI (12.7%) (p < 0.001). Dementia, preoperative sCr and any stage of AKI were independent predictors for mortality. Dementia and preoperative sCr were independently associated with post-operative AKI.

CONCLUSION

In this study AKI was a significant factor associated with a 3 -fold mortality during the first three months after surgery for low-energy trauma hip fracture.

Positive Fluid Balance and Association with Post-Traumatic Acute Kidney Injury

BACKGROUND

Acute kidney injury (AKI) is common in severely injured trauma patients and is associated with poor outcomes. A positive fluid balance is associated with AKI and poor long-term renal outcomes among general ICU and cardiac surgery patients. Currently, the optimal endpoint of resuscitation of severely injured trauma patients is unknown, which may result in excess fluid administration. We hypothesized that positive fluid balance is common after severe trauma and is associated with increased AKI development.

STUDY DESIGN

A cohort study of adult (≥16 years old) trauma patients requiring ICU admission from January 2017 to June of 2017 was conducted. Patients were excluded for early death, rhabdomyolysis, or previous history of end-stage renal disease or congestive heart failure. Acute kidney injury within 7 days of admission was defined according to Kidney Disease Improving Global Outcomes creatinine-based criteria. Univariate and multivariable analyses were performed.

RESULTS

Of 364 patients, 74% were male. The median age was 41 years (interquartile range [IQR] 27 to 59 years), and the median Injury Severity Score (ISS) was 18 (IQR 10 to 29). Positive fluid balance (>2 L) was observed in 49% of patients. Acute kidney injury was diagnosed in 105 (29%) patients. After adjustment, there was an increased risk of AKI with a positive fluid balance >2 L (relative risk [RR] 1.98 [95% CI 1.24 to 3.17]). Additionally, the risk of AKI incrementally increased by 1.22 with each liter fluid positive above a zero balance (95% CI 1.11 to 1.34).

CONCLUSIONS

Positive fluid balance in excess of 2 L at 48 hours occurs in half of severely injured trauma patients, and fluid positivity is independently and incrementally associated with AKI development. Fluid responsiveness should be investigated as an end point of post-traumatic resuscitation to prevent unnecessary fluid administration and subsequent AKI.

A prospective study of acute kidney injury in the intensive care unit: development and validation of a risk prediction model

BACKGROUND

Acute kidney injury (AKI) has high morbidity and mortality in intensive care units (ICU). It can also lead to chronic kidney disease (CKD), more costs and longer hospital stay. Early identification of AKI is important.

METHODS

We conducted this monocenter prospective observational study at West China Hospital, Sichuan University, China. We recorded information of each patient in the ICU within 24 h after admission and updated every two days. Patients who reached the primary outcome were accepted into the AKI group. Of all patients, we randomly drew 70% as the development cohort and the remaining 30% as the validation cohort. Using binary logistic regression we got a risk prediction model of the development cohort. In the validation cohort, we validated its discrimination by the area under the receiver operator curve (AUROC) and calibration by a calibration curve.

RESULTS

There were 656 patients in the development cohorts and 280 in the validation cohort. Independent predictors of AKI in the risk prediction model including hypertension, chronic kidney disease, acute pancreatitis, cardiac failure, shock, pH ≤ 7.30, CK > 1000 U/L, hypoproteinemia, nephrotoxin exposure, and male. In the validation cohort, the AUROC is 0.783 (95% CI 0.730-0.836) and the calibration curve shows good calibration of this prediction model. The optimal cut-off value to distinguish high-risk and low-risk patients is 4.5 points (sensitivity is 78.4%, specificity is 73.2% and Youden's index is 0.516).

CONCLUSIONS

This risk prediction model can help to identify high-risk patients of AKI in ICU to prevent the development of AKI and treat it at the early stages. Trial registration TCTR, TCTR20170531001. Registered 30 May 2017, http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trialsearch&smenu=fulltext&task=search&task2=view1&id=2573.

Choice of Reference Creatinine for Post-Traumatic Acute Kidney Injury Diagnosis

BACKGROUND

Acute kidney injury (AKI) after trauma is associated with poor outcomes. According to current guidelines, a diagnosis of AKI should be made based on an increase in serum creatinine from a reference value. However, a true reference is often unknown in patients presenting with traumatic injury. The aim of this study was to determine the optimal reference creatinine estimate for post-traumatic AKI diagnosis and staging. The optimal reference estimate was defined by a high incidence, strong prognostic ability, and incrementality at each stage.

STUDY DESIGN

This was a cohort study of adult trauma patients (older than 16 years) requiring ICU admission between 2009 and 2018 (n = 8,026) at a single Level I trauma center. AKI was determined using the following 4 reference creatinine estimates: Modified Diet of Renal Diseases (MDRD), Trauma MDRD, admission creatinine, and the first-day creatinine nadir. Inclusivity was assessed by incidence of AKI diagnosed with different reference creatinine estimates; prognostic ability was assessed by multivariable modified Poisson regression; and incrementality was assessed by correlation of mortality risk by AKI stage.

RESULTS

There was a wide range of AKI incidence, from 21% when using admission creatinine to 76% using the Trauma MDRD. The MDRD reference creatinine estimate resulted in an AKI incidence of 41% and a diagnosis that was both prognostic of mortality and incremental with each AKI stage. All other reference estimates resulted in AKI diagnoses that were either not prognostic or not incremental.

CONCLUSIONS

Reference creatinine estimate determines the clinical importance of AKI diagnoses. In this study, the MDRD reference resulted in optimal AKI diagnoses.

Erythropoietin in traumatic brain injury associated acute kidney injury: A randomized controlled trial

BACKGROUND

Acute kidney injury (AKI) in traumatic brain injury (TBI) is poorly understood and it is unknown if it can be attenuated using erythropoietin (EPO).

METHODS

Pre-planned analysis of patients included in the EPO-TBI (ClinicalTrials.gov NCT00987454) trial who were randomized to weekly EPO (40 000 units) or placebo (0.9% sodium chloride) subcutaneously up to three doses or until intensive care unit (ICU) discharge. Creatinine levels and urinary output (up to 7 days) were categorized according to the Kidney Disease Improving Global Outcome (KDIGO) classification. Severity of TBI was categorized with the International Mission for Prognosis and Analysis of Clinical Trials in TBI.

RESULTS

Of 3348 screened patients, 606 were randomized and 603 were analyzed. Of these, 82 (14%) patients developed AKI according to KDIGO (60 [10%] with KDIGO 1, 11 [2%] patients with KDIGO 2, and 11 [2%] patients with KDIGO 3). Male gender (hazard ratio [HR] 4.0 95% confidence interval [CI] 1.4-11.2, P = 0.008) and severity of TBI (HR 1.3 95% CI 1.1-1.4, P < 0.001 for each 10% increase in risk of poor 6 month outcome) predicted time to AKI. KDIGO stage 1 (HR 8.8 95% CI 4.5-17, P < 0.001), KDIGO stage 2 (HR 13.2 95% CI 3.9-45.2, P < 0.001) and KDIGO stage 3 (HR 11.7 95% CI 3.5-39.7, P < 0.005) predicted time to mortality. EPO did not influence time to AKI (HR 1.08 95% CI 0.7-1.67, P = 0.73) or creatinine levels during ICU stay (P = 0.09).

CONCLUSIONS

Acute kidney injury is more common in male patients and those with severe compared to moderate TBI and appears associated with worse outcome. EPO does not prevent AKI after TBI.

Prevalence and risk factors for acute kidney injury among trauma patients: a multicenter cohort study

Background

Organ failure, including acute kidney injury (AKI), is the third leading cause of death after bleeding and brain injury in trauma patients. We sought to assess the prevalence, the risk factors and the impact of AKI on outcome after trauma.

Methods

We performed a retrospective analysis of prospectively collected data from a multicenter trauma registry. AKI was defined according to the risk, injury, failure, loss of kidney function and end-stage kidney disease (RIFLE) classification from serum creatinine only. Prehospital and early hospital risk factors for AKI were identified using logistic regression analysis. The predictive models were internally validated using bootstrapping resampling technique.

Results

We included 3111 patients in the analysis. The incidence of AKI was 13% including 7% stage R, 3.7% stage I and 2.3% stage F. AKI incidence rose to 42.5% in patients presenting with hemorrhagic shock; 96% of AKI occurred within the 5 first days after trauma. In multivariate analysis, prehospital variables including minimum prehospital mean arterial pressure, maximum prehospital heart rate, secondary transfer to the trauma center and data early collected after hospital admission including injury severity score, renal trauma, blood lactate and hemorrhagic shock were independent risk factors in the models predicting AKI. The model had good discrimination with area under the receiver operating characteristic curve of 0.85 (0.82–0.88) to predict AKI stage I or F and 0.80 (0.77–0.83) to predict AKI of all stages. Rhabdomyolysis severity, assessed by the creatine kinase peak, was an additional independent risk factor for AKI when it was forced into the model (OR 1.041 (1.015–1.069) per step of 1000 U/mL, p < 0.001). AKI was independently associated with a twofold increase in ICU mortality.

Conclusions

AKI has an early onset and is independently associated with mortality in trauma patients. Its prevalence varies by a factor 3 according to the severity of injuries and hemorrhage. Prehospital and early hospital risk factors can provide good performance for early prediction of AKI after trauma. Hence, studies aiming to prevent AKI should target patients at high risk of AKI and investigate therapies early in the course of trauma care.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2265-9) contains supplementary material, which is available to authorized users.

Diagnostic Utility of Serum Neutrophil Gelatinase-Associated Lipocalin in Polytraumatized Patients Suffering Acute Kidney Injury: A Prospective Study

Introduction

The incidence of acute kidney injury (AKI) considerably increases the mortality rate in polytrauma victims. Undoubtedly, early identification of patients at risk is crucial for timely implementation of preventive strategies in order to improve their prognosis. Therefore, we aimed to investigate if serum neutrophil gelatinase-associated lipocalin (sNGAL) may serve as a diagnostic biomarker of early AKI in polytrauma victims, especially considering patients needing renal replacement theory (RRT).

Material and Methods

Forty consecutive polytrauma victims (ISS ≥ 16, AIS_Thorax ≥ 1, age ≥ 18 years, survival time ≥ 48 hours), directly admitted to our level I trauma center within one posttraumatic hour, were enrolled in our prospective study. sNGAL-levels were assessed at admission (initial) and on day 2 after trauma. AKI was diagnosed by an increase of serum creatinine (sCr) level of at least 0.3 mg/dl within 48 hours.

Results

Out of 30 men and 10 women (mean age, 43 years; mean ISS, 29), seven patients developed AKI, four of them needing RRT. AKI was diagnosed in 86% of the affected individuals until day 2. Day2-sNGAL-levels were higher in the AKI-group, compared to the no-AKI-group (p=0.049), and in patients treated with RRT than in individuals not needing RRT (p=0.037). Noteworthy, in patients not needing RRT sNGAL-levels significantly decreased from initial to day2-measurement (p=0.040). Furthermore, at any time point during our observation period polytraumatized patients with AKI and day2-sNGAL-levels of at least 181.0 ng/mL presented with higher sCr-levels compared to polytraumatized patients without AKI and day2-sNGAL-levels lower than 181.0 ng/mL (p≤0.029).

Conclusion

In polytrauma victims suffering AKI an increase in sNGAL-level from initial to day2-assessment may signalize deterioration in kidney function and thus indicate AKI progression. Unlike initial sNGAL-levels day2-sNGAL-levels might be an appropriate tool to define AKI and to signify the need of RRT in polytraumatized patients.

Acute kidney injury in trauma patients

PURPOSE OF REVIEW

To review epidemiology and pathophysiology of acute kidney injury (AKI) in trauma patients and propose strategies that aim at preventing AKI after trauma.

RECENT FINDINGS

AKI in trauma patients has been reported to be as frequent as 50% with an association to a prolonged length of stay and a raise in mortality. Among the specific risk factors encountered in trauma patients, hemorrhagic shock, rhabdomyolysis severity, age, and comorbidities are independently associated with AKI occurrence. Resuscitation with balanced solutes seems to have beneficial effects on renal outcome compared with NaCl 0.9%, particularly in the context of rhabdomyolysis. However, randomized clinical studies are needed to confirm this signal. Abdominal compartment syndrome (ACS) is rare but has to be diagnosed to initiate a dedicated therapy.

SUMMARY

The high incidence of AKI in trauma patients should lead to early identification of those at risk of AKI to establish a resuscitation strategy that aims at preventing AKI.

Acute Kidney Injury in Western Countries

BACKGROUND

Acute kidney injury (AKI) is frequent and is associated with poor outcomes, including increased mortality, higher risk of chronic kidney disease, and prolonged hospital lengths of stay. The epidemiology of AKI mainly derives from studies performed in Western high-income countries. More limited data are available from Western low-income and middle-income countries (LMICs) located in Central and South America.

SUMMARY

In this review, we summarize the most recent data on the epidemiology of AKI in Western countries, aiming to contrast results from industrialized high-income countries with LMICs. The global picture of AKI in LMICs is not as well characterized as in the USA and Europe. In addition, in some LMICs, the epidemiology of AKI may vary depending on the region and socioeconomic status, which contributes to the difficulty of getting a better portrait of the clinical condition. In low-income regions and tropical countries, AKI is frequently attributed to diarrhea, infections, nephrotoxins, as well as obstetric complications. As opposed to the situation in high-income countries, access to basic care in LMICs is limited by economic constraints, and treatment is often delayed due to late presentation and recognition of the condition, which contribute to worse outcomes. In addition, dialysis is often not available or must be paid by patients, which further restricts its use.

KEY MESSAGES

There are great disparities in the epidemiology of AKI between Western high-income countries and Western LMICs. In LMICs, education and training programs should increase the public awareness of AKI and improve preventive and basic treatments to improve AKI outcomes.

FACTS FROM EAST AND WEST

(1) More than 90% of the patients recruited in AKI studies using KDIGO-equivalent criteria originate from North America, Europe, or Oceania, although these regions represent less than a fifth of the global population. However, the pooled incidence of AKI in hospitalized patients reaches 20% globally with moderate variance between regions. (2) The lower incidence rates observed in Asian countries (except Japan) may be due to a poorer recognition rate, for instance because of less systematically performed serum creatinine tests. (3) AKI patients in South and Southeastern Asia are younger than in East Asia and Western countries and present with fewer comorbidities. (4) Asian countries (and to a certain extent Latin America) face specific challenges that lead to AKI: nephrotoxicity of traditional herbal and less strictly regulated nonprescription medicines, environmental toxins (snake, bee, and wasp venoms), and tropical infectious diseases (malaria and leptospirosis). A higher incidence and less efficient management of natural disasters (particularly earthquakes) are also causes of AKI that Western countries are less likely to encounter. (5) The incidence of obstetric AKI decreased globally together with an improvement in socioeconomic levels particularly in China and India in the last decades. However, antenatal care and abortion management must be improved to reduce AKI in women, particularly in rural areas. (6) Earlier nephrology referral and better access to peritoneal dialysis should improve the outcome of AKI patients.

Early Acute Kidney Injury based on Serum Creatinine or Cystatin C in Intensive Care Unit after Major Trauma

BACKGROUND

Acute kidney injury (AKI) is a common problem in critically ill patients and is independently associated with increased morbidity and mortality. Recently, serum cystatin C has been shown to be superior to creatinine in early detection of renal function impairment. We compared estimated GFR based on serum cystatin C with estimated GFR based on serum creatinine for early detection of renal dysfunction according to the RIFLE criteria.

METHODS

During 9 months, three hundred post trauma patients that were referred to the intensive care unit of a referral trauma hospital were recruited. Serum creatinine and serum cystatin C were measured and the estimated GFR within 24 hours of ICU admission was calculated. The primary outcome was the incidence of AKI according to the RIFLE criteria within 2(nd) to 7(th) day of admission.

RESULTS

During the first week of ICU admission, 21% of patients experienced AKI. After adjusting for major confounders, only the patients with first day's serum cystatin level higher than 0.78 mg/l were at higher risk of first week AKI (OR=6.14, 95% CI: 2.5-14.7, P<0.001). First day's serum cystatin C and injury severity score were the major risk factors for ICU mortality (OR=3.54, 95% CI: 1.7-7.4, P=0.001) and (OR=4.6, 95% CI: 1.5-14, P=0.007), respectively.

CONCLUSION

Within 24 hours after admission in ICU due to multiple trauma, high serum cystatin C level may have prognostic value in predicting early AKI and mortality during ICU admission. However, such correlation was not seen neither with creatinine nor cystatin C based GFR.

A Prospective International Multicenter Study of AKI in the Intensive Care Unit

BACKGROUND AND OBJECTIVES

AKI is frequent and is associated with poor outcomes. There is limited information on the epidemiology of AKI worldwide. This study compared patients with AKI in emerging and developed countries to determine the association of clinical factors and processes of care with outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This prospective observational study was conducted among intensive care unit patients from nine centers in developed countries and five centers in emerging countries. AKI was defined as an increase in creatinine of ≥0.3 mg/dl within 48 hours.

RESULTS

Between 2008 and 2012, 6647 patients were screened, of whom 1275 (19.2%) developed AKI. A total of 745 (58% of those with AKI) agreed to participate and had complete data. Patients in developed countries had more sepsis (52.1% versus 38.0%) and higher Acute Physiology and Chronic Health Evaluation (APACHE) scores (mean±SD, 61.1±27.5 versus 51.1±25.2); those from emerging countries had more CKD (54.3% versus 38.3%), GN (6.3% versus 0.9%), and interstitial nephritis (7.0% versus 0.6%) (all P<0.05). Patients from developed countries were less often treated with dialysis (15.5% versus 30.2%; P<0.001) and started dialysis later after AKI diagnosis (2.0 [interquartile range, 0.75-5.0] days versus 0 [interquartile range, 0-5.0] days; P=0.02). Hospital mortality was 22.0%, and 13.3% of survivors were dialysis dependent at discharge. Independent risk factors associated with hospital mortality included older age, residence in an emerging country, use of vasopressors (emerging countries only), dialysis and mechanical ventilation, and higher APACHE score and cumulative fluid balance (developed countries only). A lower probability of renal recovery was associated with residence in an emerging country, higher APACHE score (emerging countries only) and dialysis, while mechanical ventilation was associated with renal recovery (developed countries only).

CONCLUSIONS

This study contrasts the clinical features and management of AKI and demonstrates worse outcomes in emerging than in developed countries. Differences in variations in care may explain these findings and should be considered in future trials.

The incidence and outcomes of acute kidney injury amongst patients admitted to a level I trauma unit

PURPOSE

This study aimed to identify the incidence and outcomes of patients with trauma related acute kidney injury (AKI), as defined by RIFLE criteria, at a single level I trauma centre and trauma ICU.

METHODS

We performed a retrospective observational study of 666 patients admitted to a trauma ICU from a level I trauma unit from March 2008 to March 2011. We conducted multivariable logistic regression to identify independent predictors for AKI and mortality.

RESULTS

The overall incidence of AKI was 15% (n=102). Median injury severity score (ISS) was 25 (inter quartile range [IQR] 16-34) and mean age was 39 (SD 16.3) in the AKI group. Thirteen patients (13%) were referred with rhabdomyolysis associated renal Failure. Overall mortality in the AKI group was 57% (n=58) but was significantly lower in the rhabdomyolysis Failure group (23% versus 64%; p=0.012). AKI was independently associated with older age, base excess (BE)<-12 (odd ratio [OR] 22.9, 95% confidence interval [CI] 1.89-276.16), IV contrast administration (OR 2.7 95% CI 1.39-5.11) and blunt trauma (OR 2.2 95% CI 1.04-4.71). AKI was an independent predictor of mortality (OR 8.5, 95% CI 4.51-15.95). Thirty-nine (38%) patients required renal replacement therapy.

CONCLUSIONS

AKI in critically ill trauma patients is an independent risk factor for mortality and is independently associated with increasing age and low BE. Renal replacement therapy utilisation is high in this group and represents a significant health care cost burden.

Incidence and outcome of early acute kidney injury in critically-ill trauma patients

Objective

To determine the incidence and effect on mortality of early acute kidney injury in severely injured trauma patients using the Acute Kidney Injury Network creatinine criteria.

Design

A retrospective cohort study of severely injured trauma patients admitted to the shock trauma intensive care unit.

Setting

Texas Trauma Institute, a state designated level I trauma unit certified by the American College of Surgeons Committee on Trauma.

Patients

901 severely injured trauma patients admitted over a 15 month period to the shock trauma intensive care unit.

Interventions

Retrospective analysis of prospectively collected data abstracted from an electronic trauma database.

Measurements and Main Results

Of 901 eligible patients admitted to the shock trauma intensive care unit after traumatic injury, 54 patients (6%) developed acute kidney injury, of whom 10 (19%) required renal replacement therapy. The 30-day mortality rate for the entire cohort was 83/901 (9.2%). Patients with early acute kidney injury had a mortality rate of 16/54 (29.6%). When corrected for multiple covariates including injury severity scores, the development of early acute kidney injury was associated with a significantly higher risk of death at 30 days with an OR of 3.4 (95% CI 1.6-7.4).

Conclusions

Applying the Acute Kidney Injury Network creatinine criteria in severely injured trauma patients, the incidence of early acute kidney injury was 6%. After correction for injury severity, development of early acute kidney injury was independently associated with significantly higher 30-day mortality.

A novel experimental model of orthopedic trauma with acute kidney injury in obese Zucker rats

Obesity is associated with an increased risk of acute kidney injury (AKI) after blunt traumatic injury in humans. Because limitations exist in studying trauma in human patients, animal models are necessary to elucidate mechanisms of remote organ injury after trauma. We developed a model of severe orthopedic trauma in lean (LZ) and obese (OZ) Zucker rats, in which OZ develop greater kidney dysfunction after trauma than LZ. Orthopedic trauma was inflicted via bilateral hindlimb soft tissue injury, fibula fracture, and injection of homogenized bone components. Mean arterial pressure (MAP) and heart rate (HR) were measured for 6 h after trauma, and again at 24 h after trauma. Urine was collected for 24 h before and after trauma to measure urine albumin excretion. Glomerular filtration rate (GFR), renal plasma flow (RPF), plasma interleukin-6 (IL-6), and renal macrophage infiltration (ED-1 [CD68 Antibody] immunostaining) were measured in animals with and without trauma. MAP and HR were similar between LZ and OZ throughout the study, with the exception that OZ had a 18 mmHg lower pressure 24 h posttrauma. GFR and RPF were decreased significantly (∼50%), while urine albumin excretion, plasma IL-6, and renal ED-1-positive cells were increased in OZ 24 h after trauma compared to both OZ without trauma and LZ after trauma. In conclusion, these data are consistent with studies in humans that show that AKI develops more frequently in obese than in lean individuals. This model will be an important experimental tool to better understand the underlying mechanisms of poor outcomes after trauma in obese patients.

Acute kidney injury is associated with early cytokine changes after trauma

BACKGROUND

Acute kidney injury (AKI) occurs in 26% of trauma patients and is associated with increased mortality and risk for nosocomial infections (NCIs). We compared serial plasma cytokine levels in patients with posttraumatic AKI to determine whether the early cytokine changes are associated with the occurrence of AKI and NCI.

METHODS

We performed a secondary analysis of the Inflammation and the Host Response to Injury database to include adult blunt trauma patients who had available plasma proteomic analyses. AKI was defined by the RIFLE (Risk, Injury, Failure, Loss, and End-stage Kidney) classification, which requires a 50% increase in serum creatinine. The association among AKI, NCI, and plasma cytokines was analyzed using a mixed model analyses and logistic regression.

RESULTS

Among 147 patients in the cohort, prevalence of NCI was 73% and 52% for patients with and without AKI, respectively. In mixed model analyses adjusted for clinical factors, AKI patients developed significant early increase in IL-1ra, IL-8, MCP1, and IL-6; early decrease in sTNFR2; and late decrease in IL-1ra, IL-4, and IL-6 concentrations, compared with patients without AKI and regardless of NCI. The change in cytokine pattern differed for sIL1R2, CXCL1, and MIP1β, depending on the occurrence of NCI. Patients with AKI and NCI had lower early and late sIL1R2 and higher early and late CXCL1 and MIP1β levels. Within the first 24 hours of injury, adding plasma levels of IL-1ra, IL-8, MCP1, IL-6, and sTNFR2 to clinical parameters of injury severity provided a predictive model for AKI superior to clinical model only (p < 0.001).

CONCLUSION

AKI trauma patients exhibit simultaneous changes in proinflammatory and anti-inflammatory serial plasma cytokine levels. The predictive model for AKI that combines plasma cytokine levels with clinical data within 24 hours of injury requires further prospective validation in larger studies.

LEVEL OF EVIDENCE

Prognostic study, level III.

Incidence, risk factors and prognosis of acute kidney injury after transcatheter aortic valve implantation

AIM

  Transcatheter aortic valve implantation (TAVI) poses a significant risk of acute kidney injury (AKI). Little is known of the impact of TAVI and AKI on long-term kidney function and health cost. We explored the predictive factors and prognostic implications of AKI following TAVI.

METHODS

  Single-centre retrospective analysis of 52 elderly patients undergoing TAVI was conducted. The primary endpoint was renal outcome which included the incidence of AKI and 12-month renal function after TAVI. Secondary endpoints were mortality, the length of hospital stay (LOS) and cost.

RESULTS

  AKI occurred in 15/52 (28.8%) patients (mean age 84 ± 6) and three patients (6%) required dialysis. Patients with AKI (AKI+) had greater comorbidity (diabetes and cerebrovascular disease) and a trend towards reduced estimated glomerular filtration rate (eGFR) at baseline compared with those without AKI (56.6 vs AKI-: 65.7 mL/min per 1.73 m(2) , P = 0.07). Following TAVI, AKI- patients experienced an immediate improvement in eGFR, which remained significantly higher at all time points compared with AKI+ patients (70.4 vs 46.9 at 6 months and 73.7 vs 53.0 at 12 months, P < 0.001). Cumulative mortality for AKI+versus AKI- group was 26.7% and 2.7% (P = 0.006). LOS doubled (P < 0.001) and average hospitalization cost per patient was 1.5 times higher in the AKI+ group (P < 0.001). Independent predictors of AKI were peri-procedural blood transfusion (OR: 2.4, 95% CI: 2.0-3.1), trans-apical approach (OR: 9.3, 95% CI: 4.3-23.7) and hypertension (OR: 6.4, 95% CI: 2.9-17.3).

CONCLUSION

  AKI developed in 28.8% of patients after TAVI and was associated with procedural technique and transfusion requirement, and an increased LOS and mortality. However, most patients achieved a significant and sustained improvement in eGFR.

Acute kidney injury in patients with hemorrhagic fever with renal syndrome caused by Hantaan virus: comparative evaluation by RIFLE and AKIN criteria

Acute kidney injury (AKI) is one of the most prominent characteristics of hemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus. The present study evaluated the incidence and severity of AKI classified by both the RIFLE and AKIN criteria in 120 HFRS patients at 48  h and 1 week of the patient admission. The agreements between RIFLE and AKIN and RIFLE and AKIN defined by serum creatinine (AKINc and RIFLEc) were examined by Kappa statistics. AKI occurred in 79.2% and 82.5% at 48  h and in 84.2% and 89.2% at 1 week of admission by RIFLE and AKIN criteria, respectively. RIFLE and AKIN showed very good agreement in classifying AKI at 48  h and 1 week of admission (κ > 0.900). RIFLE and RIFLEc and AKIN and AKINc at 48  h and 1 week of admission had almost perfect agreement (κ > 0.900). The classifications of RIFLE and RIFLEc and AKIN and AKINc at 48  h and 1 week were in good agreement (κ > 0.650). AKI classifications by RIFLE and AKIN were associated with mortality, occurrence of complications, and length of hospital stay. We conclude that AKI occurs in nearly 90% of HFRS patients during the disease course. RIFLE and AKIN classify AKI in HFRS with similar sensitivity. RIFLEc and AKINc may be used as alternatives of standard RIFLE and AKIN in the settings of general wards. The AKI classifications defined at 48  h of admission have predictive value for HFRS disease progression and severity.

Incidence, clinical predictors, genomics, and outcome of acute kidney injury among trauma patients

OBJECTIVE

To determine clinical and genomic characteristics and in-hospital mortality risk associated with acute kidney injury (AKI) in the multicenter prospective cohort of patients with blunt trauma.

SUMMARY BACKGROUND DATA

Less severe stages of AKI characterized by small changes in serum creatinine (sCr) are inadequately studied among trauma patients.

METHODS

We performed a secondary analysis of the "Inflammation and the Host Response to Injury" (Glue Grant) database to include adult blunt trauma patients without history of kidney disease. AKI was defined by the Risk, Injury, Failure, Loss, and End-stage Kidney (RIFLE) classification, which requires a 50% increase in sCr and stratifies patients into following 3 severity stages: risk, injury, and failure. Association between all stages of AKI and in-hospital mortality was analyzed using a multivariable logistic regression analysis. Genome-wide expression analysis was performed on whole blood leukocytes obtained within 12 hours of trauma.

RESULTS

AKI occurred in 26% of 982 patients. The adjusted risk for hospital death was 3 times higher for patients with AKI compared with patients without AKI (odds ratio = 3.05) (95% confidence interval, 1.73-5.40). This risk was evident in a dose-response manner and even patients with mild AKI had odds ratio for dying of 2.57 (95% confidence interval, 1.19-5.50) compared with patients without AKI. Genome-wide expression analysis failed to show a significant number of genes whose expression could discriminate among patients with and without AKI.

CONCLUSIONS

In a multicenter prospective cohort of blunt trauma patients, AKI characterized by small changes in sCr was associated with an independent risk of hospital death.

A multi-center evaluation of early acute kidney injury in critically ill trauma patients

RATIONALE

Few studies have evaluated the epidemiology of acute kidney injury (AKI) in trauma.

OBJECTIVE

To evaluate the incidence, risk factors, and outcomes associated with early AKI (evident within 24 hours of admission) in critically ill trauma patients.

METHODS

A retrospective interrogation of prospectively collected data from the Australian New Zealand Intensive Care Society Adult Patient Database. A total of 9,449 trauma patients were admitted for >or=24 hours to 57 intensive care units across Australia from January 1(st), 2000, to December 31(st), 2005.

MAIN FINDINGS

The crude incidence of AKI was 18.1% (n = 1,711). Older age, female sex (OR 1.60, 95% CI, 1.43-1.78, p < 0.0001), and the presence of co-morbid illness (OR 2.70, 95% CI 2.3-3.2, p < 0.0001) were associated with higher odds of AKI. Those with trauma not associated with brain injury (OR 2.40, 95% CI, 2.1-2.7, p < 0.0001) and a higher illness severity (OR 1.12, 95% CI, 1.11-1.12, p < 0.001) also had higher likelihood of AKI. Overall, AKI was associated with a higher crude mortality (16.7% vs. 7.8%, OR 2.36, 95% CI, 2.0-2.7, p < 0.001). Each RIFLE category of AKI was independently associated with hospital mortality in multi-variable analysis (risk: OR 1.69; injury OR 1.88; failure 2.29).

CONCLUSIONS

Trauma admissions to ICU are frequently complicated by early AKI. Those at high risk for AKI appear to be older, female, with co-morbid illnesses, and present with greater illness severity. Early AKI in trauma is also independently associated with higher mortality. These data indicate a higher burden of AKI than previously described.