CHANGES IN LUNG AND CHEST-WALL PROPERTIES WITH ABDOMINAL INSUFFLATIONOF CARBON-DIOXIDE ARE IMMEDIATELY REVERSIBLE

Previously we have reported that large increases in lung and chest wal l elastances as well as lung resistance occur with abdominal insufflat ion of carbon dioxide during laparoscopic surgery. To examine whether these effects were reversible with abdominal deflation, we calculated lung and chest wall elastances and resistances from measurement of air way flow and pressure and esophageal pressure in 17 anesthetized/paral yzed patients undergoing laparoscopic surgery. Measurements were made immediately prior to abdominal insufflation and after deflation. Lung and chest wall elastances and resistances were not changed from baseli ne (P > 0.05), although total respiratory elastance remained slightly increased compared to baseline (P < 0.05). The change in total respira tory elastance did not correlate with abdominal insufflation time, sur gical site, smoking history, or physical characteristics of the patien ts. There were no differences in frequency and tidal volume dependence s of the elastances and resistances before and after abdominal insuffl ation (P > 0.5). We conclude that residual changes in respiratory mech anics caused by carbon dioxide insufflation during laparoscopic surger y are minor, and that the reported compromise of respiratory function indicated by pulmonary function tests after laparoscopy does not appea r to be due to changes in passive mechanical properties of the lungs o r chest wall.