Transesophageal echocardiography in the evaluation of a transmediastinal gunshot wound: case report

Transmediastinal gunshot wounds in a mature trauma centre: changing perspectives

BACKGROUND

Transmediastinal gunshot wounds are associated with a high mortality and frequently require operative intervention. The purpose of this study was to identify the diagnostic and therapeutic challenges of these injuries in a mature trauma system with decreasing prehospital time intervals.

METHODS

Patients admitted to a large urban Level 1 trauma centre between 1/2006 and 12/2010 sustaining a firearm injury to the torso were identified. Transmediastinal gunshot wounds were defined as missile tracts traversing the mediastinum identified on CT images, operative notes or autopsy reports.

RESULTS

Overall, 133 patients met study criteria. A total of 116 patients (87.2%) were haemodynamically unstable or had no vital signs on arrival to the Emergency Department. Ninety-seven (83.6%) of these patients required a resuscitative thoracotomy resulting in 8 survivors (6.0%). There were 17 haemodynamically stable patients (12.8%) identified, 14 of whom underwent CT scan evaluation. Six patients subsequently required operative intervention. Only 11 patients (8.3%) in the study population were successfully managed nonoperatively. The overall mortality was 78.9%, and for those who reached the hospital with vital signs, the mortality was 24.3%.

CONCLUSIONS

Transmediastinal gunshot wounds encountered in a mature trauma centre are highly lethal injuries requiring resuscitative thoracotomy in most instances. Changing perspectives in these injuries may reflect the effects of an evolving prehospital care.

Transesophageal ultrasonography of the normal canine mediastinum

The mediastinum of eight normal research dogs was examined by transesophageal ultrasonography with a 5 MHz frequency transducer to establish a baseline for future use of this new imaging modality as a diagnostic tool. Each examination consisted of 360 degree scans in both transverse and sagittal planes from the thoracic inlet to the esophageal hiatus. Dissections of four of these research dogs were then performed to confirm transesophageal ultrasonography findings. Transesophageal ultrasonography of the mediastinum was a good imaging modality for the evaluation of the heartbase, the major cranial mediastinal vessels, the descending aorta, and occasionally part of the azygos vein. Anatomic orientation was best obtained by beginning the examination at the heart base. Lymph nodes and smaller caliber vessels could not be distinguished from surrounding tissues; however, Doppler ultrasound was useful for identifying the smaller vessels. Although a 5 MHz frequency transducer is preferred for transesophageal echocardiography, a higher frequency transducer would improve the resolution of the images of small near-field structures and may be more appropriate for mediastinal imaging.

Ultrasound detection of foreign bodies and procedure guidance

As emergency physicians become familiar with the use of ultrasonography, this safe procedure will likely become a standard technique having multiple uses in the emergency department. Ultrasonography assists in foreign body localization and retrieval and is potentially important in applications, such as reliable endotracheal tube placement, visualization of ingested medication, vascular access, and drainage of collected fluids.

Transesophageal echocardiography

This article presents an overview of the benefits and efficacy of transesophageal echocardiography (TEE) in the critically ill patient. The echocardiographic evaluation of ventricular function both regional and global, is discussed with special emphasis on ischemic heart disease; assessment of preload, interrogation of valvular heart disease (prosthetic and native) and its complications; endocarditis and its complications; intracardiac and extracardiac masses, including pulmonary embolism; aortic diseases (e.g., aneurysan, dissection, and traumatic tears); evaluation of patent foramen ovale and its association with central and peripheral embolic events; advancements in computer technology; and finally, the effect of TEE on critical care.