Microalbuminuria in acute burn injury

Clinical outcomes following burn injury across the continuum of chronic glycemic control

Diabetes has been associated with poor outcomes following burn injury. There is limited data related to prediabetes in burn injury, and no studies to date have compared clinical outcomes inpatients without diabetes, with prediabetes, and with diabetes. Therefore, this study aimed to compare clinical outcomes after burn injury across the continuum of pre-injury glucose control. A propensity score weighted cohort study of adult patients admitted for initial management of burn injury was performed. Patients were categorized as no diabetes, prediabetes or diabetes based on their admission hemoglobin A1c and past medical history. The primary outcome was length of stay per percent Total Body Surface Area (TBSA) burn. Secondary outcome measures included length of stay, all-cause hospital mortality, disposition at discharge, re-grafting of same site, and amputations. A total of 2450 patients were screened; 1137 patients were included for evaluation (236 diabetes, 191 prediabetes, 710 no diabetes). After inverse probability weighing to adjust for potentially confounding factors, patients in the diabetes group had longer length of stay/%TBSA burn than both the no diabetes group (ratio of geometric means (95% CI) = 1.65 (1.25, 2.18), p < 0.001) and the prediabetes group (ratio (95% CI) = 1.49 (1.10, 2.02), p = 0.01). No statistically significant differences in secondary outcomes were observed between groups other than a higher rate of amputations in the diabetes group (2.7%) compared to the no diabetes (0.7%, p = 0.047) and prediabetes (0%, p = 0.04) groups. Further studies are needed to delineate the differences across the continuum of pre-injury glucose control in order to identify mechanisms to optimize burn-related outcomes.

Factors influencing post-exercise proteinuria after marathon and ultramarathon races

Post-exercise proteinuria is one of the most common findings observed after short and intensive physical activity, but is observed also after long runs with low intensity. The aim of this study was to analyze factors influencing proteinuria after marathon runs. Two groups of male amateur runners were studied. The results of 20 marathon finishers (42.195 m), with a mean age of 49.3 ± 6.85 years; and 17 finishers of a 100-km ultramarathon with a mean age of 40.18±4.57 years were studied. Urine albumin to creatinine ratio (ACR) was calculated before and after both races. The relationship between ACR and run pace, metabolites (lactate, beta hydroxybutyrate), markers of inflammation (CRP, IL-6) and insulin was studied. The significant increase in ACR was observed after both marathon races. ACR increased from 6.41 to 21.96 mg/g after the marathon and from 5.37 to 49.64 mg/g after the ultramarathon (p<0.05). The increase in ACR was higher after the ultramarathon that after the marathon. There was no correlation between run pace and proteinuria. There was no correlation between ACR and glucose, free fatty acids, lactate, beta-hydroxybutyrate and insulin levels. There was significant negative correlation between ACR and interleukin 6 (IL-6) (r =-0.59, p< 0.05) after ultramarathon. Proteinuria is a common finding after physical exercise. After very long exercises it is related to duration but not to intensity. There is no association between metabolic and hormonal changes and ACR after marathon runs. The role on inflammatory cytokines in albuminuria is unclear.

Serum cystatin C and microalbuminuria in burn patients with acute kidney injury

BACKGROUND

This study was aimed at evaluating the effectiveness of serum cystatin C and microalbuminuria as diagnostic markers for acute kidney injury (AKI) in major burn patients.

MATERIALS AND METHODS

Major burn adult patients admitted to the burn intensive care unit within 24 h from the onset of injury were enrolled. Serum cystatin C and microalbuminuria (albumin-creatinine ratio, ACR) were obtained at postburn days 1, 3, 7, 14, 21 and 28. The patients were divided into two groups of the AKI group and the nonacute kidney injury group.

RESULTS

A total of 97 patients were enrolled in this study. Acute kidney injury was diagnosed in 40 patients (41.2%) at postburn day 17.3 ± 7.9. The area under the curve of the receiver operating characteristic curve for serum cystatin C was 0.808 (95% CI, 0.711-0.905, P < 0.001) at postburn day 7 and 0.908 (95% CI, 0.843-0.973, P < 0.001) at postburn day 14. The results were 0.610 (95% CI, 0.497-0.724, P = 0.069) for ACR at postburn day 7 and 0.694 (95% CI, 0.589-0.798, P = 0.001) at postburn day 14. The optimal cut-off value of serum cystatin C at postburn day 14 and ACR at postburn day 14 were 0.85 mg/L (sensitivity, 89.5%; specificity, 82.5%) and 41.51 mg/g cre (sensitivity, 60.5%; specificity, 61.4%), respectively. Serum cystatin C at postburn day 14 was the only significant factor in relation to AKI.

CONCLUSIONS

Serum cystatin C is a valuable diagnostic marker, whereas microalbuminuria is a relatively less significant marker for AKI in major burn patients.

The utility of microalbuminuria measurements in pediatric burn injuries in critical care

PURPOSE

Microalbuminuria, as measured by urinary albumin-creatinine ratios (ACRs), has been shown to be a marker of systemic inflammation and an indicator of the potential severity of trauma and critical illness. Severe pediatric burns represent the best model in which to investigate the clinical utility of microalbuminuria. This study aims to ascertain whether ACR measurements have any role in predicting the severity or the intensive care requirements in the critically unwell pediatric burn population.

MATERIALS AND METHODS

A retrospective observational study was undertaken within a regional burn center with a dedicated 8-bed burn intensive care unit (ICU). This looked at 8 years of consecutive pediatric burns requiring intensive care support-a total of 63 patients after exclusions. Daily urinary ACR measurements were acquired from all patients.

RESULTS

All patients had greater than or equal to 1 ACR measurement out with the reference range, and only 8% (5/63) presented to the ICU with a normal ACR. The median day for the peak ACR measurement was day 4. The relative lack of mortalities (3/63) precluded adequate correlations between ACR and outcomes. Peak and mean ACR values correlate well with length of ICU stay, and the peak ACR also correlates with total length of hospital stay and severity of burn injury as measured by total body surface area burnt and number of organ systems requiring support. No significant differences were found when the patients were stratified by age. The peak ACR measurement was found to be independently predictive of the length of the ICU stay. As such, we have created a predictive model to prove that an ACR that remains less than 12 mg/mmol is predicative of an ICU stay of less than or equal to 7 days.

CONCLUSIONS

The clinical utilities of ACR measurements are demonstrated by their correlation with the severity of injury, length of ICU stay, and requirements for multiple organ support. Albumin-creatinine ratios raised over certain thresholds highlight to the clinician the need for closer observation and the potential deterioration of patients.

Increased B-type natriuretic peptide and decreased proteinuria might reflect decreased capillary leakage and is associated with a better outcome in patients with severe burns

Introduction

It is difficult to adjust fluid balance adequately in patients with severe burns due to various physical changes. B-type natriuretic peptide (BNP) is emerging as a potential marker of hydration state. Proteinuria is used as a predictor of outcome in severe illness and might correlate to systemic capillary leakage. This study investigates whether combining BNP and proteinuria can be used as a guide for individualized resuscitation and as a predictor of outcome in patients with severe burns.

Methods

From 2006 to 2009, 38 consecutive patients (age 47 ± 15 years, 74% male) with severe burns were included and followed for 20 days. All had normal kidney function at admission. BNP and proteinuria were routinely measured. Ordered and actually administered fluid resuscitation volumes were recorded. The Sequential Organ Failure Assessment (SOFA) score was used as the measure of outcome.

Results

BNP increased during follow-up, reaching a plateau level at Day 3. Based on median BNP levels at Day 3, patients were divided into those with low BNP and those with high BNP levels. Both groups had comparable initial SOFA scores. Patients with high BNP received less fluid from Days 3 to 10. Furthermore, patients with a high BNP at Day 3 had less morbidity, reflected by lower SOFA scores on the following days. To minimize effects of biological variability, proteinuria on Days 1 and 2 was averaged. By dividing the patients based on median BNP at Day 3 and median proteinuria, patients with high BNP and low proteinuria had significantly lower SOFA scores during the entire follow-up period compared to those patients with low BNP and high proteinuria.

Conclusions

Patients with higher BNP levels received less fluid. This might be explained by a lower capillary leakage in these patients, resulting in more intravascular fluid and consequently an increase in BNP. In combination with low proteinuria, possibly reflecting minimal systemic capillary leakage, a high BNP level was associated with a better outcome. BNP and proteinuria have prognostic potential in severely burned patients and may be used to adjust individual resuscitation.

The year in burns 2008

For 2008, approximately 1200 original burn research articles were published in scientific journals using the English language. This article reviews those with the most impact on burn treatment according to the Editor of one of the major journals (Burns). As in the previous year's review, articles were divided into the following topic areas: epidemiology, wound characterisation, critical care physiology, inhalation injury, infection, metabolism and nutrition, psychological considerations, pain management, rehabilitation, and burn reconstruction. Each selected article is mentioned briefly with editorial comment.

Proteinuria without albuminuria: urinary protein excretion by a subset of patients with burn injuries

BACKGROUND

There is disagreement regarding the utility of urinary albumin excretion as a marker for capillary injury in patients with severe burn injuries. We examined protein components in urine specimens from patients with burn injury.

METHODS

Detailed analysis was performed for a set of 5 urine specimens selected based on a high ratio of albumin-sized molecules by size-exclusion HPLC (Accumin) versus albumin by immunoassay methods. Specimens were analyzed for total protein, alpha(1)-microglobulin, alpha(1)-acid glycoprotein, cystatin C, and retinol-binding protein. Urine components were analyzed by chromatographic and electrophoretic methods. Major components were identified by mass spectrometry of tryptic peptides.

RESULTS

A subset of urine specimens had increased total protein with slight increases in albumin by immunoassay or by polyacrylamide gel electrophoresis. Albumin values by size-exclusion HPLC were more than 10-fold higher. Immunoassays for alpha(1)-microglobulin and alpha(1)-acid glycoprotein yielded concentrations 5-10 fold higher than for albumin. Other major components identified included zinc-alpha(2)-glycoprotein and leucine-rich-alpha(2)-glycoprotein.

CONCLUSIONS

A subset of patients with burn injury had increased total urinary protein resulting primarily from increased excretion of proteins such as alpha(1)-microglobulin and alpha(1)-acid glycoprotein with little increase in albumin excretion. The unusual composition of urinary proteins in these patients may relate to decreased filtered load of albumin and increased filtered load of acute phase reactants or to alterations in renal tubular protein processing. Thus, measurement of urinary albumin may have decreased sensitivity for detecting kidney injury in burn patients.