Shock Flashcards
What are the different types of shock?
Hypovolemic Cardiogenic Anaphylactic Septic Spinal Obstructive Hypoadrenal
What is hypovolemic shock?
Inadequate blood volume within the blood vessels.
What are common causes of hypovolemic shock?
External bleeding
Internal bleeding
Vomiting and diarrhoea
Burns
What is cardiogenic shock?
Due to inadequate cardiac output as a result of a heart problem. The most common cause is acute myocardial infarction. Usually left ventricular dysfunction.
What is anaphylactic shock?
Due to mediators released in response to a severe allergic reaction. Rapid onset multi organ, generalised hypersensitivity syndrome. Histamines cause blood vessels to vasodilate and leak resulting in decreased blood pressure.
What is septic shock?
Due to systemic inflammatory state secondary to the immune response to an infection. Causes vasodilation and capillary leak as well as impaired cardiac function.
What is spinal shock?
Due to the loss of sympathetic nervous system following spinal cord injury. Results in vasodilation and capillary leak
What is obstructive shock?
Due to pulmonary embolism causing inadequate right ventricular function or tension pneumothorax causing inadequate right ventricular filling. These cause pressure on blood vessels which obstruct blood flow and cause shock.
What is hypoadrenal shock?
Due to inadequate circulating levels of cortisol. Cortisol usually enhances the vasoconstrictive effects of adrenaline. A lack of it results in vasodilation.
What is congential adrenal hypoplasia?
Small adrenal glands - don’t produce enough cortisol. More at risk of hypoadrenal shock.
What can cause vasodilation?
Histamines
Toxins released by bacteria
Parasympathetic nervous system (of loss of SNA)
What are the three stages of shock?
Compensated
Decompensated
Irreversible
What are the compensatory mechanisms the body uses when in shock?
Increased HR Increased contractility Increased resp rate Increased breathing Diversion of blood Constriction of blood vessels
What happens in decompensated shock?
The SNS cannot ensure constant delivery of oxygenated blood. Tissues begin to release toxic metabolites. These cause vasodilation.
Heart rate cannot maintain perfusion and so blood pressure begins to fall.
What are the signs of shock?
Tachycardia Cold, clammy skin Prolonged capillary refill Tachypnoea Narrowed pulse pressure (diff between systolic and diastolic) Hypotension Confusion/altered LOC