Erschienen in:
01.10.2005 | Experimental
Response of acoustic transmission to positive airway pressure therapy in experimental lung injury
verfasst von:
Jukka Räsänen, Noam Gavriely
Erschienen in:
Intensive Care Medicine
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Ausgabe 10/2005
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Abstract
Objective
To evaluate the effect of positive end-expiratory pressure on the sound filtering characteristics of injured lungs.
Design and setting
Prospective experimental study in the animal laboratory in an academic medical center.
Patients and participants
Six 35- to 45-kg anesthetized, intubated pigs.
Interventions
Acute lung injury with intravenous oleic acid.
Measurements and results
We injected a multifrequency broad-band sound signal into the airway while recording transmitted sound at three locations bilaterally on the chest wall. Oleic acid injections effected a severe pulmonary edema predominantly in the dependent lung regions, with an average increase in venous admixture from 16±14% to 57±13% and a reduction in static respiratory system compliance from 31±6 to 16±3 ml/cmH2O. A significant concomitant increase in sound transfer function amplitude was seen in the dependent and lateral lung regions; little change occurred in the nondependent areas. The application of PEEP resulted in a decrease in venous admixture, increase in respiratory system compliance, and return of the sound transmission to preinjury levels.
Conclusions
Acute lung injury causes regional acoustic transmission abnormalities that are reversed during alveolar recruitment with PEEP.