CVS 1 Haemodynamics Flashcards
Haemodynamics meaning
Physical factors that control blood flow
What is serum?
Plasma without clotting factors
What is fluid collected from clotted blood called?
Describe the composition after centrifuging
Serum
COMPOSITION
Serum
Clot
What is fluid collected from unclotted blood called?
Describe the composition after centrifuging
Plasma
COMPOSITION
Plasma
Buffy coat - WBCS + platelets
RBCS
What can change whole blood viscosity?
Polycythemia - increased RBC
Thrombocytopenia- increased platelets
Leukaemia- increased WBCs
Causes sludgey thick blood
What can cause min changes to whole blood viscosity?
Acute phase plasma proteins
E.g. fibrinogen, compliment , C reactive protein
What is C reactive protein an indicator of?
Inflammation
Flow meaning and units
Volume of blood transferred per time unit
mL/min
What does total flow equal?
Cardiac output
Pressure meaning and units
Force per unit area
mmHg for blood pressure
How are flow and resistance related?
Reciprocally
Resistance meaning
Measure of difficulty of flow
Types of blood flow
Laminar
Turbulent
Describe laminar flow
Smooth
Silent
Maintains energy
Typical in most vessels
Describe turbulence flow
Disorganised
Noisy
Energy lost
Stenosis meaning
Abnormal discrete narrowing of an artery/open area of heart valve
What can be felt and heard in turbulent flow?
Thrill can be felt
Bruit can be heard
What is the relationship between radius and velocity?
Reciprocally
If radius decreases, velocity increases
Where do you get turbulent flow?
Changing direction of vessels-branching
Stenosed artiery
Stenotic heart valves
What factors impact flow?
Diameter- most important
Length of vessel
Viscosity
Pulse pressure equation
PP= SBP - DBP
Mean arterial pressure equation
MAP= DBP + (SBP-DBP)/3
same as
MAP= DBP + PP/3
Meaning of
PP
SBP
DBP
MAP
CO
SV
HR
TPP
Pulse pressure
Systolic blood pressure
Diastolic blood pressure
Mean arterial pressure
Cardiac output
Stroke volume
Heart rate
Total peripheral pressure
What happens if MAP is <70mmHg?
Organ perfusion becomes imparid
Perfusion meaning
Passage of blood
Cardiac output equation
CO= SV x HR
Mean arterial pressure equation
MAP= CO x TPP
What do you listen for when measuring blood pressure?
Korotkoff sounds - tapping sound
What happens to BP reading if cuff size if too
small?
Overestimate
What happens to BP reading if cuff size if too big?
Underestimate
How should patient be sat when measuring BP?
Legs uncrossd
Feet on ground
Pulse meaning
Shock wave that arrives slightly before blood itself
Types of rhythm
Regular
Regularly irregular
Irregularly irregular
Regular rhythm
Lub dub sound
Regularly irregular rhythm
Abnormal beat with a repeated pattern
Irregularly irregular
Abnormal beat and no pattern
E.g. atrial fibrillation
Bradycardia meaing
Slow heart rate
<60bpm
Tachycardia meaning
Fast heart rate
>100bpm
Types of pulse character
Thready
Bounding pulse
Thready pulse meaning
Weak pulse
End systolic pressure is lower
Bounding pulse meaning
Strong pulse
Diastolic pressure is lower
Common pulse location
Radial
Brachial
Carotid
Femoral
Popliteal
Dorsalis pedis
Posterior tibial
Explain taking manual BP
1- inflate cuff to ~20mmHg over suspected systolic reassure
2- slowly deflate cuff
3- systolic pressure - when first sound is heard
4- diastolic pressure - when sound disappears
