Respiratory volume-timing relationship during sustained elevation of functional residual capacity

摘要: In 7 spontaneously breathing dial-urethane anesthetized cats a negative pressure was produced around the thorax and abdomen to increase functional residual capacity (FRC) by about 1 tidal volume for up 60 min. A tracheal cannula connected resistive manifold selective loading of inspiration or expiration. Two loads occlusion were presented six times each at control FRC (FRCc), after min elevated (FRCe) 30 return FRCc. Inspiratory expiratory durations (TI TE) measured from diaphragmatic EMG. We observed that TI FRCe (0.88 +/- 0.11 sec) not significantly shorter than FRCc (1.06 0.14 sec). Tracheal caused (1.37 0.15 (1.79 0.21 (P less 0.05). The slope (m) VI-TI relationship generated steeper (m = -65 ml X sec-1) shifted upward curve (-50 6 VE-TE changed control. Thirty minutes following FRCc, still slightly (0.96 initial conclude: (1) is determined great extent total lung volume. However, under conditions sustained elevation FRC, this influenced partial adaptation slowly adapting pulmonary receptors SARs. (2) increased SAR activity end expiration during may influence TE.