Unit 2: Cardiogenic Shock Flashcards
Cardiogenic Shock
a state of hypoperfusion at the tissue level resulting from severe impairment of ventricular contraction in the presence of adequate vascular volume
-independent of fluid volume the heart muscle cannot adequately pump causing decreased CO and poor perfusion
Components of Cardiogenic Shock
- reduction of contractility b/c of damaged myocardium; reduces ejection fraction (EF)
- increased left and right filling pressures but decreased CO
- venous oxygen saturation decreases w/ increased oxygen extraction at the tissue level b/c of low cardiac output
- leads to univentricular or biventricular failure, profound hypotension, and pulmonary edema
Risk Factors for Cardiogenic Shock
- any disorder that results in acute deterioration of myocardial mechanical contraction
- end-stage congestive HF
- cardiomyopathy
- hypertension
- diabetes
- multiple-vessel coronary artery disease
- acute vascular disease
Vicious Cycle of Cardiogenic Shock
a cycle of increased oxygen demand w/ inadequate perfusion worsens ischemia ending in death if not broken
>the decreased CO leads to stimulation of compensatory mechanisms
-the SNC stimulation that increases HR, contractility, myocardial workload and oxygen demand, worsens ischemia
-systemic vasoconstriction increases the workload of an already stressed heart by increasing afterload
-fluid retention induced by the renin-angiotensin-aldosterone system increases filling pressures; contributes to development of pulmonary edema and hypoxemia
Clinical Manifestations of Cardiogenic Shock
Initial: chest pain, diaphoresis, nausea + vomiting
- decreased LOC
- decreased urine output
- poor pulses
- pale, cool skin
- decreased bowel sounds
- SOB, crackles on auscultation, decreased SpO2 d/t pulmonary edema
- increased lactate levels
- metabolic acidosis
Late Manifestations of Shock
- become more pronounced
- profound hypotension and bradycardia
- organ systems begin to fail
- increases in Creatinine and liver enzymes
- coma
- cyanotic; mottled skin
- absent bowel sounds
- hypoglycemia
- anuria
What the Hemodynamic Parameters would look like in Cardiogenic Shock
- Increased central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP)
- High systemic vascular resistance (SVR)
- Low cardiac output (CO)
- Decreased venous oxygen saturation (SvO2)
- Hypotension and Tachycardia
Lab and Diagnostic Tests
> 12-lead electrocardiogram
Cardiac enzymes
Chest Radiograph
Why 12-Lead ECG?
to r/o or rule in MI as a cause of shock
Why Cardiac Enzymes?
> Troponin, CK, CK-MB
-help confirm presence or absence of acute MI
Why Chest Radiograph?
- to r/o other causes of hypotension and shock (pneumothorax or cardiac tamponade)
- can confirm presence of pulmonary edema
Treatment Priorities for Cardiogenic Shock
- Stabilizing oxygenation
- Initiating drug therapy to increased BP and CO
- Emergency revascularization, an attempt to restore blood flow through percutaneous coronary intervention (PCI)
- Intra-aortic balloon pump (IABP) therapy to increase myocardial oxygen supply and decrease myocardial oxygen demand
- if tx not successful, use of VAD
Stabilizing Oxygenation
- 100% oxygen through a non-rebreather
- Intubation and mechanical ventilation to support ventilation and maximize oxygenation
Medications for Cardiogenic Shock
- Vasopressors
- Inotropic Support
- Nitroglycerin
- Diuretics
- Morphine Sulfate
Vasopressors/ Vasoactive meds
> Dopamine
Norepinephrine
-support BP through vasoconstriction
-to sustain BP and help maintain mean arterial pressure
>care should be taken when taken b/c the meds will increase systemic vascular resistance increasing myocardial workload
Inotropic Support
> Dobutamine
- increase myocardial contractility
- increases CO
Nitroglycerin
to decrease preload and afterload
- vasodilation
- can decrease BP
Diuretics
used w/ caution
- attempt to decrease filling volumes
- decrease vascular volume if filling pressures are extremely elevated
Morphine Sulfate
- help relieve pain d/t MI
- vasodilator that decreases venous return and preload
Emergency Revascularization
through percutaneous coronary intervention (PCI)
- insertion of a catheter through an artery up into the involved coronary artery and inflation of a balloon to break up the plaque causing the obstruction of flow
- stent is placed to maintain patency of the vessel
Intra-aortic Balloon Pump Therapy (IABP)
used when drug therapy does not improve CO
- increases myocardial oxygen supply
- decreases myocardial oxygen demand
- balloon at tip of catheter; it is timed to inflate at start of diastole (rest) and deflate before systole
- when inflates, blood is displaced toward the coronary arteries and into systemic circulation, improving coronary and systemic perfusion
- deflating the balloon decreases afterload, decreasing the workload of the left ventricle
Ventricular Assist Device (VAD)
surgically inserted mechanical pump that assists the pumping of the left ventricle and decrease workload of the heart
Nursing Management: Assessment and Analysis
clinical manifestations are r/t a decrease in CO and impaired tissue perfusion
- chest pain
- diaphoresis
- nausea
- hypotension
- tachycardia
- tachypnea
- crackles, SOB, decreased SpO2 if edema present
- decreased LOC
- weak pulses
- cold, cyanotic, mottled skin
- decreased urine output
- absent/decreased bowel sounds
> W/o successful intervention:
- profound hypotension
- bradycardia
- hypoxia
Nursing Assessments for Cardiogenic Shock
- Neurological status
- Vital Signs
- Hemodynamic parameters
- Breath sounds
- Urine output
- Skin Color + Temperature
- Lab tests; ABGs, SvO2, Metabolic profile, Lactate/Base Deficit
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
Assessments: Vital Signs
- hypotension and tachycardia b/c of decreased CO
- respiratory rate increased in an effort to increase tissue oxygenation and remove CO2 to compensate for metabolic acidosis
- oxygenation may be decreased d/t presence of pulmonary edema
Assessments: Vital Signs
- hypotension and tachycardia b/c of decreased CO
- respiratory rate increased in an effort to increase tissue oxygenation and remove CO2 to compensate for metabolic acidosis
- oxygenation may be decreased d/t presence of pulmonary edema
Hemodynamic Parameters
- both right and left preloads are increased b/c of impaired pumping ability of the heart, but CO is low
- to compensate for low CO, vasoconstriction occurs, increasing systemic vascular resistance (SVR)
Assessment: Breath Sounds
crackles d/t pulmonary edema
Assessment: Urine Output
- decreases as a result of decreased CO
- decreases as a result of stimulation of compensatory mechanisms that increase reabsorption of sodium and water
Assessments: Skin Color and Temperature
cold and clammy skin = progressing shock
Assessment: Lab Tests: ABGs
initially reflect respiratory alkalosis d/t tachypnea
-later stages = metabolic acidosis d/t anaerobic metabolism
Assessment: Labs: Venous Oxygen Saturation (SvO2)
decreased SvO2/ScvO2 = inadequate oxygen delivery (DO2)
Assessment: Labs: Metabolic Profile
- Renal failure = increase in BUN + Creatinine
- Liver Failure = increase liver function test results b/c of decreased organ perfusion
Assessment: Labs: Lactate (Lactic acid)/ Base Deficit
increase lactate level and negative (-) base deficit = poor perfusion at cellular level
Nursing Actions for Cardiogenic Shock
- Apply 100% non-rebreather oxygen mask
- Prepare for intubation and mechanical ventilation
- Administer medications as ordered: Vasoactive meds, Inotropic Meds, Diuretics, Morphine Sulfate
- Administer fluids as prescribed
- Restrict Activity
Nursing Actions for Cardiogenic Shock
- Apply 100% non-rebreather oxygen mask
- Prepare for intubation and mechanical ventilation
- Administer medications as ordered: Vasoactive meds, Inotropic Meds, Diuretics, Morphine Sulfate
- Administer fluids as prescribed
- Restrict Activity
Why Administer fluids as prescribed?
used cautiously
-to increase CO if filling pressures are low and there is no signs of pulmonary edema
Why Restrict Activity?
will decrease cardiac workload and oxygen consumption (VO2)
Nursing Education/Teaching
> Instruct about rest periods
-increased activity or stress levels cause increased myocardial oxygen consumption (VO2) and can worsen progression of shock
Teach about causes of cardiogenic shock and MI
Evaluating Care Outcomes
- rapid recognition
- inotropic and vasoactive support help maintain adequate CO and BP to ensure sufficient oxygen supply to the tissues
- monitoring of clinical manifestations and hemodynamic status helps evaluate therapeutic interventions
W/ Successful treatment
- satisfactory BP level
- satisfactory CO
- adequate tissue perfusion
