In the crowded operating room, the surgeons had made the long incision down the middle of the child¡¯s chest, cut the breastbone to spread the rib cage and reach the heart. Then the lights went out.

Generators kicked on to keep life-support equipment running Wednesday night, and nurses and surgical assistants held flashlights over the operating table, guiding the surgeons as they snipped and cut, working to save the child¡¯s life in almost total darkness.

¡°So far we are coping on our own,¡± said Borys Todurov, director of the clinic, the Heart Institute, in Kyiv, Ukraine. ¡°But every hour is getting harder. There has been no water for several hours now. We continue to do only emergency operations.¡±