Renal function and renal failure in badly burned children

Haemofiltration in the Management of Severe Paediatric Burns - Experience in a UK Burns Centre and Systematic Review

Paediatric burns are life-threatening injuries due to the acute injury and secondary complications. In acute phase burns, hypovolaemia and vasoconstriction cause renal impairment. Sepsis and multi-organ failure compound the problem resulting in morbidity and mortality. This paper outlines 5 years' experience using haemofiltration in major paediatric burns, and a review of the current literature.Retrospective patient data collection was undertaken identifying relevant paediatric burns undergoing Continuous Veno-Venous Haemofiltration. Data were analysed to identify demographics, indication, duration of therapy, and outcomes. A systematic review was also performed using PRISMA principles. PubMed, Science Direct and OVID databases were explored and relevant papers were included.From January 2015-December 2019, haemofiltration was utilised in 5 cases. Age range 3-15 years (mean: 12), 4 males / 1 female, mean weight 56kg (12-125kg). TBSA 21-61% (mean: 37.6%), mechanism of injury was scald-60%, flame-40%. Overall survival was 100%. 3 patients were filtered for a brief period during the first 24 hours to correct metabolic acidosis and control temperature. 2 patients required prolonged therapy. All patients recovered without further long term renal support. A total of 3814 papers were identified for systematic review. 3 were considered relevant for inclusion.This paper reflects the benefits of haemofiltration in the management of severe paediatric burns. Renal replacement therapy is useful in managing metabolic acidosis, temperature control and renal failure. The current literature supports judicious use on a patient-by-patient basis. Given the lack of evidence in the literature, further studies are required to establish guidelines for the use of haemofiltration in paediatric burns.

Predicting acute kidney injury among burn patients in the 21st century: a classification and regression tree analysis

Historically, acute kidney injury (AKI) carried a deadly prognosis in the burn population. The aim of this study is to provide a modern description of AKI in the burn population and to develop a prediction tool for identifying patients at risk for late AKI. A large multi-institutional database, the Glue Grant's Trauma-Related Database, was used to characterize AKI in a cohort of critically ill burn patients. The authors defined AKI according to the RIFLE criteria and categorized AKI as early, late, or progressive. They then used Classification and Regression Tree (CART) analysis to create a decision tree with data obtained from the first 48 hours of admission to predict which subset of patients would develop late AKI. The accuracy of this decision tree was tested in a separate, single-institution cohort of burn patients who met the same criteria for entry into the Glue Grant study. Of the 220 total patients analyzed from the Glue Grant cohort, 49 (22.2%) developed early AKI, 39 (17.7%) developed late AKI, and 16 (7.2%) developed progressive AKI. The group with progressive AKI was statistically older, with more comorbidities and with the worst survival when compared with those with early or late AKI. Using CART analysis, a decision tree was developed with an overall accuracy of 80% for the development of late AKI for the Glue Grant dataset. The authors then tested this decision tree on a smaller dataset from our own institution to validate this tool and found it to be 73% accurate. AKI is common in severe burns with notable differences between early, late, and progressive AKI. In addition, CART analysis provided a predictive model for early identification of patients at highest risk for developing late AKI with proven clinical accuracy.

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.

Hypercalcemia in Patients in the Burn Intensive Care Unit

Although patients with burns are known to develop hypocalcemia, the development of hypercalcemia has also been reported in a few patients in the burn intensive care unit. Here, the incidence of hypercalcemia in the burn unit of a single institution is reviewed. The records of all patients admitted to the burn intensive care unit over a period of 4 years of a single institution were reviewed. When looking at a select group of burn patients who have been hospitalized for more than 4 weeks, an unusually high incidence of hypercalcemia was found, especially in patients with renal failure (because of decreased renal clearance, patients with renal failure are prone to hypercalcemia if another inciting factor is present). As previously reported, the hypercalcemia in our patients was consistent with hypercalcemia caused by immobilization. We also observed that mortality correlated with higher calcium levels.

Contribution of acute kidney injury toward morbidity and mortality in burns: a contemporary analysis

BACKGROUND

Severe acute kidney injury (AKI) that requires dialytic support, a relatively uncommon complication in severely burned adults, is associated with a substantially increased mortality rate. It is not known whether milder forms of AKI have prognostic importance in burns.

METHODS

We performed an observational cohort analysis of consecutive patients with major burns admitted to the burn care unit of a tertiary-care center from 1998 to 2003. Our main outcome measures were AKI stratified by the Risk of renal dysfunction, Injury to the kidney, Failure of kidney function, Loss of kidney function, and End-stage kidney disease (RIFLE) classification and mortality.

RESULTS

AKI occurred in 81 of 304 patients (26.6%) with burns on 10% or greater total-body surface area. Risk factors for AKI on multivariate analysis were inhalational injury, catheter infection, and sepsis. Patients with AKI stratified by using the RIFLE classification had greater mortality, greater requirement of artificial ventilation, and longer durations of intensive care unit and hospital stays. Mortality was not significantly different among those with the "Risk" and "Injury" strata of RIFLE AKI compared with those without AKI, but mortality increased significantly with the "Failure" (60%) strata. In multivariate analysis, age, greater total-body surface area, inhalational injury, and the RIFLE classification of Failure were each independent predictors of death.

CONCLUSION

In conclusion, the mortality of patients with burns with severe AKI remains high and unchanged in the modern era of critical care medicine. The RIFLE classification added prognostic information regarding morbidity in patients with milder forms of AKI.

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

From 1995 to 1998, 12 burned patients with acute renal failure (ARF) were treated by veno-venous continuous renal replacement therapy (CRRT) at the Burn Unit of Hôtel-Dieu de Montréal. Their mean (+/-SD) age was 51+/-12 years, and the mean burned surface covered 48.6+/-15.8% of total body surface area. All patients were mechanically ventilated and presented evidence of sepsis. The mean delay before occurrence of ARF was 15+/-6 days and ARF was mainly related to sepsis and hypotension. Main reasons for CRRT initiation were azotemia and fluid overload. A total of 15 CRRT modalities were applied (12 continuous veno-venous hemodiafiltration, CVVHDF; two continuous veno-venous hemofiltration, CVVH; and one continuous veno-venous hemodialysis, CVVHD) over 14+/-13 days. For CRRT, nine patients received heparin and three were not anticoagulated. Mean values for dialysate and reinjection flow rates were 1134+/-250 ml/h and 635+/-327 ml/h, respectively. Admission weight was 78.8+/-12.7 kg with a mean weight gain before CRRT initiation of 10.0+/-5.8 kg and a mean weight loss during CRRT of 8.9+/-5.5 kg. Nine patients received enteral plus parenteral nutrition, and three, parenteral nutrition only; the total caloric intake was 31.5+/-7.0 kcal/kg/day and protein intake, 1.8+/-0.4 g/kg/day. The normalized protein catabolic rate (nPCR) was evaluated at 2.28+/-0.78 g/kg/day during CRRT. The mortality rate was 50%. The six survivors all recovered normal renal function with four of them requiring intermittent hemodialysis for short periods. In conclusion, veno-venous CRRT is particularly well suited for this selected population allowing smooth fluid removal and aggressive nutritional support.

Acute renal failure in severely burned patients

Acute renal failure (ARF) is a well known complication of severe burns and is an important factor leading to an increase in mortality. In order to analyze possible pathogenetic and prognostic factors associated with ARF in burned patients we reviewed in a retrospective study the files of 328 patients with burns > 10% body surface area (BSA), admitted to our burn unit between 01.01.94 and 01.05.98. We found 48 patients with acute renal failure corresponding with an incidence of 14.6%. Patients with ARF had a mean burned surface area of 48% (13-95) and an abbreviated burn severity index score (ABSI) of 9.8 (4-15). Thirty eight (79%) of these patients had an inhalation injury diagnosed. Renal insufficiency was divided in a late and an early form depending on its time of onset and we found 15 (31%) patients with ARF occurring within the first 5 days of the hospital stay and 33 (69%) patients with ARF developing >5 days following the thermal injury. The incidence of myoglobinuria and hypotension during the resuscitation phase was significantly higher in the group with early ARF, whereas patients with late ARF presented sepsis more frequently than patients with early occurring renal failure. Accordingly, potential nephrotoxic antibiotics were administered more often in patients with late ARF. Patients with ARF were treated by continuous arteriovenous hemofiltration (CAVH) for a mean period of 10.5 days (1-47) and CAVH was associated with a complication rate of 10%. Most of the complications were associated with the vascular access in the femoral artery. The mortality rate in patients with ARF was 85% and death was due to multiple organ failure in 83% of the cases. Only burned BSA and inhalation injury proved to be significantly correlated with the development of ARF, whereas age, third degree burn or electric injury were not significantly different between the two groups. Neither age, TBSA, day of onset of ARF nor duration of the renal replacement therapy proved to be significantly different comparing survivors with non-survivors, and thus predictive for the survival rate.

Continuous haemofiltration and haemodiafiltration for acute renal failure in severely burned patients

Among 970 burned patients admitted between April 1987 and September 1994, 16 (1.6 per cent) presented acute renal failure requiring dialytic support and were treated by continuous renal replacement therapy as first-line modality. Their mean burned surface area was 58.0 +/- 5.7 per cent. Acute renal failure mainly occurred in the second week following admission in relation to sepsis and nephrotoxic drugs. Four types of continuous renal replacement therapy were performed: continuous arteriovenous haemofiltration and haemodiafiltration (CAVH and CAVHDF) and continuous venovenous haemofiltration and haemodiafiltration (CVVH and CVVHDF). Compared to 33 critically ill patients without burns also treated for acute renal failure by continuous haemofiltration or haemodiafiltration during the same period, the mean duration of therapy was longer for the burned patients (24.2 +/- 9.4 vs. 5.3 +/- 0.8 days). Although mean urine outputs and ultrafiltration rates were similar for both groups, fluid administration was higher for burned patients (8.2 +/- 0.7 vs. 3.3 +/- 0.2 l/day). Total weight loss during therapy was significantly greater in burned patients (12.6 +/- 3.6 vs. 6.8 +/- 1.0 kg), in relation to longer treatment period. Bleeding complications were more frequent in burned patients (56 vs. 15 per cent). Mortality rates were similar in both groups (82 vs. 82 per cent). In conclusion, when aggressive initial fluid resuscitation is applied following burn injury, the occurrence of acute renal failure is low, delayed and multifactorial. Since they are haemodynamically well tolerated and provide a good metabolic and volaemic control, continuous renal replacement therapies appear to be useful modalities for burned patients with acute renal failure. However, as bleeding complications are more frequent, careful monitoring is necessary.

An unusual case of acute renal failure in burns

Nowadays acute renal failure in burns is not a common occurrence, at least not when most of the wounds have already healed. We report a case of a 6-year-old child with 45 per cent flame burns, who suffered acute renal shutdown 43 days after burns when all except 1 per cent of the raw areas had already been grafted with autologous skin. There was no identifiable focus of infection and no evidence of septicemia. The patient was not receiving any nephrotoxic drugs. The child responded well to peritoneal dialysis and recovered fully.

The dialysis debate: acute renal failure in burns patients

Acute renal failure is an uncommon occurrence in burns patients, although the mortality of this condition remains high. We review briefly the literature on the incidence and management of acute renal failure in burns patients. We discuss the results of a questionnaire sent to all units in the UK examining this problem. Our findings suggest that acute renal failure is usually part of a complex multiorgan failure. However, an aggressive approach in the management of these patients can result in a significant improvement in prognosis, in the absence of a greater understanding of prevention of the condition. We have suggested measures that could be taken to aid the care of burns patients with renal failure.

Superoxide dismutase with prolonged in vivo half-life inhibits intravascular hemolysis and renal injury in burned rats

Although superoxide radicals and related metabolites have been postulated to underlie the pathogenesis of burn injury, critical evidence supporting this hypothesis is lacking. To test whether superoxide radicals play critical roles in burn injury, the effect of a superoxide dismutase (SOD) derivative (SM-SOD) was tested on intravascular hemolysis and renal tubular injury in rats subjected to burn shock. Within 3 hours after a given full-thickness burn of approximately 24% of body surface area, plasma levels of lipid peroxides increased significantly with concomitant increase in intravascular hemolysis. Histological examination showed a marked deposition of hemoglobin-like casts in renal tubules of the burned rats. Intravenous administration of SM-SOD (10 mg/kg) 30 minutes before the burn injury significantly inhibited the increase of plasma lipid peroxides and the occurrence of intravascular hemolysis. SM-SOD also inhibited the deposition of casts in renal tubules. These results indicate that superoxide radicals play critical roles in the pathogenesis of intravascular hemolysis and renal damage induced by burn injury.

A study of renal damage in seriously burned patients

The incidence of acute renal failure (ARF) in severely burned patients ranges from 1.3 per cent to 38 per cent and this complication has always been associated with a high mortality rate, of between 73 and 100 per cent. At present the exact mechanisms responsible for the onset of this complication are not well known. In order to elucidate some of these mechanisms, 20 patients with severe burns were studied for 1 year in an attempt to assess the prevailing glomerular or tubular localization of renal damage; the organic or functional pattern of renal damage and the reliability and possible prognostic significance of some renal function indices. These included the fractional excretion of sodium (FeNa), the alpha-glucosidases, the leucine aminopeptidases (LAP) and the serum and urine beta 2-microglobulin. The incidence of ARF in the patients studied was 26 per cent and in all cases it was of polyuric type. We believe that renal damage very often remains undetected when the traditional testing methods are used and that only in some patients does it become severe enough to result in ARF. In contrast, some of the tests considered in our study are extremely useful and reveal an impairment of renal function long before it becomes clinically apparent.

Pharmacokinetics and tissue concentrations of ceftazidime in burn patients

The pharmacokinetics and tissue concentrations of ceftazidime have been investigated in 8 patients with severe burns (20-80% of body surface area) undergoing skin transplantation 2 to 21 days after injury. Two prophylactic doses of ceftazidime were administered as 1 g i.v. bolus injections with an 8 h interval. Blood, urine, burn blister fluid and tissue were frequently sampled and drug concentrations were analyzed by HPLC. The kinetics of ceftazidime was the same after each dose. In these patients the pharmacokinetics of ceftazidime was greatly altered from that in other patients and there was much interindividual variation. The mean ceftazidime elimination half-life, apparent volume of distribution and total clearance were: 2.7 h, 30.91 (0.38 1.kg-1) and 139 ml.min-1, respectively. A linear correlation was found between creatinine clearance and the renal clearance of the ceftazidime, the mean values being 108 and 95 ml.min-1, respectively. No correlation was found between creatinine clearance and the total clearance of ceftazidime. The mean percentage urine recovery was 69% of the dose. Tissue and burn blister fluid concentrations were above the MIC, and ranged from 40.0 to 3.1 mg.kg-1. A substantial increase in the apparent volume of distribution and non-renal clearance of ceftazidime was observed, probably due to increased capillary permeability and drug loss through the wound surface replacement of prior to surgery and subsequently to lost and blood fluid.

Hematuria in the burned child

Hematuria is a frequent complication in burn patients, but its clinical significance has not been reported. The incidence, etiologies, treatment, and outcome of hematuria in 1,785 burn patients treated from 1964 to 1983, have been reviewed. Ninety-one patients had hematuria (greater than 15 RBC/HPF with unspun urine). There were five main causes: urinary infections (UTI), 50 cases; renal calculi (RC), 14 cases, including 3% and 5% total body surface area burn patients; catheter trauma, 7 cases; renal vein thrombosis (RVT), 5 cases; and acute renal failure (ATN), 4 cases. Ten patients died in the UTI group, five with Candida as the infecting organism. No RC patients died, but two required surgical extraction of their stones. This incidence of RC may be due to large intake of dairy products and antacids and to prolonged immobilization. The catheter trauma group had no deaths and was the youngest group. One RVT patient was diagnosed clinically and successfully treated surgically. The other three were diagnosed at necropsy. The ATN patients all developed renal failure late as part of multiple organ system failure and all died. We conclude hematuria is a serious finding in burn patients and prompt diagnosis of its etiology and treatment are essential for maintaining renal function and patient survival.

Renal calculi in the burned child

Fifteen burned children were noted to have developed renal calculi at our institution over the past 20 years. Primary risk factors appear to be immobilization and a high intake of dairy products and antacids. Presenting symptoms and physical signs include abdominal pain, haematuria, with transient leukocytosis and elevations of the blood urea nitrogen. Conservative therapy with increased fluid administration and urine acidification were successful in 13 of the patients. The remaining two patients required surgical extraction. There were no long-term renal sequelae in any of the patients.

Acute renal failure in a burn patient: the advantages of continuous peritoneal dialysis

An 8-year-old girl sustained 65-70 per cent body surface area burns when her clothes caught fire. Two weeks later, she developed acute renal failure (ARF) and needed dialysis therapy. The extensive, infected burn area prevented the establishment of a safe vascular access for haemodialysis. Continuous peritoneal dialysis proved to be a valid alternative form of treatment and even had advantages over haemodialysis. Large amounts of fluids, calories and electrolytes could be administered via the peritoneal route. This facilitated the treatment of the catabolic state of the uraemic burn patient and served to correct the electrolyte losses via the skin. Peritoneal dialysis is a valuable adjunct to the treatment of acute renal failure in burn patients who need renal replacement therapy.

Survival from acute renal failure after severe burns

We describe a patient with 50 per cent, third degree flame burns who had a history of paint thinner inhalation for over 10 years. Moreover, chlorpromazine had been administered for the treatment of insomnia caused by chronic thinner intoxication. He developed oliguric acute renal failure soon after the burn injury, although adequate resuscitation therapy was given, and survived following frequent haemodialysis. Although survival from acute renal failure after severe burns is rare, once the diagnosis of acute renal failure has been made, haemodialysis should be instituted as early as possible. Furthermore, in a severely burnt patient with episodes of chronic and acute intoxication from organic chemicals or drugs which may have caused renal damage, acute renal failure may occur, so that careful observation is advised.

Effects of lysine-vasopressin treatment on renal function in burned pigs

The effects of lysine vasopressin (LVP) on renal excretory function and renal blood flow were studied in anesthetized and burned pigs either treated conservatively or by early excision 5 hours after burn. Renal perfusion was measured with radioactive microspheres. Diuresis and the urinary excretion of sodium and potassium were determined. Glomerular filtration rate (GFR) was measured either as the endogenous creatinine clearance rate or the clearance rate of 51Cr-EDTA. LVP-treatment in pharmacologic doses after burn caused larger diuresis, and larger sodium and potassium excretion rates than in unburned controls and animals submitted to burn only, Renal blood flow decreased significantly early after burn whether LVP was given or not. After burn, GFR was moderately higher in the LVP-treated pigs than in the animals submitted to burn only. After 24 hours S-creatinine was lower in the pigs treated by LVP and excision of the burned tissues after 5 hours, compared with the conservatively treated animals. This implies that an active surgical approach to full thickness skin burns might support renal function. LVP-induced intrarenal effects causing increased GFR and secondary medullary interstitial electrolyte concentration and osmolar changes could be the mechanisms causing the renal functional changes found in this investigation.

Acute renal failure in burns

We present the combined experience of a burns unit and a renal dialysis unit in treating acute renal failure in burn injury patients. A total of 28 cases have been treated of whom 4 regained normal renal function. We would like to emphasize the following points which may improve the usually very poor prognosis: early diagnosis, early daily haemodialysis, adequate feeding and the early amputation of non viable limbs. A search of the literature reveals that only 11 previously reported cases of burns injury patients being successfully dialysed for acute renal failure.

Presentation, management, complications, and outcome of acute renal failure in childhood: five years' experience

During 1971-5, 72 episodes of acute renal failure were treated in 70 children aged up to 16 years. The commonest causes were renal hypoperfusion (31 cases), haemolytic-uraemic syndrome (12), glomerulonephritis (9), septicaemia (5), and congenital abnormalities (6). Though referral from other hospitals was generally prompt, 10 out of 51 patients had been observed for up to seven days before transfer. Dailysis was used in 44 cases, the most common complications of which were peritonitis in those treated with peritoneal dialysis and acute changes in fluid balance in those treated with haemodialysis. Altogether 37 patients fully recovered, 10 were discharged with chronically impaired renal function, 17 died, and six entered the dialysis and transplantation programme. The mortality fell from 33% in 1972 to 20% in later years, which was due solely to maintenance dialysis being available. Though all patients with irrevocable kidney failure who were suitable entered the dialysis and transplantation programme, with current financial restrictions we doubt whether we shall be able to find places for all such patients in the future.

Burns and carbon-monoxide poisoning

In the treatment of severe burns following fires in closed spaces, attention must also be directed to the possibility of severe carbon-monoxide poisoning and pulmonary burning.

Each of these conditions possesses a high mortality-rate of its own, although admission appearances may not indicate such.

An early active approach in management should be adopted despite the absence of overt clinical indications.