Long-Term Outcome After Renal Replacement Therapy in Severe Burns

A Meta-Analysis of the Mortality and the Prevalence of Burn Complications in Western Populations

Management of burn injuries is complex, with highly variable outcomes occurring among different populations. This meta-analysis aims to assess the outcomes of burn therapy in North American and European adults, specifically mortality and complications, to guide further therapeutic advances. A systematic review of PubMed, Web of Science, and Cochrane was performed. Random-effect meta-analysis of proportions was conducted to assess the overall prevalence of the defined outcomes. In total, 54 studies were included, pooling 60 269 adult patients. A total of 53 896 patients were in North America (NA, 89.4%), and 6373 were in Europe (10.6%). Both populations experienced similar outcomes. The overall pooled prevalence of mortality was 13% (95% CI, 8%-19%) for moderate burns, 20% (95% CI, 12%-29%) for severe burns in the NA region, and 22% (95% CI, 16%-28%) for severe burns in Europe. Infectious complications were the most common across both regions. European studies showed an infection rate for patients with moderate and severe burns at 8% and 76%, respectively, while NA studies had rates of 35% and 54%. Acute kidney injury (39% vs 37%) and shock (29% vs 35%) were the next most common complications in European and NA studies, respectively. The length of stay was 27.52 days for patients with severe burns in Europe and 31.02 days for patients with severe burns in NA. Burn outcomes are similar between Western populations. While outcomes are reasonably good overall, infectious complications remain high. These findings encourage the development of further therapeutic strategies disclosing respective costs to enable cost/efficiency evaluations in burn management.

Long-term renal function after burn-related acute kidney injury with continuous renal replacement therapy

Acute kidney injury (AKI) is a common complication of severe burn injury and is associated with significant morbidity and mortality. Continuous Renal Replacement Therapy (CRRT) is the preferred treatment for stage 3 AKI due to severe burn. This retrospective cohort study at a single institution aimed to examine the long-term renal outcomes after discharge of burn survivors who underwent CRRT during their ICU stay between 2012-2021 due to burn-related AKI, hypothesizing a return to baseline renal function in the long term. Among the 31 patients meeting inclusion criteria, 22 survived their burn injuries, resulting in a 29 % mortality rate. No significant disparities were observed in demographics, comorbidities, burn characteristics, or critical care interventions between survivors and non-survivors. Serum creatinine and eGFR values normalized for 91 % of patients at discharge. Impressively, 91 % of survivors demonstrated a return to baseline renal function during long-term (>3 years) follow-up. Furthermore, only 18 % underwent dialysis after discharge, primarily within the first year. Cumulative mortality rates were 18.2 %, 22.7 %, and 31.8 % at 1, 3, and > 3 years after discharge, respectively. Causes of death were primarily non-renal. These results suggest that burn-related AKI with CRRT results in lower rates of conversion to ongoing renal dysfunction compared to general ICU cohorts. Despite limitations, this study contributes vital insights into the underexplored issue of long-term outcomes after dicharge in this patient population.

Acute kidney injury in patients with burns

Burn injury is associated with a high risk of acute kidney injury (AKI) with a prevalence of AKI among patients with burns of 9-50%. Despite an improvement in burn injury survival in the past decade, AKI in patients with burns is associated with an extremely poor short-term and long-term prognosis, with a mortality of >80% among those with severe AKI. Factors that contribute to the development of AKI in patients with burns include haemodynamic alterations, burn-induced systemic inflammation and apoptosis, haemolysis, rhabdomyolysis, smoke inhalation injury, drug nephrotoxicity and sepsis. Early and late AKI after burn injury differ in their aetiologies and outcomes. Sepsis is the main driver of late AKI in patients with burns and late AKI has been associated with higher mortality than early AKI. Prevention of early AKI involves correction of hypovolaemia and avoidance of nephrotoxic drugs (for example, hydroxocobalamin), whereas prevention of late AKI involves prevention and early recognition of sepsis as well as avoidance of nephrotoxins. Treatment of AKI in patients with burns remains supportive, including prevention of fluid overload, treatment of electrolyte disturbance and use of kidney replacement therapy when indicated.

Early acute kidney injury is associated with in-hospital adverse outcomes in critically ill burn patients: an observational study

BACKGROUND

There are no studies in large series of burn patients on the relationship between acute kidney injury (AKI) and adverse outcomes using the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines.

METHODS

We retrospectively analysed data from a cohort of burn patients admitted to the intensive care unit (ICU) with the diagnosis of burn injury. The diagnosis of AKI over the first 7 days after injury was made according to the KDIGO guidelines. The primary outcome was ICU mortality. We used estimative models using univariable and multivariable logistic regression analyses.

RESULTS

A total of 960 patients were studied and AKI was diagnosed in 50.5%. In multivariable analysis, AKI was associated, as compared with patients without AKI, with ICU mortality {adjusted odds ratio [aOR] 2.135 [95% confidence interval (CI) 1.384-3.293]} and secondary outcomes [kidney replacement therapy, aOR 4.030 (95% CI 1.838-8.835); infection, aOR 1.437 (95% CI 1.107-1.866); hospital mortality, aOR 1.652 (95% CI 1.139-2.697)]. AKI stage 1 was associated with a higher ICU [aOR 1.869 (95% CI 1.183-2.954)] and hospital mortality [aOR 1.552 (95% CI 1.050-2.296)] and infection [aOR 1.383 (95% CI 1.049-1.823)]. AKI meeting the urine output (UO) criterion alone was not associated with increased mortality. Ignoring the UO criterion would have missed 50 (10.3%) cases with AKI.

CONCLUSION

The KDIGO guidelines are useful to diagnose AKI in burn patients. Even the mild form of AKI is independently associated with increased mortality. Considering the UO criterion is important to more accurately assess the incidence of AKI, but AKI meeting the UO criterion alone is not associated with increased mortality.

Burn-Induced Acute Kidney Injury-Two-Lane Road: From Molecular to Clinical Aspects

Severe burn injuries lead to acute kidney injury (AKI) development, increasing the mortality risk up to 28-100%. In addition, there is an increase in hospitalization days and complications appearance. Various factors are responsible for acute or late AKI debut, like hypovolemia, important inflammatory response, excessive load of denatured proteins, sepsis, and severe organic dysfunction. The main measure to improve the prognosis of these patients is rapidly recognizing this condition and reversing the underlying events. For this reason, different renal biomarkers have been studied over the years for early identification of burn-induced AKI, like neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, kidney injury molecule-1 (KIM-1), tissue inhibitor of metalloproteinase-2 (TIMP-2), interleukin-18 (IL-18), and insulin-like growth factor-binding protein 7 (IGFBP7). The fundamental purpose of these studies is to find a way to recognize and prevent acute renal injury progression early in order to decrease the risk of mortality and chronic kidney disease (CKD) onset.

Long-Term Preservation of Renal Function in Septic Shock Burn Patients Requiring Renal Replacement Therapy for Acute Kidney Injury

BACKGROUND

The real impact of septic shock-associated acute kidney injury (AKI) on the long-term renal outcome is still debated, and little is known about AKI-burn patients. In a cohort of burn survivors treated by continuous renal replacement therapy (CRRT) and sorbent technology (CPFA-CRRT), we investigated the long-term outcome of glomerular and tubular function.

METHODS

Out of 211 burn patients undergoing CRRT from 2001 to 2017, 45 survived, 40 completed the clinical follow-up (cumulative observation period 4067 months, median 84 months, IR 44-173), and 30 were alive on 31 December 2020. Besides creatinine and urine albumin, in the 19 patients treated with CPFA-CRRT, we determined the normalized GFR by 99mTc-DTPA (NRI-GFR) and studied glomerular and tubular urine protein markers.

RESULTS

At the follow-up endpoint, the median plasma creatinine and urine albumin were 0.99 (0.72-1.19) and 0.0 mg/dL (0.0-0.0), respectively. NRI-GFR was 103.0 mL/min (93.4-115). Four patients were diabetic, and 22/30 presented at least one risk factor for chronic disease (hypertension, dyslipidemia, and overweight). Proteinuria decreased over time, from 0.47 g/day (0.42-0.52) at 6 months to 0.134 g/day (0.09-0.17) at follow-up endpoint. Proteinuria positively correlated with the peak of plasma creatinine (r 0.6953, p 0.006) and the number of CRRT days (r 0.5650, p 0.035) during AKI course, and negatively with NRI-GFR (r -0.5545, p 0.049). In seven patients, urine protein profile showed a significant increase of glomerular marker albumin and glomerular/tubular index.

CONCLUSIONS

Burn patients who experienced septic shock and AKI treated with CRRT had a long-term expectation of preserved renal function. However, these patients were more predisposed to microalbuminuria, diabetes, and the presence of risk factors for intercurrent comorbidities and chronic renal disease.