A Ten-Year Experience With Hemodialysis in Burn Patients at Los Angeles County + USC Medical Center:

Optimizing the timing of renal replacement therapy in burn patients with acute kidney injury

Acute kidney injury is a common complication in burn ICU patients and is associated with a high mortality rate. The optimal timing for starting renal replacement therapy (RRT) remains unknown; there is no established universal definition for early and late RRT initiation. The aims of the present narrative review are to briefly analyze the available recently published data on the timing of initiation of RRT in critically ill patients and to discuss the optimal timing of RRT in critically ill burn patients with acute kidney injury. When considering renal replacement therapy for acute kidney injury patients, physicians face the dilemma of balancing the hazards of starting too early, exposing patient to an unnecessary therapy with possible complications and costs related to treatment, and preventing a significant proportion of patients from spontaneous recovery of their renal function against the potential life-threatening harm of initiating RRT) too late. Evidence suggests that with appropriate care up to 80% of burn patients experience recovery of kidney function and the need for RRT seems to be very rare after hospital discharge. In the absence of life-threatening complications, the optimal time and thresholds for starting RRT in burn patients are uncertain. High heterogeneity exists between studies on RRT timing in burn patients.

Long-Term Effects of Severe Burns on the Kidneys: Research Advances and Potential Therapeutic Approaches

Burns are a seriously underestimated form of trauma that not only damage the skin system but also cause various complications, such as acute kidney injury (AKI). Recent clinical studies have shown that the proportion of chronic kidney diseases (CKD) in burn patients after discharge is significantly higher than that in the general population, but the mechanism behind this is controversial. The traditional view is that CKD is associated with hypoperfusion, AKI, sepsis, and drugs administered in the early stages of burns. However, recent studies have shown that burns can cause long-term immune dysfunction, which is a high-risk factor for CKD. This suggests that burns affect the kidneys more than previously recognized. In other words, severe burns are not only an acute injury but also a chronic disease. Neglecting to study long-term kidney function in burn patients also results in a lack of preventive and therapeutic methods being developed. Furthermore, stem cells and their exosomes have shown excellent comprehensive therapeutic properties in the prevention and treatment of CKD, making them increasingly the focus of research attention. Their engineering strategy further improved the therapeutic performance. This review will focus on the research advances in burns on the development of CKD, illustrating the possible mechanism of burn-induced CKD and introducing potential biological treatment options and their engineering strategies.

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.

Meta-Analysis of Renal Replacement Therapy for Burn Patients: Incidence Rate, Mortality, and Renal Outcome

Background: Renal replacement therapy (RRT) was often needed by some severe burn patients with acute kidney injury (AKI). The primary aim of this study was to review incidence rate and mortality of RRT in severe burn patients. Second aims were to review RRT complications and renal outcome.

Methods: We searched multiple databases for studies published between 1 January 1960 and 31 December 2019. Studies about adult populations with burn injury, providing epidemiologic data on prevalence or mortality of RRT, were included.

Results: A total of selected 57 studies, including 27,437 patients were enrolled in our analysis. The prevalence rates of RRT were 8.34% (95% CI 7.18–9.5%) in all burn patients and 37.05% (95% CI 29.85–44.24%) in AKI patients. The mortality of all burn patients with RRT was 65.52% (95% CI 58.41–72.64%). The prevalence rates of RRT in sample size≥100 group were 6.86% (95% CI 5.70–8.03%), which was lower than that of <100 group (17.61%, 95% CI 13.39–21.82%). With the increase of TBSA, the prevalence of RRT may have the increasing trend. The prevalence rates of RRT in Asian group was 12.75% (95% CI 9.50–16.00%), which was higher than that of European (10.45%, 95% CI 7.30–13.61%) and North America group (5.61%, 95% CI 4.27–6.95%). The prevalence rates of RRT in 2010–2019 group was 12.22% (95% CI 10.09–14.35%), which was higher than that of 2009–2000 group (5.17%, 95% CI 2.88–7.46%). The prevalence rates of RRT in 1989 and before group was the lowest, which was 1.56% (95% CI 0–3.68%). However, there was no significant correlation between the year of publication and the mortality of burn patients with RRT. Dialysis-requiring AKI in burn patients could increases the risk of chronic kidney disease progression and end-stage renal disease. About 35% of RRT patients need to maintain haemodialysis temporarily, even if they survive and leave hospital.

Conclusions: The prevalence rate of RRT is about 6–8%; approximately, one-third of burn patients with AKI need RRT. The prevalence rate of RRT increased over time, but the mortality did not change. The prevalence rates of RRT in Asian group was higher than that of European and North America group.

Early Initiation of Renal Replacement Therapy Among Burned Patients With Acute Kidney Injury

BACKGROUND

Burned patients with acute kidney injury (AKI) requiring renal replacement therapy (RRT) have exceedingly high mortality rates of 73% to 100%. Since January 2011, we have been adopting an early RRT approach in managing burned patients with AKI. Our hypothesis was that early initiation of RRT leads to improved outcome and survival among burned patients with AKI.

METHODOLOGY

We conducted a retrospective analysis of Burns Database in Singapore General Hospital from January 2011 to February 2016. Indications for dialysis included serum creatinine of greater than 1.5 times baseline or urine output of less than 0.5 mL/kg per hour for at least 6 consecutive hours. Patients with similar condition from January 2006 to December 2010 were recruited for comparison.

RESULT

A total of 27 patients with burns and AKI were recruited from January 2011 to February 2016. The mean age was 45.4 years and 88.9% were male. The mean total burn surface area (TBSA) was 54.8%. The total volume of fluid resuscitation was 2.7 mL/kg per TBSA. The time from onset of burn to RRT was 6.4 days. Most patients presented with stage 1 AKI (51.9%), whereas 22.2% and 25.9% had stage 2 and stage 3 AKI, respectively. Most patients (74.1%) received CRRT and 18.5% received SLED. The mortality rate was 37.0% with majority of death (70%) due to sepsis/multiorgan failure. Only 1 patient required long-term RRT after discharge, and there was no occurrence of abdominal compartment syndrome. The mean age of 15 patients from 2006 to 2010 was 47.8 years. The mean TBSA was 49.5%. Only 26.7% of patients were started on RRT. The mortality rate was 66.7%, which was higher than that of subjects from 2011 to 2016 (37.0%) (P = 0.039).

CONCLUSIONS

Optimal timing of RRT for burned patients with AKI has not been established and data on early RRT approach are scarce. The findings of our study suggested that early RRT was associated with lower mortality rates among burned victims with AKI.

Long-Term Outcome After Renal Replacement Therapy in Severe Burns

Acute kidney injury is a common sequela after major burn injury, but only a small proportion of patients need renal replacement therapy. In the majority of patients, need for renal replacement therapy subsides before discharge from the burn center but limited literature exists on long-term outcomes. A few studies report an increased risk for chronic renal failure after burn injury. We investigated the long-term outcome of severely burned patients receiving renal replacement therapy during acute burn injury treatment. Data on 68 severely burned patients who received renal replacement therapy in Helsinki Burn Centre between November 1988 and December 2015 were collected retrospectively. Thirty-two patients survived and remained for follow-up after the primary hospital stay until December 31, 2016. About 56.3% of discharged patients were alive at the end of follow-up. In 81.3% of discharged patients, need for renal replacement therapy subsided before discharge. Two patients received renal replacement therapy for longer than 3 months; however, need for renal replacement therapy subsided in both patients. One patient required dialysis several years later on after the need for renal replacement therapy had subsided. This study showed that long-term need for renal replacement therapy is rare after severe burn injury. In the vast majority of patients, need for renal replacement therapy subsided before discharge from primary care. Acute kidney injury in association with burns is a potential but small risk factor for later worsening of kidney function in fragile individuals.

Coupled-plasma filtration and adsorption for severe burn patients with septic shock and acute kidney injury treated with renal replacement therapy

BACKGROUND

Coupled-plasma filtration adsorption (CPFA) is a sorbent-based technology aimed at removing soluble mediators of septic shock. We present our experience on the use of CPFA in septic shock severe burn patients with acute kidney injury (AKI) needing renal replacement therapy (RRT) with the main goal to evaluate efficacy and safety of CPFA in this specific subset of septic shock patients.

METHODS

In this observational study, we retrospectively reviewed the medical notes of all burn patients admitted to our adult Burn Center who received CPFA, as part of the septic shock treatment requiring RRT, between January 2001 and December 2017 (CPFA group). We compared CPFA group with all the burn patients admitted to our Center in the same period of time, with the same range of relevant clinical characteristics, who developed AKI and were treated with RRT, but not CPFA (control group). We collected demographic characteristics, burn size, Sequential Organ Assessment Failure (SOFA) score, microbiological data, and patient outcome, in terms of in-hospital mortality rate and the probability of survival calculated using the revised Baux score. We also collected data regarding CPFA safety (hemorrhagic episodes, catheter associated-complications, hypersensitivity reactions) and efficiency (number and duration of CPFA sessions, plasma treated amount, plasma processed dose).

RESULTS

39 severe burn patients were treated with CPFA (CPFA group) (mean age 46.0 years, range 40.0-56.0 years; mean burn size 48.0% TBSA, range 35.0-60.0% TBSA), and 87 patients treated with RRT, but not CPFA, who had similar clinical characteristics (control group). Observed mortality rate was 51.3% in the CPFA group and 77.1% in the control group (p 0.004). Regarding factors affecting survival in the CPFA group, SOFA score on the 1st day of CPFA resulted significant (OR 2.016, 95% CI, 1.221-3.326; p < 0.004) in the multivariate analysis logistic model.

CONCLUSIONS

CPFA treatment for burn patients with AKI-RRT and septic shock, sustained by bacterial strains non or poorly responsive to therapy, was associated with a lower mortality rate, compared to RRT alone. However, further research, such as large prospective studies, is required to clarify the role of CPFA in the treatment of burns with septic shock and AKI-RRT.

Improved outcomes of renal injury following burn trauma

BACKGROUND

Acute kidney injury (AKI) is common in major burn injuries and associated with increased mortality. With advances in surgical and critical care it is unclear if mortality in this population remains this high. This study aims to describe incidence and outcomes of patients admitted to intensive care (ICU) with a burn injury who develop AKI. We additionally sought to determine risk factors for developing AKI.

METHODS

A historical cohort study of patients admitted to ICU from 2010 to 2016 with major burn injury was conducted. Demographic, laboratory, and clinical information was collected. AKI was defined by Acute Kidney Injury Network (AKIN) classification. Multivariable logistic regression was used to model association between baseline risk factors and risk of AKI.

RESULTS

Of the 151 patients included, 64 people developed AKI (42%) defined by stages 1-3 of AKIN criteria. The median TBSA was 20% (IQR 9-41). Renal replacement therapy was required in 18/64 (28%) who developed AKI. Multivariable logistic regression demonstrated association between AKI and the following variables: APACHE II score (OR 1.2, 95%CI 1.1-1.3, P = 0.001), age (OR 1.8 per 10-year increase, 95%CI: 1.2-2.5, P = 0.002) and log(TBSA). Fractional polynomial regression analysis demonstrates that the best functional form of TBSA was in the natural logarithm (OR 2.7, 95%CI: 1.5-4.7, p = 0.001). Compared to those without AKI, patients with AKI had longer duration of mechanical ventilation, (median 11 [IQR 6-19] vs. 4 [IQR 2-9] days), ICU stay (15 [IQR 9-22] vs. 6 [IQR 3-10] days), and increased mortality (14 of 64(22%) vs. 4 of 87(5%).

CONCLUSIONS

AKI is common in patients with a major burn injury. However, mortality is lower than described in the literature, particularly for those who required renal replacement therapy.