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Electronic Supplementary Material – Supplementary Figures

Title: Variable ventilation improves ventilation and lung compliance in preterm lambs

J. Jane Pillow1, Gabrielle C. Musk1, Carryn M. McLean, Graeme R Polglase1, Richard G.B. Dalton1, Alan H. Jobe1,2, Béla Suki3.

Running Title: ESM - Variable ventilation in preterm lambs

Supplementary Figures

Figure 1: Study Protocol – Flow Diagram


Figure 2 Distribution of tidal volume and respiratory rate during conventional and variable ventilation: Plots show average time-based distribution of A) tracheal tidal volume (VT,tr) and (B) respiratory rate (RR) for CV (black line) and VV (grey line) resulting from the pre-programmed ventilation pattern. The middle panels illustrate a representative probability distribution of VT,tr (C) and respiratory rates (D) in the VV group on a log-log scale. Tidal volumes above and respiratory rates below the average values (vertical black lines) were distributed according to a power law.


Figure 3 Gas Exchange and Arterial Oxygenation: Plots depict (A) arterial pH, (B) oxygenation index (OI) and (C) arterial-Alveolar (aA) ratio in conventional (open circle) and variable ventilation (closed circle) groups. OI data are displayed as median (25th – 75th centile). * p<0.05

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Figure 4 Lung mechanics (right) Plots depict (A) mean tracheal pressure (Ptr), (B) dynamic resistance (Rdyn) and (C) ventilation efficiency index, VEI. Symbols represent control (open circle) and variable ventilation (closed circle) groups. VEI increased while Ptr decreased over the duration of the study in the variable ventilation group compared to the conventional ventilation group. * p<0.05; ** p<0.01

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Figure 5 Bronchoalveolar Lavage Inflammatory Cell Count: Figure shows the BAL inflammatory cell count as a percentage of total cells in nonventilated (NVC – white bar), control ventilation (CV- light grey bar) and variable ventilation (VV-dark grey bar) lamb groups. The % inflammatory cell count and lung tissue IL-1b mRNA were higher in ventilated compared to nonventilated groups, but no differences were apparent between control and variable ventilation groups. Data are shown as the box plot (median, 25th-75th centile), and individual data points * p<0.05