The surgeon had a full house as this procedure had never been performed before and was assisted by both Cuddy and House. It was his job to open up the thorax of the fetus to determine the underlying problem and then to repair the damage. However, Emma was already in deep distress and was on the verge of dying herself.
The surgeon identified the problem as congenital cystic adenomatoid malformation and started to repair it. However, House saw that Emma's vital signs were failing and wanted to abort the fetus, which would allow Emma to recover. However, Cuddy instead used the defibrillator on Emma's heart, nearly shocking House in the process. The procedure worked and Emma was soon back on the road to recovery without losing the fetus.