Shock Flashcards
(37 cards)
What is haemodynamic shock?
A life-threatening, generalized form of acute circulatory failure associated with inadequate oxygen utilization by the cells.
What are the three key factors involved in haemodynamic regulation?
Blood pressure, circulating volume, and vascular resistance.
What system regulates blood pressure and circulation via nerves and hormones?
Neurohumoral control of circulation.
What are the key neurological control systems of haemodynamics?
Arterial baroreceptor reflex and cardiopulmonary baroreceptors.
What hormone system plays a major role in humoral control of circulation?
Renin-angiotensin system (RAS).
What are the four main mechanisms of shock?
Hypovolaemic, cardiogenic, obstructive, and distributive.
What are examples of distributive shock?
Septic shock, anaphylaxis, neurogenic shock, SIRS.
What can cause obstructive shock?
Pulmonary embolism, cardiac tamponade, tension pneumothorax, constrictive pericarditis.
What defines cardiogenic shock?
Pump failure due to systolic or diastolic dysfunction.
What causes hypovolaemic shock?
Loss of intravascular volume (e.g., bleeding, burns, vomiting, DKA, third spacing).
What are the four stages of shock?
Initial, compensatory (nonprogressive), progressive (intermediate), and refractory (irreversible).
What happens in the initial stage of shock?
Anaerobic metabolism begins, often not clinically apparent.
What defines the progressive stage of shock?
Organ dysfunction due to failure of compensatory mechanisms.
What is the hallmark of the refractory stage of shock?
Irreversible cellular damage; recovery is unlikely.
What are the three clinical “windows” for detecting tissue hypoperfusion?
Peripheral (skin), renal (urine output), and neurologic (mental state).
What urine output is considered a sign of shock?
< 0.5 mL/kg/h.
Is hypotension always present in shock?
No, shock can occur with normal BP due to compensation.
What lactate level supports a diagnosis of shock?
> 2 mmol/L (hyperlactatemia).
What tool can help distinguish the type of shock?
Echocardiography.
Key signs of hypovolaemic shock?
Anxiety, tachycardia, pallor, cool/clammy skin, weak pulses, oliguria/anuria.
Causes of cardiogenic shock?
MI, arrhythmias, myocarditis, valve disease, tamponade, blunt trauma.
Key signs of cardiogenic shock?
Dyspnoea, tachycardia, hypotension, cold extremities, pulmonary oedema.
What are signs of obstructive shock?
Tachycardia, chest pain, air hunger, hypotension.
What causes excessive afterload in obstructive shock?
Tension pneumothorax, tamponade, constrictive pericarditis.
