ISSN:
1432-1238
Keywords:
Static compliance
;
Pressure volume curve
;
Pulmonary mechanics
;
Acute respiratory failure
;
Adult respiratory distress syndrome
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract A new method for determination the static compliance of the respiratory system is described (“static compliance by automated single steps”-SCASS). In 12 ventilated patients pressure/volume (P/V) curves were determined by automated repetitive occlusion (6 s) at single volume steps and compared to the conventional syringe method (SM). All measurements were corrected for effects of temperature, humidity and pressure (THP). SM was found to be significantly influenced by intrapulmonary gas exchange causing an effective mean volume deficit of 217.4±65.7 ml (BTPS) at the end of the deflation. In contrast to that, the short duration of occlusion in SCASS minimize the gas exchange effects. The methodical differences between both methods result in overestimation of the inflation compliance in the uncorrected SM (SMuncorr: 83.4±12.6; SCASS: 76.0±11.9 ml/cmH2O.p〈0.01) and underestimation of the deflation compliance resp. (SMuncorr: 58.3±7.5; SCASS: 79.1±15.0 ml/cmH2O.p〈0.005). In contrast to the P/V curves by SM no significant hysteresis was found by SCASS. Gas exchange seems to be the main reason for the hysteresis. Even after correcting gas exchange and THP effects a significant hyseresis remained. The SCASS method avoids these problems and allows furthermore an accurate checking of leaks.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01691433
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