Shock & Pressors

Question 1

Criteria for ARDS Diagnosis

Answer 1

1. Acute onset
2. Chest X-Ray: Bilateral diffuse infiltrates of the lungs
3. No cardiovascular lesion
4. No evidence of left atrial hypertension: PaO2/FiO2 ratio equal to or less than 200 mmHg.

Question 2

Definition of Shock

Answer 2

Failure of circulatory system to maintain adequate blood flow to end organs

Question 3

3 most common forms of shock

Answer 3

Distributive, Hypovolemic, Cardiogenic

Question 4

Common causes of distributive shock

Answer 4

Sepsis, Anaphylaxis, Neurogenic

Question 5

Equation for MAP

Answer 5

MAP = CO * SVR = SV * HR * SVR

Use this to figure out how to treat shock in the short-term

Question 6

3 Short-term interventions for shock

Answer 6

1) Fluids: inc SV –> inc CO –> inc MAP
2) Vasopressors: inc SVR –> inc MAP
3) Inotropes: inc CO –> inc MAP

Question 7

Hypovolemic Shock - PCWP / CO / SVR

Answer 7

PCWP decreases
CO decreases
SVR increases

Question 8

Cardiogenic Shock - PCWP / CO / SVR

Answer 8

PCWP increases
CO decreases
SVR increases

Question 9

Distributive Shock - PCWP / CO / SVR

Answer 9

PCWP decreases
CO increases or decreases
SVR decreases

Question 10

How to figure out PCWP and SVR of a patient clinically

Answer 10

Clinically dry - decreased PCWP
Clinically wet - increased PCWP
Cold extremities - increased SVR
Warm extremities - decreased SVR

Question 11

3 Types of Vasoactive agents used in shock

Answer 11

Vasopressors
Inodilators
Inopressors

Question 12

Receptors targeted by vasoactive agents

Answer 12

a1 - peripheral vasoconstriction
b1 - inotropy
b2 - peripheral vasodilation
V1 - peripheral vasoconstriction
D1 - selective vasodilation of renal, mesenteric, cerebral, coronary vasculature

Question 13

Volume status and Pressors

Answer 13

Aggressive IVF is key 1st step. Pressors can cause decreased end-organ perfusion if there’s inadequate circulating volume

Question 14

Name the 6 vasoactive agents commonly used

Answer 14

Dobutamine - ID
Epinephrine - IP
Dopamine - IP
Norepinephrine - IP
Phenylephrine - VP
Vasopressin - VP

Question 15

Dobutamine

Answer 15

Inodilator
0-20 mcg/kg/min
b1, b2
inc CO, dec SVR

Question 16

Epinephrine

Answer 16

Inopressor
0-10 mcg/kg/min
a1, b1, b2
inc CO, inc SVR

Question 17

Dopamine

Answer 17

Inopressor
0-20 mcg/kg/min (renal dose 0-2.5)
Renal dose: b1, D1 - inc CO, dec SVR
Higher doses: a1, b1, D1 - inc CO, inc SVR

Question 18

Norepinephrine

Answer 18

Inopressor
0-20 mcg/min
a1, b1
inc CO, inc SVR

Question 19

Phenylephrine

Answer 19

Vasopressor
0-200 mcg/kg/min
a1
inc SVR

Question 20

Vasopressin

Answer 20

Vasopressor
0.04 units/min
V1
inc SVR

Question 21

First line agents in shock

Answer 21

Norepinephrine and Dopamine
For both Cardiogenic and Septic shock
ACC/AHA and Surviving Sepsis Campaign

Question 22

SOAP II Trial (NEJM 2010)

Answer 22

Dopamine vs Norepinephrine
1679 pts in shock (cardiogenic & septic)
No mortality diff at 28 days
Dopamine had increased mortality at 28 days for pts in cardiogenic shock
Dopamine pts had more arrhythmic events

Question 23

Pressors in Sepsis Study (Chest 1993)

Answer 23

32 pts in septic shock randomized to NE vs DA. If no response, rescue w/ other agent.
DA response 31%; NE response 93%.
NE rescued 10/11 DA failures.
Survival NE 59%; DA 17%.

Question 24

Renal dose DA in sepsis study (Lancet 2000)

Answer 24

328 septic pts w/ early renal failure
Randomize to DA vs Placebo
Results: No difference in peak Cr or clinical outcomes

Question 25

Second-Line Agents for Shock

Answer 25

Phenylephrine and Epinephrine

Question 26

Phenylephrine - data for use

Answer 26

Less useful in cardiogenic shock (already increased SVR).
In sepsis, potential to lower SV b/c increases SVR w/o increasing CO
Possible dec splanchnic blood flow
May be useful in pts w tachyarrhythmia, esp if worsened with NE

Question 27

Epinephrine - data for use

Answer 27

First line for anaphylactic shock
Increases inotrophy more than NE, but more arrhythmias
Dec splanchnic Q, inc lactate

Question 28

Vasopressin - data for use

Answer 28

Only use as adjunctive agent
Studies show lower ADH lvls in sepsis
Better HD & end-organ perfusion, lower tachyarrhythmia, higher ischemic skin lesions
Use at fixed rate of 0.04u/h - no titration

Question 29

Dobutamine - data for use

Answer 29

Only use as adjunctive agent
Septic pts often have lower CO 2/2 endotoxins & cytokines.
Studies show no benefit and possibly harm (Systemic O2 delivery study NEJM 1994).
Never use only as lower SVR may reduce BP more than increased by higher CO.