Influences of Duration of Inspiratory Effort, Respiratory Mechanics, and Ventilator Type on Asynchrony With Pressure Support and Proportional Assist Ventilation

Abstract

Mechanical ventilation asynchrony was influenced by effort, respiratory mechanics, ventilator type, and ventilation mode. In PSV mode, delayed cycling was associated with shorter effort in obstructive respiratory mechanics profiles, whereas premature cycling was more common with longer effort and a restrictive profile. PAV+ prevented premature cycling but not delayed cycling, especially in obstructive respiratory mechanics profiles, and it was associated with a lower V.

Parameters for Simulation of Adult Subjects During Mechanical Ventilation

“…Unfortunately, this procedure limits the shape of the P mus (t) to the available flow shapes from the drive ventilator, which are quite limited. More recent studies [5][6][7][8][9][10][11][12][13][14][15] have used more sophisticated devices that allow high-fidelity simulation of both lung model (ie, resistance and compliance) and effort model (P mus waveform).…”

Patient-ventilator asynchrony

“…(10) Respiratory mechanics infl uences the type of patient-ventilator asynchrony, depending on neural inspiratory time and on ventilator settings. (10,11) An obstructive respiratory mechanics profi le appears to be more associated with delayed cycling asynchrony, aggravated by short neural inspiratory time, whereas a restrictive respiratory mechanics profi le with longer neural inspiratory time favors premature cycling events during pressure support ventilation (PSV) and proportional assist ventilation plus (PAV+). (11) In fact, depending on the ventilatory mode, COPD patients can also have cycle asynchrony.…”

“…(10,11) An obstructive respiratory mechanics profi le appears to be more associated with delayed cycling asynchrony, aggravated by short neural inspiratory time, whereas a restrictive respiratory mechanics profi le with longer neural inspiratory time favors premature cycling events during pressure support ventilation (PSV) and proportional assist ventilation plus (PAV+). (11) In fact, depending on the ventilatory mode, COPD patients can also have cycle asynchrony. This occurs, for instance, when patients receive PSV, whose cycling is linked to the percent reduction in inspiratory fl ow.…”

“…They use automatic trigger and cycle algorithms and interact well with patients; in addition, these devices appear to reduce auto-trigger asynchrony and to optimize trigger synchrony. (11)…”

Associação entre a mecânica respiratória e o índice de assincronia paciente-ventilador durante a ventilação mecânica invasiva

“…De Haro et al 12 também avaliaram a incidência e mecanismos fisiológicos do duplo disparo e observaram que todos os pacientes em ventilação mecânica apresentam duplo disparo, mas com menor incidência de clusters, 60% versus 87% em nosso estudo, e pequenas diferenças em relação as características dos "cluster". A maior incidência observada em nosso estudo pode ser explicada por fatores associados a ocorrência de duplo disparo, como nível de sedação, esforço inspiratório e modo e parâmetros ventilatórios 12,17,20,26,[63][64][65] ; e as diferenças em relação as características dos clusters podem ter sido influenciadas pelas características dos pacientes e pela prática local de ventilação mecânica.…”