Scientific Research Traumatology and Orthopedics Institute,

Astana, Kazakhstan,

Central Medical Unit #141, 

Udomlya, Russia

 

During polytrauma some factors exist that result in lung lesions: direct mechanic injury to the lung, shock, massive infusion and transfusion therapy, disseminated intravascular coagulation, fat embolia, aspiration. Therefore, diffuse lung injuries (DLI) are not rare in trauma. The main objective criterion of DLI is plain X-ray image of the chest. X-ray examination is usually performed during resuscitation in supination position with a portable device. In such situations X-ray images are not always characterized with good quality, and difficult interpretation in presence of DLI is usual.

Patient’s state severity does not always allow performing computer tomography. FAST, BLUE [1, 2, 3], eFAST and RUSH [4, 5] protocols are not implemented widely. These protocols use ultrasound for assessing pleural fluid, particularly, fluid in lung parenchyma, and identification of pneumothorax. For bed patient with ALV the diagnostic punctures are invasive procedures with risk of lung injury and need for special needles, skills for prevention of false positive or false negative results. Percussion and auscultation results are not always informative in such severe patients.

X-ray images demonstrating DLI create difficult situations for surgeons in case of night duty and absent radiologists. It is associated with the fact that complex shading picture of pulmonary fields with spread hemothorax disguises such complication as tension pneumothorax, tension hemopneumothorax, diaphragm disruption, and combinations of these surgical pathologies with atelectasis, lung contusion, subpleural hematoma, ARDS, TRALI (Transfusion-Related Acute Lung Injury), fluid overload-associated lung edema, previously operated lung, dextrocardia, tuberculosis, pneumofibrosis et al.    

It is necessary to confirm or exclude pathology requiring surgical procedures rather than just identify an exact cause of DLI. The above mentioned surgical pathologies (tension pneumothorax, tension hemopneumothorax, diaphragm rupture) are easier to diagnose or exclude in presence of DLI, when a surgeon knows the most frequent DLI and the radiologic characteristics. In other words, diagnostics and treatment of pulmonary and pleural complications of trauma are effective, when a surgeon knows differentiation features.

Multiple focal confluent blackouts in both pulmonary fields cause embarrassment in a clinician. Interpretation difficulties of such images can result in tactical emergencies: from one side, it results in negation of surgical pathology, because shade picture is not usual for typical pneumo- or hemothorax, from other side ‒ in dangerous diagnostic punctures because of anxiety about missing pleural complications in presence of unusual radiologic picture. Reasonable and substantiated tactics is optimal for severe patients.          

Objective ‒ to develop clinical algorithm for reading supine X-ray images in wide pulmonary field blackout.  

 

MATERIALS AND METHODS

The analysis included 6 variants of radiologic pictures as the most common among patients with DLI. The study was performed with the archive materials (X-ray images and case histories). The information is anonymous. The study with administration of the archive recordings corresponds to the ethical standards from the bioethics committee, Scientific Research Traumatology and Orthopedics Institute, with compliance with Helsinki Declaration ‒ Ethical Principles for Medical Research with Human Subjects 2000 and “The Rules for Clinical Practice in Russian Federation” confirmed by the Order of Russia Health Ministry, 19.06.2003, #266.

At first sight, all X-ray images are similar, but each image is characterized with features optimizing differential diagnostics. All 6 anterior-posterior X-ray images (Fig. 1) are related to the patients with isolated and concomitant chest injuries. The first image presents the case of the male patient, age of 46, with traumatic brain injury, concomitant chest injury. The second image is related to the female patient, age of 34, with spleen rupture and hemorrhagic shock. The third image is the case of the male patient, age of 44, with chest injury. The fourth case is the male patient, age of 37, with injuries to the chest, the pelvis and extremities. The fifth image is the male patient, age of 43, with abdominal injuries and peritonitis. The sixth case is the female patient, age of 43, with multiple fractures of the pelvis, the lower extremities and chest injury. The images are performed in different time periods after injury. Radiologic analysis of shade picture was carried out in cooperation with radiologists for identification of the supporting points for creation of reading algorithm for clinicians.

Figure 1

X-ray images with diffuse lung injuries

 1.1  1.2

 1.3  1.4

 1.5  1.6

 

RESULTS AND DISCUSSION

In radiologic picture of DLI it is insufficient to get one image with one view and without dynamics for substantiated discussion about probability of pathology. Shade picture should be described on the image. Description in combination with other clinical signs and anamnesis will allow substantiated reasoning about genesis of X-ray picture.

The general elements were defined for identification of the supporting elements for reading algorithm for such images. The characteristics of visualization of bone structures in all images allow accepting such images as satisfactory according to quality. The general signs in the images are bilateral wide decrease in pulmonary field transparency, non-homogenous (except for 6^th image) characteristics by means of combination of prominence of perihilar markings, different-calibre focal confluent shadows and parts of saved pulmonary tissue, without significant mediastinum displacement. The view of DLI is symmetrical except for 5^th image with greater lesion of the right side.

On the basis of the above mentioned general signs one can suppose that radiologic picture corresponds to shock lung/subtotal bilateral pneumonia with edema on all images except for sixth one. Base on these facts one can separate 5 main criteria for interpreting images with DLI:

1) image  quality,

2) bilateral characteristics,

3) symmetry,

4) homogenicity,

5) position and laying of mediastinum.

The next step in the radiologic analysis was identification of differentiating characteristics for each image. The gradual increasing blackout with caudal direction on the first image can indicate gravitational dependent hydrostatic lung edema. The second image testifies pneumomediastinum (?) and left subcutaneous emphysema on the basis of lucent stripes along heart outline. There are dense locations (signs of tuberculosis) behind the subcutaneous and intermuscular emphysema in the upper lobe to the left on the image 3. The second image demonstrates dense foci with the fragment of X-ray image 3. The fourth image demonstrates prevailing focal confluent changes that indicate predominant parenchymal lesion. The fifth image demonstrates asymmetry of blackouts and ring-shaped shadows in the middle lobe to the right that suppose destructive pneumonia. The figure 3 demonstrates the part of the image 5 with the ring-shaped shadow at the background of infiltrate. The image 6 shows homogenous blackout of pulmonary fields, with non-visualized contours of diaphragm on both sides. It is common for hemothorax in lying position.

Figure 2 The part of the X-ray image 3. The arrows indicate dense locations and the focuses on the right lung apex in the drain region

Figure 3 The part of the X-ray image 5. The arrows show the ring blackout ‒ destruction cavity in the middle lobe of the right lung in the plane of 7th intercostal space along the paravertebral line

                      

With use of the above mentioned main criteria of DLI, without consideration of image quality, the authors developed the algorithm scheme for interpreting X-ray images and correspondence of main blackout characteristics to pleural and pulmonary complications in traumatized patients in supine position (Fig. 4).    

It is difficult to use a diagram to demonstrate the variety of combinations of different pulmonary and pleural complications in injuries. The main signs in X-ray image interpretation (shown in grey color) navigates a physician according to possible genesis of shadows that confirmed by comparison between descriptions of 6 X-ray images and case histories.

The analysis of the case histories showed the following facts: the first image was made at the level of respiratory insufficiency conditioned by lung edema because of fluid overload; the second image was made on day 2 after injury, after massive transfusion therapy and development of ARDS; the third image is related to the patient with disseminated tuberculosis at phase of disintegration and infiltration; the fourth image was made on the day 3 after injury, after massive infusion and transfusion therapy at the background of extensive lung contusions; the fifth image is related to the patient with septic abscess forming pneumonia; on the sixth image the bilateral hemothorax was confirmed with ultrasound examination and was drained.

 

CONCLUSION

Lund edema of different genesis (cardiogenic, fluid overload, ARDS, TRALI, Mendelson's syndrome [aspiration]) has similar features on X-ray images. It is important to distinguish lung edema from pleural complications requiring draining, and from atelectasis requiring bronchoscopy. Four identified criteria optimize image interpretation quality.

The authors express gratitude to Anatoly Vladimirovich Shumakov, the docent of radiology chair, Lugansk Medical University, for his review for the article.