1. Shock (overview)

Question 1

Although blood pressure (hypotension) is generally thought of when discussing shock, shock is actually a

Answer 1

CELLULAR DISEASE due to either inadequate perfusion (the O2 demand is greater than the oxygen delivered) or the inability of cells to utilize the delivered oxygen (issues with oxygen utilization/consumption).

Question 2

Refer to figure 5-1 to study the pathophysiology of shock

Answer 2

Inadequate tissue perfusion OR impaired O2 uptake

Question 3

There are 3 stages of all types of shock:

Answer 3

1. Compensatory
2. Progressive
3. Refractory

Question 4

The rapidity with which a pt progresses thru these shock stages ___

Answer 4

varies depending upon many factors.

Question 5

During the COMPENSATORY STAGE of shock (figures 5-2 and 5-3), the blood pressure (bp)

Answer 5

is maintained as a result of 2 mechanisms: stimulation of the sympathetic nervous system and activation of the renin-angiotensin-aldosterone system (RAAS).

Question 6

Sympathetic Nervous System Stimulation
figure 5-2 (physiology of compensatory stage of shock)

Answer 6

Decrease in cardiac output/circulating volume or increased oxygen utilization
I
V
sympathetic stimulation
I
V
(HR) Vasoconstriction (contractility)
I I I
I V I
I——> BP maintained <—————-I

Question 7

Renin-Angiotensin-Aldosterone System (RAAS) Activation
Figure (5-3) Compensatory stage of shock due to RAAS

Answer 7

Decrease in CO/circulating volume or increased o2 utilization leads to RAAS ACTIVATION which
leads to

a) Renin secretion –>Angiotensin I–>Angiotensin II ———->Vasoconstriction—->BP maintained

b)Aldosterone release–>Na+ and H20 retention–>BP maintained

Question 8

Clinical Signs/Symptoms of the Compensatory Stage of Shock (BP maintained)

Answer 8

-tachycardia
-tachypnea, respiratory alkalosis
-Normal PaO2
-Oliguria
-Skin is pale, cool (except in early sepsis)
-Restlessness, anxiety
-Complaints of thirst
-Remember, BP IS MAINTAINED

Question 9

Clinical Signs/Symptoms of the PROGRESSIVE Stage of Shock (Compensatory mechanisms failing)

Answer 9

-HYPOTENSION
-Worsening tachycardia, tachypnea, oliguria
-metabolic acidosis
-decreased PaO2
-clammy, mottled skin
-further change in LOC
-the pt may complain of nausea

Question 10

Clinical Signs/Symptoms of the REFRACTORY Stage of Shock

Answer 10

-pt not responsive to interventions

-Severe systemic hypoperfusion, MULTIPLE ORGAN DYSFUNCTION SYNDROME (MODS)

-The pt may survive shock, but die from failure of one or more organs
-Pulmonary (ARDS)
-Kidney (acute tubular necrosis)
- Heart (failure, ischemia)
-Hematologic (disseminated intravascular
coagulation)
- Neurological (encephalopathy, stroke)
- Liver (failure)

Question 11

Types of Shock:

Answer 11

-Hypovolemic
-Septic
-Anaphylactic
-Neurogenic (seldom tested)
-Cardiogenic (covered in CV)
-Obstructed (covered in CV and Resp chapters)
-Tension pneumothorax
-Massive pulmonary embolism
-Cardiac tamponade