Sesison 12 Flashcards
What is a possible complication of varicose veins?
Venous ulcers
What is cardiac arrest and what can cause it?
Unresponsiveness associated with a lack of pulse. Can be due to:
Asystole - loss of electrical and mechanical activity
Pulseless electrical activity (PEA)
Ventricular fibrillation - most common. Often following MI/electrolyte imbalance/arrhythmias
What is the the treatment for cardiac arrest?
Basic life support - chest compression and external ventilation
Advanced life support - defibrillation to depolarise all cells allowing coordinated electrical activity to restart
Adrenaline - advances myocardial function and increases TPR
What is haemodynamic shock?
An acute condition of inadequate blood perfusion throughout the body. Can be due to a fall in CO or TPR (BP=CO*TPR)
Describe the different types of shock and their possible causes
Cardiogenic shock - inability of the heart to eject enough blood
Mechanical shock - restriction of filling of the heart (e.g. Cardiac tamponade) or obstruction of blood flow through the lungs (e.g. Pulmonary embolism).
Hypovolaemic shock - loss of circulating blood volume (e.g. Haemorrhage, severe burns or diarrhoea)
Normovolaemic (distributive) shock - uncontrolled decrease in TPR (e.g. Sepsis or anaphylaxis)
What are common causes of Cardiogenic shock and what are the consequences?
MI, serious arrhythmias or acute worsening of heart failure.
CVP may be normal or raised. Dramatic drop in BP means tissues poorly perfumed - coronary arteries exacerbate problem.
What is cardiac tamponade?
A build up of blood/fluid in the pericardial cavity that restricts the filling of the heart in diastole. Results in a high CVP, low arterial BP and normal electrical activity.
Describe the changes and compensatory response resulting from a 30-40% blood loss
Following haemorrhage, CVP falls, CO falls and arterial BP falls which is detected by baroreceptors.
There is a compensatory response to increase sympathetic stimulation resulting in tachycardia, increased force of contraction, vasoconstriction and venoconstriction.
Describe the process of decompensation following the compensatory response of the body to a haemorrhage
The increased TPR reduces the capillary hydrostatic pressure so fluid moves in to the vessels. This impairs tissue perfusion so there will be tissue damage due to hypoxia and a release of chemical vasodilators. TPR will then fall, rapidly decreasing BP so vital organs are no longer be perfused, resulting in multiple organ failure.
Describe how septicaemia results in toxic shock and how patients would present
Endotoxins released by bacteria cause profound vasodilation, impairing perfusion to vital organs. This overrides the vasoconstrictor effect of the sympathetic response.
Patients have tachycardia and warm, red extremities. Treated with adrenaline to cause vasoconstriction and antibiotics.
Describe how anaphylactic shock comes about
A severe allergic reaction causes histamine to be released from mast cells. This has a powerful vasodilator effect, reducing total peripheral resistance and also causes bronchoconstriction and laryngeal oedema, making it difficult to breathe. Treated with adrenaline to cause vasoconstriction and anti-histamine.
