BACKGROUND: To evaluate effects of 5 expiratory sensitivity (ESENS) levels (5%; 15%; 25%; 35%; 45%) on lung mechanics and the effects depending on the two P(0.1) levels (<3 cm H2O; > or =3 cm H2O). METHODS: Prospective, randomized, physiologic study for intubated adult patients during weaning from mechanical ventilation. Patients were randomly submitted to the 5 settings of ESENS in the Galileo ventilator (Galileo Gold, Hamilton Medical AG, Switzerland). Physiologic variables were continuously measured using a Bicore CP-100 pulmonary mechanics monitor (CP-100, Bicore, USA). RESULTS: Thirteen patients, ten men and three women, with a mean age of 65.2+/-16.1 yr were studied. Tidal volume (V(T)) decreased significantly from ESENS 5% to 45%. With increasing levels of ESENS, respiratory rates (RR) steadily increased from ESENS 5% to 35% and 45%. Shallow breath index (F/V(T)) increased significantly from ESENS 5% to 45%. Inspiratory time (T(I)) decreased gradually significantly from ESENS 5% to 45%. RR and F/V(T) increased from ESENS 5% to 15% and 45% and V(T) decreased gradually in patients with P(0.1)<3 cm H2O group, but not in patients with P(0.1)> or =3 cm H2O. CONCLUSIONS: The proper adjustment of expiratory sensitivity (ESENS) levels improved patient-ventilator synchrony and decreased respiratory rates and shallow breath index, especially in P(0.1)<3 cm H2O during PSV in ventilator weaning patients. Lower ESENS level would be more appropriate in terms of lung mechanics in patients with less than 3 cm H2O of P(0.1).
Adult ; Female ; Humans ; Lung* ; Male ; Mechanics* ; Prospective Studies ; Respiration, Artificial ; Respiratory Rate ; Tidal Volume ; Ventilation* ; Ventilator Weaning ; Ventilators, Mechanical ; Weaning ; Work of Breathing