Should we have a few, large neonatal intensive care units?

A recent post highlighted the complexity of neonatal intensive care unit (NICU) patients. I showed data indicating that although there were several severe problems that were commonly seen, most patients also had one or more rare problems. Given that the patients are so different, finding the best ways to care for them is a hard problem.

So what really distinguishes a good NICU? You would think it would be something like "association with a medical school", because that is where you would expect to find the real experts. In the data available to me, however, having medical school professors working in your NICU doesn't seem to help. The only thing I have found that helps is having your NICU see a lot of cases. To the right I have plotted clinic volume and mortality rates for NICUs. The horizontal access fn the plot is the number of admissions to each NICU over about two years, in a logarithmic scale. The vertical access is the percentage of those infants who died on the unit. You can see that, with the exception on one small unit in the lower left corner, seeing more patients was associated with fewer patients dying. (The association is highly statistically significant, even including this apparent outlier. However, the line I fit to the data does not include the outlier. I'm guessing that unit was just lucky.)

This pattern of higher volume and better outcomes is seen in a lot of adult and pediatric data. It helps to specialize, to get your doctors doing fewer things better and to have a lot of doctors together doing that same thing. There is a learning by doing effect here, and perhaps a collective learning by doing effect. This in itself is kind of interesting. We think of medical care as improving as a result of breakthroughs and sudden leaps. But a lot of it seems to be just the accumulation of solutions to a lot of microproblems.

Does that mean, however, that we should close down small NICUs? Probably. But if you did, you would need to transport infants longer distances to get to these larger, specialist NICUs. That's expensive, and it may not be best for the infant. So we don't yet know what's best to do.