Twenty-eight years ago, I wrote about drawing blood for the first time, about the pain of the patient and the self-doubt of the medical student. In my first clinical experience, I was learning a strange new color code: red-top tube for blood chemistries, purple top for hematology, green top, yellow top, and so on.

In pediatrics, I soon discovered, the colors were the same but the tubes themselves were much smaller. And instead of those big needles I had learned to use on adults, we used butterflies, tiny needles with plastic wings to keep them stable.

I thought: If you can get enough blood through a small butterfly needle filling a small tube to do the necessary tests, why must we jab big needles into adults and fill comparatively huge tubes to do the same assessments?

It wasn’t the last time I wondered why children were treated with more concern than adults. And now it seems that attitudes long taken for granted in the care of children might be working their way up the life span to become more standard for adults.

Take those big tubes. In a 2011 article in the journal Archives of Internal Medicine, researchers showed that adults hospitalized with heart attacks who had more blood drawn were more likely to develop anemia while in the hospital. Patients who develop such anemia have a higher risk of death.

Dr. Mikhail Kosiborod, one of the authors of the study, a cardiologist at St. Luke’s Mid America Heart Institute in Kansas City, Mo., told me that the result surprised some physicians; the average volume of blood lost did not seem substantial enough to cause anemia in healthy adults. Patients in the study who developed anemia lost 174 milliliters of blood on average during hospitalization — just under six ounces — though some lost much more. A healthy adult might not become anemic after such blood loss, but the sick and debilitated may be at higher risk.

His own hospital, like many other institutions, is now using smaller tubes, he said — not the tiniest tubes, which require special handling, but a smaller size that can still be handled routinely by the lab.

So why had anyone ever used larger tubes if smaller would work? “It just hasn’t been brought up in the adult world,” Dr. Kosiborod said. “It hasn’t been made a big issue.”

Dr. Bradley Monash, an academic hospitalist at the University of California, San Francisco, who works on both pediatric and adult wards, said: “There’s something about the care of a child that touches people. There’s something about caring for children that people address differently.”

The pain and fear that children feel about having their blood drawn, for example, probably influence the frequency with which doctors order tests.

“Fear is acceptable in pediatrics much more than it is in adults,” Dr. Monash said. “There are a lot of things we could take from pediatrics and translate into medicine.”

When children get hospitalized, for instance, we understand that they’re scared. An unfamiliar place, painful procedures, strangers with needles — all are piled atop the underlying feeling of being sick or hurt. And we routinely expect parents to stay over in their children’s hospital rooms, providing cots and chairs that unfold to lie flat.

When children need surgery, we promise company and comfort.

The children are told that “the parents are going to be going with them into the operating room, and they’re going to stay with them till they fall asleep,” said Florencia Catanzaro, who coordinates the pre-hospitalization child life program at Bellevue Hospital in New York City.

Parents are routinely allowed into recovery, so that children can see them when they wake up, or soon after. But really, are adults any less scared, uncertain or disoriented?

In adult surgery, it is not routine to promise that someone can be with you in the operating room till you go to sleep, or to have family members a standard part of recovery room care. Many hospitals will let a family member stay overnight with an adult patient, but policies vary hospital by hospital, ward by ward.

“We accommodate family members much more in pediatrics,” Dr. Monash said. “We don’t have visiting hours where everyone has to leave.”

Still, the trend in adult medicine is that new patient rooms are more likely to be constructed, as pediatric rooms are, to accommodate family members.

It seems to me we should be able to promise any hospital patient that a relative, a friend, can stay close at hand. We should be able to promise anyone going in for surgery that when she wakes up, someone familiar will be there.

It won’t always be perfectly convenient for hospital routine, but the lesson from pediatric care is that hospitals will adjust. This was all unthinkable in pediatrics, too, just over a half century ago.

The adage “children are not just small adults” is so basic in pediatrics that you can search medical journals and find it applied to treatments for facial fractures, liver failure and cardiac arrhythmias, for example. We have learned over time to fine-tune medical care to the differently wired physiologies of children, and to their emotional development.

But when it comes to certain aspects of medical treatment, especially hospitalization, perhaps it’s time to acknowledge that adults are really just big children. Illness, pain and the shadows of disability and death — all hospital familiars — make all of us vulnerable, at any age, and reassurance and comfort are welcome. Blood is a useful reminder: Every patient needs to be treated in a way that conserves every drop of strength and resilience.