Thursday, February 14, 2008

Insight into fetal pain

Fascinating NYT Mag article on fetal pain. I've only read the first 2 pages of the article so far, but I had to share some excerpts.

The First Ache

25 years ago newborn and premature babies did not receive anesthesia when undergoing surgery! This is the man who figured out they could feel pain and needed it:

Twenty-five years ago, when Kanwaljeet Anand was a medical resident in a neonatal intensive care unit, his tiny patients, many of them preterm infants, were often wheeled out of the ward and into an operating room. ... The babies came back in terrible shape: their skin was gray, their breathing shallow, their pulses weak. Anand spent hours stabilizing their vital signs, increasing their oxygen supply and administering insulin to balance their blood sugar.

“What’s going on in there to make these babies so stressed?” Anand wondered. ...“That’s when I discovered that the babies were not getting anesthesia,” he recalled recently. Infants undergoing major surgery were receiving only a paralytic to keep them still. Anand’s encounter with this practice occurred at John Radcliffe Hospital in Oxford, England, but it was common almost everywhere. Doctors were convinced that newborns’ nervous systems were too immature to sense pain, and that the dangers of anesthesia exceeded any potential benefits.

...In a series of clinical trials, he demonstrated that operations performed under minimal or no anesthesia produced a “massive stress response” in newborn babies, releasing a flood of fight-or-flight hormones like adrenaline and cortisol. Potent anesthesia, he found, could significantly reduce this reaction. ... Anesthesia even made them more likely to survive. ... These were extraordinary results, and they helped change the way medicine is practiced. Today, adequate pain relief for even the youngest infants is the standard of care, and the treatment that so concerned Anand two decades ago would now be considered a violation of medical ethics. ...

Like the assumption that newborns didn't feel pain, now the prevailing view is that fetuses don't either. Although I'm not quite sure what the difference is between a premature baby and a fetus of the same gestational age - isn't it just location? Shouldn't they have the same responses? Why is this so shocking?

Some tests were done to observe physiological reactions:

Nicholas Fisk is a fetal-medicine specialist and director of the University of Queensland Center for Clinical Research in Australia. For years, he says, “I would be doing a procedure to a fetus, and the mother would ask me, ‘Does my baby feel pain?’ The traditional, knee-jerk reaction was, ‘No, of course not.’ ” But research in Fisk’s laboratory (then at Imperial College in London) was making him uneasy about that answer. It showed that fetuses as young as 18 weeks react to an invasive procedure with a spike in stress hormones and a shunting of blood flow toward the brain — a strategy, also seen in infants and adults, to protect a vital organ from threat. Then Fisk carried out a study that closely resembled Anand’s pioneering research, using fetuses rather than newborns as his subjects. He selected 45 fetuses that required a potentially painful blood transfusion, giving one-third of them an injection of the potent painkiller fentanyl. As with Anand’s experiments, the results were striking: in fetuses that received the analgesic, the production of stress hormones was halved, and the pattern of blood flow remained normal.

Fisk says he believes that his findings provide suggestive evidence of fetal pain — perhaps the best evidence we’ll get. Pain, he notes, is a subjective phenomenon; in adults and older children, doctors measure it by asking patients to describe what they feel. ...In the absence of such first-person testimony, he concludes, it’s better to err on the safe side and assume that the fetus can feel pain starting around 20 to 24 weeks.

How do fetuses react physically to painful stimulation?

... When the surgeon lowered his scalpel to the 25-week-old fetus [for surgery not abortion], Paschall saw the tiny figure recoil in what looked to him like pain. A few months later, he watched another fetus, this one 23 weeks old, flinch at the touch of the instrument. That was enough for Paschall. In consultation with the hospital’s pediatric pain specialist, “I tremendously upped the dose of anesthetic to make sure that wouldn’t happen again,” he says. In the more than 200 operations he has assisted in since then, not a single fetus has drawn back from the knife.
“I don’t care how primitive the reaction is, it’s still a human reaction,” Paschall says. “And I don’t believe it’s right. I don’t want them to feel pain.”

On the other hand, critics explain this away...

What about a fetus that draws back at the touch of a scalpel? Rosen says that, at least early on, this movement is a reflex, like a leg that jerks when tapped by a doctor’s rubber mallet. Likewise, the release of stress hormones doesn’t necessarily indicate the experience of pain; stress hormones are also elevated, for example, in the bodies of brain-dead patients during organ harvesting. [But, isn't it possible that "brain-dead" patients feel the pain of their organs being ripped out, too?]

Not only may fetuses feel pain, they may feel it worse than full grown babies and adults:

The fetus’s undeveloped state, in other words, may not preclude it from feeling pain. In fact, its immature physiology may well make it more sensitive to pain, not less: the body’s mechanisms for inhibiting pain and making it more bearable do not become active until after birth.

Now I will go back to finishing the article and hope you will, too.

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