Vaso-Active Agents in the

Vaso-Active Agents in the Emergency DepartmentMichael C. Bond, MDObjectives

1. Review the definition of SIRS and Shock

2. Review the different classifications of shock

3. Review vasopressors and their mechanisms of action

a. Dopamine

b. Dobutamine

c. Epinephrine

d. Norepinephrine

e. Phenylephrine

f. Vasopressin

4. Review the pathophysiology of septic shock and current treatment

Systemic Inflammatory Response Syndrome

1. Any two or more of the following are present

a. Heart rate > 90 beats per minute

b. Body temperature < 36 or > 38C

c. Hyperventilation (high respiratory rate) > 20 breaths per minute or, on blood gas, a PaCO2 < 4.3 kPa (32 mm Hg)

d. White blood cell count < 4000 cells/mm3 or > 12000 cells/mm3 (< 4 x 109 or > 12 x 109 cells/L), or the presence of greater than 10% immature neutrophils.Causes of SIRS

1. Severe trauma

2. Surgery, complication of

3. Burns

4. Acute pancreatitis

5. Immunodeficiency (such as AIDS)

6. Infection

SIRS versus Sepsis

SIRS with a confirmed infection, proven through a positive blood culture or tissue sample positive for pathogenic organisms, is called sepsis.

Shock Definition:

1. Inadequate tissue perfusion that impairs cellular metabolism

2. Oxygen Supply < Oxygen Demand

3. SBP 70%2. If patient received adequate fluid resuscitation and CvO2 still 30%b. Dobutamine therapy started3. Patients improved in the EGT group4. Rhodes A, Bennett ED. Early goal-directed therapy: An evidence-based review. Critical Care Medicine 2004; 32 (Suppl.):S448-S450.

a. Specific targets that should be reached during the first 6 hours of resuscitation are:

i. Central Venous Pressure (8-12 mm Hg)

ii. Mean Arterial Pressure 65 mm Hg

iii. Urine Output of 0.5 ml/kg/hr

iv. SvO2 65% or ScO2 70%

b. If these targets can not be reached you should

i. Transfuse packed red blood cells to achieve HCT 30%

ii. Administer dobutamine infusion (up to a maximum of 20 mcg/kg/min)5. Trzeciak S, Dellinger RP, Abate NL. A 1-Year Experience with implementing Early Goal-Directed Therapy for Septic Shock in the Emergency Department. Chest 2006; 129:225-232.a. All end points achieved in 20 of 22 casesb. EGDT was associated with decreased ICU pulmonary artery catheter use (9.1% vs. 43.7%)c. Volume Infused went from 3.5 L to 5.6 L in the ED, and 9L to 7.9 for first 24 hours.

Summary

1. Low dose dopamine should NOT be used for renal protection.

2. Norepinephrine has better outcomes than dopamine with no affect on dopamine receptors in the brain

3. Phenylephrine and Epinephrine should not be used as first line agents in septic shock.

4. Dobutamine is the agent of choice to increase cardiac output, and it should not be used to increase cardiac output above physiologic levels.

5. Vasopressin should be a second line agent due to the effects it might have on splanchnic blood flow.

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