Prehospital Blood Pressure and Lactate are Early Predictors of Acute Kidney Injury After Trauma

Mean arterial pressure to norepinephrine equivalent dose ratio for predicting renal replacement therapy requirement: a retrospective analysis from the MIMIC-IV

BACKGROUND

This study aimed to assess the predictive value of the ratio of mean arterial pressure (MAP) to the corresponding peak rate of norepinephrine equivalent dose (NEQ) within the first day in patients with shock for the subsequent renal replacement therapy (RRT) requirement.

METHODS

Patients were identified using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The relationship was investigated using a restricted cubic spline curve, and propensity score matching(PSM) was used to eliminate differences between groups. Odds ratios (OR) with 95% confidence intervals (CI) were calculated using logistic regression. Variable significance was assessed using extreme gradient boosting (XGBoost), and receiver operating characteristic (ROC) curves were generated.

RESULTS

Of the 5775 patients, 301 (5.2%) received RRT. The MAP/NEQ index showed a declining L-shaped relationship for RRT. After PSM, the adjusted OR per 100 mmHg/mcg/kg/min for RRT was 0.93(95% CI 0.88-0.98). The most influential factors for RRT were fluid balance, baseline creatinine, and the MAP/NEQ index. The threshold for the MAP/NEQ index predicting RRT was 161.7 mmHg/mcg/kg/min (specificity: 65.8%, sensitivity: 74.8%) with an area under the ROC curve of 75.9% (95% CI 73.1-78.8).

CONCLUSIONS

The MAP/NEQ index served as an alternative predictor of RRT necessity based on the NEQ for adult patients who received at least one vasopressor over 6 h within the first 24 h of intensive care unit(ICU) admission. Dynamic modulation of the MAP/NEQ index by the synergistic use of various low-dose vasopressors targeting urine output may be beneficial for exploring individualized optimization of MAP.

Impact of lactate/albumin ratio on prognostic outcomes in patients with concomitant heart failure and chronic kidney disease

Previous studies have linked the lactate/albumin (L/A) ratio to poor outcomes in various conditions, but its connection to mortality in patients with both heart failure (HF) and chronic kidney disease (CKD) remains unclear. Using data from 1537 patients in MIMIC-IV, this study examined the relationship between L/A ratio and in-hospital and one-year mortality, employing Cox models, Kaplan-Meier (KM) analysis, and restricted cubic splines (RCS). The non-survivor group showed higher L/A ratios than survivors (1.04 ± 0.78 vs. 0.58 ± 0.29, p < 0.001), indicating a significant link between higher L/A ratios and mortality. Cox analysis identified the L/A ratio was significantly related to all-cause mortality both in-hospital (HR 2.033; 95% CI 1.576-2.624; p < 0.001) and one-year (HR 1.723; 95% CI 1.428-2.078; p < 0.001). The association between L/A ratio and mortality was non-linear and increasing. The KM survival curves demonstrated significantly poorer survival outcomes for the high L/A group compared to the low L/A group, a difference that was statistically validated by a significant log-rank test (log-rank p < 0.001). L/A ratio has a significant association with poor prognosis in patients with HF and CKD patients in a critical condition. This finding demonstrates that L/A ratio might be useful in identifying patients with HF and CKD at high risk of all-cause death. Further large-scale prospective studies are needed to verify these results and inform clinical decisions.

X-Ray-Based 3D Histopathology of the Kidney Using Cryogenic Contrast-Enhanced MicroCT

The kidney's microstructure, which comprises a highly convoluted tubular and vascular network, can only be partially revealed using classical 2D histology. Considering that the kidney's microstructure is closely related to its function and is often affected by pathologies, there is a need for powerful and high-resolution 3D imaging techniques to visualize the microstructure. Here, we present how cryogenic contrast-enhanced microCT (cryo-CECT) allowed 3D visualization of glomeruli, tubuli, and vasculature. By comparing different contrast-enhancing staining agents and freezing protocols, we found that the preferred sample preparation protocol was the combination of staining with 1:2 hafnium(IV)-substituted Wells-Dawson polyoxometalate and freezing by submersion in isopentane at -78°C. This optimized protocol showed to be highly sensitive, allowing to detect small pathology-induced microstructural changes in a mouse model of mild trauma-related acute kidney injury after thorax trauma and hemorrhagic shock. In summary, we demonstrated that cryo-CECT is an effective 3D histopathological tool that allows to enhance our understanding of kidney tissue microstructure and their related function.

Serum Lactate Level in Early Stage Is Associated With Acute Kidney Injury in Traumatic Brain Injury Patients

Background

Acute kidney injury (AKI) is a common complication in the clinical practice of managing patients with traumatic brain injury (TBI). Avoiding the development of AKI is beneficial for the prognosis of patients with TBI. We designed this study to testify whether serum lactate could be used as a predictive marker of AKI in patients with TBI.

Materials and Methods

In total, 243 patients with TBI admitted to our hospital were included in this study. Univariate and multivariate logistic regression analyses were utilized to analyze the association between lactate and AKI. The receiver operating characteristic (ROC) curves were drawn to verify the predictive value of lactate and the logistic model.

Results

Acute kidney injury group had higher age (p = 0.016), serum creatinine (p < 0.001), lactate (p < 0.001), and lower Glasgow Coma Scale (GCS; p = 0.021) than non-AKI group. Multivariate logistic regression showed that age [odds ratio (OR) = 1.026, p = 0.022], serum creatinine (OR = 1.020, p = 0.010), lactate (OR = 1.227, p = 0.031), fresh frozen plasma (FFP) transfusion (OR = 2.421, p = 0.045), and platelet transfusion (OR = 5.502, p = 0.044) were risk factors of AKI in patients with TBI. The area under the ROC curve (AUC) values of single lactate and predictive model were 0.740 and 0.807, respectively.

Conclusion

Serum lactate level in the early phase is associated with AKI in patients with TBI. Lactate is valuable for clinicians to evaluate the probability of AKI in patients with TBI.

Prediction of early acute kidney injury after trauma using prehospital systolic blood pressure and lactate levels: A prospective validation study

BACKGROUND

Acute kidney injury (AKI) after trauma is a major complication independently associated with a prolonged hospital stay and increased mortality. We previously reported that the prehospital systolic blood pressure (SBP) and early hospital arterial lactate level, along with specific cut-off values, show good performance in the early prediction of AKI using AUC-ROC [1]. The purpose of this study was to prospectively validate whether or not these parameters are predictive of newly occurring AKI after trauma.

METHODS

This was a prospective review of trauma patients who were admitted to a single trauma center from January to December 2019. Patients who were <16 years old, who had burns, and who had chronic kidney disease were excluded. AKI was defined according to the Risk, Injury, Failure, Loss of the kidney function, and End-stage kidney disease (RIFLE) classification based on serum creatinine alone. Patients with a low prehospital SBP (≤126 mmHg) and high lactate levels (≥2.5 mmol/L) were defined as the high-risk group, and other patients were defined as the low-risk group.

RESULTS

A total of 489 trauma patients were admitted to our center, of whom 403 were eligible for the study. The high-risk group consisted of 38 patients, and the low-risk group consisted of 365 patients. The incidence of severe AKI in Stage Injury and Failure was significantly higher in the high-risk group (5 patients, 13.2%) than in the low-risk group (7 patients, 1.9%), with an odds ratio of 7.75 and 95% confidence interval of 2.33-25.77.

CONCLUSIONS

These predictors showed good performance in the early prediction of severe AKI after trauma. Early prediction of the high-risk groups for severe AKI after trauma prompting early treatment may help improve the prognosis of trauma patients.