Heparin

Question 1

Heparin Class

Answer 1

Anticoagulant

Question 2

Heparin MOA

Answer 2

Accelerates the rate at which antithrombin neutralizes thrombin & factors VII, IX, X, XI.

Anticoagulaiton depends on the presence of adequate amounts of antithrombin

Question 3

Heparin dosage

Answer 3

Prophylaxis: ratio of PTT to baseline PTT 1.2-1.5; prosthetic heart valves, DVT, PE, recurrent embolism 1.5-2
For CABG: maintain AACT 400-800 sec
Prophylactic/Low dose SC: 5000 units q 8-12 hrs
IV inf: load w/ 70units/kg (3,000-10,000 units)
Continuous: 13-16 units/kg/hr (750-1300 units/hr)

Question 4

Heparin characteristics

Answer 4

O:IV immediate; SC 20-30 min

P: N/A

D: half life & duration increase w/ increasing dose

h/l: 1 hr

Question 5

Heparin E/M

Answer 5

Precise pathway uncertain

Question 6

Heparin considerations

Answer 6

Tx is monitored to maintain the ratio of activated partial thromboplastin time (aPTT) but can be falsely increased w/ deficiencies

Monitor PTT ( goal 1.5-2.5x normal typically 30-35 sec)

HIT can begin w/in hrs of exposure- 50% drop in platelet count

For sx prophylaxis start 2 hrs preop; d/c infusion 4-6 hrs before regional/neuraxial anesthesia

Reversal: Protamine