Circulation Flashcards
What is Blood Pressure?
BP = CO x SVR
What is Cardiac Output?
CO = SV x HR
Draw the Arterial Blood Pressure waveform
- Systolic Peak
- Dicrotic notch (aortic valve closure)
- Diastolic Trough
What is MAP?
MAP = 1/3rd of distance from diastolic to systolic BP
It is the area under the curve of the arterial BP waveform
What blood products do you know of?
Blood products:
- RBC
- Platelets
- Fresh Frozen Plasma
- Cryoprecipitate
Plasma Products:
- Human Albumin Solution
- Coagulation factor concentrate
- Immunoglobulins
What are the constituents of RBC and how is it treated and stored etc?
RBC = Red Blood Cells
Stored at 2-6 degrees
Lasts 35 days from donation
Irradiated for graft vs host and washed for plasma
What are the constituents of Platelets and how is it stored?
Platelets
Stored at room temperature
Shelf life of 5 days
What are the constituents of Plasma and how is it stored and treated?
Plasma taken from Males only to avoid transfusion related lung injury
Cryoprecipitate + cryosupernatant (factors)
Storage at -25 degrees
Lasts 36 months frozen but 24 hours once thawed
Methylene blue inactivates bacteria/viruses
What are the constituents of cryoprecipitate?
The supernatant obtained from thawing FFP.
Generally used as a more concentrated form of fibrinogen than FFP (promotes clotting)
What is blood screened for?
Hep B Hep C HIV HTLV (human T-Lymphocyte Virus) Syphillis ?CMV if required Removal of leucocytes to avoid CJD
How can you classify the complications of blood transfusion?
- Complications of massive transfusion
- Complications of repeated transfusion
- Infective
- Immune
Define a massive transfusion, and list some complications
Whole blood volume in 24 hours (5-6L)
Complications:
- Fluid Overload
- Reduced functioning platelets (thrombocytopenia)
- deficiency of coagulation factors
- 2,3-BPG does not store well so can cause reduced oxygen capacity
- Hypothermia
- Hypocalcaemia (chelating agent in citrate)
- Hyperkalaemia (leakage from stored cells)
When would you suspect that unit of blood has bacterial contamination?
- Clots in the bag
- High degree of haemolysed cells
- this can cause lethal septic shock
What immune reactions can occur after transfusion, and how might you classify these?
Severe (life-threatening):
- Acute haemolytic reaction (ABO)
- Anaphylaxis
- Allergy to IgA (rare)
- Transfusion related Lung injury - antibodies causing oedema.
- Overload
Less Severe:
1. Febrile non-haemolytic transfusion reaction (pyrexia and shivering)
Delayed:
- Delayed haemolytic transfusion reaction (<24 hours)
- Purpuric Reaction (5-12 days)
- Graft vs Host (HLA incompatible) (7-14 days fatal)
How do you manage an immediate haemolytic transfusion reaction?
ABCDE approach
- Stop infusion
- Give fluids and maintain output
- Repeat crossmatch
- Coomb’s test
- Full set of bloods especially for DIC
- Send blood cultures
Define major haemorrhage
- Loss of blood volume in 24 hours
2. Loss of 50% in <3 hours
In a typical PQRST ECG waveform, where do the heart sounds occur?
1st Heart sound = AV node closure = end of R wave
2nd Heart sound = VA node closure = end of T wave
What does the P wave represent?
Atrial depolarisation
How do you measure the PR interval and what does it represent?
Measure from start of P to start of Q
Should be 3-5 small squares
Represents SA node signal to ventricle
What does the QRS complex represent?
Ventricular Depolarisation
< 3 squares
Define and how would you measure the QT interval?
This is from start of Q to end of T wave
Represents complete Ventricular depolarisation and repolarisation cycle
What is QTc
This is QT standardised to 60bpm
Normal range is around 1 big wave
What does the T wave represent and why is it in the same direction as the QRS?
Ventricular Repolarisation
Occurs in opposite direction to QRS depolarisation from episode to endocardium
What are the different types of Heart Block?
1st Degree: prolonged PR
2nd Degree Type I: gradually lengthening PR till skipped beat
2nd Degree Type II: randomly missed Beat following P
3rd Degree: Complete block. No relationship between P and QRS
what are the fluid compartments of the body and their percentages?
Total = 42L
2/3rds Intracellular
1/3rd Extracellular
