title: Monitoring of coagulation status using thrombelastography during paediatric open heart surgery.
abstract: Thrombelastography (TEG) has proved useful in identifying coagulopathies (via assessment of clot elasticity properties) during hepatic surgery, but its role in cardiac surgery has as yet not been defined. Twenty-two children [11M, 11F, mean age (range) 4.9 (0.1-16) years] undergoing open heart surgery were investigated [1] preoperatively, [2] 15 min post protamine, [3] 2 h and [4] 24 h postoperatively using TEG. Comparisons were made between pre- and postoperative measurements and haematological indices. The values obtained from the TEG were: R phase (indicative of thrombokinase and thrombin formation disorders), K phase (indicative of fibrinogenesis) and MA phase (providing information on clot stability and platelet function). The patients were divided into two groups based upon 24 h blood loss; Group 1 - blood loss less than 0.7 ml/kg/h and Group 2 - blood loss greater than 0.7 ml/kg/h. In Group 2 there was a highly significant correlation between post-protamine MA phase and platelet number (r = 0.93, p less than 0.001) but there was no correlation in Group 1 (p greater than 0.1). Furthermore, in Group 2 elevated postoperative blood loss was associated with a prolonged K phase (mean [SD] 12.0 [6.0] versus 6.3 [2.1] min, p less than 0.05) and diminished MA phase (37 [12.5] versus 56 [4.9] mm, p less than 0.01) relative to preoperative values. In Group 1, K and MA phase did not alter significantly (p greater than 0.5 and p greater than 0.2, respectively). TEG predicted with 100% (8/8) accuracy increased post-operative bleeding. The specificity of TEG prediction of future bleeding was 73% [8/11]. Alterations in TEG parameters merit further evaluation as markers of postoperative haemorrhage.
authors.affiliation: Department of Cardiothoracic Surgery, Killingbeck Hospital, Leeds, England.
authors.forename: P
authors.initials: P
authors.lastname: Martin
authors.forename: F
authors.initials: F
authors.lastname: Horkay
authors.forename: S M
authors.initials: SM
authors.lastname: Rajah
authors.forename: D R
authors.initials: DR
authors.lastname: Walker
mesh_terms: D001777:Blood Coagulation / Q000502:physiology; D016063:Blood Loss, Surgical; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods*; D013916:Thrombelastography