Spectral features of non-nutritive suck dynamics in extremely preterm infants.

Background: Non-nutritive suck (NNS) is used to promote ororhythmic patterning and assess oral feeding readiness in preterm infants in the neonatal intensive care unit (NICU). While time domain measures of NNS are available in real time at cribside, our understanding of suck pattern generation in the frequency domain is limited. The aim of this study is to model the development of NNS in the frequency domain using Fourier and machine learning (ML) techniques in extremely preterm infants (EPIs). Methods: A total of 117 EPIs were randomized to a pulsed or sham orocutaneous intervention during tube feedings 3 times/day for 4 weeks, beginning at 30 weeks post-menstrual age (PMA). Infants were assessed 3 times/week for NNS dynamics until they attained 100% oral feeding or NICU discharge. Digitized NNS signals were processed in the frequency domain using two transforms, including the Welch power spectral density (PSD) method, and the Yule-Walker PSD method. Data analysis proceeded in two stages. Stage 1: ML longitudinal cluster analysis was conducted to identify groups (classes) of infants, each showing a unique pattern of change in Welch and Yule-Walker calculations during the interventions. Stage 2: linear mixed modeling (LMM) was performed for the Welch and Yule-Walker dependent variables to examine the effects of gestationally-aged (GA), PMA, sex (male, female), patient type [respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD)], treatment (NTrainer, Sham), intervention phase [1, 2, 3], cluster class, and phase-by-class interaction. Results: ML of Welch PSD method and Yule-Walker PSD method measures revealed three membership classes of NNS growth patterns. The dependent measures peak_Hz, PSD amplitude, and area under the curve (AUC) are highly dependent on PMA, but show little relation to respiratory status (RDS, BPD) or somatosensory intervention. Thus, neural regulation of NNS in the frequency domain is significantly different for each identified cluster (classes A, B, C) during this developmental period. Conclusions: Efforts to increase our knowledge of the evolution of the suck central pattern generator (sCPG) in preterm infants, including NNS rhythmogenesis will help us better understand the observed phenotypes of NNS production in both the frequency and time domains. Knowledge of those features of the NNS which are relatively invariant vs. other features which are modifiable by experience will likewise inform more effective treatment strategies in this fragile population.

Extracorporeal membrane oxygenation in piglets using a polymerized bovine hemoglobin-based oxygen-carrying solution (HBOC-201).

PURPOSE: The purpose of this study was to determine if the polymerized bovine hemoglobin-based oxygen-carrying solution HBOC-201 is an acceptable substitute for blood in a healthy porcine, extracorporeal membrane oxygenation (ECMO) model. METHODS: Ten piglets (15 to 25 kg) were placed on venoarterial ECMO. Four animals received blood-primed ECMO, and 6 animals received HBOC-201-primed ECMO. Hemodynamic variables, urine output, blood gas analyses, complete blood counts, and lactate levels were followed for 6 hours. Data were analyzed using a nonparametric sign test and repeated measures analysis of variance (ANOVA). RESULTS: All animals survived the 6-hour ECMO procedure. Heart rate, mean arterial pressure, urine output, and serum lactate levels were not significantly different between groups. Postpriming volume was 176 +/- 156 mL in the blood group. None of the animals in the HBOC-201 group required additional volume to maintain target flow during ECMO (P <.05). Arterial pH, pO2, and oxygen content between groups were not significantly different. Hematocrit for the HBOC-201 group was significantly (P <.05) lower than the blood group. CONCLUSIONS: HBOC-201-primed ECMO in a healthy porcine model showed similar hemodynamics and equivalent oxygen carrying capacity to blood-primed ECMO. Postpriming volume requirement was decreased significantly in the HBOC group. ECMO using HBOC-201 instead of blood appears promising and warrants further investigation.

A 16-year neonatal/pediatric extracorporeal membrane oxygenation transport experience.

OBJECTIVE: To characterize the population and survival of neonatal and pediatric patients transported by Wilford Hall Medical Center (WHMC) on extracorporeal membrane oxygenation (ECMO) since 1985. STUDY DESIGN: A retrospective chart, literature, and database review of pediatric and neonatal patients transported on ECMO by the WHMC ECMO transport team. In addition, a subpopulation analysis was performed comparing neonates with meconium aspiration syndrome (MAS) placed on ECMO at WHMC with those infants with MAS transported on ECMO. Characteristics of interest for this comparison included disease severity before ECMO, age at initiation of ECMO, survival, ECMO-related complications, and duration of ECMO support. RESULTS: Forty-two patients transported on ECMO were identified: 23 neonatal respiratory cases (survival 57%), 7 pediatric respiratory cases (survival 71%), 4 cardiac cases (survival 50%), and 8 extra-institutional ECMO transports (survival 63%). In the MAS subpopulation, there was significantly greater survival in the in-house group--97% (31/32)--than in the ECMO transport group--75% (9/12); there were no other significant differences between these groups. Overall, no ECMO-related complications leading to patient demise could be identified in the ECMO transport group. CONCLUSIONS: ECMO transport, although demonstrating acceptable survival, is a risk-laden modality that should not replace early referral to an ECMO center.