Predictors of mortality in pulmonary contusion

Evaluating the Limits in the Biomechanics of Blunt Lung Injury

Thoracic blunt trauma is evident in up to one fifth of all hospital admissions, and is second only to head trauma in motor vehicle crashes. One of the most problematic injury mechanisms associated with blunt thoracic trauma is pulmonary contusion, occurring in up to 75% of blunt thoracic trauma cases. The source and effects of pulmonary contusion caused by blunt lung injury are not well defined, especially within the field of continuum biomechanics. This, paired with unreliable diagnostics for pulmonary contusion, leads to uncertainty in both the clinical entity and mechanics of how to predict presence of injury. There is a distinct need to combine the clinical aspects with mechanical insights through the identification and mitigation of blunt lung trauma and material testing and modeling. This is achieved through using the mechanical insights of lung tissue behavior in order to better understand the injurious mechanisms and courses of treatment of blunt-caused pulmonary contusion. This paper hopes to act as a step forward in connecting two perspectives of blunt lung injury, the clinical entity and mechanical testing and modeling, by reviewing the known literature and identifying the unknowns within the two related fields. Through a review of related literature, clinical evidence is correlated to mechanical data to gain a better understanding of what is being missed in identification and response to blunt lung injury as a whole.

Fluid Therapy in Pulmonary Disease: How Careful Do We Need to Be?

Intravenous fluid therapy is a vital and life-saving therapeutic in veterinary medicine. In the absence of heart or lung disease, trauma or sepsis there is limited evidence that fluid therapy will have a detrimental effect on lung function. In healthy dogs there is a reasonable level of experimental evidence that supraphysiologic rates of fluid are required before signs of fluid overload are made evident. In cats, however, this may not be the case. There are higher rates of asymptomatic myocardial disease, but even in the absence of that it seems that some cats may be susceptible to fluid overload. Where systemic inflammation already exists the careful homeostatic and protective mechanisms within the lung are deranged and increases in hydrostatic pressure are more likely to result in fluid movement into the lung tissues. Strategies including restricting the use of intravenous crystalloid fluid administration and using blood products for management of severe hemorrhage are of increasing importance in human trauma and seem to be associated with fewer pulmonary complications, and lower mortality. Managing dogs and cats with sepsis and acute respiratory distress syndrome is already challenging, but ensuring adequate vascular expansion needs to be balanced with avoiding excessive volume administration which may negatively impact pulmonary function. While fluids remain crucial to management of these conditions, there will be an ongoing requirement to balance need without providing excess. The use of point of care ultrasound may provide clinicians with a non-invasive and accessible way to do this.

Evaluation of Lung Contusion, Associated Injuries, and Outcome in a Major Trauma Center in Shiraz, Southern Iran

Objective

Blunt chest trauma as one of the most common injuries in trauma cases can cause significant morbidity and mortality. The purpose of this study was to determine the clinical course of traumatic injuries with an initial diagnosis of a pulmonary contusion in patients.

Method

In this retrospective study, we evaluated the demographic and clinical features of patients who were referred to a major trauma center in southern Iran. In our study, patients were enrolled with the diagnosis of pulmonary contusion. All included patients were above 16 years of age, with an initial CT scan in favor of pulmonary contusion, while patients not being hospitalized for more than 48 hours were excluded from the study.

Results

Among the 434 patients included in our study, 366 (84%) were male and the mean age was 41.17 (SD = 17.89). Among them, the majority (80.4%) had right side lung contusion and 47 patients (10.8%) had right rib fracture. The most common injuries were head and neck injury (56.9%) and limbs (30%). In 25% of cases, pulmonary contusion was associated with pneumothorax and 15.8% with hemothorax. Also, 49.6% of patients were transferred to the ICU. The mortality rate in our study was 15.2% (n = 66).

Conclusion

Although recent advances in pulmonary care and ventilator management have been achieved, there is still considerable morbidity and mortality associated with this condition. Therefore, there is a need to provide a national guideline based on native patient information for better management.

Lung Contusion in Polytrauma: An Analysis of the TraumaRegister DGU

Background Thorax trauma frequently occurs in which injuries to the bony chest, lung contusions (LCs), and others are diagnosed. The significance of this violation is described very differently and is mostly based on monocentric data.

Methods A retrospective analysis of the TraumaRegister DGU® (TR-DGU) dataset (Project 2014–062) was performed between 2009 and 2014 (injury severity score [ISS] ≥ 16, primary admission to a trauma center, no isolated traumatic brain injury). Patients with LC (Abbreviated Injury Scale [AIS] 3 + 4) were compared with the control group, and an analysis of different age groups was performed.

Results A total of 49,567 patients were included, thereunder 14,521 (29.3%) without relevant thoracic trauma (TT); 95.9% blunt traumas. 18,892 patients (38.1%) had LC and 14,008 (28.3%) had severe LC with AIS 3 + 4; thereunder 72.7% males. For severe LC, the average age was the lowest (44.7 ± 19.7 years) and ISS the highest (30.4 ± 12.1 points).

Intubation, intensive care, (multi-) organ failure, sepsis, and extrathoracic injuries were most common in severe LC. Shock, chest tubes, further thoracic injuries, and patient death occurred most frequently in TT without LC.

Younger patients showed a higher incidence of LC than the older ones; however, high patient age was a highly significant risk factor for the development of complications and poor outcome.

Conclusion Since LC was present in almost 40% of the severely injured and was related to higher morbidity, LC should be detected and managed at the earliest possible time. Proper follow-ups employing chest X-rays and computed tomography (CT) scans are recommended.

Effect of nitric oxide synthase inhibitors in acute lung injury due to blunt lung trauma in rats

Background

This study aims to investigate the effects of blunt lung trauma performed in experimental rat model on lung tissue and blood as well as proinflammatory cytokines, oxidant-antioxidant enzymes and histopathological parameters after Ngamma-nitro-L-arginine methyl ester and N-iminoethyl-L-ornithine administration.

Methods

The study included 50 adult male Wistar albino rats (weighing 350 to 400 g). Rats were randomly allocated into four groups. Except in the control, moderate-level pulmonary contusion was created in all other groups. Intraperitoneal saline solution was performed in groups 1 and 2, 25 mg.kg-1 Ngamma-nitro-L-arginine methyl ester in group 3, and 20 mg.kg-1 N-iminoethyl-L-ornithine in group 4. Blood and lung tissues were studied biochemically and histopathologically.

Results

Best outcomes were recorded statistically significantly in groups with administration of Ngamma-nitro-L-arginine methyl ester and N-iminoethyl-L-ornithine when malondialdehyde response, mucous and histopathological values were examined. Significant improvement was detected in superoxide dismutase values in the group with administration of competitive nitric oxide synthase inhibitor Ngamma-nitro-L-arginine methyl ester. Nitric oxide values were substantially decreased in N-iminoethyl-L-ornithine group, while no significance was detected.

Conclusion

Free oxygen radicals and lipid peroxidation played a role in pulmonary contusion after blunt lung trauma. According to biochemical and histopathological outcomes, effects of inflammation were decreased and protective effects were formed with administration of both Ngammanitro- L-arginine methyl ester and N-iminoethyl-L-ornithine.

Short-term effects of low-volume resuscitation with hypertonic saline and hydroxyethylstarch in an experimental model of lung contusion and haemorrhagic shock

OBJECTIVES

This study aimed to assess the short-term respiratory tolerance and haemodynamic efficiency of low-volume resuscitation with hypertonic saline and hydroxyethylstarch (HS/HES) in a pig model of lung contusion and controlled haemorrhagic shock. We hypothesised that a low-volume of HS/HES after haemorrhagic shock did not impact contused lungs in terms of extravascular lung water 3hours after trauma.

METHODS

A lung contusion resulting from blunt chest trauma was induced in 28 anaesthetised female pigs with five bolt-shots to the right thoracic cage, followed by haemorrhagic shock and fluid resuscitation. Pigs were randomly allocated into two groups: fluid resuscitation by 4ml/kg of HS/HES, or fluid resuscitation by 10ml/kg of normal saline (NS). Monitoring was based on transpulmonary thermodilution and a pulmonary artery catheter. After 3h, animals were euthanized to measure extravascular lung water (EVLW) by gravimetry.

RESULTS

Blunt chest trauma was followed by a transient collapse and hypoxaemia in both groups. Post-mortem gravimetric assessment demonstrated a significant difference between EVLW in the NS-group (8.1±0.7ml/kg) and in the HS/HES-group (6.2±0.6ml/kg, P=0.038). Based on a pathological EVLW threshold of > 7ml/kg, results indicated that only the NS-group experienced moderate pulmonary oedema, contrary to the HS/HES-group. After haemorrhagic shock, HS/HES infusion enabled the restoration of effective mean arterial pressure and cardiac index. Intrapulmonary shunting increased transiently after fluid resuscitation but there was no significant impairment of oxygenation.

CONCLUSION

In this pig model of lung contusion, the short-term assessment of fluid resuscitation after haemorrhagic shock with 4ml/kg of HS/HES showed that pulmonary oedema was avoided compared to fluid resuscitation with 10ml/kg of NS.

Alveolar macrophage depletion increases the severity of acute inflammation following nonlethal unilateral lung contusion in mice

BACKGROUND

Lung contusion (LC) is a common injury resulting from blunt thoracic trauma. LC is an important risk factor for the development acute lung injury, adult respiratory distress syndrome, and ventilator-associated pneumonia, all of which increase mortality from trauma. LC produces a nonspecific immune cellular response. Neutrophil recruitment is known to increase the severity of inflammation during LC. However, the exact role of macrophages in modulating the response to LC has not been well described.

METHODS

We used a cortical contusion impactor to induce unilateral LC in mice. Thoracic micro computed tomographic scans of these animals were obtained to document radiologic changes over time following LC. To understand the role of macrophages during LC, liposomal clodronate was used to deplete macrophage levels before traumatic insult. Acute inflammatory attributes after LC were assessed, by measuring pressure-volume mechanics; quantifying bronchial alveolar lavage levels of leukocytes, albumin, and cytokines; and finally examining lung specimen histopathology at 5, 24, 48, and 72 hours after injury.

RESULTS

After LC, alveolar macrophage numbers were significantly reduced and exhibited slowed recovery. Simultaneously, there was a significant increase in bronchial alveolar lavage neutrophil counts. The loss of macrophages could be attributed to both cellular apoptosis and necrosis. Pretreatment with clodronate increased the severity of lung inflammation as measured by worsened pulmonary compliance, increased lung permeability, amplification of neutrophil recruitment, and increases in early proinflammatory cytokine levels.

CONCLUSION

The presence of regulatory alveolar macrophages plays an important role in the pathogenesis of acute inflammation following LC.

Electroporation-mediated delivery of genes in rodent models of lung contusion

Several of the biological processes involved in the pathogenesis of acute lung injury and acute respiratory distress syndrome after lung contusion are regulated at a genetic and epigenetic level. Thus, strategies to manipulate gene expression in this context are highly desirable not only to elucidate the mechanisms involved but also to look for potential therapies. In the present chapter, we describe mouse and rat models of inducing blunt thoracic injury followed by electroporation-mediated gene delivery to the lung. Electroporation is a highly efficient and easily reproducible technique that allows circumvention of several of lung gene delivery challenges and safety issues present with other forms of lung gene therapy.

Antioxidant vitamins C, E and coenzyme Q10 vs dexamethasone: comparisons of their effects in pulmonary contusion model

Background

The goal of our study is to evaluate the effects of antioxidant vitamins (vitamin C and E), Coenzyme Q10 (CoQ10) and dexamethasone (Dxm) in experimental rat models with pulmonary contusion (PC).

Methods

Rats were randomly divided into six groups. Except for the control, all subgroups had a moderate pulmonary contusion. Animals in the group I and group II received intraperitoneal saline, group III received 10mg.kg-1 CoQ10 group IV received 100mg.kg-1 vitamin C, group V received 150mg.kg-1 vitamin E, and group VI received 10mg.kg-1 Dxm. Blood gas analysis, serum nitric oxide (NO) and malondialdehyde (MDA) levels as well as superoxide dismutase (SOD) activity assays, bronchoalveolar lavage (BAL) fluid and histopathological examination were performed.

Results

Administration of CoQ10 resulted in a significant increase in PaO2 values compared with the group I (p = 0.004). Levels of plasma MDA in group II were significantly higher than those in the group I (p = 0.01). Early administration of vitamin C, CoQ10, and Dxm significantly decreased the levels of MDA (p = 0.01). Lung contusion due to blunt trauma significantly decreased SOD activities in rat lung tissue compared with group I (p = 0.01). SOD levels were significantly elevated in animals treated with CoQ10, Vitamin E, or Dxm compared with group II (p = 0.01).

Conclusions

In our study, CoQ10, vitamin C, vitamin E and Dxm had a protective effect on the biochemical and histopathological outcome of PC after experimental blunt thorax trauma.

Lung contusion: inflammatory mechanisms and interaction with other injuries

This article reviews current animal models and laboratory studies investigating the pathophysiology of lung contusion (LC), a common and severe condition in patients with blunt thoracic trauma. Emphasis is on studies elucidating cells, mediators, receptors, and processes important in the innate pulmonary inflammatory response that contribute to LC injury. Surfactant dysfunction in the pathogenesis of LC is also discussed, as is the potential role of epithelial cell or neutrophil apoptosis. Studies examining combination injuries where LC is exacerbated by secondary insults such as gastric aspiration in trauma patients are also noted. The need for continuing mechanism-based research to further clarify the pathophysiology of LC injury, and to define and test potential therapeutic interventions targeting specific aspects of inflammation or surfactant dysfunction to improve clinical outcomes in patients with LC, is also emphasized.

Effects of early administration of dexamethasone, N-acetylcysteine and aprotinin on inflammatory and oxidant-antioxidant status after lung contusion in rats

INTRODUCTION

This experimental setting was undertaken to elucidate and confirm the role of inflammatory and oxidant-antioxidant mechanisms on blunt injury induced moderate pulmonary contusion (PC). We intended to determine the effects of dexamethasone (DXM), N-acetylcysteine (NAC) and aprotinin (APR) in terms of their ability to diminish the consequences of acute lung injury due to PC.

METHODS

Rats were allocated to five subgroups. Except for the control, all subgroups had a moderate pulmonary contusion. Following 45 min of observation, animals in groups I and II received intraperitoneal saline, group III 10 mg/kg DXM, group IV 500 mg/kg NAC and group V 30,000 kIU/ml APR. After the procedure, 6 h after contusion, blood gas analysis, lung tissue nitric oxide (NO) and malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activity, bronchoalveolar lavage (BAL) fluid and histopathological examination were performed.

RESULTS

All PaO(2) values decreased significantly in contused rats as compared with the control group (p<0.05). DXM, NAC and APR resulted in a slight increase in PaO(2) values compared with group II (p<0.05). Lung tissue levels of MDA and NO were higher in the contusion group than in the control (p<0.05). DXM, NAC and APR all decreased the levels of MDA and NO (p<0.05), however the decrease in NO was not found to be significant with APR (p>0.05). SOD and CAT activities increased significantly after contusion compared to control group (p<0.05). There was no significant difference even though SOD levels were elevated in groups III, IV and V compared with contused animals (p>0.05). Neutrophils in BAL fluid significantly increased in contused animals (p<0.05). Only DXM significantly decreased neutrophil population in BAL fluid (p<0.05). Scores for alveolar haemorrhage/oedema were higher in all contusion-performed rats than those in the control (p<0.05). Compared with the other drugs, only APR significantly improved the haemorrhage/oedema scores compared to sham animals (p=0.024).

CONCLUSIONS

Our findings demonstrate that moderate bilateral PC induced by blunt chest trauma leads to an early inflammatory process which is clearly associated with activation of the oxidant-antioxidant cascade. On this basis, early supportive treatment with DXM, NAC and APR may yield favourable results on pulmonary pathophysiological parameters which are adversely affected due to PC.

Prognostic analysis of patients with blunt chest trauma admitted to an intensive care unit

BACKGROUND/PURPOSE

Predictors of mortality in blunt chest trauma patients have mostly been studied by univariate analysis. This study used multivariate analysis to identify the independent predictors in these patients admitted to a surgical intensive care unit (SICU).

METHODS

One hundred and twenty-seven blunt thoracic trauma patients consecutively admitted to a SICU were enrolled and evaluated by quantified injury severity scores including Acute Physiology and Chronic Health Evaluation II (APACHE II), Glasgow Coma Scale (GCS), Therapeutic Intervention Scoring System (TISS) and Injury Severity Score (ISS). Incidence of thoracic and extrathoracic injuries, transfusion and resuscitation volumes, PaO2/FIO2 ratio and the presence of shock were also evaluated.

RESULTS

In the univariate analysis, clinical characteristics of survivors (n = 113) and non-survivors (n = 14) at admission were similar regarding age, gender, incidence of intrathoracic injuries and extrathoracic injuries and ISS. The following variables were higher for non-survivors: APACHE II score, 19 +/- 6 vs.12 +/- 6 (p = 0.002); TISS points, 39 +/- 13 vs. 29 +/- 15 (p = 0.019); the presence of shock, 93% vs. 42% (p < 0.001). Non-survivors also had lower GCS, 8 +/- 5 vs.14 +/- 3 (p < 0.001), and PaO2/FIO2 ratio, 211 +/- 124 vs. 340 +/- 145 (p = 0.002). Of the shock patients, they had significantly higher volumes of blood transfusions and fluid resuscitations (p < 0.001) and a higher incidence of abdominal injuries (p = 0.031) and mortality rate (p < 0.001) than non-shock patients. Multivariate logistic regression analysis identified three independent risk factors of mortality: GCS (adjusted odds ratio [OR], 0.76; 95% confidence interval [CI], 0.64-0.89; p = 0.001), PaO2/FIO2 ratio (adjusted OR, 0.75; 95% CI, 0.58-0.98; p = 0.036) and shock (adjusted OR, 3.8; 95% CI, 1.24-11.69; p = 0.020).

CONCLUSION

Blunt chest trauma was usually associated with injuries of other organ systems, especially of the abdomen and head. Besides a decreased PaO2/FIO2, a lower GCS and a presence of shock were also independent prognostic predictors of mortality for these patients admitted to the ICU.

The evolution of isolated bilateral lung contusion from blunt chest trauma in rats: cellular and cytokine responses

Lung contusion is the leading cause of death from blunt thoracic trauma in adults, but its mechanistic pathophysiology remains unclear. This study uses a recently developed rat model to investigate the evolution of inflammation and injury in isolated lung contusion. Bilateral lung contusion with minimal cardiac trauma was induced in 54 anesthetized rats by dropping a 0.3-kg hollow cylindrical weight onto a precordial shield (impact energy, 2.45 Joules). Arterial oxygenation, pressure-volume (P-V) mechanics, histology, and levels of erythrocytes, leukocytes, albumin, and inflammatory mediators in bronchoalveolar lavage (BAL) were assessed at 8 min, at 4, 12, 24, and 48 h, and at 7 days after injury. The role of neutrophils in the evolution of inflammatory injury was also specifically studied by depleting these cells with intravenous vinblastine before lung contusion. Arterial oxygenation was severely reduced at 8 min to 24 h postcontusion, but became almost normal by 48 h. Levels of erythrocytes, leukocytes, and albumin in BAL were increased at <or=24 h, and returned toward normal by 48 h. Deficits in P-V mechanics were most apparent at 24 h postcontusion. Levels of macrophage inflammatory polypeptide-2, cytokine-induced neutrophil chemoattractant-1, and interleukin 6 in BAL peaked at 24 h, whereas monocyte chemoattractant protein-1 and interleukin 1beta peaked at 24 to 48 h postcontusion. Histology showed early hemorrhagic injury (8 min-12 h), with neutrophilic infiltration at 24 h and areas of bronchiolitis obliterans organizing pneumonia-associated fibrosis at 7 days. Vinblastine-treated neutropenic rats had significantly reduced lung injury based on total lung volume at 4 h and on BAL albumin levels at 24 h postcontusion. Inflammatory injury from isolated bilateral lung contusion in rats is most severe in the acute period (8 min-24 h) after initial blunt trauma, and includes a component of neutrophil-dependent pathology.

A rat model for isolated bilateral lung contusion from blunt chest trauma

Lung contusion affects 17%-25% of adult blunt trauma patients, and is the leading cause of death from blunt thoracic injury. A small animal model for isolated bilateral lung contusion has not been developed. We induced lung contusion in anesthetized rats by dropping a 0.3-kg weight onto a precordial protective shield to direct the impact force away from the heart and toward the lungs. Lung injury was characterized as a function of chest impact energy (1.8-2.7 J) by measurements of arterial oxygenation, bronchoalveolar lavage (BAL) albumin and cytology, pressure-volume mechanics, and histopathology. Histology confirmed bilateral lung contusion without substantial cardiac muscle trauma. Rats receiving 2.7 J of chest impact energy had 33% mortality that exceeded prospectively defined limits for sublethal injury. Hypoxemia in rats with maximal sublethal injury (2.45 J) met criteria for acute lung injury at < or =24 h, improving by 48 h. BAL albumin levels were highest at < or =24 h, and remained elevated along with increased BAL leukocytes and decreased lung volumes at 48 h. We concluded that an impact energy of 2.45 J induces isolated, bilateral lung contusion and provides a useful model for future mechanistic pathophysiological assessments.

Bench-to-bedside review: oxygen debt and its metabolic correlates as quantifiers of the severity of hemorrhagic and post-traumatic shock

Evidence is increasing that oxygen debt and its metabolic correlates are important quantifiers of the severity of hemorrhagic and post-traumatic shock and and may serve as useful guides in the treatment of these conditions. The aim of this review is to demonstrate the similarity between experimental oxygen debt in animals and human hemorrhage/post-traumatic conditions, and to examine metabolic oxygen debt correlates, namely base deficit and lactate, as indices of shock severity and adequacy of volume resuscitation. Relevant studies in the medical literature were identified using Medline and Cochrane Library searches. Findings in both experimental animals (dog/pig) and humans suggest that oxygen debt or its metabolic correlates may be more useful quantifiers of hemorrhagic shock than estimates of blood loss, volume replacement, blood pressure, or heart rate. This is evidenced by the oxygen debt/probability of death curves for the animals, and by the consistency of lethal dose (LD)_25,50 points for base deficit across all three species. Quantifying human post-traumatic shock based on base deficit and adjusting for Glasgow Coma Scale score, prothrombin time, Injury Severity Score and age is demonstrated to be superior to anatomic injury severity alone or in combination with Trauma and Injury Severity Score. The data examined in this review indicate that estimates of oxygen debt and its metabolic correlates should be included in studies of experimental shock and in the management of patients suffering from hemorrhagic shock.

Emergency department spirometric volume and base deficit delineate risk for torso injury in stable patients

Background

We sought to determine torso injury rates and sensitivities associated with fluid-positive abdominal ultrasound, metabolic acidosis (increased base deficit and lactate), and impaired pulmonary physiology (decreased spirometric volume and PaO₂/FiO₂).

Methods

Level I trauma center prospective pilot and post-pilot study (2000–2001) of stable patients. Increased base deficit was < 0.0 in ethanol-negative and ≤ -3.0 in ethanol-positive patients. Increased lactate was > 2.5 mmol/L in ethanol-negative and ≥ 3.0 mmol/L in ethanol-positive patients. Decreased PaO₂/FiO₂ was < 350 and decreased spirometric volume was < 1.8 L.

Results

Of 215 patients, 66 (30.7%) had a torso injury (abdominal/pelvic injury n = 35 and/or thoracic injury n = 43). Glasgow Coma Scale score was 14.8 ± 0.5 (13–15). Torso injury rates and sensitivities were: abdominal ultrasound negative and normal base deficit, lactate, PaO₂/FiO₂, and spirometric volume – 0.0% & 0.0%; normal base deficit and normal spirometric volume – 4.2% & 4.5%; chest/abdominal soft tissue injury – 37.8% & 47.0%; increased lactate – 39.7% & 47.0%; increased base deficit – 41.3% & 75.8%; increased base deficit and/or decreased spirometric volume – 43.8% & 95.5%; decreased PaO₂/FiO₂ – 48.9% & 33.3%; positive abdominal ultrasound – 62.5% & 7.6%; decreased spirometric volume – 73.4% & 71.2%; increased base deficit and decreased spirometric volume – 82.9% & 51.5%.

Conclusions

Trauma patients with normal base deficit and spirometric volume are unlikely to have a torso injury. Patients with increased base deficit or lactate, decreased spirometric volume, decreased PaO₂/FiO₂, or positive FAST have substantial risk for torso injury. Increased base deficit and/or decreased spirometric volume are highly sensitive for torso injury. Base deficit and spirometric volume values are readily available and increase or decrease the suspicion for torso injury.

Novel resuscitation strategy for pulmonary contusion after severe chest trauma

BACKGROUND

Adenosine A2a receptor stimulation can increase coronary perfusion and also reduce leukocyte-mediated inflammatory responses in some conditions. Hextend is a novel colloid solution that may have antioxidant properties. All these actions might be beneficial after severe chest trauma, but have never been investigated. To fill these gaps, this study evaluated the therapeutic potential of a novel adenosine A2a agonist during fluid resuscitation from severe chest trauma with either standard-of-care crystalloid or Hextend.

METHODS

Anesthetized, ventilated swine received unilateral, blunt trauma to the right chest via captive bolt gun, followed by a 10- to 12-mL/kg arterial hemorrhage. After 25 minutes of shock, ATL-146e was started (10 ng/kg/min intravenously for 180 minutes). After an additional 5 minutes, the minimum amount of either colloid (Hextend, 5% hetastarch in lactate-buffered, balanced electrolyte solution) or crystalloid (lactated Ringer's [LR] solution) was administered to maintain mean arterial pressure > 70 mm Hg and heart rate < 100 beats/min and to correct lactate for 180 minutes postinjury. Cardiopulmonary function was monitored and serial bronchoalveolar lavage samples were analyzed for protein, leukocyte infiltration, and expression of cyclooxygenase (COX)-1 and COX-2 isozymes as markers of the inflammatory cascade.

RESULTS

Fluid requirements were reduced by half with Hextend compared with LR (p < 0.05). ATL-146e in either Hextend or LR transiently increased cardiac output, cardiac contractility, and systemic oxygen delivery (all p < 0.05). Pao(2)/Fio(2) ratio was 50 to 100 higher and bronchoalveolar lavage leukocytes were reduced by half with Hextend versus LR (both p < 0.05), but there was no added effect of ATL-146e. COX-1 expression was induced in macrophages (Mphis), whereas COX-2 was induced in neutrophils. Neither Hextend nor ATL-146e reduced COX expression.

CONCLUSION

Hextend reduced the volume for initial resuscitation, which may offer logistical advantages in prehospital field conditions or whenever there is limited medical resources or prolonged transport times; ATL-146e improved early cardiac performance without causing hypotension or bradycardia; when administered 25 to 30 minutes after injury, neither Hextend nor ATL-146e altered inflammatory changes in pulmonary Mphis or infiltrating PMNs; and further studies are needed to determine whether these short-term benefits correlate with long-term outcome.

[Lung contusion: relevance of initial injured pulmonary volume measurement by computed tomography]

OBJECTIVE

To evaluate computed tomography quantification of injured pulmonary volume after thoracic trauma and its relevance for severity grade of patients with lung contusion.

STUDY DESIGN

Retrospective study in a major French Level I university trauma center.

PATIENTS AND METHODS

Clinical and biological data including oxygenation index (PaO2/FIO2) and therapeutics modalities during the first 5 days: positive end expiratory pressure (Peep) and nitric oxide (NO), were collected on 49 patients with lung contusion resulting from thoracic trauma. Injured pulmonary volume was evaluated on initial thoracic tomodensitometry by 2 senior radiologists. The correlation between oxygenation index, therapeutics modalities and initial injured pulmonary volume was assessed for signification.

RESULTS

Injured pulmonary volume larger than 37.75% of total lung volume is associated with both hypoxemia at the twenty-fourth hour (PaO2/FIO2 <300), and need for Peep >6 cm H2O and /or ongoing NO administration on day 5.

CONCLUSION

Injured parenchymal pulmonary volume evaluation on initial tomodensitometry seems to be an important indicator of lung contusion severity. Thoracic computed tomography provides additional prognostic information in the initial evaluation of thoracic trauma with parenchymal injury.

Radiographic and CT findings in blunt chest trauma

Injuries of the thorax are a major cause of morbidity and mortality in blunt trauma patients. Radiologic imaging plays an important role in the workup of the patient with thoracic trauma. The chest radiograph is the initial imaging study obtained, but computed tomography (CT) is now used frequently in the evaluation of chest trauma. The primary role of chest CT has been to assess for aortic injuries, but CT has been shown to be useful for the evaluation of pulmonary, airway, skeletal, and diaphragmatic injuries as well. Magnetic resonance imaging (MRI) has a limited role in the initial evaluation of the trauma patient, but may be of use for the evaluation of the spine and diaphragm in patients who are hemodynamically stable.

Ventilatory management of pulmonary contusion patients

BACKGROUND

The goal of this study was to evaluate two modes of mechanical ventilation in patients with pulmonary contusion: pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV).

METHODS

One hundred and thirty-five patients with pulmonary contusion, defined as an infiltrate on admission chest x-ray and hypoxemia, were treated over 45 months; 59 patients who required more than 48 hours of mechanical ventilation were initially managed with VCV.

RESULTS

Twenty patients were converted from VCV to PCV when pulmonary function deteriorated. With PCV, peak inspiratory pressure decreased from 49 +/- 1 to 31 +/- 1 cm H2O, the alveolar-arterial oxygen difference decreased from 491 +/- 36 mm Hg to 300 +/- 36 mm Hg. These findings were significantly different (P < 0.05, by Student's paired t-test). Twenty patients managed with PCV had equivalent duration of mechanical ventilation and days in intensive care units to 39 patients with less pulmonary dysfunction managed with VCV. None of the 10 patients who died expired from pulmonary failure.

CONCLUSIONS

PCV is an alternative mode to VCV in patients with poorly compliant lungs after pulmonary contusion.

CT in blunt chest trauma: pulmonary, tracheobronchial, and diaphragmatic injuries

Routine use of CT in the initial evaluation of blunt chest trauma is controversial. CT however, has been shown to be useful in the diagnosis of unsuspected chest injuries and in directing therapeutic interventions. This review discusses the CT findings in patients with pulmonary, tracheobronchial, and diaphragmatic injuries after blunt chest trauma.