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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.

SUMMARY Operative balloon dilatation of the aortic valve was performed in seven neonates with critical stenosis of the aortic valve. The procedure was followed by the development of severe aortic regurgitation in four patients. Necropsy was performed in three and revealed partial detachment of the right coronary cusp of the aortic valve. Damage to the valve leaflet caused by balloon dilatation was probably the result of using a balloon with a diameter that was too large in relation to the aortic valve ring diameter and of shearing forces created in the aortic wall by the contracting ventricle. The diameter of the inflated balloon should not be larger than the diameter of the aortic valve ring.Percutaneous balloon dilatation of the pulmonary1 or aortic valve2 3 has been used to relieve critical valvar stenosis in children and adults.4 Experimental and necropsy findings after this procedure have shown linear tears of the valve or transverse tears in the aortic wall.5 We report four cases of operative balloon dilatation of the aortic valve that damaged the valve leaflets. Patients and methodsSeven infants underwent operative balloon dilatation of critical aortic stenosis presenting in the neonatal period. Accepted for publication 19 November 1986 defect, which was worsened by the critical obstruction of the left ventricular outflow tract. The echocardiographic estimate of the diameter of the valve ring was 6mm. On the forty-seventh day the ventricular septal defect was closed surgically and at the same time balloon dilatation of the aortic valve was performed through an apical left ventricular stab incision with an 8mm diameter balloon catheter. There was some improvement immediately after the operation but she died the next day.

subjects with RP had significantly lower blood flow at all stages of the test; moreover, their digital rewarming response following central cooling was considerably prolonged when compared with controls. Body temperature was lower and dropped significantly more in the RP group following the cold challenge. The authors conclude that subjects with RP have an impaired thermoregulatory mechanism. This may partially explain cold sensitivity.