Prediction of Mortality in Patients With Major Burns

Serum albumin concentration on admission as a predictor of morbidity and mortality in patients with burn injuries

Efforts have been made to determine new predictors of morbidity and mortality in patients with severe burn injuries. This prospective cohort study aimed to determine the association of serum albumin concentration on admission and renal failure, pulmonary infection, sepsis, and death in patients with burn injuries. We included 141 patients, aged >18 years, who were admitted to our institution between April and August 2018. Among them, 59.1% were male and 83.8% had burns covering <20% of the body surface area. Scalds were the most common cause of burns (34.8%). Twelve patients died, of whom eight (66.6%) had an Abbreviated Burn Severity Index (ABSI) ≥8. Patients with serum albumin ≤2.2 g/dL had a higher mortality rate than those with >2.2 g/dL (odds ratios [OR]: 18.7; 95% confidence interval [CI]: 4.9-70.8). Serum albumin ≤2.2 g/dL was also significantly associated with pulmonary infection (OR: 13.1, 95%CI: 3.8-45.7), renal failure (OR: 30.2, 95% CI: 7.4-122.3), and sepsis (OR: 16.9, 95% CI: 4.9-58.3). Serum albumin concentration cut-points and ABSIs were determined to be death predictors using areas under the receiver operating characteristic curves (AUCs). The AUCs with albumin or ABSI alone were 0.89 (95% CI: 0.79-0.98) and 0.92 (95% CI: 0.87-0.96), respectively. The AUC including both albumin and ABSI was 0.96 (95% CI: 0.90-0.98), indicating that the combination is a better death predictor than either measure alone. We confirmed that burn patients with a serum albumin concentration ≤2.2 g/dL on admission have substantially increased morbidity and mortality.

Prevalence and prognostic impact of inhalation injury among burn patients: A systematic review and meta-analysis

BACKGROUND

The objective of our study was to perform a systematic review and meta-analysis aimed at assessing the prevalence of inhalation injury in burn patients and its prognostic value in relation to in-hospital mortality.

METHODS

We searched the PubMed and EMBASE databases for noninterventional studies published between 1990 and 2018 investigating in-hospital mortality predictors among burn patients.The primary meta-analysis evaluated the association between inhalation injury and mortality. A secondary meta-analysis determined the global estimate of the prevalence of inhalation injury and the rate of mortality. Random effects models were used, and univariate meta-regressions were used to assess sources of heterogeneity. This study is registered in the PROSPERO database with code CRD42019127356.

FINDINGS

Fifty-four studies including a total of 408,157 patients were selected for the analysis. A pooled inhalation prevalence of 15.7% (95% confidence interval, 13.4%-18.3%) was calculated.The summarized odds ratio of in-hospital mortality secondary to an inhalation injury was 3.2 (95% confidence interval, 2.5-4.3). A significantly higher odd of mortality was found among the studies that included all hospitalized burn patients, those that included a lower proportion of male patients, those with a lower mean total body surface area, and those with a lower prevalence of inhalation injury.

CONCLUSION

Despite our study's limitations due to the high risk of bias and the interstudy heterogeneity of some of our analyses, our results revealed a wide range of prevalence rates of inhalation injury and a significant association between this entity and in-hospital mortality in burn patients. However, this association is not significant if adjusted for disease severity.

LEVEL OF EVIDENCE

Systematic review/meta-analysis, level III.

Ubiquitin Urine Levels in Burn Patients

The objective of this study was to determine whether urine ubiquitin levels are elevated after burns and to assess whether urine ubiquitin could be useful as a noninvasive biomarker for burn patients. Forty burn patients (%TBSA: 20 ± 22; modified Baux scores: 73 ± 26) were included (control: 11 volunteers). Urine was collected in 2-hour intervals for 72 hours, followed by 12-hour intervals until discharge from the intensive care unit. Ubiquitin concentrations were analyzed by enzyme linked immunosorbent assay and Western blot. Total protein was determined with a Bradford assay. Patient characteristics and clinical parameters were documented. Urine ubiquitin concentrations, renal ubiquitin excretion, and excretion rates were correlated with patient characteristics and outcomes. Initial urine ubiquitin concentrations were 362 ± 575 ng/ml in patients and 14 ± 18 ng/ml in volunteers (P < .01). Renal ubiquitin excretion on day 1 was 292.6 ± 510.8 μg/24 hr and 21 ± 27 μg/24 hr in volunteers (P < .01). Initial ubiquitin concentrations correlated with modified Baux scores (r = .46; P = .02). Ubiquitin levels peaked at day 6 postburn, whereas total protein concentrations and serum creatinine levels remained within the normal range. Total renal ubiquitin excretion and excretion rates were higher in patients with %TBSA ≥20 than with %TBSA <20, in patients who developed sepsis/multiple organ failure than in patients without these complications and in nonsurvivors vs survivors. These data suggest that ubiquitin urine levels are significantly increased after burns. Renal ubiquitin excretion and/or excretion rates are associated with %TBSA, sepsis/multiple organ failure, and mortality. Although these findings may explain previous correlations between systemic ubiquitin levels and outcomes after burns, the large variability of ubiquitin urine levels suggests that urine ubiquitin will not be useful as a noninvasive disease biomarker.

Standardised mortality ratio based on the sum of age and percentage total body surface area burned is an adequate quality indicator in burn care: An exploratory review

Standardised Mortality Ratio (SMR) based on generic mortality predicting models is an established quality indicator in critical care. Burn-specific mortality models are preferred for the comparison among patients with burns as their predictive value is better. The aim was to assess whether the sum of age (years) and percentage total body surface area burned (which constitutes the Baux score) is acceptable in comparison to other more complex models, and to find out if data collected from a separate burn centre are sufficient for SMR based quality assessment. The predictive value of nine burn-specific models was tested by comparing values from the area under the receiver-operating characteristic curve (AUC) and a non-inferiority analysis using 1% as the limit (delta). SMR was analysed by comparing data from seven reference sources, including the North American National Burn Repository (NBR), with the observed mortality (years 1993-2012, n=1613, 80 deaths). The AUC values ranged between 0.934 and 0.976. The AUC 0.970 (95% CI 0.96-0.98) for the Baux score was non-inferior to the other models. SMR was 0.52 (95% CI 0.28-0.88) for the most recent five-year period compared with NBR based data. The analysis suggests that SMR based on the Baux score is eligible as an indicator of quality for setting standards of mortality in burn care. More advanced modelling only marginally improves the predictive value. The SMR can detect mortality differences in data from a single centre.