This happened many years ago, in the early 1990's or late 1980's. Unfortunately, in the history of neonatology there have been many times when babies have been under anesthesized or not given adequate pain relief. It's a dark spot in our field, but fortunately now there is an increasing emphasis on pain relief. We're getting better at it, but there are still some problems.
The biggest problem with neonatal pain relief, as I see it, is that there are two opposing principles involved. One, we know that repetitive unrelieved pain is not good for babies and can lead to increased sensitivity to pain later in life. On the other hand, though, we know we shouldn't give treatments that have unknown effects on a baby's long term outcome. And there's the rub; we don't know what repetitive use of many of our analgesics does to the baby's developing brain. Does frequent stimulation of the opioid receptors in an immature brain change the formation of that brain and its pathways? It's hard to believe it doesn't, and not all of the data is reassuring.
One pain reliever used for newborns is sucrose, that is, sugar water. It's well established that a little bit of sucrose, combined with sucking on a pacifier, prior to a painful procedure offers pain relief. It probably works because the sweetness stimulates the release of the baby's own natural (endogenous) opiates. We're having a discussion now in our NICU whether we can use this routinely and frequently in premature babies, who can have hundreds of painful procedures like blood draws and IV starts done during their hospitalization. It sounds innocuous - hey, it's only sugar water - and some of the nurses want to be very liberal with it. But frankly, I'm a little leary of it; we don't have long term follow up information about what sucrose's repetitive use does to the immature brain. It may be only sugar water, but somehow it affects the brain - otherwise it wouldn't offer pain relief - and therefore, it seems, could affect brain development.
We could talk a long time about this topic, but this post is too long already. When in doubt, primum non nocere. First of all, do no harm.