Integrity of airway epithelium in pediatric burn autopsies: Association with age and extent of burn injury

Duration of cooling with water for thermal burns as a first aid intervention: A systematic review

BACKGROUND

Cooling thermal burns with running water is a recommended first aid intervention. However, guidance on the ideal duration of cooling remains controversial and inconsistent across organisations.

AIM

To perform a systematic review of the evidence for the question; Among adults and children with thermal burn, does active cooling using running water as an immediate first aid intervention for 20 min or more, compared with active cooling using running water for any other duration, change the outcomes of burn size, burn depth, pain, adverse outcome (hypothermia) or complications?

METHOD

We searched Medline, Embase, Cochrane Database of Systematic Reviews and used ROBINS-I to assess for risk of bias. We used Grading of Recommendations, Assessment, Development and Evaluation methodology for determining the certainty of evidence. We included all studies that compared the selected outcomes of the duration of cooling of thermal burns with water in all patient ages. (PROSPERO registration number: CRD42021180665). From 560 screened references, we included four observational studies. In these studies, 48% of burns were cooled for 20 min or more. We found no benefit for a duration of 20 min or more of cooling when compared with less than 20 min of cooling for the outcomes of size and depth of burn, re-epithelialization, or skin grafting. The evidence is of very low certainty owing to limitations in study design, risk of bias and indirectness.

CONCLUSION

The optimal duration of cooling for thermal burns remains unknown and future prospective research is indicated to better define this treatment recommendation.

The Outcomes of Inhalation Injuries in Lesser Burns: Still a Deadly Injury

BACKGROUND

Although it has been widely proposed that inhalation injuries worsen burn outcomes, large-scale studies have yet to demonstrate the exact relationship. This study proposes inhalation injuries as an independent risk factor that worsens burn outcomes.

METHODS

A retrospective review of the American Burn Association Registry from 2002 to 2011 was conducted. Inclusion criteria included burn patients with a total body surface area (TBSA) of less than 15% and adequate data recording of the inhalation injury within the registry. Patients were stratified into 2 groups: inhalation injuries (group 1) vs non-inhalation injuries (group 2). Outcome measures included in-hospital mortality rate, hospital length of stay (LOS), intensive care unit (ICU) LOS, and days on a ventilator.

RESULTS

A total of 93781 burn patients met the inclusion criteria. There were 4204 patients in group 1 and 89577 patients in group 2. There was no statistically significant difference between the 2 groups in terms of TBSA, with 3.50% in group 1 and 3.58% in group 2. There was a significantly higher ICU LOS at 8.55 days in group 1 compared to 6.27 days in group 2. There was a significantly higher hospital LOS at 11.48 days in group 1 compared to 6.27 days in group 2. The in-hospital mortality was significantly higher in group 1 at 8.54% vs group 2 at 1.42%.

CONCLUSION

The presence of inhalation injury may be a predictor of increased mortality and poor outcome in burn patients, even in those with small sized burns.

Effects of adjunct treatments on end-organ damage and histological injury severity in acute respiratory distress syndrome and multiorgan failure caused by smoke inhalation injury and burns

BACKGROUND

We investigated effects of mesenchymal stem cells (MSC) or low-flow extracorporeal life support (ECLS) as adjunctive treatments for acute respiratory distress syndrome (ARDS) due to inhalation injury and burns. We hypothesized that these interventions decrease histological end-organ damage.

METHODS

Anesthetized female swine underwent smoke inhalation injury and 40% TBSA burns, then critical care for 72h. The following groups were studied: CTR (no injury, n = 4), ICTR (injured untreated, n = 10), Allo (injured treated with allogenic MSC, n = 10), Auto (injured treated with autologous MSC, n = 10), Hemo (injured and treated with the Hemolung low flow ECLS system, n = 9), and Nova (injured and treated with the NovaLung low flow ECLS system, n = 8). Histology scores from lung, kidneys, liver, and jejunum were calculated. Data are presented as means±SEM.

RESULTS

Survival at 72h was 100% in CTR; 40% in ICTR; 50% in Allo; 90% in Auto; 33% in Hemo; 63% in Nova. ARDS developed in 0/10 CTR; 10/10 ICTR; 8/9 Hemo; 5/8 Nova; 9/10 Allo; 6/10 Auto. Diffuse alveolar damage (DAD) was present in all injured groups. MSC groups had significantly lower DAD scores than ICTR animals (Allo 26.6 ± 3.4 and Auto 18.9 ± 1.5 vs. ICTR 46.8 ± 2.1, p < 0.001). MSC groups also had lower DAD scores than ECLS animals (Allo vs. Nova, p < 0.05, Allo vs. Hemo p < 0.001, Auto vs. Nova p < 0.001, Auto vs. Hemo, p < 0.001). Kidney injury ICTR (p < 0.05) and Hemo (p < 0.01) were higher than in CTR. By logistic regression, a PaO₂-to-FiO₂ ratio (PFR) < 300 was a function of the DAD score: logit (PFR < 300) = 0.84 + 0.072*DAD Score, odds ratio 1.074 (1.007, 1.147, p < 0.05) with a ROC AUC of 0.76, p < 0.001.

CONCLUSION

Treatment with Auto MSC followed by Allo and then Nova were most effective in mitigating ARDS and MOF severity in this model. Further studies will elucidate the role of combination therapies of MSC and ECLS as comprehensive treatments for ARDS and MOF.

Xanthine oxidase contributes to sustained airway epithelial oxidative stress after scald burn

Respiratory tract infections and pneumonia are major causes of morbidity and mortality in burn victims, however, limited studies have examined the effects of burn injury on airway epithelium. The current study examines the effect of scald burn injury on rat tracheal epithelium at 5 days after injury and tests the hypothesis that treatment with febuxostat (FBX), an inhibitor of xanthine oxidase (XO), can be protective of cell homeostasis. Sprague Dawley rats were randomly divided into uninjured (sham), injured (control) and injured and FBX treated groups, n = 8. Control and FBX treated groups received 60% total body surface area scald burn injury. The FBX group received an i. p. dose (1 mg/kg) at 1 hour after injury and every 24 hours. At 5 days after injury, the animals were sacrificed and tracheal epithelial cell lysates were collected. Malondialdehyde (MDA), ATP, and XO activity were measured. Formation of 8-OHdG in tracheal epithelium was determined using immunohistochemistry (IHC) and immunoreactivity was quantitated. MDA levels were significantly increased in injured control animals (24.8 ± 2.3) compared to sham (7.93 ± 1.2, p = 0.002). FBX treatment attenuated this response (12.6 ± 2.7, p = 0.02). ATP levels were significantly decreased in control (0.7 ± 0.16) compared to sham, (2 ± 0.14, p = 0.01). ATP levels were increased with FBX treatment (1.8 ± 0.1, p = 0.03) compared to controls. There was a significant increase in XO activity in control animals, 1.04 ± 0.06 compared to sham (0.34 ± 0.05, p = 0.03), and this response decreased with FBX treatment 0.46 ± 0.07 (p = 0.04). Immunolabeling of 8-OHdG in control animals was significantly increased (25.1 ± 0.7 compared to the sham group 5.5 ± 1.9 (p = 0.01)), and was decreased with FBX treatment (7.0 ± 2.3 compared to control (p = 0.03)). The current study indicates that lipid peroxidation and ATP depletion persist in tracheal epithelium for 5 days after injury along with increased XO activity and 8-OHdG. These effects were significantly attenuated by FBX treatment, suggesting that reactive oxygen species generated by XO contribute to airway epithelial injury following scald burn.

Burn Injury Leads to Increased Long-Term Susceptibility to Respiratory Infection in both Mouse Models and Population Studies

Background

Burn injury initiates an acute inflammatory response that subsequently drives wound repair. However, acute disruption to the immune response is also common, leading to susceptibility to sepsis and increased morbidity and mortality. Despite increased understanding of the impact of burn injury on the immune system in the acute phase, little is known about long-term consequences of burn injury on immune function. This study was established to determine whether burn injury has long-term clinical impacts on patients’ immune responses.

Methods

Using a population-based retrospective longitudinal study and linked hospital morbidity and death data from Western Australia, comparative rates of hospitalisation for respiratory infections in burn patients and a non-injured comparator cohort were assessed. In addition, a mouse model of non-severe burn injury was also used in which viral respiratory infection was induced at 4 weeks post-injury using a mouse modified version of the Influenza A virus (H3NN; A/mem/71-a).

Results and conclusions

The burn injured cohort contained 14893 adult patients from 1980–2012 after removal of those patients with evidence of smoke inhalation or injury to the respiratory tract. During the study follow-up study a total of 2,884 and 2,625 respiratory infection hospital admissions for the burn and uninjured cohorts, respectively, were identified. After adjusting for covariates, the burn cohort experienced significantly elevated admission rates for influenza and viral pneumonia (IRR, 95%CI: 1.73, 1.27–2.36), bacterial pneumonia (IRR, 95%CI: 2.05, 1.85–2.27) and for other types of upper and lower respiratory infections (IRR, 95% CI: 2.38, 2.09–2.71). In the mouse study an increased viral titre was observed after burn injury, accompanied by a reduced CD8 response and increased NK and NKT cells in the draining lymph nodes. This data suggests burn patients are at long-term increased risk of infection due to sustained modulation of the immune response.

Burns and long-term infectious disease morbidity: A population-based study

BACKGROUND

There is a growing volume of data that indicates that serious injury suppresses immune function, predisposing individuals to infectious complications. With recent evidence showing long-term immune dysfunction after less severe burn, this study aimed to investigate post-burn infectious disease morbidity and assess if burn patients have increased long-term hospital use for infectious diseases.

METHODS

A population-based longitudinal study using linked hospital morbidity and death data from Western Australia for all persons hospitalised for a first burn (n=30,997) in 1980-2012. A frequency matched non-injury comparison cohort was randomly selected from Western Australia's birth registrations and electoral roll (n=123,399). Direct standardisation was used to assess temporal trends in infectious disease admissions. Crude annual admission rates and length of stay for infectious diseases were calculated. Multivariate negative binomial and Cox proportional hazards regression modeling were used to generate adjusted incidence rate ratios (IRR) and hazard ratios (HR), respectively.

RESULTS

After adjustment for demographic factors and pre-existing health status, the burn cohort had twice (IRR, 95% confidence interval (CI): 2.04, 1.98-2.22) as many admissions and 3.5 times the number of days in hospital (IRR, 95%CI: 3.46, 3.05-3.92) than the uninjured cohort for infectious diseases. Higher rates of infectious disease admissions were found for severe (IRR, 95%CI: 2.37, 1.89-2.97) and minor burns (IRR, 95%CI: 2.22, 2.11-2.33). Burns were associated with significantly increased incident admissions: 0-30days (HR, 95%CI: 5.18, 4.15-6.48); 30days-1year (HR, 95%CI: 1.69, 1.53-1.87); 1-10 years (HR, 95%CI: 1.40:1.33-1.47); >10years (HR, 95%CI: 1.16, 1.08-1.24). Respiratory, skin and soft tissue and gastrointestinal infections were the most common. The burn cohort had a 1.75 (95%CI: 1.37-2.25) times greater rate of mortality caused by infectious diseases during the 5-year period after discharge than the uninjured cohort.

CONCLUSIONS

These findings suggest that burn has long-lasting effects on the immune system and its function. The increase in infectious disease in three different epithelial tissues in the burn cohort suggests there may be common underlying pathophysiology. Further research to understand the underlying mechanisms are required to inform clinical interventions to mitigate infectious disease after burn and improve patient outcomes.

Respiratory Morbidity After Childhood Burns: A 10-Year Follow-up Study

BACKGROUND AND OBJECTIVE

The systemic responses triggered by burns and resuscitative measures may cause pulmonary damage and edema in the acute phase. These effects may occur in the absence of inhalation injury. Currently, there is a paucity of data on the recovery of the respiratory system postburn. This study aimed to examine 10-year hospital service use for respiratory morbidity in children with cutaneous burns and no smoke inhalation injury.

METHODS

A population-based longitudinal study with 10-year follow-up using linked hospital and death from Western Australia for children <5 years when hospitalized for a first burn injury (n = 5290) between 1980 and 2012 and a frequency matched noninjury comparison cohort, randomly selected from Western Australia's birth registrations (n = 27 061). Multivariate negative binomial and Cox proportional hazards regression models were used to generate adjusted incidence rate ratios (IRR) and hazard ratios, respectively.

RESULTS

After adjustment for demographic factors and preexisting health status, the burn cohort had higher rates of admissions for influenza and viral pneumonia (IRR, 1.78; 95% confidence interval [CI], 1.10-2.87), bacterial pneumonia (IRR, 1.34; 95% CI, 1.06-1.70), and other respiratory infections (IRR, 1.65; 95% CI, 1.43-1.90. No significant difference was found for other upper respiratory tract conditions (IRR, 1.10; 95% CI, 0.98-1.23) or chronic lower respiratory diseases (IRR, 0.99; 95% CI, 0.80-1.23) compared with the uninjured cohort.

CONCLUSIONS

These findings demonstrated increased respiratory infection admissions after burns. These outcomes suggest that immune changes triggered by a burn injury may persist in some children for at least 10 years after wound healing.