Platelet Function Assays
OVERVIEW
- PFA-100 = citrated whole blood placed in a disposable cartridge containing a membrane coated with collagen/adrenaline or collagen/ADP into which a microscopic aperture has been cut -> with high shear rates contact of blood with the membrane causes platelets to aggregate and occlude the aperture.
- time to occlude the aperture is recorded (closure time)
- very rapid + simple
- has largely replaced the bleeding time.
INTERPRETATION
- subject to a number of variables:
- platelet count
- haematocrit
- ABO blood groups
- plasma vWF
- a normal test has a high negative predictive value
CAUSES OF QUALITATIVE PLATELET DYSFUNCTION
- renal failure
- hepatic failure
- drugs: anti-platelets
- DIC
- autoantibodies (HITTS)
- haematological problems: vWD
References and Links
CCC Transfusion Series
Blood Products: Cryoprecipitate, Fresh Frozen Plasma (FFP), Platelets, Red Cells (RBCs)
>>> Factor Concentrates: Prothrombinex, Factor VIIa, Fibrinogen Concentrate
Reversal Agents:
>>> Rivaroxaban / Apixaban / Enoxaparin: Andexanet Alfa, Rivaroxaban and Bleeding
>>> Dabigatran: Idarucuzimab, Dabigatran and bleeding
>>> Heparin: Protamine
>>> Warfarin: Vitamin K, FFP, PTx, Warfarin Refersal, Warfarin Toxicity
Testing: Coagulation Studies, TEG / ROTEM (Thromboelastography), Platelet function assays
Conditions: Acute Coagulopathy of Trauma, Disseminated Intravascular Coagulation (DIC), Massive Blood Loss
General Topics: Blood Bank, Blood Conservation Strategies, Blood Product Compatibilities, Blood Transfusion Risks, Massive Transfusion Protocol (MTP), Modifications to Blood Components, Procedures and Coagulopathy, Storage Lesions, TRALI, Transfusion Literature, Transfusion Reactions
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Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC