Wk 5 Flashcards
Haemodynamic monitoring
Study of movement and forces of blood within the cardiovascular system using sophisticated equipment and or special catheters
Can be invasive or noninvasive
Blood pressure
Pressure exerted by blood upon walls of blood vessel
Generated by contraction of myocardium (left ventricle)
Depends on CO
Preload
After load
Contractility and HR
Cardiac cycle
Atrial diastole: blood returns to atria, all heart is relaxed, all valves closed
Atrial systole: atria contract, AV valves open, blood to ventricle
Ventricular systole: ventricles contract, semilunar valves open, blood lasses to arteries
Ventricular diastole: all heart relaxes, all valves close, blood returns to atria
Resistance to blood flow
Opposition or impedance to blood flow as a result of force of friction between blood cells, proteins and blood vessels. Depends on: Viscosity Vessel length Vessel radius
Oxygen delivery governed by ….?
CO stroke volum X HR
Hameoglobin 1 gram can carry 1.34 ml o2
O2 sats
Noninvasive monitoring
Doesnt require a device to be put into body Does not breach skin ECG Pulse oximetry Arterial and venous Doppler Expire carbon monoxide monitors
Cardiac ECG monitoring
Cardiac arrest Arrhythmia Chest pain Heart failure Collapse Shock and hypotension Palpitations Breathing difficulty
Basic conduction
Depolarisation initiated in sinoatrial node SA
Slow conduction through AV node atrioventricular node
Rapid conduction through purkinje fibres
Muscle contraction should follow
Cardiac action potentials
HR and rhythm determined by conduction system
Action potential responsible for depolarisation of cardiac muscle
Ion exchange between Na, K and Ca
Echocardiogram
Ultrasound Size and shape of Heart Pumping capacity Location and extent of tissue damage CO
Invasive monitoring
Vascular system to be cannulated, and pressure or flow writhing the circulation interpreted
What are transducers
Medical pressure measurement systems
Clinical pressure waves converted into electrical signals
Direct pressure readings of arterial, central and pulmonary artery
Arterial blood pressure
Why: continuous monitoring, sensitive and accurate, assess effectiveness of Tx, repeated samples.
Arterial lines
In patients with unstable BP IV vasoactive drugs such as inotropes Patients In shock Burn patients Sites: radial arteries, femoral arteries
Managing arterial lines
Infection control Label in red arterial line Satisfactory wave form Check tubing for leaks Observe cannula site Observe limb colour and movement
