The effect of preexisting respiratory co-morbidities on burn outcomes

VARIABLES INFLUENCING THE DIFFERENTIAL HOST RESPONSE TO BURNS IN PEDIATRIC AND ADULT PATIENTS

ABSTRACT

Burn injury is a significant source of morbidity and mortality in the pediatric population. Although 40,000 pediatric patients in the United States are admitted to the hospital with burn wounds annually, significant differences exist in the management and treatment of these patients, even among highly specialized burn centers. Some aspects of pediatric burn research, such as metabolic changes and nutritional support after burn injury, have been studied extensively; however, in many aspects of burn care, pediatric research lags behind the study of adult populations. This review compares and contrasts a wide array of physiologic and immune responses between children and adults after burn injury. Such a review elucidates where robust research has been conducted, where adult research is applicable to pediatric patients, and where additional pediatric burn research needs to be conducted.

Prognostic Nutritional Index and Postoperative Pulmonary Complications in Patients With Major Burns

INTRODUCTION

Burns can cause multiple organ systemic derangements, particularly in respiratory systems. The prognostic nutritional index (PNI) can predict postoperative outcomes. We evaluated the incidence and risk factors, including PNI, for postoperative pulmonary complications (PPCs) in patients with major burns.

METHODS

PNI was calculated as 10 × (serum albumin level) + 0.005 × (total lymphocyte count). Major burn patients admitted to the ICU without burn-induced lung injuries were retrospectively included. The incidence of PPCs was measured within 1 wk of burn surgery. A multivariable logistic regression analysis was performed to evaluate the risk factors for PPCs. Receiver operating characteristic curve analysis and propensity-score matched analysis were conducted to estimate the influence of PNI on PPCs. Outcomes after burn surgery were also assessed.

RESULTS

Of 444 major burn patients, 138 (31.1%) showed PPCs. Risk factors for PPCs were PNI, gender, total body surface area burned, interval between burn and surgery, and red blood cell transfusion rate. The area under the curve of PNI for predicting PPCs was 0.709 (cutoff value = 31.5). The incidence of PPCs was significantly higher in the PNI ≤ 31.5 group than in the PNI > 31.5 group (55.7% versus 22.8%, P < 0.001) after propensity-score matching. The intensive care unit stay duration was longer and 90-d mortality was higher in patients who developed PPCs (19 [9-27] d versus 8 [4-17] d, P < 0.001; 11.6% versus 0.3%, P < 0.001).

CONCLUSIONS

The prevalence of PPCs in patients with major burns was 31.1% and preoperative PNI was a predictor of PPCs in these patients. PNI ≤ 31.5 was significantly related to a higher incidence of PPCs.

Age-dependent influence of premorbid underweight status on mortality in severe burn patients: An administrative database study

PURPOSE

To examine the associations between premorbid nutritional status and in-hospital mortality in severe burn patients according to age in Japan.

METHODS

We retrospectively extracted the data of 14,345 patients aged 18-84 years admitted for burns from April 1, 2014, to March 31, 2018, using the Japanese Diagnosis Procedure Combination database. The exclusion criteria were out-of-hospital cardiac arrest, death in the emergency room, readmission, and planned admission. We collected data on age, sex, height, weight, comorbidities, burn index, and mechanical ventilation use and performed age-stratified multilevel logistic regression analyses to estimate associations between premorbid body mass index (BMI) and in-hospital mortality.

RESULTS

We analyzed 2968 patients with a burn index ≥10, including 831 elderly aged 75-84 years. In patients aged 18-74 years, being underweight (BMI < 18.5) significantly decreased mortality (0.34 [0.15-0.77]; P = 0.010). In contrast, in patients aged 75-84 years, being underweight significantly increased mortality (2.11 [1.05-4.25]; P = 0.036). Being overweight (BMI >25) increased mortality in both age groups, but not significantly.

CONCLUSIONS

The results suggest that pre-morbidly underweight elderly patients aged 75-84 years with severe burns have high mortality risks. Further research is needed to identify optimal care strategies for this population.

Respiratory Management in Smoke Inhalation Injury

Smoke inhalation injury (SII) is a major morbidity and cause of mortality in patients with burns. Damage caused by inhalation of thermal or chemical irritants, including toxic fumes and chemicals, leads to respiratory cilia and epithelial cell injuries, which turn to severe bronchospasm and alveolar damage and results in acute respiratory distress syndrome. Respiratory management plays a vital role in the treatment of SII. In this review, we provide an overview of SII with emphasis on respiratory management, including aerosol therapy, bronchial hygiene therapy, advanced ventilation modes, and heated humidified high-flow nasal cannula. In summary, the information may be helpful for further improvements in outcomes.

Re-evaluation of the Effect of Age on In-hospital Burn Mortality in a Resource-Limited Setting

BACKGROUND

This global burden of burn injury is suffered disproportionately by people in low-income and middle-income countries, where 70% of all burns occur. Models based in high-income countries to prognosticate burn mortality treat age as a linearly increasing risk factor. It is unclear whether this relationship is similar in resource-limited settings.

METHODS

We analyzed patients from the Kamuzu Central Hospital Burn Registry in Lilongwe, Malawi, from 2011 to 2019. We examined the relationship between burn-associated mortality and age using adjusted survival analysis over 60 d, categorized into four groups: (1) younger children <5 y; (2) older children 5-17 y; (3) adults 18-40 y; and (4) older adults >40 y.

RESULTS

A total of 2499 patients were included. Most patients were <5 y old (n = 1444) with only 133 patients >40 y. Older adults had the highest crude mortality at 34.6% and older children with the lowest at 13%. Compared to younger children, the hazard ratio adjusted for sex, percent total body surface area, and operative intervention was 0.59 (95% confidence interval, 0.44, 0.79) for older children and 0.55 (95% confidence interval, 0.40, 0.76) for adults. Older adults were statistically similar to younger children.

CONCLUSIONS

We show in this cohort study of burn-injured patients in a resource-limited environment that the relationship between mortality and age is not linear and that the use of age-categorized mortality prediction models is more accurate in delineating mortality characteristics. Categorizing age based on local burn epidemiology will help describe burn mortality characteristics more accurately, leading to better-informed management strategies aimed at attenuating burn mortality for different populations.

Admission Neutrophil-Lymphocyte Ratio (NLR) Predicts Survival in Patients with Extensive Burns

BACKGROUND

Extensive burns is one of the most common severe injuries, with a high annual death rate. Previous studies showed that the neutrophil to lymphocyte ratio (NLR) is a prognostic factor for some inflammatory diseases. However, until now, no study has evaluated the clinical prognostic value of NLR in extensively burned patients. The aim of this study was to investigate the prognostic value of NLR in this medical condition to provide clinical guidance.

METHODS

271 patients diagnosed with extensive burns were analysed retrospectively between 2005 and 2018 in the Department of Burn Surgery of Changhai Hospital. NLR cut-off values at the first 3 days of hospitalization were calculated by the ROC analysis.

RESULTS

Of the 271 patients in this study, the majority (82.3%) were injured by flame. The median total body surface area (TBSA) was 55% (IQR, 40% to 85%) and the median full thickness burn (FTB) was 20% (IQR, 3%-44%). The patients' NLR declined within the first 3 days after admission, and we found that NLR was negatively correlated with the ventilator-free days at day 28 (r = -0.127, P = 0.048). In a multivariate logistic regression analysis, higher admission NLR was independently predictive of higher mortality. According to the ROC curve, the best cut-off values for day 1 (or admission day), day 2 and day 3 NLR were 14, 13 and 7.5, respectively. We then performed a survival analysis, finding that those NLR above the cut-off point had decreased overall survival compared to those with NLR below the cut-off point (p = 0.023, 0.045 and 0.019 for day 1, 2, and 3, respectively).

CONCLUSIONS

NLR continuously decreased in the first 3 days of hospitalization. Admission NLR above 14 is associated with a decreased survival in patients with extensive burns. These findings demonstrate that NLR has prognostic value in these patients.

Sex-Based Differences in Inpatient Burn Mortality

BACKGROUND

Among burn patients, research is conflicted, but may suggest that females are at increased risk of mortality, despite the opposite being true in non-burn trauma. Our objective was to determine whether sex-based differences in burn mortality exist, and assess whether patient demographics, comorbid conditions, and injury characteristics explain said differences.

METHODS

Adult patients admitted with burn injury-including inhalation injury only-between 2004 and 2013 were included. Inverse probability of treatment weights (IPTW) and inverse probability of censor weights (IPCW) were calculated using admit year, patient demographics, comorbid conditions, and injury characteristics to adjust for potential confounding and informative censoring. Standardized Kaplan-Meier survival curves, weighted by both IPTW and IPCW, were used to estimate the 30-day and 60-day risk of inpatient mortality across sex.

RESULTS

Females were older (median age 44 vs. 41 years old, p < 0.0001) and more likely to be Black (32% vs. 25%, p < 0.0001), have diabetes (14% vs. 10%, p < 0.0001), pulmonary disease (14% vs. 7%, p < 0.0001), heart failure (4% vs. 2%, p = 0.001), scald burns (45% vs. 26%, p < 0.0001), and inhalational injuries (10% vs. 8%, p = 0.04). Even after weighting, females were still over twice as likely to die after 60 days (RR 2.87, 95% CI 1.09, 7.51).

CONCLUSION

Female burn patients have a significantly higher risk of 60-day mortality, even after accounting for demographics, comorbid conditions, burn size, and inhalational injury. Future research efforts and treatments to attenuate mortality should account for these sex-based differences. The project was supported by the National Institutes of Health, Grant Number UL1TR001111.

Mortality From Burns Sustained on Home Oxygen Therapy Exceeds Predicted Mortality

The Boston Criteria and the Abbreviated Burn Severity Index are two widely accepted models for predicting mortality in burn patients. We aimed to elucidate whether these models are able to predict the risk of mortality in patients who sustain burns while smoking on home oxygen given their clinical fragility. We conducted a retrospective chart review of 48 patients admitted to our burn center from November 2013 to September 2017 who sustained a burn while smoking on home oxygen. Yearlong mortality was the primary outcome of the investigation; secondary outcomes included discharge to facility, length of stay, and need for tracheostomy. We calculated the expected mortality rate for each patient based on Boston Criteria and Abbreviated Burn Severity Index and compared the mortality rate observed in our cohort. Patients in our cohort suffered a 54% mortality rate within a year of injury, compared to a 23.5% mortality predicted by Boston Criteria, which was found to be statistically significant by chi-square analysis (P &lt; .05). Abbreviated Burn Severity Index predicted mortality was 19.7%. While the absolute value of the difference in mortality was greater, this was not significant on chi-square analysis due to sample size. Our secondary outcomes revealed 42% discharge to facility, the average length of stay of 6.2 days, and 6.25% required tracheostomy. Patients whose burns are attributable to smoking on home oxygen may have an increased risk of mortality than prognostication models would suggest. This bears significant clinical impact, particularly regarding family and provider decision making in pursuing aggressive management.

Effect of comorbidities on clinical outcome of patients with burn injury - An analysis of the German Burn Registry

BACKGROUND

Severe burn injuries are associated with high morbidity and mortality. Well-implemented scoring systems for patients with major burns exist in the literature. A major disadvantage of these scores is the partial non-consideration of patient-related comorbidities. Published data on this matter is limited to small study cohorts and/or single center studies. Further, the effect of comorbidities on clinical outcome of patients with severe burn injuries has not yet been examined nationwide in a large cohort in Germany. Hence, the aim of this study was to examine the influence of comorbidities on clinical outcome of these patients based on data from the national registry.

METHODS

Anonymized data from a total of 3455 patients with documented burns of 1% or more Total Burn Surface Area (TBSA) and over 16 years of age included in the German Burn Registry between 2017 and 2018 were analyzed retrospectively. Data included burn extent, body weight, age, burn depth, inhalation injury, comorbidities, mortality, number of operations and length of hospital stay (LOS).

RESULTS

In the logistic regression analysis age (OR 1.07 [1.06-1.09], p < 0.001), TBSA (OR 1.09 [1.08-1.11], p < 0.001), IHT (OR 2.15 [1.44-3.20], p < 0001), third degree burn (OR 2.08 [1.39-3.11], p < 0.001), Chronic Obstructive Pulmonary Disease (COPD) (OR 2.45 [1.38-4.35], p = 0.002) and renal insufficiency (OR 2.02 [1.13-3.59], p = 0.017) influenced mortality significantly. If a patient had more than one comorbidity, mortality was higher and in-hospital length of stay (LOS) longer. Renal insufficiency was significantly (p < 0.001) associated with the most prolonged LOS by 11.44 days. TBSA (p < 0.001), Abbreviated Burn Severity Index (ABSI) > 3 (p < 0.001) and IHT (p = 0.001) correlated with the amount of required surgeries and significantly predicted the need for intubation. Patients with arrhythmia significantly required more surgeries (p = 0.041), whereas patients with COPD required significantly less surgical interventions (p = 0.013).

CONCLUSION

Preexisting comorbidities have a significant impact on the clinical outcome of patients with severe burn injuries. Further investigation is warranted in order to supplement existing prognostic scores with new mortality-associated parameters.