Dynamic behaviour of the chest and of the abdomen in anaesthetized piglets during rapid insufflation.
Three piglets were ventilated with a TVM-ventilator, which releases predetermined volumes of compressed gas into the airways. The inspiratory flow depends on the pressure and volume of the compressed gas and compliance, resistance and inertia of the lungs, thorax and abdomen of the subject. The time for half filling of the chest was less than that of the abdomen and the difference increased with high driving pressure (with high acceleration). The difference was thus most probably a result of greater inertia of the abdomen. Inertia also seemed to influence the emptying of the lungs. This was so slow that increase of FRC--air trapping--was seen at a ventilatory frequency of 30 b.p.m. The practical consequences of these findings are that the abdomen (diaphragm) will take less and less part in ventilation and that a phase lag between chest and abdominal breathing should become larger with increasing ventilatory frequency. FRC will increase in regions with expiratory obstruction and lung rupture may follow.
D000005:Abdomen / Q000502:physiology*; D000818:Animals; D005652:Functional Residual Capacity; D008168:Lung / Q000502:physiology; D009407:Nerve Block; D011312:Pressure; D012121:Respiration, Artificial; D013552:Swine; D013909:Thorax / Q000502:physiology*; D013990:Tidal Volume; D013997:Time Factors