Intra-arterial blood sampling for clotting studies. Effects of heparin contamination.
Prothrombin time and activated partial thromboplastin time were measured in two groups of 30 patients each. Blood sampled from an arterial line after various discard volumes and from a central venous line were compared with direct venipuncture control samples. The arterial line flushing solution contained 1 unit of heparin per ml in group 1 and 2 units per ml in group 2. Our results confirmed that clotting studies carried out on blood samples from an arterial line or central venous line correlate well with those obtained from a venipuncture sample. The only exception was activated partial thromboplastin time in group 2 patients when the discard volume from the arterial line is only 2.5 ml above the deadspace volume of the connecting line. At least 5 ml of discard volume must be withdrawn before sampling, to obtain reliable results.
Chinese University of Hong Kong, Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, Shatin, NT.
J K
JK
Lew
R
R
Hutchinson
E S
ES
Lin
D001780:Blood Coagulation Tests; D001800:Blood Specimen Collection / Q000379:methods*; D002405:Catheterization, Central Venous; D002408:Catheters, Indwelling; D003422:Critical Care; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D010314:Partial Thromboplastin Time; D011517:Prothrombin Time
D006493:Heparin