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