Complications of Veipuncture

• Veins may roll
• Needle could be through the veinà Bring back slowly
• Needle is not deep enoughà Push needle gently in more
• Vasovagal "Fear" responseà The blood vessels dilate and drops the blood pressure while at the same time the Vagus nerve slows the heart rate and the patient passes out.
• Treated by lying the patient down and elevating the legs of the patient and trying t cool them.

Coagulation Cascade

• Platelets can be activated by the endothelial wall and a glass tube, more platelets then collect on top of the other platelets which then forms a plug and draws more latelets to form a more permanent clot.
• Platelets come in contact with surfaces such as glass, collagen fibers or other activated plateletsà Factor XII + Activated Platelets in plugà Factor XIIa + Factor XIà Factor XIa + Factor VIII + Calciumà Factor IXa + Factor Xà Factor Xa (Tissue Factor VII + Factor Xà Factor Xa) Factor II (prothrombin) + Factor Xa + Factor V & Calciumà Thrombin + Factor I (Fibrinogen)à Fibrin Monomer + cross connectionà Fibrin polymer insoluble clot.
• Anti coagulants-
• Heparin in green top tube. Can be given by an I.V. and starts working immeadiately due to it directly inhibiting thrombin.
• Asprin- anti coagulant destroys platelets
• Warfarin- may be taken orally and may take one of these pills, sometimes refered to as a blood thinner.
• Takes two or three days to take effect and knocks out the production of the clotting factors

Advantages of the Cascade scheme