Advanced Search

Home > Journals > Minerva Anestesiologica > Past Issues > Minerva Anestesiologica 2012 September;78(9) > Minerva Anestesiologica 2012 September;78(9):996-1004



A Journal on Anesthesiology, Resuscitation, Analgesia and Intensive Care

Official Journal of the Italian Society of Anesthesiology, Analgesia, Resuscitation and Intensive Care
Indexed/Abstracted in: Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 2,036

Frequency: Monthly

ISSN 0375-9393

Online ISSN 1827-1596


Minerva Anestesiologica 2012 September;78(9):996-1004


Influence of different flow-triggering levels on the breathing effort of mechanically ventilated patients

Ou C.-Y. 1, Yang S.-C. 1, Chen C.-W. 2

1 Division of Chest Medicine, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan;
2 Medical Intensive Care Unit and Medical Device Innovation Center, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan

BACKGROUND: Although a sensitive flow triggering (FT) level is supposed to be associated with reduced breathing effort, the incidence of autotriggering (AT) is likely to be increased. The actual effects of various FT levels on the work of breathing and occurrence of AT in mechanically ventilated patients are unknown. We investigated the effects of different FT levels (1-8 L/min) on breathing effort and incidence of AT in mechanically ventilated patients under pressure support ventilation using a Puritan-Bennett 840 ventilator.
METHODS: Eight FT levels were randomly studied in mechanically ventilated patients under pressure support ventilation. The triggering effort (pressure-time product of triggering, PTPtr) was assessed by quantitating a segment of the pressure-time product of the esophagus (PTPes). The total PTPes, inspiratory work of breathing (Wi) and P0.1 were determined.
RESULTS: Nine patients with appropriately recorded signals were included. The incidence of AT significantly decreased with increasing FT level (FT1, 1 L/min: 30.7%, FT8: 0.2%). PTPtr significantly increased with increasing FT level (0.020 ± 0.004 cmH2O • S in FT1 to 0.190±0.017 cmH2O • S in FT8), but P0.1 remained similar. PTPtr accounted for only1-3% of total PTPes. Wi and PTPes were significantly lower only at FT1, but there was no significant difference in Wi and PTPes at different FT levels when AT breaths were excluded.
ONCLUSION: A higher FT level was associated with lower incidence of AT, but without a significant increase in breathing effort. A higher FT level may be more reasonable in mechanically ventilated patients with this particular ventilator.

language: English


top of page