Q: What are some of the complications associated with mechanical ventilation in small children? A: In animal models, as few as six breaths at large tidal volumes have been shown to initiate lung injury and impair the effectiveness of surfactant. Aside from excessive tidal volumes (volutrauma) and inadequate lung volumes (atelectrauma) being culprits, there is new evidence to support the endotracheal tube (endotrauma) as a cause for increased complications in newborns.
Q: What strategies are used to prevent neonatal lung damage during ventilation? A: The best way to avoid ventilator induced lung injury is to avoid invasive ventilation altogether. However, 40- 50% of newborns will fail nasal CPAP and require invasive ventilation. During invasive ventilation, pressure control ventilation is still considered a widely accepted mode. With improvements in ventilator technology, proximal flow sensors have provided a useful tool for monitoring and limiting appropriate tidal volume delivery. A proliferation of new ventilator technologies have ushered in ‘volume-targeted’ ventilation; wherein, pressure control breaths are automatically adjusted by the machine to guarantee a
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pre-set tidal volume. These modes are especially useful in premature babies with variable compliance (following surfactant) and reduce the risk of volutrauma and hypocapnia in babies. New evidence suggests that volume-targeted modes can provide substantial benefits over pressure control ventilation in premature infants. High Frequency Ventilation continues to be a useful mode in infants failing conventional ventilation. Recent evidence suggests that HFOV may provide better outcomes if started earlier, rather than as a ‘rescue’ mode of ventilation in newborns.
Q: I understand you are currently working on the design of a low-cost neonatal ventilator for use in low- income parts of the world. Can you tell us a bit about this and how it could benefit hospitals in Egypt and other parts of the MENA region? A: We have recently received a 2.4 million dollar grant from the Bill and Melinda Gates Foundation to develop a simple, inexpensive bubble CPAP device that is capable of providing a higher level of respiratory support than conventional or ‘home-made’ bubble CPAP systems. Compared with conventional B-CPAP, we have demonstrated that this modality provides better gas exchange and lower work of breathing in spontaneously breathing, surfactant-deficient
subjects. I have seen first-hand in resource- limited settings that not everyone owns a ventilator. In some places, clinicians may own several donated ventilators but they are complicated to use or do not have replacement parts so they sit in the corner collecting dust. Babies are being supported with bubble CPAP in these places but if they fail this modality, many will die without access to simple devices that provide higher support. We are very excited about the new device and the potential impact it may have in reducing neonatal mortality across the world. I am especially looking forward to presenting our research with this device and discussing future steps that will be needed in order to get this device in the hands of clinicians in Egypt and other parts of the MENA region.
Q: Finally, on a more personal note, why did you decide to specialise in paediatric respiratory care? A: I decided to specialize in respiratory care because I was diagnosed with asthma as a child. I know what it is like not being able to breathe well. Luckily, I am over asthma but I realize that there is so much that still needs to be done to improve the care that our smallest patients require. I am fortunate to have a full-time position doing respiratory care related research. I hope to collaborate with researchers across the world for years to come. ■
AH
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