Veno-venous continuous renal replacement therapy for burned patients with acute renal failure

Routinely collected burn clinical data in Canada: Determining the knowledge gap

Unlike other developed countries that hold national burn registries to monitor burn injury and care, Canada relies on single-centre secondary datasets and administrative databases as surveillance mechanisms. The objective of this study was to determine the knowledge gap faced in Canada for not having a dedicated burn registry. A comprehensive scoping review was conducted to identify the burn literature that has arisen from secondary datasets in Canada. Literature of all study designs was included with the exception of case reports and cases series. Once data extraction was concluded, a thematic framework was constructed based on the information that arose from nations that hold national burn registries. Eighty-eight studies were included. Twelve studies arose from national datasets, and 18 from provincial databases, most of which were from Ontario and British Columbia. Only seven studies were conducted using a combination of Canadian units' single-centre datasets. The majority of included studies (58%) resulted from non-collaborative use of single-centre secondary datasets. Research efforts were predominantly conducted by burn units in Ontario, British Columbia, Manitoba and Alberta. A significant number of the included studies were outdated and several provinces/territories had no published burn data whatsoever. Efforts should be made towards the development of systems to surveil burn injury and care in Canada. This study supports the development of a nation-wide burn registry to bridge this knowledge gap.

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.

Assessing the NephroCheck® Test System in Predicting the Risk of Death or Dialysis in Burn Patients

Acute kidney injury (AKI) is associated with high mortality in burn patients. Urinary biomarkers can aid in the prediction of AKI and its consequences, such as death and the need for renal replacement therapy (RRT). The purpose of this study was to investigate a novel methodology for detecting urinary biomarkers, the NephroCheck® Test System, and assess its ability to predict death or the need for RRT in burn patients. Burn patients admitted to the United States Army Institute of Surgical Research (USAISR) burn intensive care unit were prospectively enrolled between March 2016 and April 2018. A urine sample was obtained from all study participants using the NephroCheck® system. Patient and injury characteristics were gathered, and descriptive statistics were calculated and multivariable logistic regression analyses were performed using these data. Of the 69 patients in this study, 15 patients (21.7%) attained the composite outcome of death or needing RRT within 30 days of urine collection. NephroCheck® scores were higher for patients with the composite outcome, with P = 0.06 for centrifuged scores and P = 0.04 for noncentrifuged scores. Centrifuged and noncentrifuged scores were in high agreement and correlation (R2 = 0.97, P < 0.0001). Noncentrifuged scores were significant in the unadjusted analysis, but they were not significant in the adjusted analysis. Although these scores had a lower sensitivity and negative predictive value compared with other parameters, they had the second highest specificity and positive predictive value. NephroCheck® scores were higher in burn patients with the composite outcome of death or needing RRT, and they demonstrated comparable sensitivity and specificity to creatinine and TBSA.

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.

Renal outcomes of intensive care burn patients in an Asian tertiary centre

INTRODUCTION

Acute kidney injury (AKI) is a frequent complication of severe burn injury and is associated with a high mortality rate of up to 80%. We aimed to establish the incidence, mortality rate, and factors related to mortality in adult patients with severe burn injury and AKI with renal replacement therapy (RRT) in Singapore.

METHODS

We performed a retrospective cohort study of severely burned patients who were admitted to the Burns Intensive Care Unit (BICU) at the Singapore General Hospital (SGH) from January 2008 to December 2016. We compared patients with AKI with RRT who survived with those who did not survive. As there were changes in the protocol for burns management after 2013, we also compared patients with AKI with RRT who survived with non-survivors in each of the 2008-2012 and 2013-2016 cohorts.

RESULTS

Data of 201 patients were studied. The incidence of AKI with RRT use in severe burn injury was 21.9% and their mortality rate was 50.0%. The non-survivors had significantly higher median burned total body surface area (p = 0.043), earlier AKI (p = 0.046), earlier use of RRT (p = 0.035), lower rate of renal recovery (p = <0.0001), higher rates of adult respiratory distress syndrome (ARDS) (p = 0.005) and shock with vasopressors (p = 0.009) compared to the survivors. The survival rate was 36.8% in the 2008-2012 cohort, but improved to 60.0% in the 2013-2016 cohort. In the 2008-2012 cohort, the non-survivors developed AKI earlier (day 0 admission vs. day 3 admission, p = 0.039), and were initiated on RRT at lower serum creatinine level (173.5 μmol/L vs. 254.0 μmol/L, p = 0.042), when compared to the survivors in this same cohort. On the other hand, there were no significant differences in the renal status and fluid balance parameters between the non-survivors and survivors in the 2013-2016 cohort.

CONCLUSIONS

The incidence of AKI with RRT in the Singapore study cohort was high, but their mortality rate was relatively lower compared to other study cohorts. Severity of AKI and use of RRT were associated with poor prognosis. Large scale study is required to further study the risk factors for mortality in this group of patients and establish cause-and-effect relationship.

The progress of Chinese burn medicine from the Third Military Medical University-in memory of its pioneer, Professor Li Ao

Professor Li Ao was one of the founders of Chinese burn medicine and one of the most renowned doctors and researchers of burns in China. He established one of the Chinese earliest special departments for burns at Third Military Medical University (TMMU) in 1958. To memorialize Professor Li Ao on his 100th birthday in 2017 and introduce our extensive experience, it is our honor to briefly review the development and achievement of the Chinese burn medicine from TMMU. The epidemiology and outcomes of admitted burn patients since 1958 were reviewed. Furthermore, main achievements of basic and clinical research for the past roughly 60 years were presented. These achievements mainly included the Chinese Rule of Nine, fluid resuscitation protocol, experience in inhalation injury, wound treatment strategies, prevention and treatment of burn infections, nutrition therapy, organ support therapies, and rehabilitation. The progress shaped and enriched modern Chinese burn medicine and promoted the development of world burn medicine.

Relation between proteinuria and acute kidney injury in patients with severe burns

Introduction

Proteinuria in burn patients is common, and may be associated with acute kidney injury (AKI) and adverse outcomes. We evaluated the incidences, outcomes, characteristics and determinants of proteinuria and its influence on AKI and outcomes in burn patients.

Methods

This retrospective study was carried out in a hospital's burn department. The study population consisted of patients with burn injuries admitted during a five-year period. Positive urine dipstick readings were defined as mild (± or 1+) or heavy (≥ 2+) proteinuria, and AKI was diagnosed and staged according to the Risk, Injury, Failure, Loss, End Stage (RIFLE) classification system. Patient characteristics, management and outcomes were evaluated for associations with proteinuria using nonparametric tests, chi-square (χ²) tests and binary logistic regression.

Results

Of the patients admitted to the burn unit during the study period (n = 2,497), 865 (34.64%) were classified as having proteinuria. In the patients whose total burn surface areas (TBSA) were > 30% (n = 396), 271 patients (68.43%) had proteinuria and 152 of these patients (56.09%) met AKI criteria. No patients without proteinuria developed AKI. Intensive care unit (ICU) mortality rates were 0.8%, 16.67% and 30.77% (P < 0.001) in the groups with no, mild and heavy proteinuria, respectively. Logistic regression analysis identified proteinuria (OR 4.48; 95% CI, 2.824 to 7.108; P < 0.001) and sequential organ failure assessment (OR 1.383; 95% CI, 1.267 to 1.509; P < 0.001) as risk factors for AKI.

Conclusions

We observed a high prevalence of proteinuria in patients with severe burns (> 30% TBSA). Severely burned patients with proteinuria had a high risk of developing AKI and a poor prognosis for survival. This suggests that proteinuria should be used for identifying burn patients at risk of developing AKI.

A portable continuous blood purification machine for emergency rescue in disasters

BACKGROUND

Continuous renal replacement therapy plays an important role in emergency rescue. Currently, no continuous renal replacement therapy machine can be used under unstable conditions as the fluid flow of these machines is controlled electronically. A novel machine that can provide emergency continuous renal replacement therapy in disaster rescue is therefore needed.

METHODS

Based on a volumetric metering method, a prototype portable continuous blood purifier based on a volumetric metering method was developed. Basic performance tests, special environmental tests, animal experiments and clinical use of the novel machine were completed to test and verify its performance under unstable conditions.

RESULTS

All tests completed showed that the machine met the requirements of the national industry standards with a size reduced to approximately one half of the Baxter Aquarius machine. The clearance of harmful substances by the machine described here was equal to that of the Baxter Aquarius machine and was adequate for clinical purposes.

CONCLUSIONS

The novel prototype performed well in all situations tested and can aid rescue work on disaster sites.

Normal citratemia and metabolic tolerance of citrate anticoagulation for hemodiafiltration in severe septic shock burn patients

PURPOSE

Anticoagulation during renal replacement therapy remains an important challenge for burn patients due to their high risk of bleeding. In this study we compared the efficacy and safety of citrate anticoagulation to heparin anticoagulation for hemodiafiltration (HDF) in severe burn patients, focusing on metabolic tolerance and handling of citrate.

METHODS

Retrospective observational study (January 2000-December 2007) at a university teaching hospital. Among 548 patients admitted with burns, 70 severe burn septic shock patients (median age 57.5 years, interquartile range 42-76 years; median burned surface area 40%, interquartile range 30-60%) who underwent HDF for more than 24 h were included.

RESULTS

Of the 70 HDF patients, 31 at high risk of bleeding were treated with citrate and 39 with heparin, with a mortality rate of 70.9 and 71.8%, respectively. In continuous venovenous hemodiafiltration (CVVHDF), the filter survival was higher with citrate, and hemorrhagic complications were lower (0.035 vs. 0.145 episodes/day, respectively). During citrate CVVHDF [median delivered dialysis dose: 578.9 ml kg(-1) day(-1) (461.5-769.2 ml kg(-1) day(-1))] in catecholamine-supported patients (norepinephrine 0.53 μg kg(-1) min(-1)), no metabolic derangements in pH, bicarbonates, Na+, K+, Ca++, and ionized calcium were observed. Systemic citratemia was within the normal range (<0.4 mmol/l) and was associated with a marked citrate removal in the effluent (5 patients, 36-60% of infused amount).

CONCLUSIONS

In septic shock burn patients, citrate for CVVHDF was efficient and safe, and superior to heparin for hemorrhagic complications and filter survival. Observed metabolic stability was most likely due to a marked loss of citrate in effluent volume and subsequent low total citrate load for the patient.

Outcome of acute kidney injury in severe burns: a systematic review and meta-analysis

PURPOSE

The main objective of this review was to analyse the prevalence and outcome of acute kidney injury (AKI) in patients with severe burn injury. AKI is a common complication in patients with severe burn injury and one of the major causes of death (often combined with other organ dysfunctions). Several definitions of AKI have been used, but the RIFLE 'consensus' classification is nowadays considered the gold standard, enabling a more objective comparison of populations.

METHODS

We performed a systematic literature search (1960-2009), involving PubMed, the Web of Science, the search engine Google and textbooks. Reference lists and the Science Citation Index search were also consulted. Attributable mortality was assessed by performing a meta-analysis.

RESULTS

This search yielded 57 articles and abstracts with relevant epidemiologic data of AKI in the burn population. Of these, 30 contained complete mortality data of the burn and control population, which revealed a 3- to 6-fold higher mortality for AKI patients in univariate analysis, depending on the applied definition. When defined by the RIFLE consensus classification, AKI occurred in one quarter of patients with severe burn injury (median mortality of 34.9%), and when defined by the need for renal replacement therapy (RRT), AKI occurred in 3% (median mortality of 80%). The prevalence of AKI slightly increased, but AKI-RRT decreased. However, the outcome in both groups improved.

CONCLUSION

Despite the wide variation of the analysed burn populations and definitions of AKI, this review clearly showed that AKI remains prevalent and is associated with increased mortality in patients with severe burn injury.

Fluid resuscitation of the thermally injured patient

Increased capillary permeability and reduced plasma colloid osmotic pressure following burn injury result in hypovolemia and development of edema in the burn and nonburn tissues. Replenishment of the intravascular deficit with crystalloid fluid has been the mainstay of resuscitation for the better part of four decades. A progressive but as yet unexplained trend toward provision of resuscitation volumes well in excess of those predicted by the Parkland formula, associated with numerous edema-related complications, has been repeatedly observed recently. Correction of this phenomenon, called fluid creep, will likely revolve around several strategies, which may include tighter control of titration, re-emergence of colloids and hypertonic salt solutions, and possibly the use of adjunctive markers of resuscitation other than urinary output.

The protein equivalent of nitrogen appearance in critically ill acute renal failure patients undergoing continuous renal replacement therapy

OBJECTIVE

To assess the nutritional status of critically ill patients with acute renal failure on continuous renal replacement therapy (CRRT) and their protein needs by estimating the protein equivalent of nitrogen appearance (PNA).

DESIGN

Prospective, observational study.

SETTING

A 74-bed intensive care unit in a single tertiary care hospital.

PATIENTS

Twenty-five consecutive critically ill patients with acute renal failure on CRRT.

METHODS

The patients were studied over a period of 24 hours, at initiation on CRRT. The nutritional status was assessed by anthropometry and bioimpedance analysis. The PNA was estimated using the Bergstrom equation and PNA was normalized to body weight.

RESULTS

The mean age was 58.2 +/- 17 years and 20 (80%) were male. The mean weight was 67 +/- 12 kg, body mass index was 25 +/- 3.5 kg/m(2), and triceps and subscapular skin fold thickness were 13 +/- 4.6 mm and 15 +/- 2.5 mm, respectively. Bioimpedance studies showed that the total body water was increased at 61.7 +/- 5.5% and body fat was 31.8 +/- 5.4%. The PNA was 103 +/- 35 g/day and normalized PNA was 1.57 +/- 0.4 g/kg/day. The mean protein intake was 0.56 +/- 0.38 g/kg/day, resulting in mean net negative protein balance of 1.0 +/- 0.6 g/kg/day.

CONCLUSIONS

Malnutrition was uncommon in patients with acute renal failure at the time of initiation on CRRT, but their total body water was increased. They exhibited hypercatabolism and the mean normalized PNA was 1.57 g/kg/day. A large negative nitrogen balance was observed in them, since their protein intake was suboptimal.

Causes of mortality by autopsy findings of combat casualties and civilian patients admitted to a burn unit

BACKGROUND

Approximately 5% of combat-related injuries include burns. Previous studies have shown similar mortality rates between military and civilian burn casualties; but causes of death were not detailed.

STUDY DESIGN

We retrospectively reviewed autopsy reports of patients with burns treated at the US Army Institute of Surgical Research Burn Center from 2004 to 2007.

RESULTS

Of 1,255 admissions, 100 (8%) died, with autopsies performed on 74 (36 burned during military operations). Causes of death included infection (61%); disorders of the pulmonary (55%), cardiac (36%), renal (27%), gastrointestinal (27%), and central nervous (11%) systems; and multiorgan dysfunction (15%). Patients burned as a result of military operations were younger men with more associated inhalation injuries, greater severity of injury, and longer time from injury to admission and to death. They died more frequently of infection (notably fungus, Pseudomonas, and Klebsiella) and gastrointestinal complications; and those not burned in military operations had greater numbers of cardiac and renal causes of death.

CONCLUSION

Casualties of military operations are clinically different and die from different causes than patients not burned during military operations. The differences are likely reflective of a younger population, with greater severity of illness and longer times from injury to admission. Therapeutic interventions should focus on prevention of infection and gastrointestinal catastrophes in military burn casualties, which are similar to younger burn patients in the US, and minimizing cardiac complications in civilian burn casualties, who are typically older patients and possibly reflective of patients with more comorbidities.

Acute kidney injury is common, parallels organ dysfunction or failure, and carries appreciable mortality in patients with major burns: a prospective exploratory cohort study

INTRODUCTION

The purpose of this study was to determine the incidence, time course, and outcome of acute kidney injury after major burns and to evaluate the impact of possible predisposing factors (age, gender, and depth and extent of injury) and the relation to other dysfunctioning organs and sepsis.

METHOD

We performed an explorative cohort study on patients with a TBSA% (percentage burned of total body surface area) of 20% or more who were admitted to a national burn centre. Acute kidney injury was classified according to the international consensus classification of RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease). Prospectively collected clinical and laboratory data were used for assessing organ dysfunction, systemic inflammatory response, and sepsis.

RESULTS

The incidence of acute kidney injury among major burns was 0.11 per 100,000 people per year. Of 127 patients, 31 (24%) developed acute kidney injury (12% Risk, 8% Injury, and 5% Failure). Mean age was 40.6 years (95% confidence interval [CI] 36.7 to 44.5), TBSA% was 38.6% (95% CI 35.5% to 41.6%), and 25% were women. Mortality was 14% and increased with increasing RIFLE class (7% normal, 13% Risk, 40% Injury, and 83% Failure). Renal dysfunction occurred within 7 days in 55% of the patients and recovered among all survivors. Age, TBSA%, and extent of full thickness burns were higher among the patients who developed acute kidney injury. Pulmonary dysfunction and systemic inflammatory response syndrome were present in all of the patients with acute kidney injury and developed before the acute kidney injury. Sepsis was a possible aggravating factor in acute kidney injury in 48%. Extensive deep burns (25% or more full thickness burn) increased the risk for developing acute kidney injury early (risk ratio 2.25).

CONCLUSIONS

Acute kidney injury is common, develops soon after the burn, and parallels other dysfunctioning organs. Although acute kidney injury recovered in all survivors, in higher acute kidney injury groups, together with cardiovascular dysfunction, it correlated with mortality.

Acute renal failure in intensive care burn patients (ARF in burn patients)

The purpose of this study was to establish the incidence and mortality of burn patients with acute renal failure (ARF) at the Helsinki Burn Centre and to analyze the associated factors. The files of 238 intensive care (ICU) patients of a total of 1380 burn patients admitted to our institution between November 1988 and December 2001 were studied retrospectively. Of all admitted burn patients, 17.2% needed ICU. According to our criteria (S-Cr >120 micromol/l = 1.4 mg/dl), 39.1% of the ICU patients suffered from ARF and one in three of these required renal replacement therapy. The proportion of all admitted burn patients requiring renal replacement therapy was 2.3%. The mortality of ICU patients with ARF was 44.1% whereas that of patients without ARF was only 6.9%. Renal function recovered in all survivors. The nonsurvivors had a larger burned total body surface area, were older, and had more inhalation injuries and a higher abbreviated burn severity index score. The prognosis for patients with early ARF was worse than that for patients with late ARF. Rhabdomyolysis caused by flame injury was associated with high mortality. In this study we observed that ARF is associated with higher mortality even in minor burns when compared with patients without ARF. Flame burn with rhabdomyolysis and subsequent ARF predicts very poor survival. If a patient with severe ARF survives, the renal failure recovers over time.

Circulating plasma factors induce tubular and glomerular alterations in septic burns patients

Background

Severe burn is a systemic illness often complicated by sepsis. Kidney is one of the organs invariably affected, and proteinuria is a constant clinical finding. We studied the relationships between proteinuria and patient outcome, severity of renal dysfunction and systemic inflammatory state in burns patients who developed sepsis-associated acute renal failure (ARF). We then tested the hypothesis that plasma in these patients induces apoptosis and functional alterations that could account for proteinuria and severity of renal dysfunction in tubular cells and podocytes.

Methods

We studied the correlation between proteinuria and indexes of systemic inflammation or renal function prospectively in 19 severe burns patients with septic shock and ARF, and we evaluated the effect of plasma on apoptosis, polarity and functional alterations in cultured human tubular cells and podocytes. As controls, we collected plasma from 10 burns patients with septic shock but without ARF, 10 burns patients with septic shock and ARF, 10 non-burns patients with septic shock without ARF, 10 chronic uremic patients and 10 healthy volunteers.

Results

Septic burns patients with ARF presented a severe proteinuria that correlated to outcome, glomerular (creatinine/urea clearance) and tubular (fractional excretion of sodium and potassium) functional impairment and systemic inflammation (white blood cell (WBC) and platelet counts). Plasma from these patients induced a pro-apoptotic effect in tubular cells and podocytes that correlated with the extent of proteinuria. Plasma-induced apoptosis was significantly higher in septic severe burns patients with ARF with respect to those without ARF or with septic shock without burns. Moreover, plasma from septic burns patients induced an alteration of polarity in tubular cells, as well as reduced expression of the tight junction protein ZO-1 and of the endocytic receptor megalin. In podocytes, plasma from septic burns patients increased permeability to albumin and decreased the expression of the slit diaphragm protein nephrin.

Conclusion

Plasma from burns patients with sepsis-associated ARF contains factors that affect the function and survival of tubular cells and podocytes. These factors are likely to be involved in the pathogenesis of acute tubular injury and proteinuria, which is a negative prognostic factor and an index of renal involvement in the systemic inflammatory reaction.

Continuous arteriovenous hemodialysis and continuous venovenous hemofiltration in burn patients with acute renal failure

Acute renal failure (ARF) is a very common condition that may occur in patients with major burn injuries. The majority of burn patients with ARF have a high mortality rate, ranging from 73% to 100%. There are several ways to treat ARF in burn patients, including peritoneal dialysis (PD), intermittent hemodialysis, and continuous renal replacement therapy (CRRT). CRRT is generally used in patients in whom intermittent hemodialysis has failed to control hypovolemia, as well as in patients who cannot tolerate intermittent hemodialysis. Additionally, PD is not suitable for patients with burns within the abdominal area. For these reasons, most patients with unstable hemodynamic conditions receive CRRT. In this study (conducted in our burn unit between 1997 and 2004), six burn patients received CRRT: three received continuous arteriovenous hemodialysis (CAVHD) and the other three received continuous venovenous hemofiltration (CVVH). The patients were all males, with a mean age of 49.8 years (range, 27-80 years), and a mean burnt surface area of 65.1% (range, 30-95%). Four patients died due to multiple organ failure, and two patients recovered from severe ARF. CRRT has been proven safe and useful for burn patients with ARF. According to this study, we conclude that CVVH is an appropriate tool for treating ARF, with a lower incidence of vascular complications than CAVHD.

Recent clinical advances in the management of critically ill patients with acute renal failure

BACKGROUND

Significant progress has been made in the field of renal replacement therapy for critically ill patients with acute renal failure (ARF) over the past few years. This review highlights these developments.

METHODS

Recent studies assessing the clinical utility of the RIFLE classification system for the diagnosis of ARF were reviewed. Clinical outcome studies evaluating the effect of continuous renal replacement therapy (CRRT) dose and timing of initiation were assessed. The final review topic was the effect of dialysis modality on the recovery of renal function in ARF patients.

CONCLUSIONS

Based on recent clinical studies, the increasing use of the RIFLE criteria is justified, as this approach appears to be a robust method for both the diagnosis of and prognostication in ARF. A large randomized trial involving convective CRRT supports the commonly used prescription of 35 ml/ kg/h in clinical practice. Moreover, numerous recent outcome studies, also largely involving convective CRRT, provide a clinical rationale for the increasingly common clinical practice of earlier initiation. Finally, several recent studies suggest CRRT, relative to conventional hemodialysis, results in a greater rate of renal recovery in ARF patients.

Removal of inflammatory cytokines and endotoxin by veno-venous continuous renal replacement therapy for burned patients with sepsis

OBJECTIVE

To evaluate the effect of veno-venous continuous renal replacement therapy (CRRT) on the plasma levels of endotoxin and cytokines in severely burned patients with sepsis.

METHODS

Twenty adult severely burned patients with sepsis were studied. For the diagnosis of sepsis, patients were randomly divided into CRRT (n=10) and Control (n=10). Both groups received conventional therapy after admission. Veno-venous CRRT was administered to 10 patients in the CRRT group whenever patients were determined to be septic. The plasma level of endotoxin, TNF-alpha, IL-1 beta, IL-6 and IL-8 were measured at 0, 1, 2, 6, 12, 36 and 60 h after CRRT initiation, and at 0, 12, 36 and 60 h after the patients were diagnosed as having sepsis in the Control group.

MAIN RESULTS

Plasma level of endotoxin and all the cytokines after CRRT initiation were significantly lower than those before the treatment (P<0.01). The serial change of endotoxin, IL-1 beta, IL-6 and IL-8 was significantly lower at 12, 36 and 60 h after treatment compared with Control groups (P<0.01). A significant decrease in plasma TNF-alpha levels was seen at 36 and 60 h after treatment compared with Control groups (P<0.01).

CONCLUSION

Plasma endotoxin and cytokines (TNF-alpha, IL-1 beta, IL-6 and IL-8) can be removed effectively with CRRT in severely burned patients with sepsis.

Improvements of postburn renal function by early enteral feeding and their possible mechanisms in rats

AIM: To investigate the protective effects of early enteral feeding (EEF) on postburn impairments of renal function and their possible mechanisms.

METHODS: Wistar rats with 30% of total body surface area (TBSA) full-thickness burn were adopted as the experimental model. The effects of EEF on the postburn changes of gastric intramucosal pH(pHi), endotoxin levels in portal vein, water contents of renal tissue, and blood concentrations of tumor necrosis factor (TNF-α), urea nitrogen (BUN), creatinine (Cr), as well as the changes of clearance of creatinine (CCr) were dynamically observed within 48 h postburn.

RESULTS: EEF could significantly improve gastric mucosal acidosis, reduce portal vein endotoxin levels and water contents of renal tissue, as well as blood concentrations of TNF-α after severe burns (P < 0.01). The postburn elevations of BUN and BCr were not found to be recovered by EEF. However, the CCr in EEF group was greatly increased by 4.67-fold compared with that of the non-feeding burned control (16.43 ± 2.90 vs. 3.52 ± 0.79, P < 0.01).

CONCLUSION: EEF has beneficial effects on the improvement of renal function in severely burned rats, which may be related to its increase of splanchnic blood flow, decrease of the translocation of gut-origin endotoxin and the release of inflammatory mediators.

Renal failure and renal replacement therapy

Continuous renal replacement therapy is an effective means for fluid and solute management in ARF/MOSF. Prospective studies have examined issues of anticoagulation, the impact of replacement/dialysis, the effects of bicarbonate-versus lactate-based solutions, and nutritional and medication clearance. Speculation and bias exists concerning when and for what indications CRRT should be initiated. Many clinicians, supported by data from Ronco and Goldstein, would contest that early institution is better if the risks (eg, access, anticoagulation) are minimal and the possible benefits are maximal. The authors, examining the issues as an intensivist and as a nephrologist, believe that early institution, aggressive replacement/dialysis, and use of citrate-based replacement fluids provide substantive advantages. With the advent of Ronco's recent data on sepsis managed with filtration and plasma absorption, the indication for use of CRRT in MOSF may become more evident regardless of the presence or absence of ARF.

Escherichia coli endotoxin enhances acute renal failure in rats after thermal injury

This study was designed to evaluate the burned rat model to determine whether there are any differences in endotoxin-sensitive kidney functions between an infant rat (10-day-old pup) and an adult rat (10-week-old rat). Renal failure was observed in the infant burned rat and histological changes showed the adhesion of inflammatory cells in the glomerular capillaries and vacuolar changes in the renal proximal tubular cell. A horseradish peroxidase (HRP) tracer experiment suggested that the intestinal barrier damage of the infant burned rat was more severe than that of the adult burned rat. Therefore, more bacterial translocation of the intestinal flora, rich in endotoxin, might be expected in the infant versus the adult rats. Renal failure was not observed in the adult burned rat, so we investigated to determine the effects of endotoxin on the kidney function of the adult burned rat with low lethal lipopolysaccharide (LPS) or carrageenan (CAR). CAR is known to increase sensitivity to the lethal effects of endotoxin in rodents. Our present data demonstrated that renal failure was observed in the LPS- or CAR-treated adult burned rat and LPS- and CAR-treated adult rat (non-burned). These results show the possibility that endotoxin enhances renal failure in a burned rat model and provide additional support for the hypothesis that postburn renal failure is mediated, in part, by endotoxin associated with bacterial translocation.

Development of a continuous renal replacement program in critically ill patients

BACKGROUND

Critically ill patients encounter many obstacles, such as acute renal failure, that increases length of stay as well as hospital cost. Dialysis in these patients is often ineffective thereby prolonging the inevitable and significantly increasing the cost of care. A dialysis program that could improve patient care, potentially improve outcome and be "revenue neutral" would be ideal.

METHODS

A continuous renal replacement therapy (CRRT) program was developed to significantly impact the care of critically ill patients Using the latest CRRT equipment along with an innovative hands-on CRRT training program, a specialized CRRT team was created. Working in conjunction with the hospital business office, new revenue charge codes were created and existing codes were updated. Patients who underwent CRRT had their financial records reviewed for: hospital cost to perform CRRT, total hospital billing to the payer, CRRT revenue 881 (billing units) charged to the payer, total charges and reimbursement for the account, percentage of reimbursement, collected revenue, and payer.

RESULTS

From April 2000 to February 2002, 39 critically ill patients underwent CRRT. Initial set-up cost was US$79,622.80 and the cost of CRRT was US$222,323.98. The hospital billed for US$656,090.63 and assuming 100% reimbursement, the potential profit was US$427,678.50. However, loss of revenue, mainly from noncompliance with charge capture resulted in the hospital billing only US$386,794.32 with a total reimbursement of US$165,779.86. The 21 burn patients who underwent CRRT yielded a net profit of US$10,294.12, with the highest reimbursement from workman's compensation and private payers. The overall mortality rate was 59% and 65% for the burn patients; significantly lower than published national averages.

CONCLUSIONS

An in-house CRRT program improved patient care by providing dialysis in patients who normally would not tolerate the procedure. Although there was a loss of revenue, CRRT in the burn patients appeared "revenue neutral." Although not specifically studied in this review, based on published data, mortality rates in this population were lower than expected especially in critically ill burn patients.

How well does the Parkland formula estimate actual fluid resuscitation volumes?

We had anecdotally observed that fluid resuscitation volumes often exceed those estimated by the Parkland Formula in adults with isolated cutaneous burns. The purpose of this study was to compare estimated and actual fluid resuscitation volumes using the Parkland Formula. We performed a retrospective study of fluid resuscitation in patients with burns > or = 15% TBSA. Patients with inhalation injury, high voltage electrical injury, delayed resuscitation, or associated trauma were excluded. We studied 31 patients (mean age 51 +/- 20 years, mean TBSA burn 27 +/- 10%). The 24 hour resuscitation volume of 13 354 +/- 7386 ml (6.7 +/- 2.8 ml/kg/%TBSA) was significantly greater than predicted (P = 0.001) and exceeded estimated volume in 84% of the patients. The mean urine output in the first 24 hrs was 1.2 +/- 0.6 ml/kg/hr. After the first 8 hours of resuscitation, the infusion rate decreased by 34% in 16 patients (DCR group), while in 15 patients the rate increased by 47% (INCR group). Both the DCR and INCR groups received significantly more fluid than predicted, (5.6 +/- 2.1 ml/kg/%TBSA and 7.7 +/- 3.1 ml/kg/%TBSA respectively). The INCR patients had significantly larger full thickness burns (14 +/- 11% vs 3 +/- 6%, P < 0.001). Our findings reveal that despite its effectiveness, the Parkland Formula underestimated the volume requirements in most adults with isolated cutaneous burns, and especially in those with large full thickness burns.