Fifty grueling hours into an unprecedented operation to separate adult twins conjoined at the head, Dr. Keith Goh's heart sank.
He was working furiously Tuesday to save Laleh Bijani, who began bleeding profusely the moment surgeons made the final cut to separate her from her sister, Ladan.
Gone was the sound of classical music that played the day before in the small, gleaming operating room crowded with doctors and assistants in aqua scrubs. The room was mostly silent except for the surgeons' instructions and the beeps and pulses of the monitors.
Then Goh glanced over at Ladan. She was losing blood even faster.
The 29-year-old Iranian twins died shortly thereafter _ Ladan at 2:30 p.m. (2:30 a.m. EDT) and Laleh 90 minutes later. Both were under anesthesia.
"I was very saddened," said Goh, the lead surgeon. "I saw them struggling _ of course at the same time we were struggling, too."
Now a debate begins anew over whether it was ethical for doctors to agree to the surgery.
"When we undertook this challenge, we knew the risks were great," said Dr. Loo Choon-yong, chairman of Raffles Hospital in Singapore, where the operation took place.
Dr. Madjid Samii, a German neurosurgeon, talked to the twins and their family in 1988 when the girls were 14, but decided then the operation was too hazardous.
"When I heard a couple of weeks ago that they were going to do it, I was very surprised because I was convinced there was no chance of success," he said.
Carol Taylor, director of Georgetown University's bioethics center, questioned whether the doctors might have been overly optimistic.
"It raises serious questions, very definitely, whether there was sufficient medical precedent to say the expected benefits outweighed the very obvious serious harms," she said.
However, several ethicists said it appears the doctors acted ethically by assembling a competent team, taking reasonable chances and making sure the patients knew they might die.
"This operation seemed to have met the medical and technical standards that we and other groups think are essential for innovative surgery," said Dr. Mark Siegler, head of the University of Chicago's medical ethics center.
Dr. C. Rollins Hanlon, a former president of the American College of Surgeons, said once the doctors decided they had a reasonable chance of success and explained the hazards, it was the twins' decision.
"They said this was an intolerable situation, and they'd rather be dead than continue, and that's the way it turned out," he said. "That doesn't mean it was unwarranted. It just means a big risk was taken, and it turned out badly."
But Samii also believes doctors should have halted the surgery once they ran into trouble.
The operation was fraught with difficulties not seen in infants, the age at which the only successful surgeries of this type had been performed.
Surgeons repeatedly encountered surprises that preoperative scans and tests couldn't detect. The skull was denser and harder to cut than expected, the twins' distinct brains had fused together with tissue and their blood pressures and brain pressures proved unstable.
Ultimately, it was the unpredictable changes in how their blood flowed, and surgeons' inability to cope with those changes, that killed the sisters, Goh said.
Over three days, the team of 28 doctors and about 100 medical assistants worked in tight spaces in front of and behind the twins, who were in a sitting position in a custom-built brace connected to IVs and monitors.
Surrounded by a dozen nurses and technicians, surgeons stood Tuesday on either side of the sisters, cradling their heads to support them as the final cut was made.
The blood started flowing uncontrollably the instant the surgeon cut through the point where the bottom of the brain touched the bone. One doctor said it was like a fountain.
The twins were delicately placed on their sides on opposing operating tables as surgeons administered blood transfusions and battled to stabilize them.
Thirty-two hours into the procedure, surgeons had stopped the operation and considered calling it off _ leaving the twins joined _ because blood wasn't flowing properly through a finger-thick vein they had stitched to Ladan's brain to compensate for the coming loss of a shared vein that drained blood to their hearts.
Late Monday, surgeons faced the dilemma of leaving the twins joined and hoping they would recover or to "continue with the final stage of the surgery, which we knew would be very, very risky," Choon-yong said.
The team consulted with friends of the twins who had come from Iran and stayed at a suite at the 380-bed hospital to be near them during surgery.
"The team wanted to know once again, "What are the wishes of Ladan and Laleh?' " Loo said. "We were told that Ladan and Laleh's wishes were to be separated under all circumstances."
In their homeland, Iranians cried out in shock or wept as state television announced the deaths of the twins from a poor family who touched the world with their determination to lead separate lives.
"Is my beloved Ladan really not with us anymore?" Zari, an elder sister, said after the first death was reported in Iran. Seconds later, she fainted.
At their news conference in June, the Bijanis explained how, despite having lived every moment of their lives together, they had developed divergent interests. Laleh liked computer games, newspapers and books. Ladan like to chat on the Internet, read the Koran and pray. But one desire remained foremost, they said.
"We want to see each other _ face to face," Laleh said.
"We want to see each other," Ladan added, "without a mirror."
On Tuesday, diplomats were arranging for the return of their bodies to Iran for burial _ in separate caskets.
_ Information from the Associated Press and New York Times was used in this report.
Iranian children look at photographs of Laden and Laleh Bijani posted outside the Tehran apartment block where the conjoined twins lived. The twins died Tuesday after 50 hours of surgery to separate them.