Patient-ventilator asynchronies: may the respiratory mechanics play a role?

Crit Care. 2013 Mar 25;17(2):R54. doi: 10.1186/cc12580.


Introduction: The mechanisms leading to patient/ventilator asynchrony has never been systematically assessed. We studied the possible association between asynchrony and respiratory mechanics in patients ready to be enrolled for a home non-invasive ventilatory program. Secondarily, we looked for possible differences in the amount of asynchronies between obstructive and restrictive patients and a possible role of asynchrony in influencing the tolerance of non-invasive ventilation (NIV).

Methods: The respiratory pattern and mechanics of 69 consecutive patients with chronic respiratory failure were recorded during spontaneous breathing. After that patients underwent non-invasive ventilation for 60 minutes with a "dedicated" NIV platform in a pressure support mode during the day. In the last 15 minutes of this period, asynchrony events were detected and classified as ineffective effort (IE), double triggering (DT) and auto-triggering (AT).

Results: The overall number of asynchronies was not influenced by any variable of respiratory mechanics or by the underlying pathologies (that is, obstructive vs restrictive patients). There was a high prevalence of asynchrony events (58% of patients). IEs were the most frequent asynchronous events (45% of patients) and were associated with a higher level of pressure support. A high incidence of asynchrony events and IE were associated with a poor tolerance of NIV.

Conclusions: Our study suggests that in non-invasively ventilated patients for a chronic respiratory failure, the incidence of patient-ventilator asynchronies was relatively high, but did not correlate with any parameters of respiratory mechanics or underlying disease.

MeSH terms

  • Aged
  • Chronic Disease
  • Female
  • Humans
  • Male
  • Middle Aged
  • Prospective Studies
  • Respiration, Artificial / methods*
  • Respiration, Artificial / standards
  • Respiratory Insufficiency / diagnosis*
  • Respiratory Insufficiency / physiopathology
  • Respiratory Insufficiency / therapy*
  • Respiratory Mechanics / physiology*