Non-invasive detection of respiratory muscles activity during assisted ventilation.
The instantaneous pressure applied by the respiratory muscles [Pmus(t)] of a patient under ventilatory support may be continuously assessed with the help of a model of the passive respiratory system updated cycle by cycle. Inspiratory activity (IA) is considered present when Pmus goes below a given threshold. In six patients, we compared IA with (i) inspiratory activity (IAref) obtained from esophageal pressure and diaphragmatic EMG and (ii) that (IAvent) detected by the ventilator. In any case, a ventilator support onset coincides with an IA onset but the opposite is not true. IA onset is always later than IAref beginning ((0.21 +/- 0.10 s) and IA end always precedes IAref end (0.46 +/- 0.16 s). These results clearly deteriorate when the model is not updated.
Heyer
Laurent
L
Laboratoire TIMC/IMAG, faculté de médecine de Grenoble, université Joseph-Fourier, 38700 La Tronche, France.
Baconnier
Pierre F
PF
Eberhard
André
A
Biot
Loïc
L
Viale
Jean-Paul
JP
Perdrix
Jean-Pierre
JP
Carry
Pierre-Yves
PY
D000368:Aged; D004576:Electromyography; D006801:Humans; D001239:Inhalation / Q000502:physiology; D008875:Middle Aged; D008954:Models, Biological; D012016:Reference Values; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000503:physiopathology* / Q000628:therapy; D012132:Respiratory Muscles / Q000503:physiopathology*; D012143:Respiratory Physiological Phenomena