Ventilator-associated pneumonia in severe traumatic brain injury

Predicting nosocomial pneumonia of patients with acute brain injury in intensive care unit using machine-learning models

Introduction

The aim of this study is to construct and validate new machine learning models to predict pneumonia events in intensive care unit (ICU) patients with acute brain injury.

Methods

Acute brain injury patients in ICU of hospitals from January 1, 2020, to December 31, 2021 were retrospective reviewed. Patients were divided into training, and validation sets. The primary outcome was nosocomial pneumonia infection during ICU stay. Machine learning models including XGBoost, DecisionTree, Random Forest, Light GBM, Adaptive Boost, BP, and TabNet were used for model derivation. The predictive value of each model was evaluated using accuracy, precision, recall, F1-score, and area under the curve (AUC), and internal and external validation was performed.

Results

A total of 280 ICU patients with acute brain injury were included. Five independent variables for nosocomial pneumonia infection were identified and selected for machine learning model derivations and validations, including tracheotomy time, antibiotic use days, blood glucose, ventilator-assisted ventilation time, and C-reactive protein. The training set revealed the superior and robust performance of the XGBoost with the highest AUC value (0.956), while the Random Forest and Adaptive Boost had the highest AUC value (0.883) in validation set.

Conclusion

Machine learning models can effectively predict the risk of nosocomial pneumonia infection in patients with acute brain injury in the ICU. Despite differences in populations and algorithms, the models we constructed demonstrated reliable predictive performance.

MIP-3-Alpha and MIP-3-Beta as Early Predictors of Pneumonia in Polytraumatized Patients

INTRODUCTION

Pneumonia is one of the most common complications in patients suffering multiple traumas and is associated with an exceptionally high mortality rate. MIP-3-alpha and MIP-3-beta are pro-inflammatory chemokines expressed in the pulmonary mucosa and are reported to play a crucial role in inflammation. Thus, the present study aimed to investigate whether there is an association between MIP-3-alpha- and MIP-3-beta expression and manifestation of pneumonia in patients suffering polytrauma.

MATERIAL AND METHODS

This prospective outcome study was conducted at our level I trauma center, and 110 polytraumatized patients (Injury Severity Score ≥ 16, ≥ 2 body regions) were prospectively enrolled (median age, 39 years; median Injury Severity Score (ISS), 33; 70.9% male) over four years. Protein levels were assessed at admission (day 0) and subsequently on days 1, 3, 5, 7, and 10 during routine blood draws, utilizing one separation gel tube for each measurement. Furthermore, the correlation between MIP-3-alpha- and MIP-3-beta expression and the manifestation of pneumonia was calculated.

RESULTS

We observed significantly higher levels of MIP-3-beta expression over the entire time course in the pneumonia cohort. MIP-3-alpha levels were elevated on days 3, 5, 7, and 10 post-trauma in patients suffering from pneumonia. In contrast, no comparable pattern was observed for other pro- and anti-inflammatory cytokines (e.g., IL-6 or TNF-alpha). A peak of serum level expression was documented on day 5 in both biomarkers (MIP-3-alpha 51.8 pg/mL; MIP-3-beta 328.0 pg/mL). ROC analysis provided a cut-off value of 19.3 pg/mL (sensitivity 0.87, specificity 0.33; AUC 0.757) for MIP-3-alpha, whereas a cut-off value of 209.5 pg/mL (sensitivity 0.78, specificity 0.34; AUC 0.757) was determined for MIP-3-beta on day 5.

CONCLUSION

The present study demonstrated elevated MIP-3-alpha and MIP-3-beta levels as sensitive pneumonia predictors in patients with multiple traumas. These biomarkers allow for identifying patients at high risk of developing pneumonia at an early stage.

Ventilator-Associated Pneumonia Predicts Severe Cognitive Disability in Severe Traumatic Brain Injury

Background: Ventilator-associated pneumonia (VAP) is linked to poor outcomes in patients with severe traumatic brain injury (TBI), yet its effect on cognitive disability is unknown. We hypothesized that there would be an association between severe cognitive disability and VAP in this patient population. Methods: We performed a post hoc analysis of a prospective, multi-center, observational study of adults with a severe, blunt TBI from 2020 to 2023. Patients were grouped by whether they developed VAP. Our primary outcome was severe cognitive disability, defined as a disability rating scale (DRS) score >13 at discharge (or 28 days post-injury if not discharged). Results: There were 309 patients in the cohort; 31.7% (n = 98) developed VAP. The VAP group had greater incidences of diffuse axonal injury (37.3% vs. 22.3%, p = 0.004), neurosurgical interventions (63.3 vs. 38.4%, p < 0.001), and tracheostomies (72.5% vs. 28.9%, p < 0.001). Patients with VAP had a longer duration of mechanical ventilation (13 d vs. 3 d, p < 0.001). Among patients with VAP, median time to diagnosis was 7 days (4-12), time to tracheostomy was 10 days (7-16), and time between the two events was 4 days (2-11). Greater proportions of cognitive disability (64.3% vs. 19.9%, p < 0.001) and worse median DRS scores (8 vs. 2, p < 0.001) occurred in the VAP group. On multi-variable regression analysis, VAP was an independent risk factor for severe cognitive disability (adjusted odds ratio [aOR]: 4.2, 95% CI: 2.2-7.8). Conclusion: Ventilator-associated pneumonia is common among patients with a severe TBI and is a risk factor for severe cognitive disability. Adherence to VAP prevention techniques may help mitigate cognitive impairment in this population.

Risk factors and outcomes of ventilator-associated pneumonia in patients with traumatic brain injury: A systematic review and meta-analysis

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common complication in traumatic brain injury (TBI) patients, which increases morbidity and negatively affects outcomes. Risk factors and outcomes in these patients remain controversial. The aim of the present study is to explore the risk factors and clinical outcomes of patients with VAP and TBI.

METHODS

Two researchers conducted independent systematic literature searches of Pubmed, Cochrane Database, Scopus, Medline Ovid, Science Direct databases, published from inception to January 2024. The Newcastle-Ottawa scale was used to assess study quality. A meta-analysis was performed using a random-effects model when heterogeneity I2 > 50 % and a fixed-effects model when I2 < 50 %; in addition, a subgroup analysis was performed to explore VAP risk factors, and publication bias was assessed with the funnel plot and Begg's and Egger's tests. All results were considered statistically significant when p < 0.05. The certainty of the evidence was evaluated using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methodology.

RESULTS

Twelve studies were included in the meta-analysis with a total of 2883 patients. Male gender [OR 1.58 (95 % CI 1.23, 2.02) p < 0.05 I2 0 %] and abbreviated injury scale (head: H-AIS) [≥ 3 OR 2.79 (95 % CI 1.58, 4.93) p < 0.05 I2 0 %] increased the risk of VAP. After subgroup analysis, blood transfusion on admission [OR 1.97 (95 % CI 1.16-3.35) p ≤0.05 I2 5 %] and barbiturate infusion [OR 3.55 (95 % CI 2.01-6.30) p ≤0.05 I2 0 %] became risk factors. Prophylactic antibiotic use [OR 0.67 (95 % CI 0.51-0.88) p ≤0.05 I2 0 %] and younger age MD -3.29 (95 % CI -5.18, -1.40) p ≤0.05 I2 41 %] emerged as significant protective factors. In VAP patients ICU stay [MD 7.02 (95 % CI 6.05-7.99) p ≤0.05 I2 37 %], duration of mechanical ventilation [MD 5.79 (95 % CI 4.40, 7.18) p ≤0.05 I2 79 %] and hospital stay [MD 11.88 (95 % CI 8.71-15.05) p ≤0.05 I2 0 %] were significantly increased. The certainty of the evidence was moderate-high for the outcomes studied.

CONCLUSIONS

Male gender, H-AIS ≥ 3, blood transfusion on admission, and barbiturate infusion were risk factors for VAP. In patients with VAP, ICU stay, duration of mechanical ventilation, hospital stay were significantly increased.

Peripheral immune cell dysregulation following diffuse traumatic brain injury in pigs

Traumatic brain injury (TBI) is a global health problem affecting millions of individuals annually, potentially resulting in persistent neuropathology, chronic neurological deficits, and death. However, TBI not only affects neural tissue, but also affects the peripheral immune system's homeostasis and physiology. TBI disrupts the balanced signaling between the brain and the peripheral organs, resulting in immunodysregulation and increasing infection susceptibility. Indeed, secondary infections following TBI worsen neurological outcomes and are a major source of mortality and morbidity. Despite the compelling link between the damaged brain and peripheral immune functionality, little is known about how injury severity affects the peripheral immune system in closed-head diffuse TBI, the most common clinical presentation including all concussions. Therefore, we characterized peripheral blood mononuclear cells (PBMCs) and plasma changes over time and across injury severity using an established large-animal TBI model of closed-head, non-impact diffuse rotational acceleration in pigs. Across all timepoints and injury levels, we did not detect any changes to plasma cytokine concentrations. However, changes to the PBMCs were detectable and much more robust. We observed the concentration and physiology of circulating PBMCs changed in an injury severity-dependent manner, with most cellular changes occurring within the first 10 days following a high rotational velocity injury. Here, we report changes in the concentrations of myeloid and T cells, changes in PBMC composition, and changes in phagocytic clearance over time. Together, these data suggest that following a diffuse brain injury in a clinically relevant large-animal TBI model, the immune system exhibits perturbations that are detectable into the subacute timeframe. These findings invite future investigations into therapeutic interventions targeting peripheral immunity and the potential for peripheral blood cellular characterization as a diagnostic tool.

Association of Dynamics of Anellovirus Loads With Hospital-Acquired Pneumonia in Patients With Brain Injury During the Intensive Care Unit Stay

BACKGROUND

Critical illness induces immune disorders associated with an increased risk of hospital-acquired pneumonia (HAP) and acute respiratory distress syndrome (ARDS). Torque teno virus (TTV), from the Anelloviridae family, is proposed as a biomarker to measure the level of immunosuppression. Our objective was to describe the kinetics of TTV DNA loads and their association with critical illness-related complications.

METHODS

We performed a longitudinal study in 115 patients with brain injury from a prospective cohort, collected endotracheal and blood samples at 3 successive time points after admission in the intensive care unit (ICU) (T1, 0-4 days post ICU admission; T2, 5-10; T3, 11-18), and measured viral DNA loads using the TTV R-GENE kit (BioMérieux) and a pan-Anelloviridae in-house quantitative real-time polymerase chain reaction.

RESULTS

TTV DNA was detected in the blood of 69%, 71%, and 64% of patients with brain injury at T1, T2, and T3, respectively. Time-associated variations of TTV and anellovirus DNA loads were observed. Using a linear mixed-effects model, we found that HAP and ARDS were associated with lower blood anellovirus DNA loads.

CONCLUSIONS

Our results show that HAP or ARDS in patients who are critically ill is associated with changes in anellovirus DNA loads and should be evaluated further as a biomarker of immune disorders leading to these complications.

Pharyngeal Electrical Stimulation prior to extubation - Reduction of extubation failure rate in acute stroke patients?

PURPOSE

The aim of our study was to assess if PES before extubation can minimize the extubation failure risk in orally intubated, mechanically ventilated stroke patients at high risk of severe dysphagia.

MATERIALS AND METHODS

Thirty-two ICU patients were prospectively enrolled in this study presenting with a high risk for dysphagia as defined by a DEFISS (Determine Extubation Failure In Severe Stroke) risk score and compared 1:1 to a retrospective matched patient control group. The prospective patient group received PES prior to extubation. Endpoints were need for reintubation, swallowing function as assessed with FEES, pneumonia incidence and length of stay after extubation.

RESULTS

Post-extubation, the Fiberoptic Endoscopic Dysphagia Severity Score (FEDSS, 4.31 ± 1.53vs.5.03 ± 1.28;p = 0.047) and reintubation rate within 72 h (9.4vs.34.4%;p = 0.032) were significantly lower in the PES group than in the historical control group. Pulmonary infections after extubation were less common in PES-treated patients although this difference was not significant (37.5vs.59.4%;p = 0.133). Time from extubation to discharge was significantly shorter after PES compared with the control group (14.09 ± 11.58vs.26.59 ± 20.49 days;p = 0.003).

CONCLUSIONS

In orally intubated and mechanically ventilated stroke patients at high risk of severe dysphagia, PES may improve swallowing function, reduce extubation failure risk and decrease time from extubation to discharge. Further research is required.

Immunonutrition with Omega-3 Fatty Acid Supplementation in Severe TBI: Retrospective Analysis of Patient Characteristics and Outcomes

Early evidence-based medical interventions to improve patient outcomes after traumatic brain injury (TBI) are lacking. In patients admitted to the ICU after TBI, optimization of nutrition is an emerging field of interest. Specialized enteral nutrition (EN) formulas that include immunonutrition containing omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been developed and are used for their proposed anti-inflammatory and proimmune properties; however, their use has not been rigorously studied in human TBI populations. A single-center, retrospective, descriptive observational study was conducted at the LAC + USC Medical Center. Patients with severe TBI (sTBI, Glasgow Coma Scale score ≤ 8) who remained in the ICU for ≥2 weeks and received EN were identified between 2017 and 2022 using the institutional trauma registry. Those who received immunonutrition formulas containing n-3 PUFAs were compared with those who received standard, polymeric EN with regard to baseline characteristics, clinical markers of inflammation and immune function, and short-term clinical outcomes. A total of 151 patients with sTBI were analyzed. Those who received immunonutrition with n-3 PUFA supplementation were more likely to be male, younger, Hispanic/Latinx, and have polytrauma needing non-central nervous system surgery. No differences in clinical markers of inflammation or infection rate were found. In multivariate regression analysis, immunonutrition was associated with reduced hospital length of stay (LOS). ICU LOS was also reduced in the subgroup of patients with polytrauma and TBI. This study identifies important differences in patient characteristics and outcomes associated with the EN formula prescribed. Study results can directly inform a prospective pragmatic study of immunonutrition with n-3 PUFA supplementation aimed to confirm the biomechanistic and clinical benefits of the intervention.

The Impact of Pulmonary Disorders on Neurological Health (Lung-Brain Axis)

The brain and lungs, vital organs in the body, play essential roles in maintaining overall well-being and survival. These organs interact through complex and sophisticated bi-directional pathways known as the 'lung-brain axis', facilitated by their close proximity and neural connections. Numerous studies have underscored the mediation of the lung-brain axis by inflammatory responses and hypoxia-induced damage, which are pivotal to the progression of both pulmonary and neurological diseases. This review aims to delve into how pulmonary diseases, including acute/chronic airway diseases and pulmonary conditions, can instigate neurological disorders such as stroke, Alzheimer's disease, and Parkinson's disease. Additionally, we highlight the emerging research on the lung microbiome which, drawing parallels between the gut and lungs in terms of microbiome contents, may play a significant role in modulating brain health. Ultimately, this review paves the way for exciting avenues of future research and therapeutics in addressing respiratory and neurological diseases.

Experimental Models of Hospital-Acquired Infections After Traumatic Brain Injury: Challenges and Opportunities

Patients hospitalized after a moderate or severe traumatic brain injury (TBI) are at increased risk of nosocomial infections, including bacterial pneumonia and other upper respiratory tract infections. Infections represent a secondary immune challenge for vulnerable TBI patients that can lead to increased morbidity and poorer long-term prognosis. This review first describes the clinical significance of infections after TBI, delving into the known mechanisms by which a TBI can alter systemic immunological responses towards an immunosuppressive state, leading to promotion of increased vulnerability to infections. Pulmonary dysfunction resulting from respiratory tract infections is considered in the context of neurotrauma, including the bidirectional relationship between the brain and lungs. Turning to pre-clinical modeling, current laboratory approaches to study experimental TBI and lung infections are reviewed, to highlight findings from the limited key studies to date that have incorporated both insults. Then, practical decisions for the experimental design of animal studies of post-injury infections are discussed. Variables associated with the host animal, the infectious agent (e.g., species, strain, dose, and administration route), as well as the timing of the infection relative to the injury model are important considerations for model development. Together, the purpose of this review is to highlight the significant clinical need for increased pre-clinical research into the two-hit insult of a hospital-acquired infection after TBI to encourage further scientific enquiry in the field.

Machine learning algorithms for prediction of ventilator associated pneumonia in traumatic brain injury patients from the MIMIC-III database

BACKGROUND

Ventilator associated pneumonia (VAP) is a common complication and associated with poor prognosis of traumatic brain injury (TBI) patients.

OBJECTIVES

This study was conducted to explore the predictive performance of different machine-learning algorithms for VAP in TBI patients.

METHODS

TBI patients receiving mechanical ventilation more than 48 hours from the Medical Information Mart for Intensive Care-III (MIMIC-III) database were eligible for the study. The VAP was confirmed based on the ICD-9 code. Included patients were separated to the training cohort and the validation cohort with a ratio of 7:3. Predictive models based on different machine learning algorithms were developed using 5-fold cross validation in the training cohort and then verified in the validation cohort by evaluating the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, accuracy and F score.

RESULTS

786 TBI patients from the MIMIC-III were finally included with the VAP incidence of 44.0%. The random forest performed the best on predicting VAP in the training cohort with a AUC of 1.000. The XGBoost and AdaBoost were ranked the second and the third with a AUC of 0.915 and 0.789 in the training cohort. While the AdaBoost performed the best on predicting VAP in the validation cohort with a AUC of 0.706. The XGBoost and random forest were ranked the second and the third with the AUC of 0.685 and 0.683 in the validation cohort. Generally, the random forest and XGBoost were likely to be over-fitting while the AdaBoost was relatively stable in predicting the VAP.

CONCLUSIONS

The AdaBoost performed well and stably on predicting the VAP in TBI patients. Developing programs using AdaBoost in portable electronic devices may effectively assist physicians in assessing the risk of VAP in TBI.

Microbiological Profile and the Resistance Pattern of Pathogens in Neurosurgical Patients from a New Delhi Trauma Center

BACKGROUND

Neurosurgical patients are considered to be at higher risk for infections including nosocomial infections compared with other critically ill individuals. Empirical antimicrobial therapy is of utmost importance for the survival of infected neurosurgical patients.

METHODS

The microbial distribution and antimicrobial resistance patients from January 2012 to December 2021 (10 years) were analyzed retrospectively. Identification was done using VITEK-2 and MALDI-TOF systems. Antimicrobial susceptibility testing was determined by the Kirby Bauer Disk Diffusion Agar method (Clinical and Laboratory Standards Institute) and VITEK-2.

RESULTS

A total of 48,474 samples were received, out of which 10,134 (21%) had growth. Respiratory specimens showed the maximum isolation of pathogens (42% n = 4292). The predominant bacterial pathogens were gram negative (n = 8972; 88.5%), whereas gram positives were only 11.5% (n = 1162) of the total organisms. Among the gram positives, the most common was Staphylococcus aureus (64.6%), and among gram negatives, the most common pathogen was Acinetobacter baumanni (38.6%). The weighted average of the drug-resistance profile across all gram positives was >50% for fluoroquinolones (levofloxacin, ciprofloxacin), gentamicin, erythromycin, and ampicillin, and in the case of gram negatives it was >90% for ampicillin-sulbactam, ticarcillin, cefazolin, cefotaxime, and ceftriaxone. Thirty-two patients were found to have candidemia, out of which 6 were C. albicans and the rest were nonalbican. Six neurosurgery patients had infection with C. auris, 4 from blood samples and 2 from urine.

CONCLUSIONS

This study will add to the current knowledge and provide a better understanding of pathogen profile and resistance patterns in traumatic brain injury patients.

Risk factors and outcomes of lower respiratory tract infections after traumatic brain injury: a retrospective observational study

Background

Traumatic brain injury (TBI) is a public health problem with a high burden in terms of disability and death. Infections are a common complication, with respiratory infections being the most frequent. Most available studies have addressed the impact of ventilator-associated pneumonia (VAP) after TBI; therefore, we aim to characterize the hospital impact of a broader entity, lower respiratory tract infections (LRTIs).

Methods

This observational, retrospective, single-center cohort study describes the clinical features and risk factors associated with LRTIs in patients with TBI admitted to an intensive care unit (ICU). We used bivariate and multivariate logistic regressions to identify the risk factors associated with developing LRTI and determine its impact on hospital mortality.

Results

We included 291 patients, of whom 77% (225/291) were men. The median (IQR) age was 38 years (28-52 years). The most common cause of injury was road traffic accidents 72% (210/291), followed by falls 18% (52/291) and assault at 3% (9/291). The median (IQR) Glasgow Coma Scale (GCS) score on admission was 9 (6-14), and 47% (136/291) were classified as severe TBI, 13% (37/291) as moderate TBI, and 40% (114/291) as mild TBI. The median (IQR) injury severity score (ISS) was 24 (16-30). Nearly 48% (141/291) of patients presented at least one infection during hospitalization, and from those, 77% (109/141) were classified as LRTIs, which included tracheitis 55% (61/109), ventilator-associated pneumonia (VAP) 34% (37/109), and hospital-acquired pneumoniae (HAP) 19% (21/109). After multivariable analysis, the following variables were significantly associated with LRTIs: age (OR 1.1, 95% CI 1.01-1.2), severe TBI (OR 2.7, 95% CI 1.1-6.9), AIS thorax (OR 1.4, 95 CI 1.1-1.8), and mechanical ventilation on admission (OR 3.7, 95% CI 1.1-13.5). At the same time, hospital mortality did not differ between groups (LRTI 18.6% vs. No LRTI 20.1%, p = 0.7), and ICU and hospital length of stay (LOS) were longer in the LRTI group (median [IQR] 12 [9-17] vs. 5 [3-9], p < 0.01) and (median [IQR] 21 [13-33] vs. 10 [5-18], p = 0.01), respectively. Time on the ventilator was longer for those with LRTIs.

Conclusion

The most common site/location of infection in patients with TBI admitted to ICU is respiratory. Age, severe TBI, thoracic trauma, and mechanical ventilation were identified as potential risk factors. LRTI was associated with prolonged ICU, hospital stay, and more days on a ventilator, but not with mortality.

[Infectious complications in acute period after traumatic brain injury]

Patients with traumatic brain injury (TBI) are at high risk of infection.

OBJECTIVE

To delineate infections in acute period of TBI, association between intracranial lesion type and risk of infection, as well as to estimate treatment outcomes in these patients depending on infection.

MATERIAL AND METHODS

This study included 104 patients with TBI (80 men and 24 women) aged 33.01±14.35 years. All patients met the inclusion criteria: admission within 72 hours after TBI, age 18-75 years, ICU-stay >48 hours, available brain MRI data. Mild, moderate and severe TBI were diagnosed in 7%, 11% and 82% of patients, respectively. Analysis of infections was performed in accordance with the definitions of the Centers for Disease Control/National Healthcare Safety Network (CDC/NHSN).

RESULTS

Acute period of TBI is associated with high incidence of infection (73%), and prevalent infection is pneumonia (58.7%). Severe intracranial damage in acute period of TBI (grade 4-8 according to MR-based classification by A.A. Potapov and N.E. Zakharova) is associated with higher incidence of infection. Infectious complications more than twice increase duration of mechanical ventilation, ICU- and hospital-stay.

CONCLUSION

Infectious complications significantly affect treatment outcomes in acute period of TBI increasing duration of mechanical ventilation, ICU- and hospital-stay.

Predicting mortality in moderate-severe TBI patients without early withdrawal of life-sustaining treatments including ICU complications: The MYSTIC-score

PURPOSE

To develop and internally validate the MortalitY in Moderate-Severe TBI plus ICU Complications (MYSTIC)-Score to predict in-hospital mortality of msTBI patients without early (<24 h) withdrawal-of-life-sustaining treatments.

METHODS

We analyzed data from a Neuro-Trauma Intensive Care Unit prospectively collected between 11/2009-5/2019. Consecutive adult msTBI patients were included if Glasgow Coma Scale≤12, and neither died nor had withdrawal-of-life-sustaining treatments within 24 h of admission (n = 485). Using univariate and multivariable logistic regression in a random-split cohort approach (2/3 derivation;1/3 validation), we identified independent predictors of in-hospital mortality while adjusting for validated predictors of mortality (IMPACT-variables). We constructed the MYSTIC-Score and examined discrimination and calibration.

RESULTS

The MYSTIC-Score included the ICU complications brain edema, herniation, systemic inflammatory response syndrome, sepsis, acute kidney injury, cardiac arrest, and urinary tract infection. In the derivation cohort(n = 324), discrimination and calibration were excellent (area-under-the-receiver-operating-curve [AUC-ROC] = 0.95;Hosmer-Lemeshow p-value = 0.09, with p > 0.05 indicating good calibration). Internal validation revealed an AUC-ROC = 0.93 and Hosmer-Lemeshow-p-value = 0.76 (n = 161).

CONCLUSIONS

Certain ICU complications are independent predictors of in-hospital mortality and strengthen outcome prediction in msTBI when combined with validated admission predictors of mortality. However, external validation is needed to determine robustness and practical applicability of our model given the high potential for residual confounders.

Time to Follow Commands in Severe Traumatic Brain Injury Survivors With Favorable Recovery at 2 Years

BACKGROUND

The recovery of severe traumatic brain injury (TBI) survivors with long-term favorable outlook is understudied. Time to follow commands varies widely in this patient population but has important clinical implications.

OBJECTIVE

To (1) evaluate time to follow commands in severe patients with TBI with favorable outcomes, (2) characterize their trajectory of recovery, and (3) identify predictors associated with delayed cognitive improvement.

METHODS

Participants were recruited prospectively at a Level I trauma center through the Brain Trauma Research Center from 2003 to 2018. Inclusion criteria were age 16 to 80 years, Glasgow Coma Scale score ≤8 and motor score <6, and Glasgow Outcome Scale-Extended measure ≥4 at 2 years postinjury.

RESULTS

In 580 patients, there were 229 (39.5%) deaths and 140 (24.1%) patients had favorable outcomes at 2 years. The mean age was 33.7 ± 14.5 years, median Glasgow Coma Scale was 7 (IQR 6-7), and median Injury Severity Score was 30 (IQR 26-38). The mean time to follow commands was 12.7 ± 11.8 days. On multivariable linear regression, the presence of diffuse axonal injury (B = 9.2 days [4.8, 13.7], P < .0001) or intraventricular hemorrhage (B = 6.4 days [0.5, 12.3], P < .035) was associated with longer time before following commands and patients who developed nosocomial infections (B = 6.5 days [1.6-11.4], P < .01).

CONCLUSION

In severe TBI survivors with favorable outcomes, time to follow commands varied widely. Most patients began to follow commands within 2 weeks. Evidence of diffuse axonal injury, intraventricular hemorrhage, and infections can delay cognitive improvement in the acute period. Patients make considerable recovery up to 2 years after their injury.

Prognostic Value of Serum Procalcitonin Based Model in Moderate to Severe Traumatic Brain Injury Patients

Objective

Procalcitonin (PCT) is an acknowledged marker of systemic inflammatory response. Previous studies have not reached agreement on the association between serum PCT and outcome of traumatic brain injury (TBI) patients. We designed this study to confirm the prognostic value of PCT in isolated TBI and those with extracranial injury, respectively.

Methods

Patients hospitalized in our hospital for moderate-to-severe TBI between March 2015 and December 2019 were included. Logistic regression analysis was performed to validate the association between PCT and in-hospital mortality in these patients. AUC (area under the receiver operating characteristics curve) of PCT and constructed model were calculated and compared.

Results

Among the included 211 patients, 81 patients suffered a poor outcome, with a mortality rate of 38.4%. Non-survivors had a higher level of serum PCT (2.73 vs 0.72, p<0.001) and lower GCS (5 vs 7, p<0.001) on admission than survivors. AUC of single PCT for predicting mortality in isolated TBI and those with extracranial injury were 0.767 and 0.553, respectively. Multivariate logistic regression showed that GCS (OR=0.744, p=0.008), glucose (OR=1.236, p<0.001), cholesterol (OR=0.526, p=0.002), and PCT (OR=1.107, p=0.022) were independently associated with mortality of isolated TBI. The AUC of the prognostic model composed of GCS, glucose, cholesterol, and PCT was 0.868 in isolated TBI.

Conclusion

PCT is an efficient marker of outcome in isolated moderate-to-severe TBI but not those with extracranial injury. A prognostic model incorporating PCT is useful for clinicians to make early risk stratification for isolated TBI.

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.

Pneumonia in Nervous System Injuries: An Analytic Review of Literature and Recommendations

Pneumonia is one of the most common complications in intensive care units and is the most common nosocomial infection in this setting. Patients with neurocritical conditions who are admitted to ICUs are no exception, and in fact, are more prone to infections such as pneumonia because of factors such as swallow dysfunction, need for mechanical ventilation, longer length of stay in hospitals, etc. Common central nervous system pathologies such as ischemic stroke, traumatic brain injury, subarachnoid hemorrhage, intracerebral hemorrhage, neuromuscular disorders, status epilepticus, and demyelinating diseases can cause long in-hospital admissions and increase the risk of pneumonia each with a mechanism of its own. Brain injury-induced immunosuppression syndrome is usually considered the common mechanism through which patients with critical central nervous system conditions become susceptible to different kinds of infection including pneumonia. Evaluating the patients and assessment of the risk factors can lead our attention toward better infection control in this population and therefore decrease the risk of infections in central nervous system injuries.

Inflammation and the role of infection: Complications and treatment options following neurotrauma

Traumatic brain injury can have devastating consequences for patients and extended hospital stays and recovery course. Recent data indicate that the initial insult causes profound changes to the immune system and leads to a pro-inflammatory state. This alteration in homeostasis predisposes patients to an increased risk of infection and underlying autoimmune conditions. Increased emphasis has been placed on understanding this process both in the clinical and preclinical literature. This review highlights the intrinsic inflammatory conditions that can occur within the initial hospital stay, discusses long-term immune consequences, highlights emerging treatment options, and delves into important pathways currently being investigated with preclinical models.

Brain-lung interactions and mechanical ventilation in patients with isolated brain injury

During the last decade, experimental and clinical studies have demonstrated that isolated acute brain injury (ABI) may cause severe dysfunction of peripheral extracranial organs and systems. Of all potential target organs and systems, the lung appears to be the most vulnerable to damage after brain injury (BI). The pathophysiology of these brain–lung interactions are complex and involve neurogenic pulmonary oedema, inflammation, neurodegeneration, neurotransmitters, immune suppression and dysfunction of the autonomic system. The systemic effects of inflammatory mediators in patients with BI create a systemic inflammatory environment that makes extracranial organs vulnerable to secondary procedures that enhance inflammation, such as mechanical ventilation (MV), surgery and infections. Indeed, previous studies have shown that in the presence of a systemic inflammatory environment, specific neurointensive care interventions—such as MV—may significantly contribute to the development of lung injury, regardless of the underlying mechanisms. Although current knowledge supports protective ventilation in patients with BI, it must be born in mind that ABI-related lung injury has distinct mechanisms that involve complex interactions between the brain and lungs. In this context, the role of extracerebral pathophysiology, especially in the lungs, has often been overlooked, as most physicians focus on intracranial injury and cerebral dysfunction. The present review aims to fill this gap by describing the pathophysiology of complications due to lung injuries in patients with a single ABI, and discusses the possible impact of MV in neurocritical care patients with normal lungs.

Neutrophil-to-Lymphocyte Ratios and Infections after Traumatic Brain Injury: Associations with Hospital Resource Utilization and Long-Term Outcome

Traumatic brain injury (TBI) induces immune dysfunction that can be captured clinically by an increase in the neutrophil-to-lymphocyte ratio (NLR). However, few studies have characterized the temporal dynamics of NLR post-TBI and its relationship with hospital-acquired infections (HAI), resource utilization, or outcome. We assessed NLR and HAI over the first 21 days post-injury in adults with moderate-to-severe TBI (n = 196) using group-based trajectory (TRAJ), changepoint, and mixed-effects multivariable regression analysis to characterize temporal dynamics. We identified two groups with unique NLR profiles: a high (n = 67) versus a low (n = 129) TRAJ group. High NLR TRAJ had higher rates (76.12% vs. 55.04%, p = 0.004) and earlier time to infection (p = 0.003). In changepoint-derived day 0–5 and 6–20 epochs, low lymphocyte TRAJ, early in recovery, resulted in more frequent HAIs (p = 0.042), subsequently increasing later NLR levels (p ≤ 0.0001). Both high NLR TRAJ and HAIs increased hospital length of stay (LOS) and days on ventilation (p ≤ 0.05 all), while only high NLR TRAJ significantly increased odds of unfavorable six-month outcome as measured by the Glasgow Outcome Scale (GOS) (p = 0.046) in multivariable regression. These findings provide insight into the temporal dynamics and interrelatedness of immune factors which collectively impact susceptibility to infection and greater hospital resource utilization, as well as influence recovery.

Machine Learning Model to Predict Ventilator Associated Pneumonia in patients with Traumatic Brain Injury: The C.5 Decision Tree Approach

BACKGROUND

There is paucity in the literature to predict the occurrence of Ventilator Associated Pneumonia (VAP) in patients with Traumatic Brain Injury (TBI). We aimed to build a C.5. Decision Tree (C.5 DT) machine learning model to predict VAP in patients with moderate to severe TBI.

METHODS

This was a retrospective study including all adult patients who were hospitalized with TBI plus head abbreviated injury scale (AIS) ≥ 3 and were mechanically ventilated in a level 1 trauma center between 2014 and 2019.

RESULTS

A total of 772 eligible patients were enrolled, of them 169 had VAP (22%). The C.5 DT model achieved moderate performance with 83.5% accuracy, 80.5% area under the curve, 71% precision, 86% negative predictive value, 43% sensitivity, 95% specificity and 54% F-score. Out of 24 predictors, C.5 DT identified 5 variables predicting occurrence of VAP post-moderate to severe TBI (Time from injury to emergency department arrival, blood transfusion during resuscitation, comorbidities, Injury Severity Score and pneumothorax).

CONCLUSIONS

This study could serve as baseline for the quest of predicting VAP in patients with TBI through the utilization of C.5. DT machine learning approach. This model helps provide timely decision support to caregivers to improve patient's outcomes.

Exploratory Evaluation of the Relationship Between iNKT Cells and Systemic Cytokine Profiles of Critically Ill Patients with Neurological Injury

BACKGROUND

Neurological injury can alter the systemic immune system, modifying the functional capacity of immune cells and causing a dysfunctional balance of cytokines, although mechanisms remain incompletely understood. The objective of this study was to assess the temporal relationship between changes in the activation status of circulating invariant natural killer T (iNKT) cells and the balance of plasma cytokines among critically ill patients with neurological injury.

METHODS

We conducted an exploratory prospective observational study of adult (18 years or older) intensive care unit (ICU) patients with acute neurological injury (n = 20) compared with ICU patients without neurological injury (n = 22) and healthy controls (n = 10). Blood samples were collected on days 1, 2, 4, 7, 14, and 28 following ICU admission to analyze the activation status of circulating iNKT cells by flow cytometry and the plasma concentration of inflammation-relevant immune mediators, including T helper 1 (T_H1) and T helper 2 (T_H2) cytokines, by multiplex bead-based assay.

RESULTS

Invariant natural killer T cells were activated in both ICU patient groups compared with healthy controls. Neurological patients had decreased levels of multiple immune mediators, including T_H1 cytokines (interferon-γ, tumor necrosis factor-α, and interleukin-12p70), indicative of immunosuppression. This led to a greater than twofold increase in the ratio of T_H2/T_H1 cytokines early after injury (days 1 - 2) compared with healthy controls, a shift that was also observed for ICU controls. Systemic T_H2/T_H1 cytokine ratios were positively associated with iNKT cell activation in the neurological patients and negatively associated in ICU controls. These relationships were strongest for the CD4⁺ iNKT cell subset compared with the CD4^- iNKT cell subset. The relationships to individual cytokines similarly differed between patient groups. Forty percent of the neurological patients developed an infection; however, differences for the infection subgroup were not identified.

CONCLUSIONS

Critically ill patients with neurological injury demonstrated altered systemic immune profiles early after injury, with an association between activated peripheral iNKT cells and elevated systemic T_H2/T_H1 cytokine ratios. This work provides further support for a brain-immune axis and the ability of neurological injury to have far-reaching effects on the body's immune system.

Outcome after surgical stabilization of rib fractures versus nonoperative treatment in patients with multiple rib fractures and moderate to severe traumatic brain injury (CWIS-TBI)

BACKGROUND

Outcomes after surgical stabilization of rib fractures (SSRF) have not been studied in patients with multiple rib fractures and traumatic brain injury (TBI). We hypothesized that SSRF, as compared with nonoperative management, is associated with favorable outcomes in patients with TBI.

METHODS

A multicenter, retrospective cohort study was performed in patients with rib fractures and TBI between January 2012 and July 2019. Patients who underwent SSRF were compared to those managed nonoperatively. The primary outcome was mechanical ventilation-free days. Secondary outcomes were intensive care unit length of stay and hospital length of stay, tracheostomy, occurrence of complications, neurologic outcome, and mortality. Patients were further stratified into moderate (GCS score, 9-12) and severe (GCS score, ≤8) TBI.

RESULTS

The study cohort consisted of 456 patients of which 111 (24.3%) underwent SSRF. The SSRF was performed at a median of 3 days, and SSRF-related complication rate was 3.6%. In multivariable analyses, there was no difference in mechanical ventilation-free days between the SSRF and nonoperative groups. The odds of developing pneumonia (odds ratio [OR], 0.59; 95% confidence interval [95% CI], 0.38-0.98; p = 0.043) and 30-day mortality (OR, 0.32; 95% CI, 0.11-0.91; p = 0.032) were significantly lower in the SSRF group. Patients with moderate TBI had similar outcome in both groups. In patients with severe TBI, the odds of 30-day mortality was significantly lower after SSRF (OR, 0.19; 95% CI, 0.04-0.88; p = 0.034).

CONCLUSION

In patients with multiple rib fractures and TBI, the mechanical ventilation-free days did not differ between the two treatment groups. In addition, SSRF was associated with a significantly lower risk of pneumonia and 30-day mortality. In patients with moderate TBI, outcome was similar. In patients with severe TBI a lower 30-day mortality was observed. There was a low SSRF-related complication risk. These data suggest a potential role for SSRF in select patients with TBI.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Effects of hospital-acquired pneumonia on long-term recovery and hospital resource utilization following moderate to severe traumatic brain injury

BACKGROUND

Individuals with traumatic brain injury (TBI) have extended inpatient hospital stays that include prolonged mechanical ventilation, increasing risk for infections, including pneumonia. Studies show the negative short-term effects of hospital-acquired pneumonia (HAP) on hospital-based outcomes; however, little is known of its long-term effects.

METHODS

A prospective cohort study was conducted. National Trauma Databank and Traumatic Brain Injury Model Systems were merged to derive a cohort of 3,717 adults with moderate-to-severe TBI. Exposure data were gathered from the National Trauma Databank, and outcomes were gathered from the Traumatic Brain Injury Model Systems. The primary outcome was the Glasgow Outcome Scale-Extended (GOS-E), which was collected at 1, 2, and 5 years postinjury. The GOS-E was categorized as favorable (>5) or unfavorable (≤5) outcomes. A generalized estimating equation model was fitted estimating the effects of HAP on GOS-E over the first 5 years post-TBI, adjusting for age, race, ventilation status, brain injury severity, injury severity score, thoracic Abbreviated Injury Scale score of 3 or greater, mechanism of injury, intraventricular hemorrhage, and subarachnoid hemorrhage.

RESULTS

Individuals with HAP had a 34% (odds ratio, 1.34; 95% confidence interval, 1.15-1.56) increased odds for unfavorable GOS-E over the first 5 years post-TBI compared with individuals without HAP, after adjustment for covariates. There was a significant interaction between HAP and follow-up, such that the effect of HAP on GOS-E declined over time. Sensitivity analyses that weighted for nonresponse bias and adjusted for differences across trauma facilities did not appreciably change the results. Individuals with HAP spent 10.1 days longer in acute care and 4.8 days longer in inpatient rehabilitation and had less efficient functional improvement during inpatient rehabilitation.

CONCLUSION

Individuals with HAP during acute hospitalization have worse long-term prognosis and greater hospital resource utilization. Preventing HAP may be cost-effective and improve long-term recovery for individuals with TBI. Future studies should compare the effectiveness of different prophylaxis methods to prevent HAP.

LEVEL OF EVIDENCE

Prospective cohort study, level III.

Early or Late Bacterial Lung Infection Increases Mortality After Traumatic Brain Injury in Male Mice and Chronically Impairs Monocyte Innate Immune Function

OBJECTIVES

Respiratory infections in the postacute phase of traumatic brain injury impede optimal recovery and contribute substantially to overall morbidity and mortality. This study investigated bidirectional innate immune responses between the injured brain and lung, using a controlled cortical impact model followed by secondary Streptococcus pneumoniae infection in mice.

DESIGN

Experimental study.

SETTING

Research laboratory.

SUBJECTS

Adult male C57BL/6J mice.

INTERVENTIONS

C57BL/6J mice were subjected to sham surgery or moderate-level controlled cortical impact and infected intranasally with S. pneumoniae (1,500 colony-forming units) or vehicle (phosphate-buffered saline) at 3 or 60 days post-injury.

MAIN RESULTS

At 3 days post-injury, S. pneumoniae-infected traumatic brain injury mice (TBI + Sp) had a 25% mortality rate, in contrast to no mortality in S. pneumoniae-infected sham (Sham + Sp) animals. TBI + Sp mice infected 60 days post-injury had a 60% mortality compared with 5% mortality in Sham + Sp mice. In both studies, TBI + Sp mice had poorer motor function recovery compared with TBI + PBS mice. There was increased expression of pro-inflammatory markers in cortex of TBI + Sp compared with TBI + PBS mice after both early and late infection, indicating enhanced post-traumatic neuroinflammation. In addition, monocytes from lungs of TBI + Sp mice were immunosuppressed acutely after traumatic brain injury and could not produce interleukin-1β, tumor necrosis factor-α, or reactive oxygen species. In contrast, after delayed infection monocytes from TBI + Sp mice had higher levels of interleukin-1β, tumor necrosis factor-α, and reactive oxygen species when compared with Sham + Sp mice. Increased bacterial burden and pathology was also found in lungs of TBI + Sp mice.

CONCLUSIONS

Traumatic brain injury causes monocyte functional impairments that may affect the host's susceptibility to respiratory infections. Chronically injured mice had greater mortality following S. pneumoniae infection, which suggests that respiratory infections even late after traumatic brain injury may pose a more serious threat than is currently appreciated.

Nosocomial Infection Following Severe Traumatic Injury in Children

OBJECTIVES

Nosocomial infection is a common source of morbidity in critically injured children including those with traumatic brain injury. Risk factors for nosocomial infection in this population, however, are poorly understood. We hypothesized that critically ill pediatric trauma patients with traumatic brain injury would demonstrate higher rates of nosocomial infection than those without traumatic brain injury.

DESIGN

Retrospective case-control study.

SETTING

PICU, single institution.

PATIENTS

Patients under 18 years old who were admitted to the PICU for at least 48 hours following a traumatic injury were included. Patients were admitted between September 2008 and December 2015. Patients with the following injury types were excluded: thermal injury, drowning, hanging/strangulation, acute hypoxic ischemic encephalopathy, or nonaccidental trauma. Data collected included demographics, injury information, hospital and PICU length of stay, vital signs, laboratory data, insertion and removal dates for invasive devices, surgeries performed, transfusions of blood products, and microbiology culture results. Initial Pediatric Risk of Mortality III and Pediatric Logistic Organ Dysfunction-2 scores were determined. Patients were classified as having: 1) an isolated traumatic brain injury, 2) a traumatic injury without traumatic brain injury, or 3) polytrauma with traumatic brain injury.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred three patients were included in the analyses, and 27 patients developed a nosocomial infection. Patients with polytrauma with traumatic brain injury demonstrated a significantly higher infection rate (30%) than patients with isolated traumatic brain injury (6%) or traumatic injury without traumatic brain injury (9%) (p < 0.001). This increased rate of nosocomial infection was noted on univariate analysis, on multivariable analysis, and after adjusting for other risk factors.

CONCLUSIONS

In this single-center, retrospective analysis of critically ill pediatric trauma patients, nosocomial infections were more frequently observed in patients admitted following polytrauma with traumatic brain injury than in patients with isolated traumatic brain injury or trauma without traumatic brain injury.

Incidence, Risk Factors, and Outcomes of Ventilator-Associated Pneumonia in Traumatic Brain Injury: A Meta-analysis

Ventilator-associated pneumonia (VAP) is one of the most severe complications in patients with traumatic brain injury (TBI) and is considered a risk factor for poor outcomes. However, the incidence of VAP among patients with TBI reported in studies varies widely. What is more, the risk factors and outcomes of VAP are controversial. This study estimates the incidence, risk factors, and outcomes of VAP in patients with TBI and provides evidence for prevention and treatment. PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched from the earliest records to May 2018. Data involving the incidence, risk factors, and outcomes were extracted for meta-analysis. The results showed that the incidence of VAP was 36% (95% confidence interval (CI) 31-41%); risk factors analyses showed that smoking [odds ratio (OR) 2.13; 95% CI 1.16-3.92], tracheostomy (OR 9.55; 95% CI 3.24-28.17), blood transfusion on admission (OR 2.54; 95% CI 1.24-5.18), barbiturate infusion (OR 3.52; 95% CI 1.68-7.40), injury severity score (OR 4.65; 95% CI 1.96-7.34), and head abbreviated injury scale (OR 2.99; 95% CI 1.66-5.37) were related to the occurrence of VAP. When patients developed VAP, mechanical ventilation time (OR 5.45; 95% CI 3.78-7.12), ICU length of stay (OR 6.85; 95% CI 4.90-8.79), and hospital length of stay (OR 10.92; 95% CI 9.12-12.72) were significantly increased. However, VAP was not associated with an increased risk of mortality (OR 1.28; 95% CI 0.74-2.21). VAP is common in patients with TBI. It is affected by a series of factors and has a poor prognosis.

Splenectomy does not affect the development of pneumonia following severe traumatic brain injury

The cholinergic anti-inflammatory pathway offers a proposed mechanism to describe the increased risk of pneumonia following severe traumatic brain injury (sTBI). Vagal activity transmitted to the spleen results in decreased inflammatory cytokine production and immunosuppression. However, no clinical evidence exists. We sought to compare pneumonia rates among patients with TBI and splenectomy using a retrospective analysis of all trauma patients with splenic injury requiring splenectomy or TBI admitted to an ACS verified level one trauma center from 2011 to 2016. Admission Glasgow Coma Score (GCS) ≤ 8 was used to identify sTBI. Pneumonia was defined by respiratory culture obtained by bronchoalveolar lavage. Analysis included χ2 and one-way analysis of variance followed by multivariate logistic regression to determine the association of sTBI and splenectomy of development of pneumonia. Four hundred and twenty-seven patients were included for primary analysis, 247 with sTBI, 180 with splenectomy, and 14 with both sTBI and splenectomy. Rates of pneumonia were increased, although not significant among patients with sTBI and splenectomy and both sTBI alone (71.4 vs. 49.4%, p = 0.11). On multivariate regression, the risk of pneumonia was increased with both splenectomy and sTBI (OR 3.18; 95% CI, 0.75-13.45) and sTBI alone, although significant in the latter only (OR 3.56; 95% CI, 2.12-5.97). Based on these results, splenectomy does not appear to influence the development of pulmonary immunosuppression and pneumonia following sTBI.

Healthcare-Associated Infections in the Neurocritical Care Unit

PURPOSE OF REVIEW

This article summarizes updated data and knowledge on healthcare-associated infections in the neurocritical care unit, with a focus on central nervous system infections and systemic infectious complications in patients with acute brain disease. It also reviews the concept of brain injury-induced immune modulation, an underlying mechanism to explain why the neuro-ICU population is particularly susceptible to infections.

RECENT FINDINGS

Healthcare-associated infections in the neuro-ICU are common: up to 40 % of meningitides in the developed world are now healthcare-associated. The number of gram-negative infections is rising. New diagnostic approaches attempt to aid in the diagnosis of healthcare-associated meningitis and ventriculitis. Healthcare-associated infections in the neurocritical care unit remain a challenge for diagnosis, treatment, and prevention. Gaining a better understanding of at-risk patients and development of preventative strategies will be the goal for future investigation.

Incidence of post-traumatic pneumonia in poly-traumatized patients: identifying the role of traumatic brain injury and chest trauma

Purpose

Traumatic brain injury (TBI) and chest trauma are common injuries in severely injured patients. Both entities are well known to be associated with severe post-traumatic complications, including pneumonia, a common complication with a significant impact on the further clinical course. However, the relevance of TBI, chest trauma and particularly their combination as risk factors for the development of pneumonia and its impact on outcomes are not fully elucidated.

Methods

A retrospective analysis of poly-traumatized patients treated between 2010 and 2015 at a level I trauma centre was performed. Inclusion criteria were: Injury Severity Score ≥ 16 and age ≥ 18 years. TBI and chest trauma were classified according to the Abbreviated Injury Scale. Complications (i.e. acute respiratory distress syndrome (ARDS), multi-organ dysfunction syndrome (MODS) and pneumonia) were documented by a review of the medical records. The primary outcome parameter was in-hospital mortality.

Results

Over the clinical course, 19.9% of all patients developed pneumonia, and in-hospital mortality was 25.3%. Pneumonia (OR 5.142, p = 0.001) represented the strongest independent predictor of in-hospital mortality, followed by the combination of chest injury and TBI (OR 3.784, p = 0.008) and TBI (OR 3.028, p = 0.010). Chest injury alone, the combination of chest injury and TBI, and duration of ventilation were independent predictors of pneumonia [resp. OR 4.711 (p = 0.004), OR 4.193 (p = 0.004), OR 1.002 (p < 0.001)].

Conclusions

Chest trauma alone and especially its combination with TBI represent high-risk injury patterns for the development of pneumonia, which forms the strongest predictor of mortality in poly-traumatized patients.

Infections after a traumatic brain injury: The complex interplay between the immune and neurological systems

Traumatic brain injury (TBI) is a serious global health issue, being the leading cause of death and disability for individuals under the age of 45, and one of the largest causes of global neurological disability. In addition to the brain injury itself, it is increasingly appreciated that a TBI may also alter the systemic immune response in a way that renders TBI patients more vulnerable to infections in the acute post-injury period. Such infections pose an additional challenge to the patient, increasing rates of mortality and morbidity, and worsening neurological outcomes. Hospitalization, surgical interventions, and a state of immunosuppression induced by injury to the central nervous system (CNS), may all contribute to the high rate of infections seen in the population with TBI. Ongoing research to better understand the immunomodulators that underlie TBI-induced immunosuppression may aid in the development of effective therapeutic strategies to improve the recovery trajectory for patients. This review first describes the clinical scenario, posing the question of whether TBI patients are more susceptible to infections such as pneumonia, and if so, why? We then consider how cross-talk between the injured brain and the systemic immune system occurs, and further, how the additional immune challenge of an acquired infection can contribute to ongoing neuroinflammation and neurodegeneration after a TBI. Experimental models combining TBI with infection are discussed, as well as current treatment options available for this double-barreled insult. The aims of this review are to summarize current understanding of the bidirectional relationship between the CNS and the immune system when faced with a mechanical trauma combined with a concomitant infection, and to highlight key outstanding questions that remain in the field.

Incidence of Cardiac Dysfunction After Brain Injury

Introduction:

Cardiovascular complications in patients with subarachnoid hemorrhage are considered to be a neurally mediated process rather than a manifestation of coronary artery disease.

Aim:

The aim of study is to show the incidence and type cardiac complications after traumatic and spontaneous SAH.

Patients and methods:

The study had prospective character in which included 104 patients, with diagnosed subarachnoid hemorrhage (SAH), in the period from 2014 to 2017. Two groups of patients were formed. Group I: patients with SAH caused by the rupture of a brain aneurysm. Group II: patients with SAH after traumatic brain injury.

Results:

Electrocardiogram (ECG) abnormalities was predominant after traumatic brain injury 74 %, with statistically significant difference atrial fibrillation 42.5 % (p = 0.043) and sinus bradycardia 31.4 % (p = 0.05). Hypertension are predominant in patients with spontaneous SAH with statistically significant difference (15 (27.7%) vs 36 (72%) p=0.034) and hypotension in group II (10 (18.5%) vs 2 (4%) p = 0.021 ) with traumatic SAH patients. The time in Intensive Care Unit (ICU) for traumatic SAH group was 6.1 ± 5.2 days and 3.9 ± 1.16 for spontaneous SAH group with statistical significance (p = 0.046). Respiratory support time was longer in traumatic SAH group (39.4 ± 23.44 vs. 15.66 ± 22.78) with p = 0.043.

Conclusion:

Cardiac dysfunction in patients with subarachnoid hemorrhage are considered to be a neurally mediated process rather than a manifestation of coronary artery disease. Early treatment of cerebral injury could be reduce incidence of cardiac complications after traumatic brain injury. Cardiac dysfunction in patients with SAH is still very high, despite substantial qualitative progress in their treatment.

Making sense of gut feelings in the traumatic brain injury pathogenesis

Traumatic brain injury (TBI) is a devastating condition which often initiates a sequel of neurological disorders that can last throughout lifespan. From metabolic perspective, TBI also compromises systemic physiology including the function of body organs with subsequent malfunctions in metabolism. The emerging panorama is that the effects of TBI on the periphery strike back on the brain and exacerbate the overall TBI pathogenesis. An increasing number of clinical reports are alarming to show that metabolic dysfunction is associated with incidence of long-term neurological and psychiatric disorders. The autonomic nervous system, associated hypothalamic-pituitary axis, and the immune system are at the center of the interface between brain and body and are central to the regulation of overall homeostasis and disease. We review the strong association between mechanisms that regulate cell metabolism and inflammation which has important clinical implications for the communication between body and brain. We also discuss the integrative actions of lifestyle interventions such as diet and exercise on promoting brain and body health and cognition after TBI.

Evaluation of airway care score as a criterion for extubation in patients admitted in neurosurgery intensive care unit

Background and Aims:

Early extubation in neurocritical patients has several potential benefits. Glasgow Coma Scale (GCS) is a crude measure of neurologic function in these patients and a low GCS score does not necessarily mean contraindication for extubation. Data on patients with neurosurgical or neurological pathology undergoing early extubation utilizing the airway score criteria is limited. Hence, this study was conceived to assess the usefulness of modified airway care score (ACS) as a criterion for successful extubation of neurocritical patients whilst comparing various outcomes.

Material and Methods:

One hundred and twenty four patient who underwent endotracheal intubation in the neurocritical care unit were enrolled in this prospective observational study over a period of 12 months. Patients were randomly enrolled into either the study group patients (S), who were extubated immediately after a successful spontaneous breathing trial (SBT) and an ACS ≤7 or into the control group (N), wherein patients were extubated/tracheostomized at discretion of the attending neurointensivist. Both groups were observed for comparison of preset outcomes and analyzed statistically.

Results:

Patients of study group experienced a statistically significant shorter extubation delay (3.28 h vs 25.41 h) compared to the control group. Successful extubation rate was significantly higher and reintubation rate was significantly lower in study group (6.6% vs 29.3%). Incidence of nosocomial pneumonia, duration of ICU stay and overall duration of mechanical ventilation were significantly lower in the study group. ACS and GCS had a negative correlation at the time of extubation.

Conclusion:

ACS can be used as a criterion for successful early extubation of neurocritical patients.

Differences in prevalence of ICU protocols between neurologic and non-neurologic patient populations

PURPOSE

To compare the differences in the presence of protocols aimed at addressing complications for neurologically injured patients vs. non-neurologic injured patients in a large sample of ICUs across the United States.

MATERIALS AND METHODS

Prospective observational multi-center cohort study. This was a subgroup analysis of the multi-centered prospective observational cohort study of medical, surgical, and mixed intensive care units from across the country. USCIITG-CIOS study group.

RESULTS

Sixty-nine ICUs participated in the study of which 25 (36%) were medical, 24 were surgical (35%) and 20 (29%) were of mixed type, and 64 (93%) were in teaching hospitals. There were 6179 patients across all sites with 1266 (20.4%) with central nervous system diagnoses. Protocol utilization in central nervous system vs. non- central nervous system patients was as follows: Sedation interruption 973/1266 (76.9%) vs. 3840/4913 (78.2%) (p = .32); acute lung injury ventilation 847/1266 (66.9%) vs. 4069/4913 (82.8%) (p < .0001); ventilator associated pneumonia 1193/1266 (94.2%) vs. 4760/4913 (96.9%) (p < .0001); ventilator weaning 1193/1266 (94.2%) vs. 4490/4913 (91.4%) (p = .0009); and early mobility 378/1266 (29.9%) vs. 1736/4913 (35.3%) (p = .0002).

CONCLUSION

In this cohort, we found differences in the prevalence of respiratory illness prevention protocols between critically ill patients with neurologic illness and the general critically ill population.

Low incidence of multidrug-resistant bacteria and nosocomial infection due to a preventive multimodal nosocomial infection control: a 10-year single centre prospective cohort study in neurocritical care

Background

Nosocomial infection (NI) control is an important issue in neurocritical care due to secondary brain damage and the increased morbidity and mortality of primary acute neurocritical care patients. The primary aim of this study was to determine incidence of nosocomial infections and multidrug-resistant bacteria and seek predictors of nosocomial infections in a preventive multimodal nosocomial infection protocol in the neurointensive care unit (NICU). The secondary aim focused on their impact on stay, mortality and cost in the NICU.

Methods

A10-year, single-centre prospective observational cohort study was conducted on 3464 acute brain disease patients. There were 198 (5.7%) patients with nosocomial infection (wound 2.1%, respiratory 1.8%, urinary 1.0%, bloodstream 0.7% and other 0.1%); 67 (1.9%) with Extended spectrum beta-lactamase (ESBL); 52 (1.5%) with Methicillin-resistant Staphylococcus aureus (MRSA), nobody with Vancomycin-resistant enterococcus (VRE). The protocol included hygienic, epidemiological status and antibiotic policy. Univariate and multivarite logistic regression analysis was used for identifying predictors of nosocomial infection.

Results

From 198 NI patients, 153 had onset of NI during their NICU stay (4.4%; wound 1.0%, respiratory 1.7%, urinary 0.9%, bloodstream 0.6%, other 0.1%); ESBL in 31 (0.9%) patients, MRSA in 30 (0.9%) patients. Antibiotics in prophylaxis was given to 63.0% patients (59.2 % for operations), in therapy to 9.7% patients. Predictors of NI in multivariate logistic regression analysis were airways (OR 2.69, 95% CI 1.81-3.99, p<0.001), urine catheters (OR 2.77, 95% CI 1.00-7.70, p=0.050), NICU stay (OR 1.14, 95% CI 1.12-1.16, p<0.001), transfusions (OR 1.79, 95% CI 1.07-2.97, p=0.025) antibiotic prophylaxis (OR 0.50, 95% CI 0.34-0.74, p<0.001), wound complications (OR 2.30, 95% CI 1.33-3.97, p=0.003). NI patients had longer stay (p<0.001), higher mortality (p<0.001) and higher TISS sums (p<0.001) in the NICU.

Conclusions

The presented preventive multimodal nosocomial infection control management was efficient; it gave low rates of nosocomial infections (4.2%) and multidrug-resistant bacteria (ESBL 0.9%, MRSA 0.9% and no VRE). Strong predictors for onset of nosocomial infection were accesses such as airways and urine catheters, NICU stay, antibiotic prophylaxis, wound complications and transfusion. This study confirmed nosocomial infection is associated with worse outcome, higher cost and longer NICU stay.

Non- Neurological Complications after Traumatic Brain Injury: A Prospective Observational Study

Introduction and Aims

Recognizing and treating nonneurological complications occurring in traumatic brain injury (TBI) patients during intensive care unit (ICU) stay are challenging. The aim is to estimate various nonneurological complications in TBI patients. The secondary aim is to see the effect of these complications on ICU stay, disability, and mortality.

Materials and Methods

This was a prospective observational study at the neuro-ICU of a Level-I trauma center. A total of 154 TBI patients were enrolled. The period of the study was from admission to discharge from ICU or demise. Inclusion criteria were patients aged >16 years and patients with severe TBI (Glasgow coma score [GCS] ≤8). Nonneurological complications were frequent in TBI patients.

Results

We observed respiratory complications to be the most common (61%). Other complications, in the decreasing order, included dyselectrolytemia (46.1%), cardiovascular (34.4%), coagulopathy (33.1%), sepsis (26%), abdominal complications (17.5%), and acute kidney injury (AKI, 3.9%). The presence of systemic complications except AKI was found to be significantly associated with increased ICU stay. Most of the patients of AKI died early in ICU. Respiratory dysfunction was found to be independently associated with 3.05 times higher risk of worsening clinical condition (disability) (P < 0.018). The presence of cardiovascular complications during ICU stay (4.2 times, P < 0.005), AKI (24.7 times, P < 0.02), coagulopathy (3.13 times, P < 0.047), and GCS <6 (4.2 times, P < 0.006) of TBI was independently associated with significantly increased risk of ICU mortality.

Conclusion

TBI patients tend to have poor outcome due to concomitant nonneurological complications. These have significant bearing on ICU stay, disability, and mortality.

Would "Suction above Cuff" be a Better Option than the "Standard" Endotracheal Tube for the Prevention of Ventilator-Associated Pneumonia: A Randomized Study in Postoperative Neurological Patients

Context

Ventilator associated pneumonia is one the most common nosocomial infection encountered in the ICU patients. Despite of the implementation of the VAP prevention bundle, the incidence remains high. This can be attributed to the peritubal leak and the aspiration of the oropharyngeal secretions. The secretions further forms a nidus for the growth of organisms in the lower respiratory tract. In this study, a specialised tube, named 'suction above cuff endotracheal tube' is used, which has an additional suction port opening above the cuff. This is to facilitate timely aspiration of the secretion which pent-up above the cuff and gradually trickles down the trachea resulting in pneumonia.

Aim

to compare the incidence of VAP with standard endotracheal tube (SETT) and suction above cuff endotracheal tube (SACETT) in neurological post-operative patients and its impact on clinical outcome.

Settings and Design

60 patients of post-operative neurological cases aged ≥ 18 years and requiring intubation and/or ventilation and anticipated to remain on ETT for ≥48 h were randomized to receive either SETT or SACETT.

Results

In this study involving neurological population, there was no significant difference in incidence of clinical and microbiological VAP between SETT and SACETT group, when other strategies for VAP prevention were similar. Other outcomes were similar with use of either tube for intubation.

Understanding Hospital Volume-Outcome Relationship in Severe Traumatic Brain Injury

BACKGROUND

The hospital volume-outcome relationship in severe traumatic brain injury (TBI) population remains unclear.

OBJECTIVE

To examine the relationship between volume of patients with severe TBI per hospital and in-hospital mortality, major complications, and mortality following a major complication (ie, failure to rescue).

METHODS

In a multicenter cohort study, data on 9255 adults with severe TBI were derived from 111 hospitals participating in the American College of Surgeons Trauma Quality Improvement Program over 2009-2011. Hospitals were ranked into quartiles based on their volume of severe TBI during the study period. Random-intercept multilevel models were used to examine the association between hospital quartile of severe TBI volume and in-hospital mortality, major complications, and mortality following a major complication after adjusting for patient and hospital characteristics. In sensitivity analyses, we examined these associations after excluding transferred cases.

RESULTS

Overall mortality was 37.2% (n = 3447). Two thousand ninety-eight patients (22.7%) suffered from 1 or more major complication. Among patients with major complications, 27.8% (n = 583) died. Higher-volume hospitals were associated with lower mortality; the adjusted odds ratio of death was 0.50 (95% confidence interval: 0.29-0.85) in the highest volume quartile compared to the lowest. There was no significant association between hospital-volume quartile and the odds of a major complication or the odds of death following a major complication. After excluding transferred cases, similar results were found.

CONCLUSION

High-volume hospitals might be associated with lower in-hospital mortality following severe TBI. However, this mortality reduction was not associated with lower risk of major complications or death following a major complication.

Early-Onset Ventilator-Associated Pneumonia in Patients with Severe Traumatic Brain Injury: Incidence, Risk Factors, and Consequences in Cerebral Oxygenation and Outcome

BACKGROUND

Early-onset ventilator-associated pneumonia (EOVAP) occurs frequently in severe traumatic brain-injured patients, but potential consequences on cerebral oxygenation and outcome have been poorly studied. The objective of this study was to describe the incidence, risk factors for, and consequences on cerebral oxygenation and outcome of EOVAP after severe traumatic brain injury (TBI).

METHODS

We conducted a retrospective, observational study including all intubated TBI admitted in the trauma center. An EOVAP was defined as a clinical pulmonary infection score >6, and then confirmed by an invasive method. Patient characteristics, computed tomography (CT) scan results, and outcome were extracted from a prospective register of all intubated TBI admitted in the intensive care unit (ICU). Data concerning the cerebral oxygenation monitoring by PbtO2 and characteristics of EOVAP were retrieved from patient files. Multivariate logistic regression models were developed to determine the risk factors of EOVAP and to describe the factors independently associated with poor outcome at 1-year follow-up.

RESULTS

During 7 years, 175 patients with severe TBI were included. The overall incidence of EOVAP was 60.6% (47.4/1000 days of ventilation). Significant risk factors of EOVAP were: therapeutic hypothermia (OR 3.4; 95% CI [1.2-10.0]), thoracic AIS score ≥3 (OR 2.4; 95% CI [1.1-5.7]), and gastric aspiration (OR 5.2, 95% CI [1.7-15.9]). Prophylactic antibiotics administration was a protective factor against EOVAP (OR 0.3, 95% CI [0.1-0.8]). EOVAP had negative consequences on cerebral oxygenation. The PbtO2 was lower during EOVAP: 23.5 versus 26.4 mmHg (p <0.0001), and there were more brain hypoxia episodes: 32 versus 27% (p = 0.03). Finally, after adjusting for confounders, an EOVAP was an independent factor associated with unfavorable neurologic functional outcome at the 1-year follow-up (OR 2.71; 95% CI [1.01-7.25]).

CONCLUSIONS

EOVAP is frequent after a severe TBI (overall rate: 61%), with therapeutic hypothermia, severe thoracic lesion, and gastric aspiration as main risk factors. EOVAP had a negative impact on cerebral oxygenation measured by PbtO2 and was independently associated with unfavorable outcome at 1-year follow-up. This suggests that all precautions available should be taken to prevent EOVAP in this population.

Bundle of care for blunt chest trauma patients improves analgesia but increases rates of intensive care unit admission: A retrospective case-control study

INTRODUCTION

This single-centre retrospective case-control study aimed to assess the effectiveness of a multidisciplinary clinical pathway for blunt chest trauma patients admitted in emergency department (ED).

PATIENTS AND METHODS

All consecutive blunt chest trauma patients with more than 3 rib fractures and no indication of mechanical ventilation were compared to a retrospective cohort over two 24-month periods, before and after the introduction of the bundle of care. Improvement of analgesia was the main outcome investigated in this study. The secondary outcomes were the occurrence of secondary respiratory complications (pneumonia, indication for mechanical ventilation, secondary ICU admission for respiratory failure or death), the intensive care unit (ICU) and hospital length of stay (LOS).

RESULTS

Sixty-nine pairs of patients were matched using a 1:1 nearest neighbour algorithm adjusted on age and indices of severity. Between the two periods, there was a significant reduction of the rate of uncontrolled analgesia (55 vs. 17%, P<0.001). A significant increase in the rate of primary ICU transfer during the post-protocol period (23 vs. 52%, P<0.001) was not associated with a reduction of secondary respiratory complications or a reduction of ICU or hospital LOS. Only the use of non-steroidal anti-inflammatory drugs appeared to be associated with a significant reduction of secondary respiratory complications (OR=0.3 [0.1-0.9], P=0.03).

CONCLUSION

Implementation of a multidisciplinary clinical pathway significantly improves pain control after ED management, but increases the rate of primary ICU admission without significant reduction of secondary respiratory complications.

Association between augmented renal clearance and clinical failure of antibiotic treatment in brain-injured patients with ventilator-acquired pneumonia: A preliminary study

OBJECTIVES

This preliminary study aimed to determine whether augmented renal clearance (ARC) impacts negatively on the clinical outcome in traumatic brain-injured patients (TBI) treated for a first episode of ventilator-acquired pneumonia (VAP).

METHODS

During a 5-year period, all TBI patients who had developed VAP were retrospectively reviewed to assess variables associated with clinical failure in multivariate analysis. Clinical failure was defined as an impaired clinical response with a need for escalating antibiotics during treatment and/or within 15 days after the end-of-treatment. Recurrence was considered if at least one of the initial causative bacterial strains was growing at a significant concentration from a second sample. Augmented renal clearance (ARC) was defined by an enhanced creatinine clearance exceeding 130mL/min/1.73m² calculated from a urinary sample during the first three days of antimicrobial therapy.

MAIN RESULTS

During the study period, 223 TBI patients with VAP were included and 59 (26%) presented a clinical failure. Factors statistically associated with clinical failure were GSC≤7 (OR=2.2 [1.1-4.4], P=0.03), early VAP (OR=3.9 [1.9-7.8], P=0.0001), bacteraemia (OR=11 [2.2-54], P=0.003) and antimicrobial therapy≤7 days (OR=3.7 [1.8-7.4], P=0.0003). ARC was statistically associated with recurrent infections with an OR of 4.4 [1.2-16], P=0.03.

CONCLUSION

ARC was associated with recurrent infection after a first episode of VAP in TBI patients. The optimal administration and dosing of the antimicrobial agents in this context remain to be determined.

Acute brain trauma, lung injury, and pneumonia: more than just altered mental status and decreased airway protection

Traumatic brain injury (TBI) is a major cause of mortality and morbidity worldwide. Even when patients survive the initial insult, there is significant morbidity and mortality secondary to subsequent pulmonary edema, acute lung injury (ALI), and nosocomial pneumonia. Whereas the relationship between TBI and secondary pulmonary complications is recognized, little is known about the mechanistic interplay of the two phenomena. Changes in mental status secondary to acute brain injury certainly impair airway- and lung-protective mechanisms. However, clinical and translational evidence suggests that more specific neuronal and cellular mechanisms contribute to impaired systemic and lung immunity that increases the risk of TBI-mediated lung injury and infection. To better understand the cellular mechanisms of that immune impairment, we review here the current clinical data that support TBI-induced impairment of systemic and lung immunity. Furthermore, we also review the animal models that attempt to reproduce human TBI. Additionally, we examine the possible role of damage-associated molecular patterns, the chlolinergic anti-inflammatory pathway, and sex dimorphism in post-TBI ALI. In the last part of the review, we discuss current treatments and future pharmacological therapies, including fever control, tracheostomy, and corticosteroids, aimed to prevent and treat pulmonary edema, ALI, and nosocomial pneumonia after TBI.