Shock can be classified into 3 different types: Hypovolaemic Shock, Cardiogenic Shock, and Septic Shock. Whilst the management of shock varies based on the type of shock it is, the resulting effect of all 3 types of shock is the same – decreased tissue perfusion.
Cardiogenic Shock
- impaired ability of the heart to pump blood as it should (left or right ventricle dysfunction), causing systemic hypoperfusion and tissue hypoxia
- may be caused by cardiac injury (eg. cardiac tamponade), cardiopulmonary arrest, following cardiac surgery, dysrhythmias (severe tachycardia or bradycardia), myocardial tissue necrosis following a Myocardial Infarction, or structural problems (eg. valvular damage or regurgitation, pulmonary embolus, acute myocarditis, papillary muscle rupture, intracardiac tumour, and congenital defects
- compensatory mechanisms may worsen the situation…eg. reduced cardiac output due to myocardium death causes increased contractility which further increases the heart’s workload and oxygen demand; reduced blood pressure causes the release of catecholamines which leads to vasoconstriction, subsequently leading to a further increase in cardiac workload and oxygen demand
Cardiogenic Shock Signs & Symptoms
- chest pain or chest trauma
- altered level of consciousness
- cool, pale moist skin
- weak thready pulse
- tachycardia possibly with dysrhythmias
- tachypnoea
- SBP <90mmHg and MAP 30mmHg less than normal
- urine output <30ml/hr
- jugular venous distension
- reduced cardiac output and cardiac index
- increased PAWP (Pulmonary Artery Wedge Pressure), increased RA (right atrium) pressure & increased SVR (systemic vascular resistance)
- signs of pulmonary oedema eg. hypoxaemia, crackles, and frothy sputum
Management
- Treat Underlying Cause to Prevent Further Damage & Preserve Healthy Myocardium
- Enhance Pumping Effectiveness by Increasing Cardiac Output
- Improve oxygen perfusion in the heart as well as other organs and tissues
- Increase oxygen supply and reduce oxygen demand of the heart
- provide oxygen therapy through supplementary oxygen or mechanical ventilation due to cardiac ischaemia and chest pain
- administer morphine for analgesia and sedation, and promote rest
- if patient has pulmonary oedema, administer diuretics eg. furosemide or bumetanide, and oxygen whilst monitoring haemodynamic status and ABGs of the patient; diuretics reduce fluid accumulation which causes a decrease in preload – monitor for fluid and electrolyte imbalance
- provide mechanical reperfusion through PCI (percutaneous coronary intervention) eg. angioplasty and coronary stents, or a coronary artery bypass graft (CABG)
- provide thrombolytic therapy through pharmacologic agents eg. streptokinase, urokinase, tissue plasminogen activator TPA, which dissolve clots in coronary artery BEFORE cardiogenic shock sets in; ATTENTION: watch out for bleeding!
- provide drug therapy that helps improve cardiac output by increasing cardiac contractility, decreasing preload and afterload, and stabilising the heart rate
- provide fluids with great caution since this increases risk of pulmonary oedema
- administer inotropes (eg. dobutamine or milrinone) to improve contractility and reduce afterload, and vasopressors (eg. adrenaline or noradrenaline) to increase contractility, vasoconstriction, blood pressure, and heart rate NOTE: inotropes and vasopressors can be given in combination
- administer vasodilators eg. nitrates to reduce oxygen demands by reducing preload through venous dilation, reducing afterload by arterial dilation due to less resistance, increasing oxygen supply to the myocardium due to coronary vasodilation, but ATTENTION – vasodilators cause hypotension!
- treat arrhythmias with anti-arrhythmic drugs eg. amiodarone to help increase time for ventricular filling
- make use of the intra-aortic balloon pump – a long balloon attached to a large bore catheter inserted through the femoral artery to the descending aorta, with the balloon tip placed just below the aortic arch, and the bottom tip above the renal artery; the attached machine helps by inflating the balloon with helium at the start of diastole when the aortic valve closes, and rapidly deflating it at the start of ventricular systole, just before the aortic valve opens; ATTENTION to possible complications eg. dislodgement of clots, limb ischaemia / neuropathy (check pedal pulses), bleeding (check clotting time before insertion and removal), infection, balloon rupture, and improper position
- if indicated, the Left Ventricular Assist Device may be used – flow pump which is placed across the aortic valve into the left ventricle; it draws blood continuously from the left ventricle to the proximal aorta; may be used prior to transplantation or long term for transplantation-ineligible patients
- the VA-ECMO is a device through which deoxygenated blood is drained through the central vein; blood is then oxygenated outside of the patient’s body, before being returned through the large artery; it helps improve aortic flow and organ perfusion, however, it may increase afterload and worsen pulmonary oedema; note increased risk of acute kidney injury, severe bleeding, lower limb ischaemia, and stroke
- if indicated, a patient with cardiogenic shock may undergo surgical interventions such as human heart transplantation, repair of septal, ventricular, or papillary muscle rupture, or valve repair or change
Cardiogenic Shock and Intra-aortic Balloon Pump => https://www.youtube.com/watch?v=mADxD7C8jBw
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Claire Galea is a mum of three currently in her final year following a Degree in Nursing at the Faculty of Health Sciences, University of Malta, as a mature student.
Claire is keen about public education on health-related subjects as well as holistic patient-centered care. She is also passionate about spreading awareness on the negative effects that domestic abuse leaves on its victims’ mental, emotional, social and physical wellbeing.
Claire aspires to continue studying following completion of her Nursing Degree, because she truly believes in lifelong education.
Claire is keen about public education on health-related subjects as well as holistic patient-centered care. She is also passionate about spreading awareness on the negative effects that domestic abuse leaves on its victims’ mental, emotional, social and physical wellbeing.
Claire aspires to continue studying following completion of her Nursing Degree, because she truly believes in lifelong education.
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