Shock Syndromes I
Answer: D
The patient has features of vasodilatory shock second-
ary to an immune-mediated (“anaphylactic”) reaction
(low preload, a low Scvo2 [suggestive of poor Do2], and
an elevated lactate concentration). The patient should
receive aggressive fluid resuscitation and be initiated
on a vasopressor such as norepinephrine with the pri-
mary effects of augmenting afterload (Answer D is
correct). Although the patient has features of poor Do2,
this is likely because of inadequate preload, which will
be augmented by fluid administration. Agents targeted
toward improving Cao2 (PRBCs) and CO (dobutamine
and milrinone) should not be initiated unless the patient
has inadequate Do2 and is not fluid responsive (Answers
A–C are incorrect).
Answer: A
The patient has received an initial fluid challenge of
only 23 mL/kg of crystalloids and still has evidence of
end-organ hypoperfusion (elevated lactate concentra-
tion and urinary output less than 0.5 mL/kg/hour). An
additional bolus of at least 500 mL of 0.9% sodium chlo-
ride is indicated to ensure an initial fluid challenge of at
least 30 mL/kg of crystalloids and to improve end-organ
perfusion (Answer A is correct). Because the patient has
not received a complete initial fluid challenge (or even
a substantial amount of crystalloids), albumin is not
indicated (Answer B is incorrect). Vasopressors are not
indicated right now because the patient’s MAP is above
65 mm Hg (the patient’s MAP is 67 mm Hg). In addition,
if an initial vasopressor were to be selected, norepi-
nephrine would be preferred (Answer C is incorrect).
The patient’s low Scvo2 is likely caused by inadequate
preload (resulting in inadequate SV and CO). Adequate
preload should be ensured before giving PRBCs as part
of improving Do2 (Answer D is incorrect).
Answer: A
Despite an initial fluid challenge of greater than 30 mL/
kg of crystalloids, the patient has continued evidence of
hypotension (MAP 63 mm Hg) and hypoperfusion (an
elevated lactate and a urinary output less than 0.5 mL/
kg/hour). A vasopressor should be initiated to improve
blood pressure (MAP greater than 65 mm Hg) and organ
perfusion. Norepinephrine is recommended by the SSC
as the first-line vasopressor (Answer A is correct).
Vasopressin is not recommended as the single initial
vasopressor, but it may be added to norepinephrine
(Answer B is incorrect). Phenylephrine is no longer rec-
ommended in the SSC guidelines. Although this patient
has a history of atrial fibrillation and a high heart rate,
norepinephrine should still be tried and the patient
observed for signs of worsening tachyarrhythmias
(Answer C is incorrect). Dopamine is recommended as
an alternative vasopressor to norepinephrine in select
patients, such as those with bradycardia. In a meta-
analysis of patients with septic shock, dopamine was
associated with a higher mortality rate and more fre-
quent tachyarrhythmias (Answer D is incorrect).
Answer: B
Vasopressin can be added to norepinephrine to either
increase MAP or lower norepinephrine requirements. In
the VASST (Vasopressin and Septic Shock Trial) study
comparing norepinephrine monotherapy with nor-
epinephrine plus vasopressin, mortality did not differ
between the two groups, but norepinephrine require-
ments were significantly lower in the patients allocated
to receive AVP. According to the SSC guidelines,
vasopressin can be added to norepinephrine to either
raise the MAP or decrease the norepinephrine dosage
(Answer B is correct). Although a dynamic marker of
fluid responsiveness is not presented, the patient’s CO
and cardiac preload are likely adequate, given that
his Scvo2 is 72%. Additional fluid loading is not indi-
cated, given the information presented (Answer A is
incorrect). Phenylephrine is no longer recommended
as a treatment in the SSC guidelines; however, it has
theoretical benefit as a second-line vasopressor when a
malignant tachyarrhythmia is associated with norepi-
nephrine. In this case, phenylephrine is not indicated
because sinus tachycardia is not considered a malignant
tachyarrhythmia (Answer C is incorrect). Epinephrine
is recommended when an additional agent is needed to
raise the MAP to the target. Adding epinephrine to nor-
epinephrine would only add inotropic support, but this
patient has no signs of low CO with an Scvo2 of 72%,
and the patient’s inadequate blood pressure is the most
likely reason for his hypoperfusion (elevated lactate and
low urinary output). Adding epinephrine would also
likely increase the patient’s heart rate and potential for a
tachyarrhythmia. As such, epinephrine is not indicated
(Answer D is incorrect).