[Changes in compliance of the intact thorax under rising insufflation pressure and the limits of physiological elasticity: studies on guinea pigs].
Pressure-volume curves of 26 guinea pigs, weighing 124 and 1135 grams were recorded; the curves being achieved by a gradual inflation of the lungs in the intact thorax. The presentation of the compliance alteration as a function of insufflation pressure (IFP) shows a uniform inflation characteristic, independent of body weight: the high level of compliance at the beginning of the curve starts to decrease at an IFP value of 0/76 kPa and falls gradually to approximately a third of the starting value, yet at an IFP value of 1.9 kPa the curve rises sharply again. Complete pressure-volume loops of 8 guinea pigs, achieved by inflating, relaxing and re-inflating the lungs, were also recorded. Where the IFP value was less than 1.9 kPa the inflation curves were identical. Where the IFP value, however, was greater than 1.9 kPa the adaptation phenomenon described by BERNSTEIN [6] with increasing hysteresis and "air trapping" appeared. One may conclude, therefore, that with an IFP value of 1.9 kPa the limit of the physiological expansion of the guinea pigs' lungs is reached.
D000818:Animals; D004548:Elasticity; D006168:Guinea Pigs; D007320:Inspiratory Capacity; D008170:Lung Compliance; D011312:Pressure
Anderungen der Compliance im intakten Thorax mit steigendem Insufflationsdruck und die Grenze der physiologischen Dehnbarkeit: Untersuchungen am Meerschweinchen.