Korean J Crit Care Med.  2006 Jun;21(1):8-16.

Alteration of Lung Mechanics Depending on Expiratory Sensitivity (ESENS) during Pressure Support Ventilation

• Seo KW
• Chon GR
• Ahn JJ
• Jega Y
• Hong SB
• Lim CM
• Koh Y

Abstract

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).

Keyword

Mechanical ventilation; Weaning; Work of breathing

MeSH Terms

Adult
Female
Humans
Lung*
Male
Mechanics*
Prospective Studies
Respiration, Artificial
Respiratory Rate
Tidal Volume
Ventilation*
Ventilator Weaning
Ventilators, Mechanical
Weaning
Work of Breathing