Wk5: Shock

Question 1

Definition of shock

Answer 1

Hypoperfusion of vital organs including brain, heart, kidneys, lungs, gut. NOT low BP.

Question 2

How to evaluate/track level of oxygen supply/demand imbalnce

Answer 2

Lactic acid

Question 3

Autonomic response to anaerobic metabolism

Answer 3

Constriction of arterioles and veins, increased HR, increased contractility, release of ADH, epi, dopamine, NE, cortisol

Question 4

Cellular cascade response to O2 imbalance (ATP depletion –>)

Answer 4

ATP depletion -> ion pump dysfunction -> Na influx/K efflux -> cellular edema -> lysosomal enzyme release -> cell death
(cytokine mediated)

Question 5

Typical lab findings in shock (5)

Answer 5

Hyper-K, Hypo-Na, Metabolic and Lactic acidosis, Hyperglycemia

Question 6

What are SIRS and MODS (define acronym)

Answer 6

Systemic Inflammatory Response Syndrome, Multi-Organ Dysfunction Syndrome

Question 7

What findings constitute a patient on the shock continuum? (SIRS criteria)

Answer 7

2+ of the following:

Temp 38, HR ≥ 90, RR ≥ 20, PaCO2 <32 mmHg, WBC ≤ 4k or ≥ 12k or 10% bands

Question 8

4 Clinical Stages of Shock: Stage 1

Answer 8

Mild resp alkalosis + oliguria + hyperglycemia

Question 9

4 Clinical Stages of Shock: Stage 2

Answer 9

Tachypnea + hypocapnia + hypoxia. Mod liver dysfx and poss hematologic abnormalities

Question 10

4 Clinical Stages of Shock: Stage 3

Answer 10

Azotemia + acid-base disturbance + sig coag abnormalities

Question 11

4 Clinical Stages of Shock: Stage 4

Answer 11

Vasopressor dependent + olig/anuria + ischemic colitis + lactic acidosis

Question 12

What is azotemia?

Answer 12

Abnormally high levels of nitrogen-containing compounds e.g. BUN and creat

Question 13

Classic clinical findings in shock

Answer 13

Hypotension: sys 30 < usual, urine <20 cc/hr, elevated lactic acid, altered mental status

Question 14

How might skin findings differ between types of shock?

Answer 14

Generally cool and clammy in shock BUT warm, flushed with distributive/dissociative

Question 15

Calculate shock index. What’s normal?

Answer 15

HR/sys BP: inversely related to effective LV stroke work. Normal: 0.5 - 0.7. Note ≥1 = inc mortality

Question 16

How does capillary wedge pressure work? (Not done due to associated increase in mortality)

Answer 16

Insert catheter through subclavian -> heart -> lung capillaries. Inflate balloon to stop pressure from behind. All pressure is assumed to be from front (estimate of LA and LV pressure)

Question 17

Examples of cardiogenic shock

Answer 17

Acute MI, arrhythmia, hypertrophic cardiomyopathy, aortic stenosis -> decreased CO

Question 18

Examples of distributive/ dissociative shock

Answer 18

Spinal cord injury, anaphylaxis, endo (gram neg) or exotoxin (gram pos). Dissociative = something stopping O2 from reaching cells e.g. CO, cyanide

Question 19

Extracardiac shock - definition and examples

Answer 19

Outflow obstruction -> decreased CO due to external path e.g. PE, pericardial tamponade, pulm htn

Question 20

Hypovolemic shock causes

Answer 20

Diarrhea, vom, diuretics, sweating, hemorrhage, burns, 3rd spacing (ascites)

Question 21

Step 1 of shock treatment

Answer 21

Volume replacement: NS 20-30 mL/kg, blood if hgb <7

Question 22

Treatments other than NS for shock

Answer 22

Vasopressors: NE, epi, dopamine (less so because of 3rd receptor - dopaminergic), dobutamine

Question 23

How does epi work?

Answer 23

a1 @ post-syn a2 -> arteriolar vasoconstriction. Pre-syn a2 inhibit NE release. B1 ->pos chron and inotropic. B2 -> arteriolar vasodilation, bronch sm musc relax, inc glycogenolysis

Question 24

How does dobutamine work as a vasopressor

Answer 24

Beta-adrenergic inotropic effects

Question 25

How does dopamine work as a vasopressor?

Answer 25

alpha -> vasoconstriction. beta -> ino and chronotropic + vasodilation. Nonadrenergic splanchnic and renal vasodilation

Question 26

How does NE work?

Answer 26

alpha -> vasoconstriction. beta -> ino and chronotropic

Question 27

Other than NS and vasopressors, what treatments are possible depending on the situation?

Answer 27

antibiotics, surgery, thrombolytics, anticoagulants