Power Analysis Based on our pilot data we anticipate 80% or more of the group receiving rVIIa will achieve haemostasis adequate for chest closure without any further intervention to improve coagulation. (Our primary endpoint) We conservatively estimate that only 30% or less of placebo group will achieve haemostasis adequate for chest closure without any further intervention to improve coagulation. Assuming a p value of < 0.5 and power of 0.8 analysis indicates that to show a 50% difference between groups 34 subjects are needed (17 in each arm). To allow for any withdrawals we plan to enrol 40 patients in the study. Based on current drug usage, the recruitment will take 2 years.