Birth is a critical transition for newborns, as the cardio-pulmonary system needs to quickly adapt to the new environment for them to survive. Premature birth implicates that the last stages of lung development, that normally take place in utero, occur after birth and under different environmental conditions. For this reason, preterm babies are more prone to respiratory system disorders. The heterogeneity and rapid development of their clinical conditions make it difficult to optimise the treatments. To improve our understanding of the complex interactions between breathing pattern, respirator control, ventilatory support and patient maturation, an ad-hoc device with high time resolution needs to be developed to continuously record physiological data and investigate the long-term correlation properties of these variables and their evolution. Such a device would allow to investigate the changes of the variability and correlation properties of respiratory parameters during the different treatment settings, the maturation of the baby and the resolution of the disease, especially when mechanical ventilation is applied. The first part of this study was focused on the identification of the technical and usability requirements for the device followed by its design and development. One prototype of the system was then evaluated and validated by in-vitro tests to assess its reliability and performances. After the in vitro validation, pilot measurements were performed by collecting time series of respiratory parameters on newborns admitted in a Neonatal Intensive Care Unit (NICU) and receiving respiratory support. From those tracings, an analysis of tidal volume, respiratory time parameters and diaphragmatic EMG signals was performed, with the aim of characterizing their variability and their long-term correlation characteristics. The device proved to be reliable, accurate and suitable for long-term acquisitions in NICU, opening new perspectives for studying the natural evolution due to maturation, how ventilation modes and parameters impact on the maturation of respiratory control, with the aim to identify the proper time for weaning.
Il momento della nascita è un passaggio critico per il nascituro, ed il sistema cardiocircolatorio deve adattarsi prontamente al nuovo ambiente per permettere la sopravvivenza del neonato. La nascita pretermine implica che il completamento dello sviluppo polmonare avvenga fuori dall’utero. Per questo motivo, i neonati prematuri sono ad alto rischio di sviluppo di patologie respiratorie. L’eterogeneità e i rapidi cambiamenti delle condizioni cliniche rendono difficile l’ottimizzazione del trattamento. Al fine di comprendere le interazioni complesse tra il sistema respiratorio, il controllo neurologico e l’azione del ventilatore meccanico durante la maturazione del paziente, sorge la necessità di sviluppare un dispositivo per la registrazione continua di parametri fisiologici e per l’analisi della correlazione a lungo termine tra queste variabili e la loro evoluzione. Questo dispositivo permetterebbe di studiare l’andamento della variabilità e della correlazione tra parametri respiratori durante diverse strategie di supporto ventilatorio e durante la maturazione del neonato. La prima parte di questo lavoro di tesi è stata incentrata sullo studio dei requisiti tecnici, con particolare attenzione alla facilità d’uso, e sullo sviluppo e realizzazione del dispositivo. Il sistema è stato testato in vitro per valutarne il corretto funzionamento e successivamente sono state eseguite delle misure pilota su neonati ricoverati in Terapia Intensiva Neonatale (TIN) e ventilati al fine di acquisire lunghe serie temporali di parametri respiratori. Da queste acquisizioni sono stati estratti volumi polmonari, tempi e attività del diaframma, ed è stata fatta una caratterizzazione della variabilità e della correlazione a lungo termine tra queste grandezze. Il dispositivo ha dimostrato di essere affidabile e adatto per la registrazione a lungo termine di dati in terapia intensiva, aprendo nuove possibilità per lo studio della maturazione del controllo respiratorio e delle sue interazioni con la strategia di ventilazione, al fine di identificare il momento più appropriato per lo svezzamento.
A novel device for studying breathing pattern and neural control over the first days of life in preterm newborns requiring respiratory support
MOREA, ORNELLA
2017/2018
Abstract
Birth is a critical transition for newborns, as the cardio-pulmonary system needs to quickly adapt to the new environment for them to survive. Premature birth implicates that the last stages of lung development, that normally take place in utero, occur after birth and under different environmental conditions. For this reason, preterm babies are more prone to respiratory system disorders. The heterogeneity and rapid development of their clinical conditions make it difficult to optimise the treatments. To improve our understanding of the complex interactions between breathing pattern, respirator control, ventilatory support and patient maturation, an ad-hoc device with high time resolution needs to be developed to continuously record physiological data and investigate the long-term correlation properties of these variables and their evolution. Such a device would allow to investigate the changes of the variability and correlation properties of respiratory parameters during the different treatment settings, the maturation of the baby and the resolution of the disease, especially when mechanical ventilation is applied. The first part of this study was focused on the identification of the technical and usability requirements for the device followed by its design and development. One prototype of the system was then evaluated and validated by in-vitro tests to assess its reliability and performances. After the in vitro validation, pilot measurements were performed by collecting time series of respiratory parameters on newborns admitted in a Neonatal Intensive Care Unit (NICU) and receiving respiratory support. From those tracings, an analysis of tidal volume, respiratory time parameters and diaphragmatic EMG signals was performed, with the aim of characterizing their variability and their long-term correlation characteristics. The device proved to be reliable, accurate and suitable for long-term acquisitions in NICU, opening new perspectives for studying the natural evolution due to maturation, how ventilation modes and parameters impact on the maturation of respiratory control, with the aim to identify the proper time for weaning.| File | Dimensione | Formato | |
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2019_04_Morea.pdf
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Descrizione: Testo della tesi
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https://hdl.handle.net/10589/146261