Shock Syndromes II

Answer: C

This patient presents with likely hemorrhagic shock

after blunt trauma. The extent of injuries in highly vas-

cularized areas suggests a hemorrhagic source. Given

the extent of confusion, oliguria, tachycardia, and

tachypnea, as well as the amount of blood loss (35%

of total blood volume), this patient has class III hemor-

rhage (Answer C is correct; Answers A, B, and D are

incorrect).

The Fick equation describes oxygen delivery (Do2 (mL/

minute) = 10 x CO (L/minute) x Cao2). A diagnosis of

shock is typically based on hemodynamic, clinical, and

biochemical assessment of impaired Do2. Although

an elevated INR may represent a coagulopathy that

can contribute to bleeding, it is not directly related to

impaired Do2. In addition, hematemesis is a clinical sign

of bleeding but is not necessarily specific to a shock syn-

drome (Answer A is incorrect). Although heart rate is a

determinant of CO, CO is not generally impaired unless

the patient has acute supraventricular or ventricular

tachycardia. In addition, an elevated serum creatinine

may be a biochemical sign of impaired tissue oxygen-

ation, but this generally presents in a delayed fashion and

may represent chronic renal dysfunction in this specific

patient (Answer B is incorrect). A low Scvo2 represents

the balance between oxygen consumption and delivery

(not solely delivery) and does not explain reduced Do2.

Although an elevated lactate concentration may indi-

cate impaired Do2 in shock syndrome, lactate may be

elevated secondary to altered hepatic metabolism and is

not a specific marker for circulatory shock (Answer D is

incorrect). Therefore, according to the Fick equation, a

low hemoglobin reduces the Cao2, decreasing Do2. Cold

and clammy extremities is a common clinical marker of

a shock syndrome, indicating a low-flow state (Answer

C is correct).

Answer: D

This patient presents with likely hemorrhagic shock

after blunt trauma. The patient has signs consistent

with intra-abdominal bleeding with the positive FAST

examination in hemodynamic instability; thus, urgent

intervention is required. According to the extent of

altered mentation, tachycardia, and tachypnea, this

patient has class IV hemorrhage, consistent with greater

than 40% blood loss, indicating the requirement for

erythrocyte transfusions. However, giving only eryth-

rocyte transfusions would increase oxygen-carrying

capacity but not correct the likely underlying coagu-

lopathy (Answer A is incorrect). Although warmed

lactated Ringer solution may be indicated in a trauma

patient with bleeding, excessive fluid resuscitation

(above 1.5 L) should initially be avoided (Answer B

is incorrect). Given the patient’s blood pressure, heart

rate, and positive FAST, he is at high risk of requiring

massive transfusion, which should be initiated promptly

with an empiric ratio. In addition, given the presence

of hemorrhagic shock requiring erythrocyte transfu-

sions, tranexamic acid is indicated early to improve

mortality (Answer D is correct). Although goal-directed

resuscitation is recommended for continued resuscita-

tion, empiric blood product transfusions should not be

delayed while awaiting laboratory results unless point-

of-care assays are available (Answer C is incorrect).

Answer: B

This patient has apparent warfarin toxicity contribut-

ing to an acute GI hemorrhage. Because he meets the

criteria for a major bleed, particularly associated with

hemodynamic instability, many guidelines recommend

anticoagulation reversal. Although phytonadione is

the specific reversal for warfarin to promote hepatic

production of factors II, VII, IX, and X, it does not

immediately correct coagulopathy, and factor replace-

ment is recommended (Answer D is incorrect). In

addition, when used for life-threatening hemorrhage,

intravenous administration is recommended because

of its quicker onset of action of 4–6 hours compared

with 18–24 hours for oral administration (Answer A is

incorrect). Although plasma has traditionally been used

for immediate factor replacement for warfarin reversal,

the time to laboratory reversal is inferior to PCC. In

addition, the volume of plasma needed to reverse his

INR would likely not be well tolerated by this patient

with CTEPH (Answer C is incorrect). Therefore,

4F-PCC, which contains nonactivated highly con-

centrated factors II, VII, IX, and X, is recommended

for warfarin reversal in life-threatening hemorrhage

because of its superiority for laboratory reversal and

noninferiority for clinical hemostasis. Rates of throm-

botic events appear similar when comparing 4F-PCC

with plasma for warfarin reversal in life-threatening

hemorrhage and surgical populations; however, rates