Patient-ventilator asynchrony during assisted mechanical ventilation

Abstract

One-fourth of patients exhibit a high incidence of asynchrony during assisted ventilation. Such a high incidence is associated with a prolonged duration of mechanical ventilation. Patients with frequent ineffective triggering may receive excessive levels of ventilatory support.

Neurally adjusted ventilatory assist (NAVA) improves patient–ventilator interaction during non-invasive ventilation delivered by face mask

“…Moreover, severe asynchrony (defined as an AI of more than 10 %) was present in 9 of 13 patients (69.2 %) during PS and in only 3 of 13 patients (23.1 %) during NAVA. As severe asynchrony has been associated with increased duration of mechanical ventilation [5,31] and with a poor outcome when mechanical ventilation is prolonged [31] in intubated patients, the ability of NAVA to reduce patient-ventilator asynchrony could be clinically important.…”

“…From the recorded curves, the numbers of the five types of patient-ventilator asynchronies as defined by Thille et al [5] were determined. In contrast to the study of Thille et al, EAdi was used in addition to airway pressure and flow curves to define asynchrony events [13].…”

“…Patient-ventilator asynchronies are described in detail and illustrated in the Electronic Supplementary Material. Asynchronies are expressed as the number of events per minute and as the asynchrony index (AI) as defined by Thille et al [5], that is the number of events per minute divided by the sum of triggered and nontriggered breaths. An AI of more than 10 % was considered as severe asynchrony [5].…”

“…Because patient and ventilator respiratory profiles differ, patientventilator asynchronies often occur during pressure support ventilation (PS) [4,5]. They are particularly frequent during PS-NIV because unavoidable leaks at the patient-ventilator interface interfere with pneumatic triggering (i.e.…”

No harm, no benefit: should we give up with neurally adjusted ventilatory assist?

“…In principle, while with the controlled modes the patient must be adapted to the mechanical breath, which is achieved by suppressing his or her respiratory drive by sedatives and sometimes paralysing agents, with the modes of partial support it is the machine that must adapt to the patient's own breathing activity and this interaction between patient and ventilator assumes crucial importance. The interest for this aspect has grown up in recent years, as a poor interaction leading to asynchrony between patient effort and ventilator assistance has been associated with worse outcomes, such as longer durations of mechanical ventilation [3][4][5] and ICU stay [4,5], higher rate of tracheotomy [4], and lower probabilities of survival [4] and home discharge [5].…”