Pierre Sié1, Annick Steib. 1. Hematology Laboratory, Hôpital Purpan, CHU de Toulouse 31059 France. sie.p@chu-toulouse.fr
Abstract
PURPOSE: To review laboratory investigations required for the diagnosis of a constitutional or acquired defect of hemostasis before surgery, or during the perioperative period in context of rapid evolution and possible therapeutic adjustment. METHODS: A review of the literature. PRINCIPAL FINDINGS: Systematic preoperative screening is poorly efficient. It should be restricted to patients selected on clinical history and physical examination. Intra- and postoperative investigation is oriented by the clinical circumstances. In most instances, laboratory investigation is organized as hierarchical steps, the first one including a platelet count, a prothrombin time and activated partial thromboplastin time. According to the results of these assays and to the clinical circumstances, further tests specific of primary hemostasis, coagulation or fibrinolysis are performed. Point of care (POC) monitoring has been developed more recently for the investigation of a perioperative bleeding. Several tests examine platelet functions, others measure whole blood activated partial thromboplastin time or prothrombin time and some explore global hemostasis, allowing the detection of excessive fibrinolysis. Point of care testing provides a rapid and valuable answer but, if one accepts the monitoring of unfractionated heparin during extracorporeal circulation, most assays have not been properly validated. CONCLUSION: The investigation of hemostasis at the central laboratory and POC testing have distinct objectives. The utility of the former for the diagnosis and the adjustment of therapeutics have been well demonstrated. In contrast, the experience with POC testing is relatively recent, and its utility for patient management remains to be demonstrated in proper clinical trials.
PURPOSE: To review laboratory investigations required for the diagnosis of a constitutional or acquired defect of hemostasis before surgery, or during the perioperative period in context of rapid evolution and possible therapeutic adjustment. METHODS: A review of the literature. PRINCIPAL FINDINGS: Systematic preoperative screening is poorly efficient. It should be restricted to patients selected on clinical history and physical examination. Intra- and postoperative investigation is oriented by the clinical circumstances. In most instances, laboratory investigation is organized as hierarchical steps, the first one including a platelet count, a prothrombin time and activated partial thromboplastin time. According to the results of these assays and to the clinical circumstances, further tests specific of primary hemostasis, coagulation or fibrinolysis are performed. Point of care (POC) monitoring has been developed more recently for the investigation of a perioperative bleeding. Several tests examine platelet functions, others measure whole blood activated partial thromboplastin time or prothrombin time and some explore global hemostasis, allowing the detection of excessive fibrinolysis. Point of care testing provides a rapid and valuable answer but, if one accepts the monitoring of unfractionated heparin during extracorporeal circulation, most assays have not been properly validated. CONCLUSION: The investigation of hemostasis at the central laboratory and POC testing have distinct objectives. The utility of the former for the diagnosis and the adjustment of therapeutics have been well demonstrated. In contrast, the experience with POC testing is relatively recent, and its utility for patient management remains to be demonstrated in proper clinical trials.