LOWER TRANSVERSAL LAPAROTOMY HAS NO APPRECIABLE EFFECT ON RESPIRATORYMECHANICS IN GUINEA-PIGS

Respiratory system,lung,and chest wall resistances and dynamic elastan ces were determined in six anesthetized, paralyzed, and mechanically v entilated guinea pigs both before and after lower transversal abdomina l opening performed at the level of the spina iliaca anterosuperior. F urthermore, the resistances were also split into their two components, one reflecting the Newtonian resistances and the other representing t he viscoelastic/inhomogeneous pressure dissipations in the system. The method of end-inflation occlusion during constant inspiratory flow wa s used. Chest wall configuration was also evaluated by measurements of lateral and anteroposterior diameters and circumferences at the 4th i ntercostal space and xiphoid levels both at functional residual capaci ty and at the end of tidal inspiration before and after surgery. After abdominal incision no statistically significant changes could be dete cted in any of the measured variables. It may be concluded that lower transversal abdominal opening does not alter respiratory mechanics.