Thromboelastometry (ROTEM®) in children: age-related reference ranges and correlations with standard coagulation tests

The small sample volume needed and the prompt availability of results make viscoelastic methods like rotational thromboelastometry (ROTEM (R)) attractive for monitoring coagulation in small children. However, data on reference ranges for ROTEM (R) parameters in children are scarce. Four hundred and seven children (ASA I and II) undergoing elective surgery were recruited for this prospective, two-centre, observational study. Subjects were grouped as follows: 0-3, 4-12, 13-24 months, 2-5, 6-10, and 11-16 yr. Study objectives were to establish age-dependent reference ranges for ROTEM (R) assays, analyse age dependence of parameters, and compare ROTEM (R) data with standard coagulation tests. Data from 359 subjects remained for final analysis. Except for extrinsically activated clot strength and lysis, parameters for ROTEM (R) assays were significantly different among all age groups. The most striking finding was that subjects aged 0-3 months exhibited accelerated initiation (ExTEM coagulation time: median 48 s, Q1-Q3 38-65 s; P=0.001) and propagation of coagulation (alpha angle: median 78(o), Q1-Q3 69-84(o); P < 0.001) and maximum clot firmness (median 62 mm, Q1-Q3 54-74 mm), although standard plasma coagulation test results were prolonged (prothrombin time: median 13.2 s, Q1-Q3 12.6-13.6 s; activated partial thromboplastin time: median 42 s, Q1-Q3 40-46 s). Lysis indices of < 85% were observed in nearly one-third of all children without increased bleeding tendency. Platelet count and fibrinogen levels correlated significantly with clot strength, and fibrinogen levels correlated with fibrin polymerization. Reference ranges for ROTEM (R) assays were determined for all paediatric age groups. These values will be helpful when monitoring paediatric patients and in studies of perioperative coagulation in children.