Approach to Non-Traumatic Shock

Question 1

Which type of shock has the highest in-hospital mortality rate?

Answer 1

Cardiogenic

Highest percentage in terms of ED presentation:
1. Distributive
2. Hypovolemic
3. Cardiogenic
4. Obstructive

Question 2

Define shock

Answer 2

State of circulatory insufficiency that results to an imbalance between oxgygen supply and demand leading to end organ dysfunction

Question 3

Decreased Preload
Decreased SVR
Mixed CO

Answer 3

Distributive

MC type: septic shock
40% may have transient cardiomyopathy
Others: anaphylaxis, adrenal insufficiency, neurogenic shock

Question 4

Hemodynamic changes in Cardiogenic shock

Answer 4

Increased preload
Increased afterload
Increased SVR
Decreased CO

MC cause: MI
Bradyarrhythmias = low CO
Tachycarrhythmias = low preload and stroke volume

Question 5

Decreased preload
Increased SVR
Decreased CO

Answer 5

Hypovolemic shock
Obstructive shock

Hypovolemic - decreased intravascular volume
Obstructive - decreased venous return or cardiac compliance due to LV outflow obstruction or dec preload

Question 6

Cardiac output formula

Answer 6

HR x SV

MAP is dependednt on CO and SVR

Question 7

Cardiac output is dependent on

Answer 7

1. Intropy
2. Chronotropy
3. Lusitropy

Intropy: speed and shortening of myocardium; Responds to Anrep effect (inc in afterload) or Bowditch effect (in HR)
Chronotropy: Heart contraction rate
Lusitropy: Ability of heart muscle to relax and chambers to fill

Question 8

In shock, this stretch reflex activates the sympathetic nervous system which results to what compensatory mechanisms (5)?

Answer 8

Carotid baroreceptor
1. Arteriolar vasoconstriction
2. Increase in HR and contractility
3. Constriction of venous capacitance vessels
4. Release of epinephrine, norepinephrine, dopamine, cortisol
5. Release ADH -> (+) RAAS

Question 9

A bedside assessment maneuver to determine fluid responsiveness

Answer 9

Passive leg raise

UTZ: RUSH / Abdominal and Cardiac Evaluation w Sonography

If this results to an increase in BP = fluid resuscitation is indicated:
500 or 1L isotonic crystalloid over 5 to 20 mins or 20-30cc/kg

Question 10

Targets in ensuring adequate oxygen delivery

Answer 10

≥91% O2
≥ 70 Hgb

Parameters to assess adequacy of resuscitation: Svo2 or Scvo2

Question 11

Type of fluid that results in a buffering of aceidemia

Answer 11

Lactated Ringer’s

Lactate -metabolized by the liver-> CO2 (excreted by lungs) and H20 (excreted by kidneys)

Na 130, K 3, Ca 3, Cl 109, Lactate 28

Question 11

Resuscitation goals

Answer 11

MAP ≥65mmHg
CVP 8 to 12mmHg
Scvo >70%
Urine output >0.5ml/kg/hr

Question 11

Natural colloid

Answer 11

Albumin

IV half life: 16 hours
vs crystalloids (30 to 60 mins)

HMW solutions that increase plasma oncotic pressure
Artificial - starch, dextrans, gelatins

Question 12

Fluid that should be avoided in sepsis

Answer 12

Hydroxyethyl starch