Shock Flashcards
What is the general definition of shock?
Shock is defined as low tissue perfusion resulting in cellular injury and tissue hypoxia.
What laboratory finding is commonly seen in all types of shock?
Elevated lactate dehydrogenase.
What clinical symptoms are commonly seen in patients with shock?
- Hypotension with a mean arterial pressure less than 70 mmHg.
- Clinical signs of hypoperfusion including cold skin.
- Altered mental status.
- Low urine output.
What is the normal urine output rate?
Greater than or equal to 0.5 milliliters per kilogram per hour in adults.
What is cardiac index and its normal value?
Cardiac output corrected for body surface area. Normal cardiac index is between 2.8 to 4.2 liters per minute per meter squared.
What is central venous oxygen saturation and its normal value?
A measure of oxygen delivery and utilization. Normal central venous oxygen saturation is between sixty five and seventy five percent.
What are the most common causes of hypovolemic shock?
Hemorrhage, dehydration, and burns.
How do patients with hypovolemic shock present?
Cold and clammy skin, hypotension, tachycardia, weak pulses, and decreased urine output.
What are the hemodynamic parameters in hypovolemic shock?
- Decreased central venous pressure.
- Decreased pulmonary capillary wedge pressure.
- Decreased cardiac output and cardiac index.
- Increased systemic vascular resistance.
- Decreased central venous oxygen saturation.
What is the pulse pressure in hypovolemic shock?
narrow.
What is the management for hypovolemic shock?
- Fluid resuscitation with crystalloids such as normal saline or lactated Ringer’s solution.
- Blood transfusion if hemorrhagic shock is present.
What are the most common causes of cardiogenic shock?
Acute myocardial infarction, heart failure, valvular disease, and arrhythmias.
How do patients with cardiogenic shock present?
Chest pain, tachycardia, hypotension, pulmonary congestion, and cool extremities.
What are the hemodynamic parameters in cardiogenic shock?
- Increased central venous pressure.
- Increased pulmonary capillary wedge pressure.
- Decreased cardiac index.
- Increased systemic vascular resistance.
- Decreased central venous oxygen saturation.
What is the management of cardiogenic shock?
- Inotropes such as dobutamine (perferred when the cardiac index is low but the BP is normal) or milrinone (is a PDE3 inhibitor that increases cardiac output).
- Vasopressors if hypotensive such as norepinephrine
- Mechanical support including intra-aortic balloon pump or extracorporeal membrane oxygenation.
How do patients with obstructive shock secondary to cardiac tamponade present?
- Hypotension
- Distended neck veins also known as jugular venous distension
- Pulsus paradoxus in cardiac tamponade
- In tamponade, left-sided preload is decreased, but measured PCWP is paradoxically increased due to external compression by pericardial fluid.
- Respiratory distress in pulmonary embolism or pneumothorax
What are the hemodynamic parameters in obstructive shock secondary to pulmonary embolism?
- Increased central venous pressure
- Pulmonary capillary wedge pressure is decreased in acute PE because less blood is pevented from going to lungs from the right atrium to the lungs.
- Decreased cardiac index due to obstructed flow from the lungs to the left atrium and left ventricle.
- Increased systemic vascular resistance.
- Decreased central venous oxygen saturation
What is PCWP in tension pneumothorax and pulmonary embolism?
Decreased.
What is SVR in septic shock?
Low.
