Unit 2: Obstructive Shock

Question 1

Obstructive Shock

Answer 1

caused by a mechanical barrier to ventricular filling or ventricular emptying (increased afterload) = decreased CO

Question 2

Examples of Disorders Resulting in impaired filling

Answer 2

• cardiac tamponade

- tension pneumothorax

Question 3

Example of disorders resulting in increased afterload

Answer 3

severe valvular disease

Question 4

Potential Cause of Obstructive Shock

Answer 4

• tension pneumothorax
• cardiac tamponade
• severe valvular disease

Question 5

What Hemodynamic Parameters would show in Obstructive shock

Answer 5

• Decreased CO
• Variable CVP and PAOP
• Increased SVR
• Decreased venous oxygen saturation (SvO2 or ScvO2)
• Hypotension and Tachycardia

Question 6

Risk Factors for Obstructive Shock

Answer 6

-extracardiac disorders that impair ventricular filling or emptying; impaired emptying also referred to increased right or left afterload; ex would be PE

Question 7

Pathophysiology of Obstructive Shock

Answer 7

• caused by a mechanical barrier to ventricular filling or ventricular emptying (increased afterload); decreases CO
• symptoms independent of fluid volume status
• mechanical obstruction to the pumping action of the heart results in decreased CO and poor perfusion at tissue level

Question 8

Clinical Manifestations of Obstructive Shock

Answer 8

• Decreased LOC
• Decreased urine output
• Poor pulses
• Pale, cool skin
• Decreased bowel sounds
• Chest pain
• N/V
• SOB
• Muffled heart sounds if cardiac tamponade
• Signs of R heart failure (JVD) may be noted with increased right heart afterload or impaired filling

Question 9

Hemodynamic Parameters

Answer 9

• obtained through PA catheter
• variable CVP and PAOP depending on problem, impaired filling or impaired emptying
• SVR is high
• CO is low
• SvO2 decreased (oxygen consumption)

Question 10

Medical Management

Answer 10

• oxygen through 100% non-rebreather mask
• intubation and mechanical ventilation
• vasoactive medications to help maintain BP in short term
• if cause of obstructive shock is impaired filling d/t cardiac tamponade, the blood or fluid in the pericardial sac must be removed or drained; if not death may ensue
• if cause of shock is impaired ventricular emptying d/t PE, definitive tx is to remove the clot w/ thrombolytic therapy

Question 11

Medical Management: Intubation and Mechanical Ventilation

Answer 11

improving or enhancing oxygenation may help decrease myocardial workload, increase myocardial oxygen supply, and preserve myocardial tissue

Question 12

Nursing Management: Assessment and Analysis

Answer 12

Clinical manifestations are r/t decreased CO and impaired tissue perfusion

• hypotension
• tachypnea
• tachycardia
• decreased LOC
• weak pulses
• cold, cyanotic, mottled skin
• may present w/ muffled heart sounds d/t presence of excessive fluid in the pericardial sac (cardiac tamponade) or signs of R heart failure d/t elevated right heart afterload
• decreased or absent bowel sounds
• decreased or absent urine output
• death occurs rapidly w/o treatment

Question 13

Nursing Assessments w/ Obstructive Shock

Answer 13

• Neurological Status
• Vital Signs
• Hemodynamic parameters
• Urine output
• Skin color and Temperature
• Laboratory Tests

Question 14

Assessments: Neurological Status

Answer 14

• decreased LOC occurs as a result of decreased CO and carotid vasoconstriction that occurs as a result of hyperventilation and respiratory alkalosis
• anxiety and restlessness may occur initially but will rapidly progress to a further decreased LOC w/o treatment

Question 15

Assessments: Vital Signs

Answer 15

• hypotension and tachycardia b/c of decreased CO
• respiratory rate increased in an effort to increase tissue oxygenation ad remove CO2 to compensate for metabolic acidosis

Question 16

Assessments: Hemodynamic Parameters

Answer 16

• filling pressures are variable depending on cause; elevated w/ impaired emptiness
• decreased w/ impaired filling
• right and left afterloads increase as a result of mechanical resistance to ventricular emptying
• decreased SvO2; indicates increased oxygen consumption
• CO low

Question 17

Assessment: Urine Output

Answer 17

decreased urine output as a result of decreased CO and stimulation of compensatory mechanisms that increase reabsorption of sodium + water

Question 18

Assessment: Skin color and Temperature

Answer 18

cool and clammy skin as a result of poor peripheral perfusion

Question 19

Assessments: Laboratory Tests

Answer 19

• ABGs: initial respiratory alkalosis d/t hyperventilation

- Venous oxygenation: decreased SvO2/ScvO2 = inadequate oxygen delivery

Question 20

Nursing Actions

Answer 20

• apply 100% non-rebreather oxygen mask
• prepare for intubation + mechanical ventilation
• administer meds as ordered (vasoactive, anticoagulation)
• prepare for definitive Tx of cause

Question 21

Actions: Prepare for intubation + mechanical ventilation

Answer 21

frequently necessary w/ obstructive shock in an effort to decrease oxygen consumption (VO2) and increase oxygen availability

Question 22

Vasoactive Medications

Answer 22

norepinephrine, dopamine

• produce vasoconstriction, increases BP
• allows patient to stabilize until definitive tx is implemented

Question 23

Anticoagulation

Answer 23

via Heparin if cause of obstruction is PE

• used to decrease the formation of new clot
• prevents existing clot from increasing in size while body is naturally dissolving it

Question 24

Actions: Prepare for definitive Tx: for PE

Answer 24

suction thrombectomy

-done to remove obstruction to ventricular emptying

Question 25

Nursing Teachings

Answer 25

>Causes of PE:
-avoid prolonged periods of inactivity
-walk every hour
-drink plenty of fluids
>Anticoagulation teaching

Question 26

Nurse Teachings: Causes of PE

Answer 26

> avoid prolonged periods of inactivity
walk every hour
drink plenty of fluids
-mobilization decreases the risk of likelihood of PE formation by decreasing formation of DVT
-dehydration increases tendency for blood to clot

Question 27

Anticoagulation Teaching

Answer 27

> use electric razor, soft tooth brushes, avoid contact sports
If on Coumadin (warfarin):
-regular follow-up laboratory testing (INR)
-limit foods high in vitamin K+ (leafy green vegetables)

Question 28

Evaluating Care Outcomes

Answer 28

• rapid recognition
• inotropic and vasoactive support helps maintain BP
• monitoring of clinical manifestations and hemodynamic status help evaluate therapeutic interventions
• successful tx = satisfactory BP, CO, and adequate tissue perfusion