A 26-year-old, previously healthy man is brought to the emergency department after a high-speed motor vehicle collision. He became obtunded in the field and required intubation by the paramedics. The patient also received 2 L of crystalloid on the way to the hospital. On arrival, blood pressure is 88/52 mm Hg and pulse is 128/min. Physical examination shows multiple contusions, including to the left side of the forehead, left arm, chest, abdomen, and pelvis, but there is no external hemorrhage. The trachea is midline. Breath sounds are present bilaterally and heart sounds are normal. The abdomen is nondistended and soft to palpation. Muscle tone is normal. Focused Assessment with Sonography for Trauma shows no pericardial or intraperitoneal free fluid. Which of the following is the most likely cause of this patient's hemodynamic instability?

Question

A 26-year-old, previously healthy man is brought to the emergency department after a high-speed motor vehicle collision.  He became obtunded in the field and required intubation by the paramedics.  The patient also received 2 L of crystalloid on the way to the hospital.  On arrival, blood pressure is 88/52 mm Hg and pulse is 128/min.  Physical examination shows multiple contusions, including to the left side of the forehead, left arm, chest, abdomen, and pelvis, but there is no external hemorrhage.  The trachea is midline.  Breath sounds are present bilaterally and heart sounds are normal.  The abdomen is nondistended and soft to palpation.  Muscle tone is normal.  Focused Assessment with Sonography for Trauma shows no pericardial or intraperitoneal free fluid.  Which of the following is the most likely cause of this patient's hemodynamic instability?

Quizplus · Accepted Answer

Explanation: Despite initial resuscitation (2 L of crystalloid), this patient has continued hemodynamic instability (eg, systolic blood pressure <90 mm Hg), which is consistent with shock. Because hemorrhagic shock is the most common type of shock in the trauma setting, particular attention is given during trauma survey to areas where large blood loss can occur ("blood on the floor and 4 more"): External bleeding ("the floor"): up to the entire blood volume Chest: up to 40% of the blood volume/hemithorax Abdomen (ie, peritoneal cavity): up to the entire blood volume Pelvis: up to the entire blood volume; blood loss often hidden within the retroperitoneum Thigh: up to 1-2 L/thigh This patient has no evidence of external bleeding or major hemorrhage into the chest (bilateral breath sounds), abdomen (nondistended, soft, no intraperitoneal free fluid), or thighs (normal muscle tone). Therefore, pelvic/retroperitoneal bleeding should be suspected. Pelvic fracture can cause tearing of the thin-walled venous plexus (presacral, lumbar), leading to life-threatening hemorrhage. For early detection of this potentially lethal injury, pelvic x-ray is typically performed as an adjunct to the trauma primary survey. (Choice A) Adrenal crisis can be precipitated by trauma and cause shock refractory to fluid resuscitation. However, this occurs much more commonly in patients with underlying adrenal insufficiency (eg, autoimmune-mediated adrenalitis, adrenal suppression from chronic glucocorticoid use) rather than in previously healthy patients. Bilateral adrenal infarct/hemorrhage from trauma is extremely rare. (Choices B and E) Spinal fracture can cause spinal cord injury leading to neurogenic shock. However, neurogenic shock is typically associated with flaccid paralysis (vs normal muscle tone), as well as hypotension with bradycardia (vs tachycardia) from sudden loss of sympathetic tone. Severe intracranial hemorrhage may also cause neurogenic shock or, alternately, Cushing triad (from increased intracranial pressure). However, Cushing triad is characterized by hypertension (vs hypotension), bradycardia (vs tachycardia), and irregular respiration. (Choice C) Pancreatic injury can occur with blunt abdominal trauma, especially when the pancreas is rapidly compressed (eg, steering wheel impact) against the vertebral column. However, even severe injuries (eg, transection with pancreatic fluid leakage) do not typically cause acute hemodynamic instability. They more commonly result in symptoms similar to those of pancreatitis (eg, abdominal pain, nausea, emesis). Educational objective: Hemorrhagic shock is the most common type of shock in trauma patients. Areas where large amounts of blood can be lost (or hidden) are "the floor" (external bleeding) "and 4 more": chest, abdomen, pelvis/retroperitoneum, and thigh. References: Resuscitation resequenced: a rational approach to patients with trauma in shock. (http://www.ncbi.nlm.nih.gov/pubmed/29132581) Pelvic trauma: WSES classification and guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/28115984)

A 26-Year-Old, Previously Healthy Man Is Brought to the Emergency