Cardiac Shock Cardiogenic Shock

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Cardiac ShockCardiogenic Shock

• Mella Buckley,
• Cardiothoracic
• Advanced Nurse Practitioner,
• St Jamess Hospital,
• Dublin

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Objectives

• Define Shock
• Cardiogenic Shock
• Etiology/Causes
• Pathophysiology
• Recognise clinical features/clinical
  manifestations
• Management
• Treatments
• Complications

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Definition of Shock

• Clinical condition resulting from acute
  generalised state of inadequate tissue perfusion
  causing tissue hypoxia
• Insufficient blood (oxygennutrients) reaching
  tissues and insufficient removal of waste from
  tissues
• Not to be confused with cardiac arrest which is
  the acute cessation of the cardiac pump.
• Shock can lead to a cardiac arrest.

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Different types of Shock

• Hypovolaemic Shock- Fluid loss
• Cardiogenic Shock- Failure of heart to pump
  effectively
• Distributive Shock- (septic shock, anaphylactic
  shock, neurogenic shock)-Peripheral
  vasodilatation causing a fall in the volume of
  blood returning to the heart

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Cardiogenic Shock
Failure of the heart to pump effectively
resulting in inadequate circulation of
blood Causes Myocardial Infarct Cardiomyopathy (
Heart muscle disease) Cardiac valve
disorders Congenital defects (ventralseptal
defect) Prolonged cardiopulmonary bypass

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Etiology
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Pathophysiology

• Decrease in Cardiac Output
• Fall in blood pressure
• High Left Ventricular Filling Pressures
• Compensatory response
• Increase systemic vascular resistance (increase
  blood flow to the heart)
• Increase heart rate (increase blood to the
  tissues)
• Resulting physical manifestations
• Cool peripheries
• Weak thready pulse
• Decreased urine output
• .

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Signs of decreased tissue perfusion

• Restlessness or decreased conscious level
• Hypotension
• Increased respiratory rate
• Poor urine output
• A weak thready pulse or absent pulse
• Cool, clammy, and mottled skin
• Poor signal on pulse oximeter
• Distended jugular vein
• Fatigue due to hyperventilation

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Clinical Manifestations

• Radiographic Findings
• Enlarged Heart
• Pulmonary Congestion
• Pulmonary Findings
• Dyspnoea
• Increased respiratory rate
• Inspiratory crackles, possible wheeze
• Arterial blood gases show a low O2
• Respiratory Alkalosis

• Non invasive Findings
• Thready, rapid pulse
• Narrow pulse pressure
• Distended neck veins
• Arrythmias
• Chest pain
• Cool, pale, moist skin
• Oliguria
• Decreased mentation

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Clinical Manifestations cont.

• Haemodynamic Findings
• Systolic Blood Pressure lt 90 mmHg (sustained gt
  30min.)
• Mean Arterial Pressure lt70 mmHg
• Cardiac Indexeslt 2.2 L/min/m2
• Pulmonary Artery Wedge Pressure gt 18 mmHg

• Echocardiogram image from a patient with
  cardiogenic shock shows enlarged cardiac
  chambers

Echocardiogram image from a patient with
cardiogenic shock shows enlarged cardiac
chambers
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Pulmonary Artery Wedge Pressure

• measured by a Swan-Ganz catheter, is the pressure
  measured in a pulmonary artery after occlusion of
  that artery. Because of the large compliance of
  the pulmonary circulation, it provides an
  indirect measure of the left atrial pressure.

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Cardiac Index

• Cardiac index (CI) is a parameter that relates
  the cardiac output to body surface area, thus
  relating heart performance to the size of the
  individual. Cardiac output is the volume of blood
  being pumped by the heart, in particular by a
  ventricle in a minute.
• The normal range of cardiac index is 2.6 - 4.2
  L/min per square meter.

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Management of Cardiac Shock

• Aim
• Increasing Myocardial Oxygen Delivery
• Maximising Cardiac Output
• Decreasing Left Ventricular Workload

• Treatment
• -Medications
• -IABP
• -Revascularisation

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Medication

• Fluid Resuscitation if required
• Oxygenation and Airway Protection
• Correct electrolyte imbalance
• Analgesia if required
• Discontinue - Nitrates, beta-blocker and ace
  inhibitors as they reduce blood pressure

• Inotropic Agents, increase the force of muscle
  contraction
• Diuretics, increase the excretion of water and
  therefore reduce the workload of the heart
• Nitrates once B.P. has stabilised
• Thrombolytic s??? too late

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IABPmaximise cardiac output
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Revascularisation

• Percutaneous Transluminal Coronary Angioplasty
  
• (PTCA)
• or
• Coronary Artery Bypass Grafting
• (CABG)

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Angiography/Angioplasty

• Following angioplasty of the critical
  stenosis, coronary flow is reestablished. The
  patient recovered from cardiogenic shock.

• A patient with cardiogenic shock
• demonstrates severe stenosis of

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Complications of Cardiogenic Shock

• Cardiopulmonary arrest
• Dysrythmias
• Renal failure
• Multisystem Organ Failure
• Ventricular Aneurysm
• Stroke
• Death

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The downward spiral in cardiogenic shock
Hollenberg, S. M. et. al. Ann Intern Med
199913147-59
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Mortality

• gt 55 inpatients treated medically die from
  cardiogenic shock

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Conclusion

• Cardiac shock is life-threatening
• The key to successful management is early
  diagnosis and prompt medical management
• Be aware of the signs of decreased tissue
  perfusion
• Assess total perfusion (peripheries, urine
  output) and not simply blood pressure

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References

• Towbin JA, Bowles NE. The failing heart. Nature
  2002415(6868)227-33.
• Sommers MS. The cellular basis of septic shock.
  Crit Care Nurs Clin North Am 200315(1)13-25.
• Moore PR, Kharbanda R, Banner NR. Acute heart
  failure and cardiogenic shock. Br J Hosp Med
  (Lond) 200869(1)8-12.
• http//www.emedicine.com/med/TOPIC285.HTM
• Marino, P.L. The ICU Book 3rd Ed. 2007 Lippincott
  Williams and Wilkins
• Hudak, C.M. Critical Care Nursing A Holistic
  Approach 8TH Ed. 2005 Lippincott Williams and
  Wilkins

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Any Questions?