Pulmonary impedance measurements in anesthetized mice. The diagram shows airway opening pressure plotted against time. Volume and flow excursions for each breath are maintained constant by use of a volume-cycled ventilator. Increases in the magnitude of lung impedance following acethycholine injection are assessed as the increase in pressure above baseline. Note the increased responsiveness in the A/J compared the C3He/J strain of mouse. APTI: Airway pressure time index. Used with permission .
Irvin and Bates Respiratory Research 2003 4:4 doi:10.1186/rr199