F(E(P))." In both groups the inequality applied, since F(P) defines volume in the Venegas equation and (P) pressure and the range of VTs varied within the convex interval for individual P-V curves. Over 5 hrs, there were no significant differences between groups in minute ventilation, airway pressure, blood gases, haemodynamics, respiratory compliance or IL-8 concentrations. Conclusion No difference between groups is a consequence of BVV occurring on the convex interval for individualised Venegas P-V curves in all experiments irrespective of group. Jensen's inequality provides theoretical proof of why a variable ventilatory approach is advantageous under these circumstances. When using BVV, with VT centred by Venegas P-V curve analysis at the point of maximal compliance change, some leeway in low VT settings beyond ARDSNet protocols may be possible in acute lung injury. This study also shows that in this model, the standard ARDSNet algorithm assures ventilation occurs on the convex portion of the P-V curve."/>
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Figure 3 | Respiratory Research

Figure 3

From: Mathematical modelling to centre low tidal volumes following acute lung injury: A study with biologically variable ventilation

Figure 3

Representative Pressure-Volume Curve Fit to the Venegas Equation. Representative P-V curve generated at zero end expiratory pressure in a single animal in the Experimental group. Dots are individual data points. The line represents the Venegas equation derived P-V curve. The Venegas parameters a, c and b are labelled, as well as the volume at the point of maximal compliance change (P = c - 1.317d) and the volume equivalent to 7 mL/kg in this animal. See text for further explanation.

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