Patient-ventilator asynchrony is common but under-recognized and under-reported. The frequency of PAV is reported around 23%, but up to 93% of patients have at least one episode of PVA. While sporadic asynchronies may have uncertain clinical impact, when they amount to more than 10% of the total breaths, PVA can increase the need for sedation and reduce sleep quality. In addition, they can impact on outcome by prolonging mechanical ventilation and increasing both ICU and hospital mortality.
The purpose of this review is threefold: 1) to characterise different types of patient-ventilator interaction; 2) to describe mechanisms leading to asynchrony; and 3) to describe ventilator modification to reduce patient-ventilation asynchrony.
Key words: ventilator waveforms, asynchronies, patient-ventilator interactions