Today, about one per cent of infants born as young as 22 weeks gestation can survive. (CBC)

They are the tiniest additions to the human family, in some cases barely bigger than a block of butter. But premature babies — such as the six born to a B.C. family earlier this week — are part of a scientific continuum that can be said to have revolutionized modern medicine.

Thirty or so years ago, it was rare for any preemie under 28 weeks to survive outside the womb. But decades of heroic efforts and constant medical fine tuning have pushed the barriers ever lower.

Today, about one per cent of infants born as young as 22 weeks gestation can survive — at least one is on record as having been born weighing 10 ounces — though usually not without some lifelong infirmity. (Normal gestation is 40 weeks and below 22 weeks, blood vessels in the lungs haven't formed fully, which presents an anatomical limitation.)

At 24 weeks, survival rates start to go up noticeably and at 26, like the sextuplets born in Vancouver, they can be close to 100 per cent, according to experts at Toronto's Hospital for Sick Children (Sick Kids) among other places.

Even better news, according to a British report, the incidence of neurological damage and other disabilities in preemies born at 26 weeks or older has dropped considerably in recent years. (It's currently between 10 and 25 per cent, depending on the study.) These births are still not without serious trauma to the infant as well as the mother, of course.

As the Canadian Paediatric Society says in its advice to physicians: "The birth of a child of a gestational age of 22 to 26 completed weeks is fraught with uncertainty concerning the chance of survival and the risk of impairment and disability."

What's more, the society says, it is almost impossible to know the outcome of these cases before birth or even shortly after.

"This uncertainty may cause extreme stress for parents and caregivers around the time of the birth and during the neonatal period. Moreover, despite the use of pain control, the pain and suffering experience by the infant in intensive care cannot be determined."

New guidelines

The survival of these tiny humans comes with a huge emotional and medical cost (often long-term), which is one of the reasons why an influential British group, the Nuffield Council on Bioethics, published new guidelines just before Christmas.

Basically, the guidelines said that any child born at 22 weeks and six days or younger should not be resuscitated. Any born at a full 25 weeks and above should go to intensive care, while anything in between ought to be judged on an individual basis, with the proviso that the majority do not survive.

In some respects, these guidelines can be seen as an attempt to move the yardsticks back to more conservative ground, away from the so-called heroic efforts that have characterized many preemie births in recent decades.

But these heroic efforts, emotionally-laden though they've been, have made huge medical contributions to much more than the neonatal field. Indeed, some say they have even laid the groundwork for many of the important treatment breakthroughs in cancer and organ transplants.

Preemies and the lessons learned

Dr. Keith Tanswell, the head of neonatology at Toronto's Sick Kids Hospital, explained in detail a few years ago that there have been three important developments in respiratory support that have led directly to the lower threshold for premature births. All three have broader implications for ailing adults as well:

• The first was the development of a surfactant, the chemical that helps keep the lungs lubricated and open and can take a while to develop in preemies. It is now being used in adults with pulmonary failure and also on drowning victims and those who suffer from smoke inhalation.
• The second was the high-frequency oscillator (developed by Dr. Charles Bryan at Sick Kids in the late 1970s), which is a specialized ventilator that can gently shake oxygen into the fragile lungs of young infants and children. It is now being used in some centres to assist adults suffering from advanced pneumonia and other life-threatening lung ailments.
• The third was the development of nitric oxide (grandly dubbed "molecule of the year" by Science magazine in the early 1990s). It's a gas that helps keep blood vessels open so they can absorb more oxygen. Neonatals came first: They were the group with the most obvious survival problem. But before too long nitric oxide was extended to those adults with high blood pressure and other heart ailments.

These of course are only the most obvious developments to aid in the survival of the weakest. Others include pre-birth steroids for moms who are thought likely to deliver early and special infant hormones to induce red blood cell production and so limit the need for full blood transfusions.

But the more subtle and more far-reaching impact of neonatal medicine has been the medical lesson to think in terms of the whole patient.

Initially, because these neonatal cases were such long shots at the very edge of medical understanding, physicians threw everything they could at preemies, as well as other infants with life-ending illnesses. Chemotherapy, for example, originated on the paediatric wards. So did some of the earliest attempts at utilizing genetic and biological predictors.

But soon doctors realized that some of these efforts were creating even more (especially breathing and neurological) problems down the road for survivors. So they began thinking in terms of balancing their approaches, of using a slingshot instead of a howitzer when it came to drug doses and, importantly, aiming at more than one target at a time.

From that grew the modern notion of drug cocktails, tailored to an individual's specific problems and genetic makeup, today's standard for cancer and other treatments. It is a gift, when you think of it, from the smallest and most fragile among us.

[an error occurred while processing this directive]