Unit 2: Obstructive Shock Flashcards
Obstructive Shock
caused by a mechanical barrier to ventricular filling or ventricular emptying (increased afterload) = decreased CO
Examples of Disorders Resulting in impaired filling
- cardiac tamponade
- tension pneumothorax
Example of disorders resulting in increased afterload
severe valvular disease
Potential Cause of Obstructive Shock
- tension pneumothorax
- cardiac tamponade
- severe valvular disease
What Hemodynamic Parameters would show in Obstructive shock
- Decreased CO
- Variable CVP and PAOP
- Increased SVR
- Decreased venous oxygen saturation (SvO2 or ScvO2)
- Hypotension and Tachycardia
Risk Factors for Obstructive Shock
-extracardiac disorders that impair ventricular filling or emptying; impaired emptying also referred to increased right or left afterload; ex would be PE
Pathophysiology of Obstructive Shock
- 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
Clinical Manifestations of Obstructive Shock
- 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
Hemodynamic Parameters
- 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)
Medical Management
- 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
Medical Management: Intubation and Mechanical Ventilation
improving or enhancing oxygenation may help decrease myocardial workload, increase myocardial oxygen supply, and preserve myocardial tissue
Nursing Management: Assessment and Analysis
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
Nursing Assessments w/ Obstructive Shock
- Neurological Status
- Vital Signs
- Hemodynamic parameters
- Urine output
- Skin color and Temperature
- Laboratory Tests
Assessments: Neurological Status
- 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
Assessments: Vital Signs
- 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
Assessments: Hemodynamic Parameters
- 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
Assessment: Urine Output
decreased urine output as a result of decreased CO and stimulation of compensatory mechanisms that increase reabsorption of sodium + water
Assessment: Skin color and Temperature
cool and clammy skin as a result of poor peripheral perfusion
Assessments: Laboratory Tests
- ABGs: initial respiratory alkalosis d/t hyperventilation
- Venous oxygenation: decreased SvO2/ScvO2 = inadequate oxygen delivery
Nursing Actions
- apply 100% non-rebreather oxygen mask
- prepare for intubation + mechanical ventilation
- administer meds as ordered (vasoactive, anticoagulation)
- prepare for definitive Tx of cause
Actions: Prepare for intubation + mechanical ventilation
frequently necessary w/ obstructive shock in an effort to decrease oxygen consumption (VO2) and increase oxygen availability
Vasoactive Medications
norepinephrine, dopamine
- produce vasoconstriction, increases BP
- allows patient to stabilize until definitive tx is implemented
Anticoagulation
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
Actions: Prepare for definitive Tx: for PE
suction thrombectomy
-done to remove obstruction to ventricular emptying
Nursing Teachings
>Causes of PE: -avoid prolonged periods of inactivity -walk every hour -drink plenty of fluids >Anticoagulation teaching
Nurse Teachings: Causes of PE
> 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
Anticoagulation Teaching
> 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)
Evaluating Care Outcomes
- 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
