The birth is a complex event especially for preterm, since the incomplete maturation of their respiratory system. Preterm infant may be admitted in a neonatal intensive care unit (NICU), were their condition is monitored and assisted. Standard respiratory support, even if effective, still shows limitations in its capability to interact with the patient, leading to asynchronies between the ventilators and the patients. To address this issue, a novel mechanical ventilation mode, neurally adjusted ventilatory assist (NAVA) has been introduced. This system allows synchronizing the ventilator activity to the patient’s effort, triggering the act by using the diaphragm electromyographic signal (EDi), which is also used to modulate the inspiratory pressure amplitude. Several studies demonstrated that a variable strain applied to the epithelial cells of the lungs may increase the endogenous secretion of surfactant and, compared to the standard mechanical ventilation mode used in clinical practice, NAVA might maintain the spontaneous variability of the breaths. The aim of this project is to evaluate the effect of NAVA on breathing variability compared to the standard synchronized pressure assisted ventilation mode (PC), during a randomized cross-over clinical trial on preterm newborns receiving non-invasive ventilation (NIV). During NIV, the presence of unavoidable large leaks makes unreliable the breathing volume measurements provided by the mechanical ventilator. To overcome this issue, a novel 3D camera, was used to evaluate the movements of the chest wall. This compact device performs an accurate, reliable and non-invasive measurement of objects distance from the camera, not requiring prior calibration and minimally interfering with the clinical routine. From the 14 infants enrolled up to now, NAVA shows better synchronization with the patient and a decrease of the work of breathing. The additional information coming from the cameras also show that NAVA results in a greater variability of the chest wall displacements and reduced presence of thoraco-abdominal asynchronies compared to PC, suggesting that this ventilation mode results in a more physiological breathing.
La nascita è un evento complesso per i neonati pretermine dato l’incompleto sviluppo del loro sistema respiratorio. Essi spesso necessitano di essere ricoverati in terapia intensiva neonatale (TIN), dove le loro condizioni vengono monitorate in modo continuo. I supporti respiratori standard, anche se efficienti, mostrano delle limitazioni nell’interazione con il paziente, portando anche ad eventuali asincronie tra i due. La neurally adjusted ventilatory assist (NAVA) è una nuova modalità di ventilazione che sincronizza il supporto respiratorio fornito direttamente con il segnale elettromiografico del diaframma, usato inoltre per modulare l’ampiezza della pressione inspiratoria erogata. Diversi studi hanno dimostrato che uno sforzo variabile applicato alle cellule epiteliali del polmone può aumentare la secrezione endogena di surfattante, quindi rispetto alle ventilazioni meccaniche standard, la NAVA, potrebbe mantenere la variabilità dei respiri spontanei. Lo scopo di questo progetto è quindi di valutare l’effetto della NAVA sulla variabilità del respiro rispetto a quello di una ventilazione sincronizzata standard a pressione controllata (PC) all’interno di uno studio clinico randomizzato. I neonati pretermine arruolati vengono ventilati in modalità non invasiva, durante la quale la presenza di perdite inevitabili all’interfaccia rende inaffidabile il volume calcolato dal ventilatore. Per superare questo problema è stata usata una nuova camera 3D in grado di valutare il movimento della gabbia toracica. Questo dispositivo compatto fornisce in modo non invasivo misure accurate e affidabili della distanza degli oggetti dalla camera; inoltre, non richiede nessuna calibrazione a priori e interferisce poco con la routine clinica. Nell’analisi fatta sui 14 neonati pretermine arruolati finora, la NAVA ha mostrato una migliore sincronizzazione con il paziente e una diminuzione del lavoro respiratorio. Le informazioni derivate dalle camere, mostrano che la NAVA garantisce maggiore variabilità dei movimenti toracici oltre che diminuire la presenza di asincronie toraco-addominali. Il confronto con la PC suggerisce che la NAVA garantisce una respirazione più fisiologica.
Effects of neurally adjusted ventilatory assist compared to conventional non-invasive ventilation on breathing pattern assessed by novel non-invasive tools
MALFITANA, MARIA LAURA
2018/2019
Abstract
The birth is a complex event especially for preterm, since the incomplete maturation of their respiratory system. Preterm infant may be admitted in a neonatal intensive care unit (NICU), were their condition is monitored and assisted. Standard respiratory support, even if effective, still shows limitations in its capability to interact with the patient, leading to asynchronies between the ventilators and the patients. To address this issue, a novel mechanical ventilation mode, neurally adjusted ventilatory assist (NAVA) has been introduced. This system allows synchronizing the ventilator activity to the patient’s effort, triggering the act by using the diaphragm electromyographic signal (EDi), which is also used to modulate the inspiratory pressure amplitude. Several studies demonstrated that a variable strain applied to the epithelial cells of the lungs may increase the endogenous secretion of surfactant and, compared to the standard mechanical ventilation mode used in clinical practice, NAVA might maintain the spontaneous variability of the breaths. The aim of this project is to evaluate the effect of NAVA on breathing variability compared to the standard synchronized pressure assisted ventilation mode (PC), during a randomized cross-over clinical trial on preterm newborns receiving non-invasive ventilation (NIV). During NIV, the presence of unavoidable large leaks makes unreliable the breathing volume measurements provided by the mechanical ventilator. To overcome this issue, a novel 3D camera, was used to evaluate the movements of the chest wall. This compact device performs an accurate, reliable and non-invasive measurement of objects distance from the camera, not requiring prior calibration and minimally interfering with the clinical routine. From the 14 infants enrolled up to now, NAVA shows better synchronization with the patient and a decrease of the work of breathing. The additional information coming from the cameras also show that NAVA results in a greater variability of the chest wall displacements and reduced presence of thoraco-abdominal asynchronies compared to PC, suggesting that this ventilation mode results in a more physiological breathing.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/154340