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Evaluation of the flow‐volume loop as an intra‐operative monitor of respiratory mechanics in infants
Author(s) -
Brown K.,
Sly P.D.,
MilicEmili J.,
Bates J.H.T.
Publication year - 1989
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.1950060105
Subject(s) - medicine , respiratory physiology , airway , tidal volume , mechanics , ventilation (architecture) , flow (mathematics) , volume (thermodynamics) , respiratory system , loop (graph theory) , airway obstruction , mechanical ventilation , respiratory minute volume , anesthesia , mathematics , physics , thermodynamics , combinatorics
Airway pressure is currently the primary indicator of respiratory mechanics used by the anesthetist in the operating room. This quantity can signal that the mechanical properties of the respiratory system have changed. However, there is a need for more sophisticated monitors of mechanics, capable of indicating the nature of the change. We have investigated the use of the tidal flow‐volume loop in differentiating between an obstruction of the endotracheal tube and changes in the distribution of regional ventilation, using a computer model. Endotracheal obstruction caused the descending limb of flow‐volume loop to become convex to the volume axis, whereas ventilation inhomogeneity caused the curve to become concave to the volume axis. In contrast, examination of peak airway pressure did not allow differentiation between the two conditions. We conclude that, while the peak airway pressure is useful in signaling a change in a patient's condition, the combination of airway pressure and the flow‐volume loop serves as a more comprehensive monitor of respiratory mechanics.