SEMINAR: The Newborn Respiratory System: Programmed to Respond to Variability?

The Seminar: Promotion of lung volume recruitment in atelectatic lung and maintenance of existing recruited lung are vital goals of contemporary ventilatory support. In the mature lung, the recruitment of terminal airspaces are governed by power-law distributions, arising from avalanches associated with threshold pressure phenomena propagating down a branching tree structure. There is increasing evidence that the superimposition of noise on the pressure waveform during conventional can promote recruitment of collapsed lung zones when the peak inspiratory pressure is at or around the lower inflexure and that this approach may also promote production of endogenous surfactant. The mechanism likely involves the phenomenon of stochastic resonance. Stochastic resonance is most simply described as the addition of noise to a weak input signal to enhance output in a nonlinear system. It is a widespread, naturally occurring phenomenon that can be seen reflected in the patterns of world weather, fluctuations on the stock market, population biology, and optimal functioning of neural networks, to name but a few. The essential ingredients for stochastic resonance are a nonlinear dynamic system, a weak biologic signal, and superimposed noise. Recent studies comparing variable to constant volume and rhythm ventilation patterns in newborn lambs demonstrate a physiological advantage of variable input for lung volume recruitment, and upregulation of surfactant protein and developmental genes, suggesting that the newborn lung is programmed to respond to variability, and that variability may confer survival advantage. The Speaker: Professor Jane Pillow is a clinical academic neonatologist at the University of Western Australia and Co-Director of the newly formed UWA Centre for Neonatal Research and Education. She is acknowledged internationally as an expert in the area of neonatal respiratory physiology and mechanical ventilation. Prof Pillow is internationally renowned for her particular expertise in high-frequency ventilation, having undertaken completed her PhD thesis in 2000 on “Optimising High-Frequency Oscillatory Ventilation in Neonates”. Since completing her PhD with Distinction in 2000, Prof Pillow’s research interests have expanded to include high-frequency jet ventilation, variable ventilation, bubble CPAP, patient triggered ventilation and minimising lung and diaphragmatic injury during resuscitation. Her research group in Perth undertakes animal studies using the preterm lamb as a model of neonatal respiratory distress syndrome, many of which are performed in collaboration with interstate and international colleagues in medical, physiological, anatomical and biomedical engineering departments. Future plans for the lamb work include the development of a preterm lamb intensive care unit for long term ventilation of preterm lambs. At KEMH, Professor Pillow also runs a neonatal lung function laboratory, and is involved in clinical trials and follow-up functional studies of children born prematurely in addition to involvement in clinical trials. Jane has obtained over $4.5 million AUD in research funding, including 4 grants from the NHMRC (3 as CIA) and 3 grants from the NIH and has had continuous scholarship and fellowship funding from the NHMRC and Viertel Foundation since 1997. She has extensive involvement in peer-review activities relevant to neonatal research, mechanical ventilation and respiratory physiology. In addition to her academic responsibilities, Prof Pillow is a Consultant Neonatologist in the Women’s and Newborn’s Health Service. She is currently based within the UWA Centre of Neonatal Research and Education and the Neonatal Clinical Care Unit at King Edward Memorial Hospital in Perth, which has 100 neonatal beds including 30 bed NICU, but which caters frequently for up to 40 infants on mechanical ventilation or CPAP.