Which of the following are not appropriate interventions for decreasing the incidence
of the systemic inflammatory response (SIRS) and multiple organ failure (MOF)?
- Early fixation of long bone fractures.
- Infusion of anti-TNF-α antibody.
- Early enteral feeding.
- Decreased ventilatory ti...
All are potential causes of cardiogenic shock except:
- Myocardial infarction.
- Pericardial tamponade.
- Tension pneumothorax.
- Cardiac arrhythmias.
- Excessive preload.
✓ ~~~ Excessive preload.
(Excessive preload is typically not a cause of cardiogenic shock, but is a result of
cardiogenic shock.)
A 60-year-old man has an arterial PO of 60 mm Hg when the calculated alveolar PO
is 94 mm Hg. This difference is most commonly due to
✓ ~~~ a ventilation-perfusion mismatch
oxygen delivery and consumption
✓ ~~~ - Under normal circumstances, approximately 20% to 30% of the oxygen delivered to
the capillary bed is extracted by the tissues.
- In conditions of decreased delivery of oxygen, tissues are capable of extracting up
to 50% to 60% of the oxygen content in the capillary blood.
- When cellular oxygen supply does not meet demand, anaerobic respiration results.
,(The variables in the equation for the delivery of oxygen are cardiac output,
hemoglobin level, oxygen saturation of hemoglobin, and the partial pressure of
oxygen dissolved in blood. Increases in the first three variables all yield significant
increases in the total amount of oxygen carried by blood. The partial pressure of
oxygen is multiplied by a factor of 0.003, however, and therefore has a miniscule
contribution to the total oxygen content.)
Dopamine at doses of 5 to 10 μg/kg/min
✓ ~~~ has a largely inotropic action profile
(Dopamine has a dose-dependent action profile. At 3 to 5 μg/kg/min, its actions are
largely to increase renal blood flow. At doses of 5 to 10 μg/kg/min, it largely acts to
stimulate myocardial β receptors and has an inotropic effect. At doses greater than
10 μg/kg/min, it stimulates α receptors and has a chronotropic effect.)
As oxygen delivery increases on the flat horizontal portion of the oxygen
consumption-delivery curve
✓ ~~~ Oxygen consumption remains the same
(On the flat horizontal portion of the oxygen consumption-delivery curve, oxygen
delivery meets cellular demand of oxygen; as oxygen delivery increases, oxygen
consumption remains the same.)
Most disorganized ventricular arrhythmias (frequent PVCs, ventricular fibrillation) are
caused by
, ✓ ~~~ Metabolic derangements.
(Most disorganized ventricular arrhythmias are caused by some sort of metabolic
derangement such as ischemia or magnesium or potassium deficiencies. These
abnormalities are not well treated by antiarrhythmic medications.)
The best management for a patient with a posterior knee dislocation
✓ ~~~ Arteriogram.
(The patient may have fairly normal pulses and still have an intimal injury of the
popliteal artery that is similar to the intimal disruption that can be seen in aortic
isthmus injury.)
the possible etiologies of multiorgan failure
✓ ~~~ - Anticytokine antibodies have shown therapeutic promise in animal studies.
- Evidence has shown that intestinal mucosa is made permeable by sepsis.
- The "two-hit" hypothesis postulates that after mounting an appropriate response to
some physiologic insult, the patient is left with a primed immune system which
manifests an exaggerated immune response to a second challenge.
- The early stages after injury actually appear to consist of an immediate
proinflammatory state as the organism tries to address the physiologic insult. When
properly modulated, this is an appropriate function. When overexpressed, this
proinflammatory state leads to the systemic inflammatory response syndrome. Later,
anti-inflammatory and immunosuppressive mechanisms are brought into play to
bring the organism back to homeostasis. If overmanifested, they can lead to a
relative generalized immunosuppression and late incidents of sepsis or multiorgan
failure.
, compensatory mechanisms in shock
✓ ~~~ Antidiuretic hormone causes the reabsorption of free water by the kidney and has
vasoconstrictive properties.
(Antidiuretic hormone is released from the posterior pituitary where it stimulates free
water retention by the kidney and acts as a powerful vasoconstrictor.)
A 71-year-old man with colon cancer is in the intensive care unit following a left
hemicolectomy. His blood pressure is 72/38 mm Hg, pulse rate is 114/min,
respiratory rate is 23/min, and oxygen saturation is 94% on 2 L of oxygen by nasal
cannulae. A pulmonary artery catheter shows a central venous pressure of 8 cm H
O, a pulmonary artery pressure of 22/8 mm Hg, a pulmonary artery wedge pressure
of 6 mm Hg, and a cardiac output of 3.4 L/min. The next step in management should
be the intravenous administration of
✓ ~~~ a fluid bolus
pulmonary artery catheters
✓ ~~~ Allow accurate approximation of left atrial pressure.
The magnitude of a left-to-right shunt in the presence of an ASD is determined by
✓ ~~~ Difference in compliance between left and right ventricles.
(The blood will tend to fill the more compliant ventricle which will usually be the right,
until chronic pulmonary hypertension yields right ventricular hypertrophy.)
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