Effect of interstimulus interval and age on cortical auditory evoked potentials in 10-22-week-old infants.

This study compares cortical auditory evoked potentials (CAEPs) at different interstimulus intervals (ISIs) in infants to determine the impact of stimulus rate on wave morphology. Infant CAEPs are dominated by a positive peak P1. We hypothesized that infant CAEPs would be more adult-like at longer ISI with P1, followed by negativity (labelled N450). Participants were 10 typically developing infants aged 10-13 weeks (N=4) and 20-22 weeks (N=6). CAEPs were measured in one recording session for /da/ in quiet at 55 dB SPL for ISIs of 910, 1820, 3640 and 4550 ms in a randomized order. Recordings were complete at each ISI for 7-10 infants. Seven infants who completed all testing in quiet were also tested in continuous white noise (+5 dB signal-to-noise ratio) for the shortest ISI. P1 was observable in all infants; N450 was only present in the older infants. There appeared to be no ISI effect for younger or older infants, which is not consistent with ISI findings for adults and older children. The presence of N450 in the older infants only suggests that cortical maturational differences are evident in speech-evoked CAEPs in young infants. There were minimal effects of noise on P1 latency and amplitude. Results suggest different effects of ISI for very young infants than those observed in older infants and children. CAEPs are being used to measure hearing aid effectiveness in young infants and hence it is imperative that the effects of factors such as ISI are better understood.

Evidence-based approach to change in clinical practice: introduction of expanded nasal continuous positive airway pressure use in an intensive care nursery.

OBJECTIVE: Recent studies provide evidence that nasal intermittent positive pressure ventilation (NIPPV) may stabilize the airway of extremely low birth weight infants after endotracheal extubation. The objective of this project was to introduce the use of NIPPV into a busy level 3 intensive care nursery. METHODS: This report describes the process of NIPPV introduction using a series of rapid-cycle improvement projects, as proposed by the Vermont Oxford Network. RESULTS: In the first cycle, 7 (88%) of 8 infants were successfully extubated with NIPPV after meeting criteria for reintubation on nasal continuous positive airway pressure alone. Proper positioning of the prongs in the nasopharynx was found to be an important determinant of success. In a second cycle, shorter 2.5-cm nasopharyngeal prongs were more effective than standard 4-cm prongs in 12 recently extubated infants as assessed by objective measurements and subjective nursing reports. A third cycle confirmed the acceptance of this technique in our unit and demonstrated an associated decrease in markers of chronic lung disease in extremely low birth weight infants during the 22 months after its introduction. CONCLUSION: This experience supports the role for the rapid-cycle change model in achieving effective evidence-based medical practices in a neonatal intensive care setting.