Critical Care

official impact factor 4.60

Review

Forced oscillation assessment of respiratory mechanics in ventilated patients

Daniel Navajas* and Ramon Farré

Author Affiliations

Unitat de Biofisica i Bioenginyeria, Facultat de Medicina, Institut d'Investigacions Biomèdiques August Pi Sunyer, Universitat de Barcelona, Spain

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Critical Care 2001, 5:3-9 doi:10.1186/cc972

Published: 20 December 2000

Abstract

The forced oscillation technique (FOT) is a method for non-invasively assessing respiratory mechanics that is applicable both in paralysed and non-paralysed patients. As the FOT requires a minimal modification of the conventional ventilation setting and does not interfere with the ventilation protocol, the technique is potentially useful to monitor patient mechanics during invasive and noninvasive ventilation. FOT allows the assessment of the respiratory system linearity by measuring resistance and reactance at different lung volumes or end-expiratory pressures. Moreover, FOT allows the physician to track the changes in patient mechanics along the ventilation cycle. Applying FOT at different frequencies may allow the physician to interpret patient mechanics in terms of models with pathophysiological interest. The current methodological and technical experience make possible the implementation of portable and compact computerised FOT systems specifically addressed to its application in the mechanical ventilation setting.

Keywords:
forced oscillation technique; monitoring; respiratory impedance; respiratory resistance; airway mechanics