Published in:
Open Access 01-04-2013 | Research
Patient-ventilator asynchronies: may the respiratory mechanics play a role?
Published in: Critical Care | Issue 2/2013
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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.