Objective: This study aimed to evaluate the association between electrical activity of the diaphragm (Edi) waveform patterns and peripheral oxygen saturation (SpO 2 ) in extremely preterm infants who are ventilated with neurally adjusted ventilatory assist (NAVA). Study Design:We conducted a retrospective cohort study at a level III neonatal intensive care unit. Extremely preterm infants born at our hospital between November 2019 and November 2020 and ventilated with NAVA were included. We collected Edi waveform data and classified them into four Edi waveform patterns, including the phasic pattern, central apnea pattern, irregular low-voltage pattern, and tonic burst pattern. We analyzed the Edi waveform pattern for the first 15 h of collectable data in each patient. To investigate the association between Edi waveform patterns and SpO 2 , we analyzed the dataset every 5 min as one data unit. We compared the proportion of each waveform pattern between the desaturation (Desat [+]) and non-desaturation (Desat [-]) groups.Results: We analyzed collected data for 105 h (1260 data units). The proportion of the phasic pattern in the Desat (+) group was significantly lower than that in the Desat (-) group (p < .001). However, the proportions of the central apnea, irregular low-voltage, and tonic burst patterns in the Desat (+) group were significantly higher than those in the Desat (-) group (all p < .05). Conclusion:Our results indicate that proportions of Edi waveform patterns have an effect on desaturation of SpO 2 in extremely preterm infants who are ventilated with NAVA.

Background Serum alkaline phosphatase (ALP) is a useful bone turnover marker to diagnose metabolic bone disease in preterm infants. In Japan, serum ALP levels were generally measured using the Japan Society of Clinical Chemistry (JSCC) method. It is problematic that ALP levels measured using the JSCC method tend to be higher in people with blood types B and O regardless of the disease. For international standardization, since 2020, the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) method has been used as a reference method for ALP measurement instead of the JSCC method. However, no report has investigated the correlation between these two methods in neonates. We therefore aimed to compare the JSCC and IFCC methods and demonstrate a conversion formula in neonates. Methods In this retrospective study, we used a total of 402 samples in 49 preterm and 38 term infants. Serum ALP levels were measured using the JSCC and IFCC methods. Results Alkaline phosphatase measured using the JSCC method strongly correlated with that measured using the IFCC method in all blood types in preterm and term infants (P < 0.01 for all). Conclusions We found that the serum ALP levels measured using the IFCC method could be calculated as 0.34 times the ALP levels measured using the JSCC method in preterm and term infants with any blood type: ALP levels (IFCC method) = 0.34 × ALP levels (JSCC method).

Objective This study aimed to evaluate the change in the waveform pattern of the electrical activity of the diaphragm (Edi) following the administration of doxapram in extremely preterm infants ventilated with neurally adjusted ventilatory assist (NAVA). Study Design We conducted this retrospective cohort study in our neonatal intensive care unit between November 2019 and September 2021. The study participants were extremely preterm infants under the gestational age of 28 weeks who were ventilated with NAVA and administered doxapram. We collected the data of the Edi waveform pattern and calculated the proportion. To analyze the change in the proportion of the Edi waveform pattern, we compared the proportion of the data for 1 h before and after doxapram administration. Results Ten extremely preterm infants were included. Almost all the patients’ respiratory condition improved after doxapram administration. The ventilatory parameters—Edi peak, Edi minimum, peak inspiratory pressure, time in backup ventilation, and number of switches to backup ventilation—did not change significantly. However, the proportion of phasic pattern significantly increased (before: 46% vs. after: 72%; p < 0.05), whereas the central apnea pattern significantly decreased after doxapram administration (before: 31% vs. after: 8.3%; p < 0.05). The proportion of irregular low‐voltage patterns tended to decrease, albeit with no significant changes. Conclusion Our results indicated that the proportion of Edi waveform patterns changed following doxapram administration. Edi waveform pattern analysis could be a sensitive indicator of effect with other intervention for respiratory conditions.