SummaryThere has been little published work defining 'normal' thromboelastography (TEG Ò ) values in healthy parturients, and few large studies defining reference ranges for traditional coagulation tests in this patient group. Our aim was to establish peri-operative reference ranges for TEG and for standard laboratory coagulation tests in our pregnant population. Fifty healthy term parturients presenting for elective caesarean section under spinal anaesthesia had blood samples taken pre-operatively, on arrival in the recovery room and, in a subset of 33 women, 4 h after routine thromboprophylaxis with enoxaparin 40 mg. All three samples had TEG analysis, the first and second having standard laboratory coagulation tests in addition. Reference ranges for our pregnant population were established, demonstrating a hypercoagulable state in term parturients and a significant effect of enoxaparin. The standard coagulation reference ranges were within 98% of the local non-pregnant ranges. These reference ranges provide a useful comparator for peri-operative TEG and routine coagulation analysis in term parturients.
Accepted: 26 January 2012The recent decline in direct maternal deaths in the UK has been attributed largely to reductions in deaths due to thromboembolism, and, to a lesser extent, haemorrhage [1]. With increased awareness and more widespread use of thromboprophylaxis, and the ever-present risk of maternal haemorrhage, greater importance is being placed on the assessment of coagulation status and blood product replacement during the peripartum period.Thromboelastography (TEG Ò ) is a relatively new near-patient monitor of coagulation in UK labour wards, although its use in cardiac and liver surgery is long-standing [2,3]. The TEG evaluates the mechanical strength of clot during its formation, via the torsion in a pin suspended in an oscillating heated cup that contains the blood sample [4], leading to a graphical output (Fig. 1). Compared with traditional laboratory coagulation tests, the TEG takes into account the dynamic interaction of plasma (clotting factors) and cellular (platelets) elements that occurs during in vivo clotting, thus indicating overall 'clot quality.' Test protocols can