Ellen de Kort

56 Chapter 4 Ethical approval For this observational study we received a waiver for formal ethical approval (Medical Ethical Committee, Maxima Medical Center, Veldhoven, the Netherlands, No. N18.095) according to the Dutch Law of Research with Humans. No additional parental consent was required. RESULTS Study population Inclusion of patients is shown in the study flow chart in Figure 1. During the study period LISA was performed in 111 patients with a GA <32 weeks. Twenty-five patients were excluded because the standardized registration form was not completed and therefore data regarding quality of technical conditions and success of LISA attempts were lacking, leaving 86 patients to be included. In 29 patients, data on vital parameters were not available in data warehouse and in 20 patients these data could not be retrieved because the precise starting time of LISAwas lacking. Therefore, heart rate and oxygen saturation data from 20 min before until 30 min after start of LISA were available in 37 patients. Patient characteristics of the study population are shown in Table 1. Patients inwhomvital parameter data were lacking, had younger gestational and postnatal ages compared to patients with available data. Table 1. Patient characteristics Total study population Vital parameter analysis No vital parameter analysis p-value n = 86 n = 37 n = 49 Gestational age (week), median (IQR) 28.3 (26.6-29.7) 29.0 (27.1-30.0) 27.9 (25.7-29.1) 0.007 Birth weight (g), median (IQR) 1,015 (769-1,305) 1,120 (853-1,320) 995 (715-1,255) 0.12 Birth weight <10 th percentile, n (%) 25 (29) 13 (35) 12 (25) 0.34 Postnatal age (hr), median (IQR) 3.3 (2.1-8.5) 5.4 (2.5-13.2) 2.7 (1.9-5.9) a 0.01 Male gender, n (%) 49 (57) 23 (62) 26 (53) 0.51 a Missing data in 7 patients.