Continuous Telemetric In Utero Tracheal Pressure Measurements in Fetal Lambs

Mar Janna Dahl; Stefano Robbiani; Chiara Veneroni; Anna Lavizzari; Sebastian Amos; Gabrielle C. Musk; Helen Kershaw; Jonathan W. Davis; Fabio Mosca; Peter B. Noble; Raffaele Dellacà; J. Jane Pillow

doi:10.3791/64767

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Method Article

Continuous Telemetric In Utero Tracheal Pressure Measurements in Fetal Lambs

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DOI:

10.3791/64767

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December 22nd, 2023

Mar Janna Dahl¹ , Stefano Robbiani² , Chiara Veneroni² , Anna Lavizzari³ , Sebastian Amos¹ , Gabrielle C. Musk¹^,⁴ , Helen Kershaw⁴ , Jonathan W. Davis⁵^,⁶ , Fabio Mosca³ , Peter B. Noble¹ , Raffaele Dellacà^*² , J. Jane Pillow^*¹^,⁶

¹School of Human Sciences, The University of Western Australia, ²Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano University, ³NICU, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, ⁴Animal Care Services, The University of Western Australia, ⁵Medical School, University of Western Australia, ⁶Telethon Kids Institute

^* These authors contributed equally

Summary

Optimization of occlusion pressure and duration required to improve lung hypoplasia with tracheal occlusion is essential to improve in utero corrective treatments for congenital diaphragmatic hernia (CDH). This study reports a new method for continuous measurement of the tracheal pressure in an occluded and unoccluded fetal lamb surgical model of CDH.

Abstract

Normal in utero lung development and growth rely upon the expansion of airspaces and the controlled efflux of lung liquid into the amniotic space. Infants with congenital diaphragmatic hernia (CDH) also have lung hypoplasia due to occupation of the chest cavity by the stomach and bowel and, in the most severe cases, the liver. Balloon tracheal occlusion reduces the severity of lung hypoplasia in fetuses with CDH but increases the risk of premature birth. Understanding the optimal occlusion pressure and duration required to improve lung hypoplasia with tracheal occlusion is essential to improving in utero corrective treatments for CDH. The study reports a new method for continuous measurement of the intratracheal and amniotic pressures in an unoccluded and occluded fetal lamb surgical model of CDH. Time-pregnant Merino ewes underwent two recovery hysterotomies: the first at ~80 days of gestation to create the CDH, and the second at ~101 days of gestation to occlude the fetal trachea and implant an intratracheal and amniotic pressure measurement device. Lambs were delivered at ~142 days, and the pressure measurement device was removed and cleaned. The data were downloaded and filtered using a 6 h window. Transrespiratory pressure was calculated.

Introduction

Normal lung development and growth rely upon the expansion of the potential airspaces with fetal lung liquid and the controlled efflux of the lung liquid into the amniotic space¹^,²^,³^,⁴^,⁵. Fetal lung liquid production and the resistance of the upper airways create an in utero intrathoracic pressure¹. Historically, in utero measurements of fetal airway pressures were obtained using external pressure sensors via catheters tunneled through the abdominal wall to the feta....