Trauma Answers 149the heart. The right ventricleisthe most commonly injuredbecause it is
the most anterior aspect of the heart and is closest to the sternum.
126.The answer is d.(Moore, pp 201-220.)Hypovolemia secondary to
hemorrhage is the most common cause of shock in the trauma patient. The
earliest signs of hemorrhagic shock are tachycardia and cutaneous vaso-
constriction. The amount of blood loss present can be estimated based on
the individual’s initial clinical presentation. Class I hemorrhage (aandb)
is characterized by 0% to 15% blood loss (0-750 mL). This stage exhibits
minimal clinical signs and symptoms. The patient is normotensive with a
slightly elevated HR (HR > 100). Class II hemorrhage (c)is characterized
by 15% to 30% blood loss (750-1500 mL). This stage exhibits tachycardia
(HR > 100) with a narrow pulse pressure, delayed capillary refill, mild anx-
iety, tachypnea, and a slight decrease in urine output. Class III hemor-
rhageis characterized by 30% to 40% blood loss (1500-2000 mL). This
stage exhibits tachypnea, tachycardia (HR > 120), decrease in systolic BP,
delayed capillary refill, decreased urine output, and a change in mental
status.Class IV hemorrhage (e)is characterized by blood loss greater than
40% (> 2 L). This stage exhibits obvious shock, tachycardia (HR > 140),
decreased systolic BP, extremely narrow pulse pressure, scant urine output,
delayed capillary refill, confusion, and lethargy.
127.The answer is e.(Moore, pp 21-35.)Trauma is the leading cause of
death between the ages of 1 and 44 years. Many of these injuries are treat-
able mainly because the patients are young and otherwise healthy. The pri-
mary role of the emergency physician is to assess, resuscitate, and stabilize
the trauma patient by priority. There are three peak times for trauma deaths.
The first, classified as immediate death, is the period with the greatest
number of fatalities. This occurs within seconds to minutes of the injury and
these patients generally die at the scene. The cause is most commonly
because of massive head injury, followed by high cervical spine injury with
spinal cord disruption, cardiac and great vessel rupture, and airway obstruc-
tion. The second peak period, classified as early death, occurs within min-
utes to a few hours of injury. This is the period called the “golden hour”
where intervention is critical and significantly reduces the morbidity and
mortality rate in these patients. Death in these patients is generally sec-
ondary to subdural and epidural hematomas. Other causes of death in this
group include ruptured spleen, lacerated liver, hypovolemic shock, fracture