Question

Within a P-V curve why is it non linear, what physiological mechanisms lead to less volume intake at low and high pressure, while higher volume intake at middle pressure range? This also means compliance is the slope of this curve, but what makes compliance value different at different pressure interval (so variation in volume intake at different pressure)?

Provide literature to support answer.

Answer 1

The pressure volume (P-V) curve of the respiratory system mentions the mechanical behaviour of the lungs and wall of the chest during inflation and deflation.

The P-V curve has been studied in many disease, but mostly applied to those patients who suffers from acute respiratory distress syndrome (ARDS).

The curve is obtained by slowly insufflating the chest, either continously or in samll intervals.

The intermediate segment can be considered linear and often used to measure the linear compliance between lower inflection and upper inflection point.