The guys in Melbourne have a great set up, the 2 universities collaborate, as well as working with colleagues from Sydney also. Stuart Hopper is a very innovative thinker who has re-examined a lot of older data about what happens at birth, and has a good scientific approach, but always an eye on what the clinical implications are. This latest study (Bhatt S, Alison BJ, Wallace EM, Crossley KJ, Gill AW, Kluckow M, te Pas AB, Morley CJ, Polglase GR, Hooper SB: Delaying cord clamping until ventilation onset improves cardiovascular function at birth in preterm lambs. The Journal of Physiology 2013, 591(8):2113-2126._ Examined the effects of ventilating lambs before or after the cord was clamped. The animals were instrumented before birth, then when they were delivered by cesarean, they intubated the animals. They either then cut the cord and started ventilation 2 minutes later, or started ventilation with the cord unclamped, and clamped it when the pulmonary artery flow had increased (about 3.7 minutes on average). Delayed clamping had the following benefits:
”ventilation prior to cord clamping markedly improves cardiovascular function by increasing pulmonary blood flow before the cord is clamped, thus further stabilising the cerebral haemodynamic transition.
These results show that delaying cord clamping until after ventilation onset leads to a smoother transition to newborn life, and probably underlies previously demonstrated benefits of delayed cord clamping.”
It is really starting to l0ok like the default should be to ventilate the baby BEFORE clamping the cord: even if the baby is a little bradycardic (the lambs who were clamped first dropped their heart rates, the ventilation first lambs did not), systemic blood flows were much better after this process than after immediate clamping. The clinical studies will confirm whether this is safe and effective in the very preterm, but this study gives us some mechanistic data that support the change in practice. (In addition we already know in older preterm infants and term babies that delayed clamping increases hemoglobin and reduces later transfusions).