Hylke Salverda

159 9 General discussion and future perspectives of which occur more often in unstable respiratory periods.36 We therefore deem it appropriate to limit a comparison to episodes of supplemental oxygen when viewing the entire admission, limiting the diluting effect of respiratory stability when no supplemental oxygen is given. Vital signs such as heart rate and SpO2 can change rapidly on a second-to-second basis. Researchers using vital signs in studies should carefully consider at what rate these vital signs should be recorded. In general, it can be said that a higher resolution, or higher sampling frequency, is preferred so no fluctuations can be missed. However, data storage performance restrictions or high costs associated with data storage may justify lower frequencies for routine care. In chapter 5, data from our patient data management system recorded at a frequency of one sample per minute was used. It was unclear whether this lower frequency data could be sufficient for the purpose of descriptive statistics such as time within target range. For this reason, we compared data recorded at a 1 per second rate with sampled data once per minute in chapter 5. We processed this data in such a way that it is comparable to how data is stored by our patient data management system. In this study we assessed the difference between data derived with a low vs a high sampling rate with regard to oxygenation outcomes (f.e. proportion of time within target range, proportion of SpO2<80%, average FiO2). We found no significant differences in these oxygenation outcomes when comparing one-per-second data to one-per-minute data. This increased the validity of using oneper-minute data in descriptive statistics for retrospective studies. One-per-minute data collected for routine care is often relatively easy to acquire, and reduces the burden for parents, infants and researchers. Clinical and long-term outcome after using automated oxygen controllers for preterm infants during NICU stay. Currently, there is very little data on the effect of AOC on morbidity and mortality in preterm infants. In chapter 6 and 7, we were the first to report on clinical and long termoutcome after using automated oxygen control during the stay of preterm infants of the NICU. (chapter 6). Besides observing that the use of AOC was associated with a shift toward more non-invasive ventilation, we were unable to demonstrate an effect on clinical outcome at hospital discharge (mortality; retinopathy of prematurity, ROP; Necrotising enterocolitis, NEC; Bronchopulmonary dysplasia, BPD, chapter 6). We could also not demonstrate an effect of AOC on neurodevelopmental outcome at two years of age (chapter 7). Although no effect on short and long term outcome could be detected, we could also