A few years ago I was at a conference, where Gorm Greisen made a comment, after a talk I had given, that we really needed RCTs of new monitoring techniques, and specifically NIRS. Proving that a new technique actually improved outcomes was the best way to show that it was actually measuring something important, and that responding to the monitor was a good thing to do.

I admire people who will make comments like that, and then follow through on them.

A publication from a multi-center European group, led by Gorm, has accomplished the first stage of this evaluation. About 160 very preterm babies all had NIRS devices in place over the first 72 hours of life, they were randomized to either have the results displayed to the care staff, or hidden until the end of the study. The primary outcome was the percentage of time spent outside of the target range of 55-85%, which is thought to be a safe target range, based on prior data from some of the investigators. Having the NIRS data available reduced the out of range (and particularly the hypoxia) periods dramatically.

It is not immediately clear to me from this publication exactly what the investigators did when the NIRS was too low (or too high). But another publication includes the treatment algorithm, which includes suggestions of what to do when the the cerebral oxygen saturation is below 55% or above 85%. You could argue with some of the details of the responses suggested, but in general they seem reasonable.

It seems therefore from this excellent trial, that knowing the value of the cerebral NIRS derived oxygention can help to stabilize the value within what are thought to be appropriate ranges. Hopefully the next stage in this evaluation will be to prove that this affects clinically important outcomes, in this trial mortality and severe brain injury were both less frequent in the NIRS visible group, but the differences, although large in relative terms, could well have been due to chance. A larger study focussed on these complications, with long term follow up, is now really needed, more than ever.