Article, Emergency Medicine

A patient with refractory shock induced by several factors, including obstruction because of a posterior mediastinal hematoma

Unlabelled imagerefractory shock induced “>Case Report

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American Journal of Emergency Medicine

journal homepage: www. elsevier. com/ locate/ajem

A patient with refractory shock induced by several factors, including obstruction because of a posterior mediastinal hematoma

Abstract

A 44-year-old man who drove a motorcycle experienced a collision with the side of another motorcycle. Because he had sustained a high- energy injury to the spinal cord, he was transferred to our hospital. His circulation was unstable, and received tracheal intubation in addi- tion to thoracostomy for the hemothorax. Whole-body computed to- mography (CT) revealed multiple fractures, right hemopneumothorax with pulmonary contusion, and minor liver injury. After infusing 5000 mL of lactated Ringer‘s solution and 10 units of blood, his circula- tion remained unstable. On a repeat CT examination, the left atrium was found to be compressed by a posterior mediastinal hematoma induced by the fracture of the thoracic spine, and a diagnosis of shock induced by multiple factors, including hemorrhagic, neurogenic, and obstructive mechanisms, was made. After obtaining stable circulation and respira- tions, internal fixation of the extremities and extubation were per- formed on the 12th hospital day. Chest CT performed on the 27th day showed the disappearance of compression of the left atrium by the hematoma.

This case is the first Traumatic case of refractory shock because of compression of the left atrium. Because compression of the left atrium reduces the volume of the left atrium and induces a low cardiac output leading to dyspnea, reduced exercise tolerance, or even hemodynamic instability, physicians should know such mechanism.

The causes of shock include hypovolemic, cardiogenic, distributive, and obstructive mechanisms. Cardiac tamponade and tension pneumo- thorax are representative conditions causing obstructive shock. We present the rare case of a patient with multiple injuries and refractory shock induced by a variety of factors, including obstruction because of a posterior mediastinal hematoma.

A 44-year-old man who drove a motorcycle experienced a collision with the side of another motorcycle that had attempted to go over a car. Because he had sustained a high-energy injury to the spinal cord, he was transferred to our hospital. The patient had no particular past medical or family history. On arrival, he was almost alert, with a blood pressure of 70/40 mm Hg, heart rate of 100 beats per minute, respiratory rate of 30 breaths per minute, 99% SpO2 under 10 L/min of oxygen deliv- ered via a mask, and body temperature of 38.2?C. Thoracostomy was per- formed for the hemothorax. Focus assessment sonography for trauma was negative. The patient was resuscitated with 2000 mL of lactated Ringer’s solution, and his blood pressure increased up to 110/50 mm Hg. However, the blood pressure again decreased, and treatment with a

transfusion pump was initiated in addition to tracheal intubation. Never- theless, the blood pressure did not respond to a massive transfusion, and he subsequently received an infusion of dopamine followed by additional noradrenaline. After obtaining a blood pressure of 92/60 mm Hg, whole- body computed tomography (CT) was performed, which revealed multi- ple fractures (sixth and seventh cervix, right scapula, right clavicle, multiple right ribs, thoracic spine, transverse process of the lumbar spine, right radial region, right hand, and right fibula), right hemopneumothorax with pulmonary contusion, and minor liver injury. After infusing 5000 mL of lactated Ringer’s solution and 10 units of blood, he was transferred to the intensive care unit. The patient’s systolic blood pressure subsequently decreased to 50 mm Hg, especially when the positive end-expiratory pressure increased; hence, high- PEEP therapy was not applied, and vasopressin was further added to maintain his blood pressure. On a repeat CT examination, the left atrium was found to be compressed by a posterior mediastinal hematoma in- duced by the fracture of the thoracic spine, and a diagnosis of shock in- duced by multiple factors, including hemorrhagic, neurogenic, and obstructive mechanisms, was made (Figure). Transcutaneous sonogra- phy failed to provide an outline of the left atrium, and because the patient was in severe shock, conservative treatment was selected. On the second hospital day, his blood pressure increased gradually, and the doses of va- sopressors were gradually decreased and ultimately ceased on the 10th hospital day. After obtaining stable circulation and respirations, internal fixation of the extremities and extubation were performed on the 12th hospital day. Tetraparesis below cervical 5 was confirmed. The patient again required tracheal intubation on the 16th hospital day because of as- piration and the development of atelectasis, and tracheostomy was per- formed on the 19th hospital day. Chest CT performed on the 27th day showed the disappearance of compression of the left atrium by the hema- toma. His Respiratory function became stable; therefore, the tracheal tube was removed, and the tracheostomy site closed spontaneously. He was subsequently transferred to a rehabilitation hospital for treatment of the tetraparesis.

This case involved refractory shock induced by hemorrhagic, neu-

rogenic, and obstructive mechanisms. Neurogenic shock usually re- quires treatment with a low volume of vasopressors to maintain a stable circulation, and patients requiring a high volume of vasopres- sor therapy are at risk for complications of hemorrhagic shock [1]. The present patient had multiple injuries, although a CT examination with contrast medium did not show extravasation, such that active bleeding from the site of injury necessitated a rapid massive transfu- sion or infusion. Hence, obstruction resulting in compression of the

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image of Figure

Figure. Chest CT performed on arrival (left) and on the 27th hospital day (right). Enhanced CT shows compression of the left atrium (white arrow) by the posterior mediastinal hematoma induced by the fracture of the thoracic spine (left). A Plain CT scan obtained on the 27th day reveals the disappearance of compression of the left atrium by the hematoma (right).

left atrium because of a posterior mediastinal hematoma was an im- portant factor accounting for the refractory shock observed in this case. Cases of shock induced by compression of the left atrium have rarely been reported [1,2]. Compression of the left atrium reduces the volume of the left atrium and induces a low cardiac output lead- ing to dyspnea, reduced exercise tolerance, or even hemodynamic instability [2]. To the best of our knowledge, this case is the first trau- matic case of refractory shock because of compression of the left atri- um. Maekawa et al [3] reported the case of a 76-year-old woman with postprandial loss of consciousness who was found to have a massive hiatal hernia. Both echocardiography and magnetic reso- nance imaging showed collapse of the left atrium because of hernia- tion of the stomach, and a water pouring examination successfully demonstrated a decrease in blood pressure with lightheadedness. The release of compression of the left atrium after the spontaneous absorption or distribution of the mediastinal hematoma, spontane- ous hemostasis of the site of injury, and recovery from the neurogen- ic shock helped to obtain a stable circulation in the present patient on the 10th hospital day.

The authors have no sources of financial support or any relationships that may pose a conflict of interest concerning this article.

Mariko Obinata, MD Kouhei Ishikawa, MD Hiromichi Osaka, MD, PhD Kentaro Mishima, MD Kazuhiko Omori, MD, PhD Yasumasa Oode, MD

Youichi Yanagawa, MD, PhD?

Department of Acute Critical Care Medicine, Shizuoka Hospital

Juntendo University

?Corresponding author. 410-2295, 1129 Nagaoka Izunokuni city Shizuoka

Japan. Tel.: +81 55 948 3111

E-mail address: [email protected] http://dx.doi.org/10.1016/j.ajem.2014.12.027

References

  1. Popa C, Popa F, Grigorean VT, Onose G, Sandu AM, Popescu M, et al. Vascular dysfunc- tions following spinal cord injury. J Med Life 2010;3:275-85.
  2. van Rooijen JM, van den Merkhof LF. Left atrial impression: a sign of extra-cardiac pathology. Eur J Echocardiogr 2008;9:661-4.
  3. Maekawa T, Suematsu M, Shimada T, Go M, Shimada T. Unusual swallow syncope caused by huge hiatal hernia. Intern Med 2002;41:199-201.

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