Reciprocal Risk of Acute Kidney Injury and Acute Respiratory Distress Syndrome in Critically Ill Burn Patients.

OBJECTIVE: To evaluate the association between acute respiratory distress syndrome and acute kidney injury with respect to their contributions to mortality in critically ill patients. DESIGN: Retrospective analysis of consecutive adult burn patients requiring mechanical ventilation. SETTING: A 16-bed burn ICU at tertiary military teaching hospital. PATIENTS: Adult patients more than 18 years old requiring mechanical ventilation during their initial admission to our burn ICU from January 1, 2003, to December 31, 2011. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total 830 patients were included, of whom 48.2% had acute kidney injury (n = 400). These patients had a 73% increased risk of developing acute respiratory distress syndrome after controlling for age, gender, total body surface area burned, and inhalation injury (hazard ratio, 1.73; 95% CI, 1.18-2.54; p = 0.005). In a reciprocal multivariate analysis, acute respiratory distress syndrome (n = 299; 36%) demonstrated a strong trend toward developing acute kidney injury (hazard ratio, 1.39; 95% CI, 0.99-1.95; p = 0.05). There was a 24% overall in-hospital mortality (n = 198). After adjusting for the aforementioned confounders, both acute kidney injury (hazard ratio, 3.73; 95% CI, 2.39-5.82; p < 0.001) and acute respiratory distress syndrome (hazard ratio, 2.16; 95% CI, 1.58-2.94; p < 0.001) significantly contributed to mortality. Age, total body surface area burned, and inhalation injury were also significantly associated with increased mortality. CONCLUSIONS: Acute kidney injury increases the risk of acute respiratory distress syndrome in mechanically ventilated burn patients, whereas acute respiratory distress syndrome similarly demonstrates a strong trend toward the development of acute kidney injury. Acute kidney injury and acute respiratory distress syndrome are both independent risks for subsequent death. Future research should look at this interplay for possible early interventions.

Acute Respiratory Distress Syndrome in Burn Patients: A Comparison of the Berlin and American-European Definitions.

The purpose of this study was to compare the Berlin definition to the American-European Consensus Conference (AECC) definition in determining the prevalence of acute respiratory distress syndrome (ARDS) and associated mortality in the critically ill burn population. Consecutive patients admitted to our institution with burn injury that required mechanical ventilation for more than 24 hours were included for analysis. Included patients (N = 891) were classified by both definitions. The median age, % TBSA burn, and injury severity score (interquartile ranges) were 35 (24-51), 25 (11-45), and 18 (9-26), respectively. Inhalation injury was present in 35.5%. The prevalence of ARDS was 34% using the Berlin definition and 30.5% using the AECC definition (combined acute lung injury and ARDS), with associated mortality rates of 40.9 and 42.9%, respectively. Under the Berlin definition, mortality rose with increased ARDS severity (14.6% no ARDS; 16.7% mild; 44% moderate; and 59.7% severe, P < 0.001). By contrast, under the AECC definition increased mortality was seen only for ARDS category (14.7% no ARDS; 15.1% acute lung injury; and 46.0% ARDS, P < 0.001). The mortality of the 22 subjects meeting the AECC, but not the Berlin definition was not different from patients without ARDS (P = .91). The Berlin definition better stratifies ARDS in terms of severity and correctly excludes those with minimal disease previously captured by the AECC.

A comparison of acute respiratory distress syndrome outcomes between military and civilian burn patients.

BACKGROUND: The objective of this report was to compare the prevalence of acute respiratory distress syndrome (ARDS) and associated mortality between military service members with burns sustained during or in support of combat operations and civilian burn patients treated at a single burn center. METHODS: Demographic and physiologic data were collected retrospectively on mechanically ventilated military and civilian patients admitted to our burn intensive care unit between January 2003 and December 2011. Patients with ARDS were identified and categorized as mild, moderate, or severe using the Berlin criteria. Demographics and clinical outcomes were compared. After initial comparison, propensity matching was performed and mortality compared. RESULTS: A total of 891 burn patients required mechanical ventilation during the study period; 291 military and 600 civilian. The prevalence of ARDS was 34% (n=304) for the entire cohort, 33% (n=96) for military, and 35% (n=208) for civilians (p=0.55). For the entire cohort, despite more severe injury burden, military patients had a significantly lower overall mortality (17% vs. 28%; p=0.0002) as well as ARDS mortality (33 vs. 48%, p=0.02) when compared to civilians. This difference was not significant after propensity matching based on age. CONCLUSION: In a retrospective cohort study, burned military patients on mechanical ventilation had a significantly lower overall and ARDS mortality despite larger burns and more severe injury when compared to civilian burn patients. This difference appears to be largely because of age.

Acute respiratory distress syndrome in wartime military burns: application of the Berlin criteria.

BACKGROUND: Acute respiratory distress syndrome (ARDS) prevalence and related outcomes in burned military casualties from Iraq and Afghanistan have not been described previously. The objective of this article was to report ARDS prevalence and its associated in-hospital mortality in military burn patients. METHODS: Demographic and physiologic data were collected retrospectively on mechanically ventilated military casualties admitted to our burn intensive care unit from January 2003 to December 2011. Patients with ARDS were identified in accordance with the new Berlin definition of ARDS. Subjects were categorized as having mild, moderate, or severe ARDS. Multivariate logistic regression identified independent risk factors for developing moderate-to-severe ARDS. The main outcome measure was the prevalence of ARDS in a cohort of patients burned as a result of recent combat operations. RESULTS: A total of 876 burned military casualties presented during the study period, of whom 291 (33.2%) required mechanical ventilation. Prevalence of ARDS in this cohort was 32.6%, with a crude overall mortality of 16.5%. Mortality increased significantly with ARDS severity: mild (11.1%), moderate (36.1%), and severe (43.8%) compared with no ARDS (8.7%) (p < 0.001). Predictors for the development of moderate or severe ARDS were inhalation injury (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.01-3.54; p = 0.046), Injury Severity Score (ISS) (OR, 1.04; 95% CI, 1.01-1.07; p = 0.0021), pneumonia (OR, 198; 95% CI, 1.07-3.66; p = 0.03), and transfusion of fresh frozen plasma (OR, 1.32; 95% CI, 1.01-1.72; p = 0.04). Size of burn was associated with moderate or severe ARDS by univariate analysis but was not an independent predictor of ARDS by multivariate logistic regression (p > 0.05). Age, size of burn, and moderate or severe ARDS were independent predictors of mortality. CONCLUSION: In this cohort of military casualties with thermal injuries, nearly a third required mechanical ventilation; of those, nearly one third developed ARDS, and nearly one third of patients with ARDS did not survive. Moderate and severe ARDS increased the odds of death by more than fourfold and ninefold, respectively. LEVEL OF EVIDENCE: Epidemiologic/prognostic study, level III.