Flashcards in Haemodynamic Disorders Deck (24):
Abnormal increase in interstitial fluid.
What three forces determine the movement of blood between vessels and tissue?
Capillary hydrostatic pressure.
Plasma Hydrostatic pressure.
Plasma Oncotic pressure.
What is non-cardiogenic pulmonary oedema?
ARDS, acute respiratory ditress syndrome, increased pulmonary vessel permeability often caused by sepsis, shock or trauma.
What are the four types of cerebral oedema?
Vasogenic - Break down of blood-brain barrier
Interstitial - Breakdown of CSF-brain barrier.
Cytotoic - Intracellular caused by deranement of NA-K pumps.
Osmotic - Increased plasma osmolality.
What are the possible consequences of cerebral oedema?
Herniation due to rise in intracranial pressure.
What are the two common causes of generalised oedema?
Left ventricular failure.
What is a consequence of oedema in peripheral setting?
Impaired wound healing
What are the three main factors affecting thrombus formation?
Vessel Wall Injury
What is cardiac thrombosis caused by and what is a complication?
Stasis, such as due to atrial fibrillation. Can cause systemic embolisation.
What causes arterial thrombosis?
Vessel wall injury.
What causes venous thrombosis and what is a complication?
Stasis and hypercoagulability. Can cause pulmonary embolism.
What are the four possible fates of a thrombus?
Propagation - Fibrin accumulates leading to growth
Embolisation - Dislodges and circulates in blood
Dissolution - dissolved by fibrinolytics
Organisation and Recanalisation - Lumen appears through remodelling
Where do most arterial thromboemboli originate?
A mass of extravasated blood confined within an organ or tissue.
What are the three classes of haemorrhage based on size?
Petechiae = 1-2mm
Purpura = >3mm
Ecchymoses = 1-2cm
What is shock characterised by?
What two equation are used to evaluate the effects of changes in various vascular factors?
MAP = CO X SVR
CO = HR X SV
Describe the five types of shock.
Cardiogenic - impaired heart function, reduced SV
Hypovolaemic - Lose of blood volume, reduced SV and MAP causes tachycardia
Anaphylactic - IgE mediated hypersensitivity, reduced MAP as reduced SVR
Neurogenic - Sympathetic pathway injury, Reduced SV from systemic vasodilation.
Septic - Inflammatory response, reduced SVR so reduced MAP.
Tissue necrosis due to unresolved ischaemia.
What are the two types of infarct and how do they differ?
Red - Haemorrhagic, happens in organs with dual blood supply
White - Anaemic, hapens when organ has one blood supply
How can the rates of development of the occlusion affect the
In slow occlusion, collateral vessels may be able to form.
What are the two types of myocardial infarction?
Transmural - Across whole heart wall.
Subendocardial - Only layer underendocardium affected
Describe the process of atherosclerosis.
Macrophage infiltrates tissue at point of damage, release cytokines.
Cytokines recruit LDLs which are oxidised and become pro-inflammatory. - Drive plaque progression.
Smooth muscle cells migrate from Tunica media to lesion form fibrous, collagen-rich cap.