Acute lung injury in isolated traumatic brain injury

Fingolimod Attenuates Lung Injury and Cardiac Dysfunction after Traumatic Brain Injury

Acute lung injury (ALI) and cardiac dysfunction are common in traumatic brain injury (TBI) patients and always indicate poor outcomes. Inflammatory responses play important roles in TBI-induced cardiac and pulmonary damage. Fingolimod, an immunomodulatory agent, alleviates brain edema, restores the integrity of the blood-brain barrier (BBB), and improves functional deficits by inhibiting multiple inflammatory responses. Fingolimod (1 mg/kg) was injected intraperitoneally at 2 h after the controlled cortical impact (CCI) model was established in adult male mice. The concentration of inflammatory cytokines in the lung and heart after TBI was measured with a cytokine array. The lung wet/dry weight ratio and Evans blue dye leakage were used to quantify pulmonary edema and capillary leakage. Immunofluorescence, electron microscopy, and echocardiographic examination were used to assess the pathology and functional deficits in hearts. We found that TBI caused significant heart and lung damage. The administration of fingolimod significantly reduced the elevated inflammatory cytokine production, neutrophil infiltration, the leakage of protein in bronchoalveolar lavage fluid (BALF), and the wet/dry weight ratio in lung tissue at 3 days after TBI. In addition, fingolimod treatment also alleviated the inflammatory response in the heart; decreased cardiac apoptosis, fibrosis, and histological microstructural changes; and improved cardiac function from 3 days after TBI and maintained it for 30 days after TBI as measured by echocardiography. These results suggest that TBI resulted in significant cardiac and pulmonary damage accompanied by significant inflammatory responses in heart and lung tissue. Fingolimod treatment reduced the inflammatory response and alleviated TBI-induced lung and heart injury.

Increased intracranial pressure is associated with the development of acute lung injury following severe traumatic brain injury

OBJECTIVE

This study investigated the relationship among intracranial pressure (ICP), the development of acute lung injury (ALI) and systemic inflammatory response syndrome (SIRS) following a severe traumatic brain injury (TBI).

METHODS

Post-traumatic ICP was continuously monitored for the first week following injury in a series of consecutive patients with isolated severe TBI. The initial ICP and the duration of intracranial hypertension (ICH) were calculated. The risk factors associated with the development of ALI and SIRS were evaluated.

RESULTS

Of the 86 patients enrolled, 22 patients developed ALI and 52 patients developed SIRS during the observation period. The patients with ALI presented with a significantly higher initial ICP (31.3±7.8 mmHg vs. 23.0±8.8 mmHg, p<0.001) and a longer duration of ICH (16.8±6.5 h vs. 11.9±6.0 h, p=0.002) than those without ALI. The incidence of both ALI and SIRS increased with increasing initial ICP, and the presence of SIRS was associated with a fourfold increase in the risk of developing ALI (odds ratio [OR], 4.0; 95% confidence interval [CI], 1.2-13.0).

CONCLUSIONS

Increased ICP is associated with increased risks of developing ALI and SIRS following severe TBI. Future studies designed to verify the causative relationship between increased ICP and the systemic responses are warranted.

Protective effect of erythropoietin on type II pneumocyte cells after traumatic brain injury in rats

BACKGROUND

The main objective was to evaluate the protective effect of erythropoietin on lung ultrastructure against damage in rats after traumatic brain injury.

METHODS

We used forty Wistar-Albino female rats weighing 170-200 gr. The rats were allocated into five groups. The first group was the control and the second was the craniotomy without trauma. The third group was the trauma group. The fourth and fifth groups were erythropoietin (1000 IU/kg) and vehicle (0.4 mL/rat) groups, respectively. A weight-drop method was used for achieving head trauma. Samples were obtained from pulmonary lobes 24-hour post injury. Lipid peroxidation levels were determined and electron microscopic scoring model was used to reveal the ultrastructural changes.

RESULTS

Ultrastructural evaluation revealed pathologic changes in the trauma group compared with the control group (p < 0.05). Lipid peroxidation levels were found to be higher in the trauma group (p < 0.05). Erythropoietin significantly reduced both the ultrastructural pathologic changes and the lipid peroxidation levels in the treatment group (p < 0.05).

CONCLUSIONS

Erythropoietin protects the ultrastructure of pneumocyte type II cells against damage after traumatic brain injury.

Ultrastructural changes in tracheobronchial epithelia following experimental traumatic brain injury in rats: protective effect of erythropoietin

BACKGROUND

We aimed to demonstrate the time dependent ultrastructural changes in tracheobronchial epithelia after traumatic brain injury. And also, protective effect of erythropoietin was demonstrated.

METHODS

We used 56 Wistar-Albino female rats weighing 170 to 200 g. The rats were allocated into 7 groups. First group was the control. The second underwent craniotomy without trauma. The third, fourth, and fifth groups were respectively 2-, 8-, and 24-hour trauma groups. The sixth and seventh groups were respectively treatment (erythropoietin, 1,000 IU/kg) and vehicle (0, 4 ml/rat) groups. Weight-drop method was used for achieving head trauma. Samples were obtained from both trachea and main bronchi. Modified electron microscopic scoring model was used to reveal the ultrastructural changes in both trauma and treatment groups.

RESULTS

There was no statistical difference between control and sham groups (p >0.05). Scores of all trauma groups were significantly different from the controls (p <0.05). Trauma produced obvious gradual damage on ultrastructure of the tracheobronchial epithelia. Erythropoietin decreased tracheobronchial scores after traumatic brain injury in significant levels. Erythropoietin attenuated ultrastructural scores for each organelle in significant levels (p <0.05 for each organelle).

CONCLUSIONS

The data suggested that ultrastructural damage is obvious at 2 hours deteriorating with time. Erythropoietin protects epithelia against damage after traumatic brain injury. Pharmaceutical lung preservation may help gaining efficacious donor lungs in brain death. But, further time dependent experiments are needed to determine the liability of the donor lung after traumatic brain injury. This fact is to be known for achieving higher graft survival rates.

Acute Respiratory Distress Syndrome in Blunt Trauma: Identification of Independent Risk Factors

Acute respiratory distress syndrome (ARDS) is a major contributor to morbidity and mortality in trauma patients. Although many injuries and conditions are believed to be associated with ARDS independent risk factors in trauma patients and their relative importance in development of the syndrome are undefined. The aim of this project is to identify independent risk factors for the development of ARDS in blunt trauma patients and to examine the contributions of each factor to ARDS development. Patients with ARDS were identified from the registry of a Level I trauma center over a 4.5-year period. Records were reviewed for demographics, injury characteristics, transfusion requirements, and hospital course. Variables examined included age >65 years, Injury Severity Score (ISS) >25, hypotension on admission (systolic blood pressure <90), significant metabolic acidosis (base deficit <-5.0), severe brain injury as shown by a Glasgow Coma Scale score (GCS) <8 on admission, 24-hour transfusion requirement >10 units packed red blood cells, pulmonary contusion (PC), femur fracture, and major infection (pneumonia, empyema, or intraabdominal abscess). Both univariate and stepwise logistic regression were used to identify independent risk factors, and receiver operating characteristic curve (ROC) analysis was used to determine the relative contribution of each risk factor. A total of 4397 patients having sustained blunt trauma were admitted to the intensive care unit and survived >24 hours between October 1995 and May 2000. Of these patients 200 (4.5%) developed ARDS. All studied variables were significantly associated with ARDS in univariate analyses. Stepwise logistic regression, however, demonstrated age >65 years, ISS >25, hypotension on admission, 24-hour transfusion requirement >10 units, and pulmonary contusion as independent risk factors, whereas admission metabolic acidosis, femur fracture, infection, and severe brain injury were not. Using a model based on the logistic regression equation derived yields better than 80 per cent discrimination in ARDS patients. The risk factors providing the greatest contribution to ARDS development were ISS >25 (ROC area 0.72) and PC (ROC area 0.68) followed by large transfusion requirement (ROC area 0.56), admission hypotension (ROC area 0.57), and age >65 (ROC area 0.54). Independent risk factors for ARDS in blunt trauma include ISS >25, PC, age >65 years, hypotension on admission, and 24-hour transfusion requirement >10 units but not admission metabolic acidosis, femur fracture, infection, or severe brain injury. Assessment of these variables allows accurate estimate of risk in the majority of cases, and the most potent contributors to the predictive value of the model are ISS >25 and PC. Improvement in understanding of which patients are actually at risk may allow for advances in treatment as well as prevention in the future.

The neglected prehospital phase of head injury: apnea and catecholamine surge

The prehospital phase of head injury, also called the critical phase, consists of trauma-induced apnea and stress catecholamine release. This immediate period after head injury remains poorly summarized in the literature and essentially ignored with respect to treatment. A MEDLINE search of the literature on apneustic response and catecholamine surge after head injury and a review of literature from my acquired references revealed 116 references (from more than 600) that were pertinent. Apnea induced by head injury produces hypoxia, hypercarbia, and subsequent cardiac failure and hypotension, which, along with substantially elevated catecholamine values, promote secondary mechanisms of organ injury. Treatment for this immediate period after head injury requires a rapid response to the scene of trauma and development of treatment options that can be instituted at the scene of injury.

Head injury: complications and management

Considerable effort and substantial funding has gone towards the development of a neuroprotective agent that could be given after brain trauma to reduce mortality and improve functional recovery. There have been many failed or inconclusive studies to date. In Europe two promising studies have been stopped or shelved (Lubeluzole, Janssen-Cilag and BAYx3702, Bayer) and the future of pharmacological neuroprotection after traumatic brain injury is in doubt. Clinicians managing patients with a head injury are therefore left with the detection and prevention of secondary insults to the brain, including the management of medical complications of brain injury, and non-pharmaceutical interventions that might beneficially modify the brain's response to trauma. Of the potential interventions, moderate hypothermia is the most promising.