Page 23 - Physiological based CPAP for preterm infants at birth Tessa Martherus

Previous preclinical studies in mechanically ventilated preterm sheep (75-78) have found that high-PEEP levels cause pulmonary overexpansion and compromise the cardiovascular system by reducing venous retrun and decreasing PBF. We therefore explored the effect of high-CPAP on the cardiovascular system during the neonatal transition. Prior to the experiment, fetal lambs were instrumented with flow probes and catheters for continuous flow- and pressure measurements. In the first 30 minutes after birth, preterm lambs received 5 or 15 cmH2O CPAP continuous or 15 cmH2O CPAP titrated to 8 cmH2O, after which CPAP pressures were decreased. In Chapter 4 we highlight the effect of different CPAP pressures on the pulmonary and cerebral blood flow and the jugular venous pressure to investigate any possible physiological consequences of high-CPAP levels.
To extrapolate the results of the preclinical studies into a clinical setting, a single centre randomised clinical trial was performed. In this trial the previously proposed PB-CPAP strategy was compared to standard of care which is 5-8 cmH2O CPAP. PB-CPAP meant commencing respiratory support at 15 cmH2O with stepwise titration (-2/2/3 cmH2O/min) to 8 cmH2O if the infant met set criteria (spontaneous breathing, oxygenation ≥85%, FiO2 ≤0.4 and heart rate ≥100 bpm.) The primary outcomes were oxygenation and feasibility. Secondary outcomes included heart rate, delivery room interventions and short-term outcomes. These results are presented in Chapter 5.
To conclude, the main findings of the studies presented in this thesis and the future perspectives will be discussed in the General discussion. The studies will be summarized in the English summary and Nederlandse samenvatting.
GI
General introduction
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