“…SOMNOmedics GmbH, Germany, 2013); the pleth trace peak is easier to define precisely than the mid-point of the pleth waveform increase in view of the high heart rate seen in neonates and hence used to measure PTT . [10] Because of the expected variability in neonatal heart rate, the PTT measurements were also normalised (nPTT) for the heart rate by dividing the resulting PTT by the time difference between two R waves on the ECG at the time the PTT calculation was made. For each recording, the mean value from nPTT measurements was calculated.…”