Case #1 Answers:

Answer 1
Septic, Hypovolemic, Cardiogenic.

• Would include a BRIEF discussion of other, less common, causes of shock: neurogenic, anaphylactic, and hypoadrenal.
• Would also point out that "cardiogenic" includes etiologies besides ischemia and cardiomyopathy: tamponade, valvular disease, and pulmonary vascular disease (pulmonary hypertension and pulmonary embolism).
• Would also emphasize that the three major categories of shock can be further classified as either "High-Output" or "Low-Output" and that this distinction may be made by either physical examination findings or pulmonary artery catheter data.

Emphasize that the three major categories of shock can be further classified as either “High-Output” or “Low-Output” and that this distinction may be made by either physical examination findings or pulmonary artery catheter data.

Answer 2
Septic (wide pulse pressure, warm extremities, bounding pulses, capillary refill).

• Would point out that other historical and physical exam findings may suggest infection and/or pyelonepehritis but that they are not necessarily supportive of the diagnosis of septic shock (i.e., fever, CVAT).

Answer 3
"Fluids". "Normal saline, wide open."

• Would emphasize the lack of proven benefit to colloids compared to crystalloid.
• Would also point out the large volume of fluid necessary to resuscitate most patients with shock (especially septic).
• One might also discuss the goals of resuscitation (i.e., target BP). (i.e., Goal = 500 cc every 5 minutes until shock is resolved or complications ensue.)

Answer 4
Approximately 43 mmHg (MAP = DBP + (SBP - DBP)/3).

Answer 5
a. P_CWP = 5 - 12, CO = 4 - 6 lpm, SVR = 900 - 1200, PVR = 120 - 200.
b. P_CWP is likely normal or low; CO is likely high.
c. Thermodilution.
d. The P_CWP provides an assessment of LV preload.
e.  The P_CWP may be misleading in situations of abnormal LV compliance (diastolic dysfunction), mitral valve stenosis, pulmonary venous disease (pulmonary veno-occlusive disease), and situations when the PA catheter reflects Zone I conditions (i.e., alveolar pressures exceed pulmonary vascular pressures).

Answer 6
Generally accepted indications include hypotension unresponsive to fluids, hypotension of unclear etiology, and hypoxia unresponsive to diuresis/mechanical ventilation.

• Would comment upon the lack of proven benefit associated with the use of SG catheters and some data suggesting a worse outcome with their use.

Answer 7
a. Changing intrathoracic pressures with normal respiration.
b. The PCWP is always measured at end-expiration. In the sample tracing, in which the patient is mechanically ventilated receiving positive pressure inspirations, end-expiration is measured at point "C".

Answer 8
SVR = 596. PVR = 73. (SVR = [(MAP - PRA)/CO] X 80. PVR = [(mean pulmonary artery pressure - PCWP)/CO] X 80).

Answer 9
The low SVR and high normal CO (despite a low normal PCWP) strongly suggest sepsis.

Answer 10
The MVpO2 is either normal because the CO is truly adequate or is pseudo-normal as can occur in sepsis.

Answer 11
ARDS and multisytem organ failure (MSOF).

Answer 12
“Pressors”

• Would discuss the dosage, receptor mechanism, and clinical effect of dopamine, dobutamine, and norepinephrine.

Answer 13

a. Corticosteroids

• Stress the high incidence of adrenal insufficiency in patients with septic shock (up to 60% in the Annane paper – JAMA 2002;288:862)
• There is some data that patients with biochemical evidence of hypoadrenalism in the ICU who are treated with hydrocortisone may have a better outcome.

b. Vasopressin

• Review the evidence that vasopressin levels are often depressed in patients with septic shock 2/3 patients treated with 0.01-0.04 U/min of VP were able to be weaned off of NE and showed improved U.O. and Creatinine Clearance.

c.   Activated Protein C

• As documented in the NEJM 2001;344:699 article, levels may be suppressed in up to 88% of patients with septic shock.
• Treatment with drotrecogin-alpha-activated may improve survival with a NNT = 16.
• The cost is high however and is estimated to be ~$25,000/year of life saved.

Answer 14

Goal Directed Therapy (GDT) has been associated with improved survival.
GDT is a strategy wherein the following outcomes are obtained within 6 hours of arrival in the emergency room:
1. CVP 8 – 18
2. MAP > 65
3. svO2 > 70%