An analysis of the respiratory dynamics of preterm infants

Bester, Maretha (2019-04)

Thesis (MEng)--Stellenbosch University, 2019

Thesis

ENGLISH ABSTRACT: Poor understanding of preterm infant physiology attributes to the high infant mortality rates, as well as its corresponding financial burden. Prematurity compromises the respiratory and regulatory systems of infants. This manifests itself in characteristic respiratory dynamics consisting of apneas, periodic breathing and regular breathing. These dynamics, if captured, quantified and visualised have potential to track maturational changes in infants. This can aid physicians in the difficult task of assessing a preterm infant’s level of physiological maturity and offer insight into the infant’s regulatory systems. The primary objective of this study was to develop a transition model representing the behaviour of and temporal relationship between the different respiratory states of preterm infants. Secondary objectives consisted of the following: Analysing 2 – 5 s cessations, their contribution to breathing cessation and relationship to apnea; temporally tracking the respiratory stability of preterm infants; and studying the relationship between breathing cessations and heart rate behaviour. Transition models were developed that adequately represented the respiratory dynamics of preterm infants. It showed that respiratory events are related in time, but that periodic breathing rarely precedes apnea of prematurity. On average 9% of breathing cessation and less than 1% of periodic breathing was found in the dataset. It was found that the contribution of short cessations were large, and that there is a temporal periodicity to the percentage cessations in the respiratory signal. Coupling between the respiratory and cardiac systems could be observed, with an apparent common temporal periodicity between some heart rate variability measures and percentage cessation in breathing signal. In conclusion, all objectives were successfully addressed and greater insight was gained into the physiology of preterm infants. Future value exists in applying these analyses on a larger, more longitudinal and clinically annotated dataset.

AFRIKAANSE OPSOMMING: Swak begrip van premature kinderfisiologie dra by tot wêreldwye hoë kindersterftesyfers, asook die ooreenstemmende finansiële las. Prematuriteit kompromieer die respiratoriese en regulatoriese stelsels van babas. Dit manifesteer in kenmerkende respiratoriese dinamieke wat bestaan uit apnee, periodiese asemhaling en normale asemhaling. Indien hierdie dinamieke gemonitor, gekwantifiseer en gevisualiseer kan word, het dit die potensiaal om die volwassewording van premature babas te monitor. Dit kan dokters help in die moeilike taak om 'n premature kind se vlak van fisiologiese volwassenheid te bepaal. Dit kan ook insig gee rakende die regulatoriese stelsels van die baba. Die primêre doel van hierdie studie was om 'n oorgangsmodel te ontwikkel wat die gedrag van en tydelike verband tussen die verskillende respiratoriese toestande van premature babas verteenwoordig. Sekondêre doelwitte het bestaan uit die volgende: Studie van 2 - 5 s asemhalingstakings, hul bydrae tot die totale asemhalingstaking en verhouding tot apnee; om die respiratoriese stabiliteit van premature babas relatief tot tyd te bestudeer; en die verband tussen asemhalingstake en variasie in hartklop te observeer. 'n Oorgangsmodel is ontwikkel wat die respiratoriese dinamika van premature babas voldoende verteenwoordig het. Dit het getoon dat respiratoriese gebeure verbonde is in tyd, maar dat apnee van prematuriteit selde deur periodiese asemhaling voorafgegaan word. Gemiddeld is 9% asemhalingstaking en minder as 1% periodieke asemhaling in die datastel gevind. Daar is bevind dat die bydrae van kort asemhalingstakings groot was en dat daar 'n temporale periodisiteit is vir die persentasie stakings in die respiratoriese sein. Koppeling tussen die respiratoriese en kardiale stelsels kon waargeneem word, met 'n skynbare algemene temporale periodisiteit tussen sommige hartklopveranderings-maatreëls en persentasie staking in die asemhalingssein. Ten slotte is alle doelwitte suksesvol aangespreek en is meer insig verkry in die fisiologie van premature babas. Toekomstige waarde bestaan in die toepassing van hierdie ontledings op 'n groter, meer longitudinale en klinies geannoteerde datastel.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/106144
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