TNCC Trauma Care 2 — Questions and Answers
Question 1: In the management of hemorrhagic shock, which class of hemorrhage is characterized by blood loss of 750-1,500 mL with tachycardia but normal blood pressure?
- Class I
- Class II (Correct answer)
- Class III
- Class IV
Correct answer: Class II
Class II hemorrhage involves 750-1,500 mL (15-30%) blood loss, presenting with tachycardia, tachypnea, and narrowed pulse pressure, but systolic blood pressure typically remains normal.
The ATLS/TNCC hemorrhage classification system divides blood loss into four classes: Class I (<750 mL, <15%, minimal symptoms), Class II (750-1,500 mL, 15-30%), Class III (1,500-2,000 mL, 30-40%), and Class IV (>2,000 mL, >40%). Class II is notable because compensatory mechanisms (increased heart rate, peripheral vasoconstriction) maintain systolic blood pressure, though pulse pressure narrows. The patient shows anxiety, tachycardia (100-120 bpm), and slightly decreased urine output. Crystalloid resuscitation is typically sufficient, but blood products should be anticipated.
Question 2: A patient involved in a high-speed MVC presents with a seatbelt sign across the abdomen. The nurse should have a high index of suspicion for:
- Rib fractures
- Lumbar spine fracture and hollow viscus injury (Correct answer)
- Isolated liver laceration
- Pulmonary contusion
Correct answer: Lumbar spine fracture and hollow viscus injury
The seatbelt sign across the abdomen is strongly associated with lumbar spine (Chance) fractures and hollow viscus injuries such as small bowel perforation.
The seatbelt sign — ecchymosis or abrasion across the lower abdomen from a lap belt — is a significant clinical finding associated with intra-abdominal injuries. The rapid deceleration causes the lap belt to compress abdominal contents against the spine, creating a flexion-distraction mechanism. This combination frequently produces Chance fractures (horizontal splitting of a lumbar vertebral body) and hollow viscus injuries (small bowel tears, mesenteric avulsions). Studies show that patients with a seatbelt sign have a 4-8 times higher incidence of abdominal injuries. CT imaging of the abdomen and lumbar spine is warranted.
Question 3: Which finding on a secondary survey is most indicative of a ruptured diaphragm?
- Subcutaneous emphysema over the chest
- Bowel sounds heard in the chest on auscultation (Correct answer)
- Bilateral wheezing
- Distended neck veins
Correct answer: Bowel sounds heard in the chest on auscultation
Bowel sounds auscultated in the chest cavity indicate herniation of abdominal contents through a diaphragmatic rupture.
Traumatic diaphragmatic rupture allows abdominal viscera (stomach, bowel, spleen, omentum) to herniate into the thoracic cavity. The hallmark finding is bowel sounds heard in the chest, particularly on the left side where 75-80% of traumatic diaphragmatic injuries occur (the liver provides some protection on the right). Other signs include decreased breath sounds on the affected side, a scaphoid abdomen, respiratory distress, and the nasogastric tube tip appearing in the thorax on chest X-ray. This injury is commonly caused by blunt trauma (MVCs) or penetrating thoracoabdominal wounds and requires surgical repair.
Question 4: During damage control resuscitation, the 'lethal triad' that must be aggressively corrected includes:
- Hypertension, bradycardia, hypothermia
- Hypothermia, acidosis, coagulopathy (Correct answer)
- Tachycardia, hyperglycemia, alkalosis
- Hypoxia, hypercarbia, hypovolemia
Correct answer: Hypothermia, acidosis, coagulopathy
The lethal triad of trauma — hypothermia, acidosis, and coagulopathy — creates a self-perpetuating cycle that increases mortality if not interrupted.
The lethal triad (also called the trauma triad of death) consists of hypothermia, metabolic acidosis, and coagulopathy. These three conditions are synergistic: hypothermia impairs clotting factor function and platelet aggregation, worsening coagulopathy; ongoing hemorrhage from coagulopathy leads to decreased tissue perfusion, causing lactic acidosis; acidosis further inhibits the coagulation cascade and myocardial function. Damage control resuscitation aims to break this cycle through permissive hypotension, massive transfusion with balanced ratios, aggressive rewarming, and abbreviated surgical techniques (damage control surgery) that prioritize hemorrhage control over definitive repair.
Question 5: A patient with blunt abdominal trauma has a positive FAST exam. Blood pressure is 82/60 mmHg and heart rate is 130 bpm despite 2 liters of crystalloid. The appropriate next step is:
- Repeat the FAST exam in 30 minutes
- Administer an additional 2 liters of crystalloid
- Obtain an abdominal CT scan
- Prepare for emergent exploratory laparotomy (Correct answer)
Correct answer: Prepare for emergent exploratory laparotomy
A hemodynamically unstable trauma patient with a positive FAST exam who is not responding to initial resuscitation requires emergent surgical exploration.
This patient demonstrates Class III-IV hemorrhagic shock (hypotension, tachycardia) that is unresponsive to initial crystalloid resuscitation, combined with sonographic evidence of intra-abdominal free fluid. Per TNCC and ATLS algorithms, hemodynamic instability with a positive FAST exam is an indication for emergent exploratory laparotomy — not further diagnostic imaging. CT scanning requires transporting an unstable patient and takes valuable time. Repeating the FAST or additional crystalloid delays definitive hemorrhage control. The surgeon should be notified early, the OR activated, and massive transfusion protocol continued en route to surgery.
Question 6: Which mechanism of injury has the highest association with aortic disruption?
- Fall from standing height
- Lateral-impact motor vehicle collision
- Rapid deceleration from high-speed frontal collision (Correct answer)
- Bicycle crash at moderate speed
Correct answer: Rapid deceleration from high-speed frontal collision
Rapid deceleration from high-speed frontal MVCs is the most common mechanism for traumatic aortic disruption, typically at the ligamentum arteriosum.
Traumatic aortic disruption (TAD) most commonly results from rapid deceleration injuries in high-speed frontal motor vehicle collisions or falls from significant heights (>3 stories). The injury occurs at the aortic isthmus, just distal to the left subclavian artery at the ligamentum arteriosum, where the relatively mobile aortic arch meets the fixed descending aorta. During rapid deceleration, differential movement between these segments creates shearing forces that tear the aortic wall. Over 80% of patients with complete aortic transection die at the scene. Survivors typically have a contained partial tear, and diagnosis is made by CT angiography with a widened mediastinum on chest X-ray as the screening finding.
TNCC Trauma Care 2
In the management of hemorrhagic shock, which class of hemorrhage is characterized by blood loss of 750-1,500 mL with tachycardia but normal blood pressure?