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level: Level 1

Questions and Answers List

level questions: Level 1

QuestionAnswer
Why does arterial blood pressure fall generally in shockThis can because of decrease in cardiac output and decrease in total peripheral resistance
What can cause fall in cardiac outputHypovolaemia Loss of contractility Reduced filling of the cardium
What causes the fall in Total Peripheral ResistanceProfound vasodilation
What are some causes of hypovolemic shockBlood loss due to hemorrhage Gastro-intestinal loss Burns Third space loss → fluid losses into spaces that are not visible, such as the bowel lumen (in bowel obstruction)
What is the pathophysiology behind hypovolemic shockDecreased blood volume leads to fall in venous pressure leading to reduced end-diastolic volume so there is reduced stroke volume which leads to fall in CO so a fall in mean arterial blood pressure Reduction in arterial BP is sensed by baroreceptors Which triggers a number of compensatory mechanisms: RAAS system Sympathetic system Internal transfusion
For the 3 compensatory mechanisms for hypovolemic shock, what is the pathophysiology behind thatIncreased sympathetic activity --> Increase HR, Increase contractility, Vasoconstriction , Venoconstriction RAAS --> angiotensin II leads to aldosterone release, Na+ reabsorption , vasoconstriction , releases noradrenaline to increase sympathetic activity and release of ADH from the anterior pituitary gland Internal Transfusion --> Increase in TPR leads to decrease hydrostatic pressure of the capillary which leads to net flow of fluid into the capillaries
What can prolonged shock lead toImparied tissue perfusion Tissue hypoxia release of metabolic vasodilators Fall in TPR further fall in mean arterial BP Vital organs are no longer perfused
What are some clinical features of hypovolemic shockTachycardia Sweating Weak peripheral pulses Prolonged CRT Pale skin Cold / clammy extremities Drowsiness / confusion / irritability Tachypnoea → high resp rate
Management of hypovolemic shockABCDE management : Give oxygen Replace what is lost i.e. blood or fluid Fix underlying cause e.g. surgery
If there is pulmonary embolism, how can that lead to shockA massive, proximal pulmonary embolism can occlude a large pulmonary artery, which means Right ventricle cannot empty Reduced return of the blood onto the left side of the heart Reduced left EDV Reduced Stroke Volume Reduced CO Fall in mean arterial pressure
Clinical picture of PE and managementShortness of Breath, Pleuritic chest pain, haemoptysis Raised JVP Tachycardia, hypotension, pale, sweaty Management --> warfarin and other blood thinners , also any replace any fluid
What is cardiac tamponadeWhen the heart cannot fill because there is a buildup in the pericardial space restricting filling Which leads to reduced EDV --> SV --> CO --> fall in Arterial BP
What are some causes of cardiac tamponade and clinical picture and also managementCauses --> Blunt / penetrating chest trauma or Myocardial rupture Clinical picture --> Becks Triad: ↓ BP + ↑ JVP + Muffled heart sounds, Tachycardia, SOB etc – features of compensation Management --> pericardiocentesis
What is cardiogenic shock/causesCaused by a fall in contractility so the ventricles are unable to empty properly Can be caused by : MI Acute worsening of heart failure Arrhythmias ( loss of coordinated pump action )
Pathophysiology of cardiogenic shockHeart fills but fails to pump effectively which results in Reduced SV Reduced CO fall in mean arterial BP Central venous pressure could be raised or normal
What is septic shockCirculating bacteria release endotoxins which stimulates a systemic inflammatory response, causing Vasodilation which leads to fall in TPR increased vascular permeability -> fall in intravascular fluid volume -> fall in CO Leads to fall in mean Arterial BP Baroreceptors detect drop in arterial pressure triggering increased SNS activity Increased HR + SV Vasoconstriction overridden by endotoxin effects This could also be a cause of distributive shock
What is anaphylatic shockAnaphylaxis = severe allergic reaction Hypersensitive response from the immune system to usually harmless substances Known as allergens e.g. peanuts etc. Results in release of histamine from mast cells Histamine is a potent vasodilator Fall in TPR and fall in mean arterial BP Histamine also causes bronchospasm and laryngeal oedema = difficulty breathing This could also be a cause of distributive shock
Management of anaphylatic shockABCDE management Adrenaline, hydrocortisone, chlorphenamine
What is cardiac arrestHeart suddenly stops pumping effectively – loss of cardiac output Due to a loss of effective electrical or mechanical activity Patient presents with loss of consciousness, loss of pulse, loss of breathing
Management of cardiac arrestCPR and defibrillation / drugs electrical current delivered to the heart depolarises all cells potential for coordinated electric activity to restart Drugs – adrenaline, amiodarone