Ventilator-Associated Pneumonia After Combined Burn and Trauma Is Caused by Associated Injuries and Not the Burn Wound

Severity of Inhalation Injury and Risk of Nosocomial Pneumonia: A Retrospective Cohort Study

BACKGROUND

The impact of inhalation injury on risk of nosocomial pneumonia (NP), an important complication in patients with burns, is not well established.

RESEARCH QUESTION

Is more severe inhalation injury associated with increased risk of NP?

STUDY DESIGN AND METHODS

We performed a retrospective cohort study of patients with suspected inhalation injury admitted to a regional burn center from 2011 to 2022 who underwent diagnostic bronchoscopy within 48 h of admission. We estimated the association of high-grade inhalation injury (Abbreviated Injury Scale grade 3 and 4) vs low-grade inhalation injury (Abbreviated Injury Scale grade 1 and 2) with NP adjusted for age, burn size, and comorbid obstructive lung disease. Death and hospital discharge were considered competing risks.

RESULTS

Of the 245 patients analyzed, 51 (21%) had high-grade injury, 180 (73%) had low-grade injury, and 14 (6%) had no inhalation injury. Among the 236 patients hospitalized for ≥ 48 h, NP occurred in 24 of 50 patients (48%) in the high-grade group, 54 of 172 patients (31%) in the low-grade group, and two of 14 patients (14%) in the no inhalation injury group. High-grade (vs low-grade) inhalation injury was associated with higher hazard of NP in both the proportional cause-specific hazard model (cause-specific hazard ratio, 2.04; 95% CI, 1.26-3.30; P = .004) and Fine-Gray subdistribution hazard model (subdistribution hazard ratio for NP, 2.24; 95% CI, 1.38-3.64; P = .001).

INTERPRETATION

In this study, among patients with inhalation injury, more severe injury was associated with higher hazard of NP in competing risk analysis. Additional research is needed to investigate mechanisms that may explain the relationship between inhalation injury and NP and to identify more effective risk reduction strategies.

Predictors and Impact of Pneumonia on Adverse Outcomes in Inhalation Injury Patients

Inhalation injury (II) is the third mortality prognostic factor for burn injury following age and burn size. II can lead to pulmonary complications such as pneumonia and acute respiratory distress syndrome (ARDS); all of which have been hypothesized to increase morbidity and mortality in II. Herein, we aimed to identify variables associated with the risk of developing pneumonia and to determine the impact of pneumonia on selected II outcomes. De-identified data from the Prospective Inhalation Study titled Inhalation Injury Scoring System to Predict Inhalation Injury Severity (ISIS) were used. II was confirmed by fiberoptic bronchoscopy. Demographics, injury, and hospital course information were recorded. P < .05 was considered significant. One hundred subjects were included. On univariate analysis, pneumonia was associated with burn severity, race, and receipt of colloid during the first 24 hours. Patients who developed pneumonia spent more time on a ventilator, had longer hospitalizations (LOS) and were more likely to need a tracheostomy. On multivariate analysis, total number of ventilator days was associated with pneumonia (Odd ratio (OR) = 1.122 [1.048-1.200], P = .001). Both pneumonia and receipt of colloid were predictive of increased ventilator days (OR = 2.545 [1.363-4.753], P < .001 and OR = 2.809 [1.548-5.098], P < .001, respectively). Pneumonia was not an independent predictor of LOS, ARDS, or mortality. Pneumonia remains a high-risk complication associated with two times more ventilator days in II. Future research should focus on prevention of pneumonia and the relationship between colloid fluids and pneumonia and early ventilator liberation in II patients.

Ventilator Associated Pneumonia and Intubation Location in Adults with Traumatic Injuries: Systematic Review and Meta-analysis

BACKGROUND

Ventilator associated pneumonia (VAP) is an important cause of morbidity and mortality among critically ill patients, particularly those who present with traumatic injuries. This review aims to determine whether patients with traumatic injuries who are intubated in the prehospital setting are at higher risk of developing VAP compared to those intubated in the hospital.

METHODS

A systematic review of Medline, Scopus and Cochrane electronic databases was conducted from inception through January 2021. Inclusion criteria were patients with traumatic injuries who were intubated in the prehospital or hospital settings with VAP as an outcome. Using a random effects model, the risk of VAP across study arms was compared by calculating a summary relative risk (RR) with 95% confidence intervals (CI). The results of individual studies were also summarized qualitatively.

RESULTS

The search identified 754 articles of which 6 studies (N = 2990) met inclusion criteria. All studies were good quality based on assessment with the Newcastle Ottawa scale. Prehospital intubation demonstrated an increased risk of VAP development in 2 of the 6 studies. Among the 6 studies, the overall quality weighted risk ratio was 1.09 (95% CI 0.90-1.31).

CONCLUSIONS

Traumatically injured patients who are intubated in the prehospital setting have a similar risk of developing VAP compared to those that are intubated in the hospital setting.

LEVEL OF EVIDENCE

Level IV systematic review and meta-analysis.

Infection prevention in the emergency department

Infection prevention remains a major challenge in emergency care. Acutely ill and injured patients seeking evaluation and treatment in the emergency department (ED) not only have the potential to spread communicable infectious diseases to health care personnel and other patients, but are vulnerable to acquiring new infections associated with the care they receive. This article will evaluate these risks and review the existing literature for infection prevention practices in the ED, ranging from hand hygiene, standard and transmission-based precautions, health care personnel vaccination, and environmental controls to strategies for preventing health care-associated infections. We will conclude by examining what can be done to optimize infection prevention in the ED and identify gaps in knowledge where further research is needed. Successful implementation of evidence-based practices coupled with innovation of novel approaches and technologies tailored specifically to the complex and dynamic environment of the ED are the keys to raising the standard for infection prevention and patient safety in emergency care.

A TREM-1 Polymorphism A/T within the Exon 2 Is Associated with Pneumonia in Burn-Injured Patients

Background. The triggering receptor expressed in myeloid cells (TREM-1) is a key mediator in the activation of the local inflammatory response during lung infections. We aimed to evaluate the effect of a functionally relevant TREM-1 single nucleotide polymorphism within the exon 2 (A→T) on the development of pneumonia in burn patients. Objective. To determine whether a single nucleotide polymorphism (SNP) within the exon 2 (A→T) in the TREM-1 gene is associated with ventilator-associated pneumonia (VAP) in burn-injured patients. Methods. 540 patients with ≥10% total body surface area (TBSA) burn injuries or inhalation injury were prospectively enrolled. The influence of a polymorphism (A→T) in exon 2 of the TREM-1 gene was evaluated for association with increased risk of pneumonia by logistic regression analysis. Measurements and Main Results. 209 patients met criteria for VAP. Multivariate regression analysis showed that, after adjustment for potential confounders, we found that carriage of the TREM-1 T allele is associated with more than a 3-fold increased risk of VAP (OR 6.3, 95% CI 4–9). Conclusions. A TREM-1 single nucleotide polymorphism within the exon 2 (A→T) is associated with the development of pneumonia in burn patients.

Inspissated oral secretions and a review of their clinical, biological, and physiological significance

People with some chronic diseases may dehydrate and develop thick, viscous inspissated oronasal secretions that include cellular debris. This material can lead to ductal or airway obstructions that can prove to be life threatening. Asthma, allergy with superinfection, cystic fibrosis, intubated ventilation, burn injuries, and medication-induced complications are discussed in this paper. Many patients with chronic debilitating conditions may also be unable to communicate, and so may be unable to verbally convey that they have a compromised airway or an obstruction. Therefore, it is essential to maintain hydration and good oral hygiene that not only addresses the teeth and prostheses, but also the oral mucosal surfaces. People who are institutionalized and bed-ridden, in particular, need to be closely monitored to prevent adverse sequellae. A daily oral sweep with a 4 × 4 surgical sponge moistened with chlorhexidine may prevent aspiration pneumonia or a fatality due to an airway obstruction. Human oronasal secretions are involved with immunity, digestion, lubrication, and speech. Saliva is the most volumetrically important. These secretions moisturize inspired and expired air but can lose water, causing an increase in viscosity. The viscous secretions trap particles, food debris, and bacterial colonies, thereby increasing inspissations that may obstruct the airway.

Ventilator-associated pneumonia in burn patients: a cause or consequence of critical illness?

Infectious complications are a constant threat to thermally injured patients during hospitalizations and are a predominant cause of death. Most of the infections that develop in burn patients are nosocomial and of a pulmonary etiology. The bacteria that cause ventilator associated pneumonia (VAP) take advantage of the fact that uniquely among intensive care unit patients endotracheal intubation allows them a 'free' passage to the sterile lower airways; however, the combination of severe thermal injury (systemic immunosuppression) and inhalation injury (local immunosuppression and tissue injury) create an ideal environment for development of VAP. Thus, strategies directed at preventing and treating VAP in burn patients must address not only rapid extubation and VAP prevention bundles known to work in other intensive care unit populations, but therapies directed to more rapid wound healing and restoration of pulmonary patency.

Burns, inhalation injury and ventilator-associated pneumonia: value of routine surveillance cultures

PURPOSE

Burn patients with inhalation injury are at particular risk for ventilator-associated pneumonia (VAP). Routine endotracheal surveillance cultures may provide information about the causative pathogen in subsequent VAP, improving antibiotic therapy. Our objective was to assess the incidence of VAP in burn patients with inhalation injury, and the benefit of routine surveillance cultures to predict multidrug resistant (MDR) pathogens.

PROCEDURES

Historical cohort (n=53) including all burn patients with inhalation injury requiring mechanical ventilation, admitted to the Ghent burn unit (2002-2010).

MAIN FINDINGS

Median (interquartile range) age and total burned surface area were 44y (39-55y) and 35% (19-50%). Overall, 70 episodes of VAP occurred in 46 patients (86.8%). Median mechanical ventilation days (MVD) prior to VAP onset were 7d (4-9d). The incidence was 55 episodes/1000 MVD. In 23 episodes (32.9%) at least one MDR causative pathogen was involved, mostly Pseudomonas aeruginosa and Enterobacter spp. The sensitivity and specificity of surveillance cultures to predict MDR etiology in subsequent VAP was respectively 83.0% and 96.2%. The positive and negative predictive value was 87.0% and 95.0%, respectively.

CONCLUSIONS

The incidence of VAP in burn patients with inhalation injury is high. In this cohort routine surveillance cultures had excellent operating characteristics to predict MDR pathogen involvement.

Pneumonia After Inhalation Injury

We sought to evaluate the incidence, morbidity, and mortality of pneumonia among inhalation injury patients requiring admission to our burn unit. We undertook a retrospective study of 228 consecutive patients with inhalation injury who were admitted to the burn unit of a level one trauma center between 2001 and 2004. Of the remaining 117 patients with inhalation injury and requiring hospitalization for at least 48 hours, 32 (27%) developed pneumonia. The average patient with inhalation injury and pneumonia developed their infiltrate on day 6 +/- 5 days and required 3 +/- 4 burn operations. There was no difference seen in age, sex, or carboxyhemoglobin level between inhalation injury patients with and without pneumonia (P > .05). The inhalation injury patients that had an associated TBSA burn of at least 20% had a 60% (12/20) pneumonia rate, which was significantly higher then the 21% (20/97) pneumonia rate observed in patients with an association burn less then 20%. The overall mortality of patients with inhalation injury and pneumonia was 19% (6/32), double the mortality rate of 9% (8/85) found in patients with inhalation injury and no pneumonia. The average length of stay of inhalation injury patients with pneumonia was significantly longer (47 +/- 44 days) then inhalation injury patients without pneumonia (26 +/- 54 days; P < .05). The presence of pneumonia among inhalation injury patients significantly increased length of stay and doubled mortality rates. Admission carboxyhemoglobin levels, age, and sex had no relationship to the development of pneumonia. An increase in TBSA burn was associated with a higher pneumonia rate.