Ventilatory management of pulmonary contusion patients

Small Extracellular Vesicles Propagate the Inflammatory Response After Trauma

Trauma is the leading cause of death in individuals under 44 years of age. Thorax trauma (TxT) is strongly associated with trauma-related death, an unbalanced innate immune response, sepsis, acute respiratory distress syndrome, and multiple organ dysfunction. It is shown that different in vivo traumata, such as TxT or an in vitro polytrauma cytokine cocktail trigger secretion of small extracellular nanovesicles (sEVs) from endothelial cells with pro-inflammatory cargo. These sEVs transfer transcripts for ICAM-1, VCAM-1, E-selectin, and cytokines to systemically activate the endothelium, facilitate neutrophil-endothelium interactions, and destabilize barrier integrity. Inhibition of sEV-release after TxT in mice ameliorates local as well as systemic inflammation, neutrophil infiltration, and distant organ damage in kidneys (acute kidney injury, AKI). Vice versa, injection of TxT-plasma-sEVs into healthy animals is sufficient to trigger pulmonary and systemic inflammation as well as AKI. Accordingly, increased sEV concentrations and transfer of similar cargos are observed in polytrauma patients, suggesting a fundamental pathophysiological mechanism.

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.

Impact of blunt pulmonary contusion in polytrauma patients with rib fractures

BACKGROUND

We investigated the impact of blunt pulmonary contusion (BPC) in patients with rib fractures.

METHODS

Adult patients with rib fractures caused by blunt mechanisms were enrolled over 3 years at a Level 1 trauma center. BPC was defined according to percentage of lung affected as: moderate (1-19% contusion) or severe (≥20% contusion).

RESULTS

In total, 1448 of the 7238 admitted patients had rib fractures. Of these, 321 (22.2%) had BPC: 236 moderate and 85 severe. Patients with BPC were more likely to be admitted to the ICU (moderate: OR 1.55, 95% CI 1.10-2.19; severe: OR 2.74, 95% CI 1.41-5.32). Significantly increased rates of pneumonia (OR 2.52, 95% CI 1.43-4.90) and empyema (OR 4.80, 95% CI 1.07-21.54) were found for moderate and severe BPC, respectively.

CONCLUSIONS

ICU admission and infectious pulmonary complications were more likely with BPC. The presence of BPC on admission CT is also prognostic of increased resource utilization.

Pressure-Controlled vs Volume-Controlled Ventilation in Acute Respiratory Failure: A Physiology-Based Narrative and Systematic Review

BACKGROUND

Mechanical ventilation is a cornerstone in the management of acute respiratory failure. Both volume-targeted and pressure-targeted ventilations are used, the latter modes being increasingly used. We provide a narrative review of the physiologic principles of these two types of breath delivery, performed a literature search, and analyzed published comparisons between modes.

METHODS

We performed a systematic review and meta-analysis to determine whether pressure control-continuous mandatory ventilation (PC-CMV) or pressure control-inverse ratio ventilation (PC-IRV) has demonstrated advantages over volume control-continuous mandatory ventilation (VC-CMV). The Cochrane tool for risk of bias was used for methodologic quality. We also introduced physiologic criteria as quality indicators for selecting the studies. Outcomes included compliance, gas exchange, hemodynamics, work of breathing, and clinical outcomes. Analyses were completed with RevMan5 using random effects models.

RESULTS

Thirty-four studies met inclusion criteria, many being at high risk of bias. Comparisons of PC-CMV/PC-IRV and VC-CMV did not show any difference for compliance or gas exchange, even when looking at PC-IRV. Calculating the oxygenation index suggested a poorer effect for PC-IRV. There was no difference between modes in terms of hemodynamics, work of breathing, or clinical outcomes.

CONCLUSIONS

The two modes have different working principles but clinical available data do not suggest any difference in the outcomes. We included all identified trials, enhancing generalizability, and attempted to include only sufficient quality physiologic studies. However, included trials were small and varied considerably in quality. These data should help to open the choice of ventilation of patients with acute respiratory failure.

Blunt pulmonary contusion: admission computed tomography scan predicts mechanical ventilation

BACKGROUND

Blunt pulmonary contusion (BPC) evolves over 12 to 24 hours, and the initial plain radiographs fail to reliably identify patients at risk of clinical deterioration. Admission computed tomography (CT) may offer accurate characterization of BPC and early prediction of the need for mechanical ventilation (MV).

METHODS

This was a combination of a 5-year retrospective study (January 2002 to April 2007) and a 6-month prospective study (September 2007 to February 2008) of adult blunt trauma (BT) patients with thoracic injuries and a chest CT upon hospital arrival. The primary outcome was MV due to thoracic trauma. To ensure that MV was required for BPC and not for associated injuries, all patients with significant extrathoracic injuries (Abbreviated Injury Scale score >2) were excluded. The extent of BPC was measured by two scoring systems.

RESULTS

Of 392 patients (67% males; age, 48 years ± 21 years; Abbreviated Injury Scale score chest, 3 ± 1; and Injury Severity Score [ISS], 13 ± 6), 243 (62%) had BPC. Twenty-five (6%) patients required MV and two (0.5%) died. The combination of Glasgow Coma Scale (GCS) score <14, BPC score >2, and >4 ribs fractured predicted MV in 100% of the cases, and the absence of all factors precluded MV in 100%. In the prospective period of 6 months, 55 patients had BPC and we confirmed our finding that the absence of the three factors precludes MV.

CONCLUSION

A simple score derived by the initial chest CT, in combination with GCS and the number of fractured ribs, can predict the need for MV early. In the presence of these predictors, patients should be admitted to a high level of monitoring.

Noninvasive ventilation reduces intubation in chest trauma-related hypoxemia: a randomized clinical trial

BACKGROUND

Guidelines for noninvasive mechanical ventilation (NIMV) recommend continuous positive airway pressure in patients with thoracic trauma who remain hypoxic despite regional anesthesia. This recommendation is rated only by level C evidence because randomized controlled trials in this specific population are lacking. Our aim was to determine whether NIMV reduces intubation in severe trauma-related hypoxemia.

METHODS

This was a single-center randomized clinical trial in a nine-bed ICU of a level I trauma hospital. Inclusion criteria were patients with Pao(2)/Fio(2)<200 for >8 h while receiving oxygen by high-flow mask within the first 48 h after thoracic trauma. Patients were randomized to remain on high-flow oxygen mask or to receive NIMV. The interface was selected based on the associated injuries. Thoracic anesthesia was universally supplied unless contraindicated. The primary end point was intubation; secondary end points included length of hospital stay and survival. Statistical analysis was based on multivariate analysis.

RESULTS

After 25 patients were enrolled in each group, the trial was prematurely stopped for efficacy because the intubation rate was much higher in controls than in NIMV patients (10 [40%] vs 3 [12%], P = .02). Multivariate analysis adjusted for age, gender, chronic heart failure, and Acute Physiology and Chronic Health Evaluation II at admission revealed NIMV as the only variable independently related to intubation (odds ratio, 0.12; 95% CI, 0.02-0.61; P = .01). Length of hospital stay was shorter in NIMV patients (14 vs 21 days P = .001), but no differences were observed in survival or other secondary end points.

CONCLUSION

NIMV reduced intubation compared with oxygen therapy in severe thoracic trauma-related hypoxemia.

Flail chest: pathophysiology and management

Thoracic trauma is an important cause of morbidity and mortality in the UK, frequently found in drivers of motor vehicles following high-speed accidents. One of the more serious injuries is a flail chest, particularly when there are also underlying pulmonary contusions. For many years the optimal therapeutic regimen for the management of this condition has remained somewhat controversial. More recently, the role of epidural analgesia, the use of non-invasive techniques of ventilation and identification of those who may benefit from surgical stabilisation have been more clearly defined.

The pulmonary and hepatic immune microenvironment and its contribution to the early systemic inflammation following blunt chest trauma

OBJECTIVE

Blunt chest trauma is accompanied by an early increase in plasma cytokine concentrations. However, the local sources of these mediators are poorly defined. We investigated the impact of blunt chest trauma on the inflammatory mediator milieu in different compartments (lung tissue, bronchoalveolar lavage, liver tissue, Kupffer cells, plasma) along with the time course of trauma-induced pulmonary endothelial barrier dysfunction to elucidate potential relationships. In addition, the correlation between intratracheally instilled interleukin-6 and its systemic release were studied.

DESIGN

Prospective, randomized, controlled animal study.

SETTING

Basic science laboratory of a university affiliated level 1 trauma center.

SUBJECTS

Male C3H/HeN mice, 8-9 wks old, n = 141.

INTERVENTIONS

Blunt chest trauma induced by a focused blast wave, intravenous injection of Evans blue, and intratracheal instillation of recombinant human interleukin-6.

MEASUREMENTS AND MAIN RESULTS

Two hours after blunt chest trauma, plasma interleukin-6 was markedly increased. Simultaneously, interleukin-6, tumor necrosis factor-alpha, macrophage inflammatory protein-2, monocyte chemotactic polypeptide-1 and neutrophil/monocyte accumulation in bronchoalveolar lavage and interleukin-6, monocyte chemotactic polypeptide-1, and myeloperoxidase activity in lung tissue were significantly increased. This was accompanied by a coinciding elevation in the Evans blue lung-plasma ratio. Recombinant human interleukin-6, instilled intratracheally before blunt chest trauma, was detected in a dose-dependent manner in the plasma of the mice. Additionally, Kupffer cell interleukin-6, tumor necrosis factor-alpha, and interleukin-10 production was significantly augmented as early as 30 mins after the insult.

CONCLUSIONS

These results indicate that early increased cytokine concentrations in the lung, particularly interleukin-6, are important mediator sources as their local peak coincides with the systemic inflammatory response and is accompanied by a simultaneous impaired function of the pulmonary endothelial barrier. A direct relationship between their local and systemic concentrations can be established. Furthermore, this is the first study to show that Kupffer cells are activated early after blunt chest trauma.

Blunt chest trauma: review of selected pulmonary injuries focusing on pulmonary contusion

Pulmonary injuries resulting from blunt chest trauma remain a common clinical entity for critical care and emergency nurses. In this article, the epidemiology and mechanism of injury most often observed in patients with blunt chest trauma are reviewed. Selected pulmonary injuries are discussed in terms of mechanism of injuries, assessment and diagnostic modalities, standard therapies, and cutting-edge therapies used today with a focus on pulmonary contusion. Many advances and experimental therapies currently used in the management of the patient with severe lung injuries are discussed. A case study is presented highlighting a complicated case of a blunt chest injury resulting in severe pulmonary contusion.