Shock (Nassar)

Question 1

what are the 5 types of shock?

Answer 1

• cardiogenic (eg, myocardial infarction or arrhythmia)
• hypovolemic (bleed)
• distributive (eg, sepsis)
• obstructive (eg, cardiac tamponade/Pulm embolism)
• neurogenic (form of distributive shock)

Question 2

What are the 3 most important therapies for someone in shock?

Answer 2

• volume resuscitation (fluids)
• optimization of oxygen demand (think intubation for someone who’s tachypnic, or in respiratory failure)
• support of the circulation (vasopressors and ionotropes)

Question 3

2 most common types of shock

Answer 3

septic and cardiogenic

Question 4

definition of shock

Answer 4

maldistribution of blood flow, causing an imbalance between oxygen delivery and oxygen demand, leading to tissue hypoxia

Question 5

formula determining O2 delivery

Answer 5

O2 delivery = cardiac output x arterial Oxygen

Question 6

cardiac function is dependent on which 3 things?

Answer 6

• preload
• contractility
• afterload

**intervention in shock focuses on the first 2.

Question 7

how do the baroreceptors work to regulate blood pressure?

Answer 7

• via negative feedback.

- high blood pressure activates the baroreceptors, and they in turn inhibit the sympathetic system, lowering BP.

Question 8

4 causes of distributive shock

Answer 8

• sepsis
• anaphylaxis
• liver cirrhosis
• pancreatitis

Question 9

T/F Septic shock has elements of hypovolemic shock and cardiogenic shock.

Answer 9

True.

Question 10

3 contributing factors to septic shock

Answer 10

• systemic vasodilation
• endothelial dysfunction
• capillary leak / relative hypovolemia

Question 11

what is the significance of pulse pressure in shock.

Answer 11

pulse pressure is a loose measure of stroke volume. If low, think cardiogenic shock. If large or normal, think septic shock /distributive.

Question 12

pulse, skin appearance and capillary refill in septic shock

Answer 12

pulse = bounding.

skin = flushed (vasodilation)

cap refill = brisk (vasodilation.

Question 13

pulse, skin appearance and capillary refill in cardiogenic shock

Answer 13

pulse = weak

skin = cyanotic (vasoconstriction)

capillary refill = delayed (vasoconstriction)

Note: these symptoms may also be present in hypovolemic shock. To differentiate, look at JVD

peripheral edema is also commonly present in cardiogenic shock

Question 14

Case: cold, pale, clammy, mottled skin, delayed cap refill. What does this mean? what is on the DDx?

Answer 14

low cardiac output state,

Could be cardiogenic shock or hypovolemic shock. Look at the JVD to differentiate.

Question 15

T/F - urine output provides an excellent indicator of organ perfusion.

Answer 15

True.

Question 16

Which test should be performed ASAP in any patient with shock?

Answer 16

echocardiography

Question 17

what is the best way to do a non-invasive, real time assessment of circulatory dysfunction in someone with shock?

Answer 17

• ultrasound!
• look at the heart (echo)
• look at IVC, aorta, look for DVTs,

Question 18

what causes lactate elevation in shock? - 2 things

Answer 18

• low flow states (leading to tissue hypoxia and anaerobic metabolism)
• impaired liver function (impairing clearance of lactate.)

elevated lactate helps diagnose shock

Question 19

How is mixed (central) venous O2 saturation level used in shock? What is the SVO2 level in low-flow shock and in distributive shock?

Answer 19

the lower it is, the more oxygen tissues are stripping off (the more hypoxic they are).

low flow state (or anemia) - it will be low

distributive/septic shock - it will be normal or high.

Question 20

4 ways to intervene to improve O2 delivery in shock (in order of priority)

Answer 20

intravascular volume – fluids

vascular resistance - vasopressors

hemoglobin - blood transfusion (if hb

Question 21

What are some non-invasive ways to determine if patients could benefit from fluids (and that they would not be harmed)

Answer 21

• passive leg raising (increases the blood to the heart by about 500cc - if their stroke output increases then they will be responsive to fluids.)
• inferior vena cava diameter - (ultrasound) - if collapsed, need fluids.

Question 22

exclusive inotropes

Answer 22

• dobutamine

- isoproterenol

Question 23

vasoconstrictor of choice for septic shock.

Answer 23

norepinephrine

Question 24

when should mechanical ventilation be used in pt’s with shock?

Answer 24

• tachypnic patients (excessive O2 utilization by breathing mm
• patient with respiratory failure / low O2 sat.