Normal blood pressure…

One day we may abandon measuring blood pressure in favour of direct ascertainment of brain perfusion or oxygenation. Until that day arrives, we will need to interpret measurements of blood pressure while knowing that it does not reflect more important parameters such as cardiac output. As long as we do this, we will need thresholds at which we treat babies' hypotension, and one way of establishing these thresholds is to try to relate early blood pressure to later neurodevelopmental status. As Logan et al point out, the existing literature is contradictory on the relationship between blood pressure measured in early life and later neurodevelopmental outcome, but the authors fail to show any convincing relationship between hypotension and subsequent developmental delay in their large study. They speculate on possible reasons for this, including the unpalatable possibility that we call babies ‘hypotensive’ at levels of blood pressure that are not harmful and then expose them to therapies that …