Baby brain damage due to early anesthesia
According to new studies commonly used anesthetics may be causing brain damage in people, especially babies who receive them while their brains are still developing.
According to Associate Professor Andrew Davidson, an anaesthetist at the Royal Children's Hospital in Melbourne, there was mounting evidence in animals that a range of anesthetics used on humans were toxic for the brain and could cause lasting damage, including learning and memory difficulties.
He explained that there have been studies of five-day-old monkeys that revealed that when they were given ketamine, an anesthetic commonly used in hospitals, the drug caused some of their brain cells to die. When these monkeys were assessed at two and three years of age, they had significant learning deficits. Other common anesthetic agents like propofol, midazolam, isoflurane, desflurane and sevoflurane showed to cause rats' brain cells to die, affecting their ability to complete simple tasks.
He added that large studies of children who had received anesthetics as babies were under way to see if the animal findings could be validated. He said learning difficulties had been noted in children who had major surgery as babies, but that it was unclear what exactly had caused their brain damage. “If there is potential injury, it has huge implications for what we are going to do and how we are going to anesthetize babies because there is evidence that if we don't anaesthetize babies, they will have a poor outcome as well,” he said yesterday at the Australian and New Zealand College of Anesthetists’ annual scientific meeting in Hong Kong. He also expressed his concern regarding use of the agents in pregnant women in their third trimester because some of the anesthetic could theoretically reach their fetus. Older children could also be at risk.
Commenting on general practice today he said that although there was no proof of the problem in humans yet, doctors were already using ketamine less often on children and reconsidering minor surgical procedures in babies because they feared the anesthetics could cause more damage than what they would endure without. He assured that parents whose children had had anesthetics as babies should not be alarmed because many babies who had had major surgery had not suffered brain damage. “There are many babies who have had major surgery who are now professors… . We can't quantify the risk at the moment. But we can't ignore it either, we need to do more research,” he said.
Another anesthetist, Associate Professor David Scott, yesterday told the meeting that anesthetics may also be causing cognitive dysfunction, including dementia, in people over 65 who have surgery. Every day, about 17,000 people in Australia and New Zealand are given anesthetics. In Australia, about 5 per cent of children and 1 per cent of babies receive anesthetics each year.
Awake during anesthesia
Experts at the same convention said that thousands of patients undergoing surgery every year may be paralysed but awake for at least part of their operations, leaving many with long-lasting post-traumatic psychological problems caused by the extreme fear they experience.
They add that this was not rare but happened to a number of patients every day in Australia as a result of receiving an insufficient dose of the anaesthetic drugs that make the brain unconscious. In the most serious cases, patients can recall entire conversations between doctors when they were meant to be out cold and a few even report full sensation while their bodies are cut open.
According to Dr. Davidson, although pain was usually masked by the simultaneous use of regional nerve-blocking drugs, the fear caused by even partial wakening was enough to traumatise some patients. “The worst cases are where people are paralysed, they are awake and cannot move (or alert theatre staff)…They usually give a fairly harrowing description of exactly what happened . . . some people are very fearful about having another anaesthetic,” he said.
Professor Davidson estimated one patient in 1,000 experienced awareness, but Kate Leslie, president of the Australian and New Zealand College of Anaesthetists, said awareness during surgery might affect one in 500. With more than 17,000 Australians undergoing surgery every day, this meant the problem was “very common”, she said.
“Every day in Australia there are a number of people who are aware (during surgery),” Professor Leslie said. “We did research that showed about 70 per cent of them developed post-traumatic stress disorder that's longstanding and disabling. We think it's important to prevent awareness - that's personally why I use a brain monitor with every patient who I feel is at risk of awareness,” she explained.
This group included trauma victims who are bleeding heavily, people with heart conditions, people who had lost a lot of blood, and women having a caesarean section under general anaesthetic - all of whom often could not tolerate the full dose of anaesthetic drugs due to their condition. Professor Leslie said most anaesthetists “would deny ever having had a patient with awareness, and the reason is they don't ask them”. “It's a difficult thing to confront them with - it's their job to keep patients asleep,” she said.