The effects of pressurization rate on breathing pattern, work of breathing, gas exchange and patient comfort in pressure support ventilation

Chiumello, Davide; Pelosi, Paolo; Croci, M.; Bigatello, Luca M.; Gattinoni, Luciano

doi:10.1183/09031936.01.00083901

Cited by 84 publications

(58 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Further increases of PIF f1.1 did not affect the WOB [5]. In a previous study, similar results were obtained by the present authors, by increasing the PIF during PSV, where the highest PIF did not further reduce the WOB and was associated with patient discomfort [36]. Both these studies suggest that there is a threshold of flow demand below which a lower flow rate increases the WOB and above which a further increase of flow rate is not beneficial and may be uncomfortable [33,35].…”

Section: Assist Control Ventilation: Effect Of Different Peak Inspirasupporting

confidence: 77%

Different modes of assisted ventilation in patients with acute respiratory failure

Chiumello¹,

Pelosi²,

Calvi³

et al. 2002

Eur Respir J

Self Cite

View full text Add to dashboard Cite

The aim of the present study was to verify that the patient/ventilator interaction is similar, regardless of the mode of assisted mechanical ventilation (i.e. pressure-or volume-limited) used, if tidal volume (VT) and peak inspiratory flow (PIF) are matched. Therefore, the authors compared the effects of three different modes of assisted ventilation on the work of breathing (WOB) and gas exchange in patients with acute respiratory failure.For Protocol 1, in seven patients, the authors compared pressure support, assist pressure control and assist control (with square and decelerating wave inspiratory flow pattern) set to deliver the same VT and PIF. For Protocol 2, in another 10 patients, the authors compared pressure support and assist control with high (0.8 L?s -1 ) and low (0.6 L?s -1 ) PIFs set to deliver the same VT.In Protocol 1, there was no difference in WOB and gas exchange between the three modes of assisted ventilation tested. In Protocol 2, the decrease of PIFs during assist control significantly increased WOB.In conclusion, different modes of assisted ventilation similarly reduce work of breathing and provide adequate gas exchange at fixed tidal volume and peak inspiratory flow only. During assist control, tidal volume and peak inspiratory flow (set by the physician) are the main determinants of the patient/ventilator interaction. A primary goal of mechanical ventilation is to improve gas exchange and reduce the work of breathing (WOB) of patients with acute respiratory failure, without causing iatrogenic lung injury [1]. Assisted ventilation allows the patient to contribute to minute ventilation (V9E) and offers several advantages over controlled ventilation. It can reduce the need for sedation and paralysis, decrease the risk of barotrauma [2], improve intrapulmonary gas distribution [3], and prevent muscle atrophy [4,5]. During assisted ventilation, the WOB is dependent on both the ventilator settings and the patient9s ventilatory demand and mechanics.Pressure support ventilation (PSV) is a pressurelimited, flow-cycled mode of assisted ventilation, in which each breath is supported by a constant level of pressure at the airway (Paw), so that the tidal volume (VT) and inspiratory flow are more adaptable to the patient9s own ventilatory demand [6]. This manner of supporting the patient9s own ventilatory effort may be responsible for an improved comfort and synchrony with the ventilator, and has been shown to reduce the WOB and prevent diaphragmatic fatigue in patients with respiratory failure [7]. The main disadvantage of PSV is that it only works best in patients with stable respiratory conditions (i.e. an adequate sufficient ventilatory drive and somewhat preserved respiratory mechanics [8,9]).Assist control ventilation (ACV) is a volume-limited mode of assisted ventilation, in which the VT and the peak inspiratory flow (PIF) are set by the clinician and are not altered by the patient9s ventilatory demand. If the required VT and inspiratory flow are higher than what the ventilator suppli...

show abstract

Section: Assist Control Ventilation: Effect Of Different Peak Inspirasupporting

confidence: 77%

Different modes of assisted ventilation in patients with acute respiratory failure

Chiumello¹,

Pelosi²,

Calvi³

et al. 2002

Eur Respir J

Self Cite

View full text Add to dashboard Cite

show abstract

“…4). 13 Compared with the baseline pressurization rate, the highest setting did not further reduce work rate.…”

Section: Post-triggering Phasementioning

confidence: 99%

“…As shown in Figure 4, the perception of dyspnea followed a U-shape pattern, with the worst dyspnea at the lowest and highest pressurization rates. 13 At the lowest pressurization rate the sensation of dyspnea was perceived as "air hunger," with the afferent signal arising from the chest. At the highest pressurization rate, the sensation of dyspnea was perceived as "airway discomfort," with the afferent signal originating from the upper airways.…”

Section: Post-triggering Phasementioning

confidence: 99%

“…The effects of the pressurization rate on inspiratory muscle work, expressed as work rate (Joules/min) and the sensation of dyspnea were studied in patients with acute lung injury, employing a 5 or 15 cm H 2 O pressure-support level. 13 The pressurization rate-an arbitrary dimensionless scale of Ϫ9 (lowest) to ϩ9 (highest)-was varied at 5 levels: a baseline or default level and 2 below and 2 above it. Overall work rate was lower with a high PS level.…”

Section: Post-triggering Phasementioning

confidence: 99%

See 1 more Smart Citation

Triggering of the Ventilator in Patient-Ventilator Interactions

Sassoon

2011

Respir Care

View full text Add to dashboard Cite

With current ventilator triggering design, in initiating ventilator breaths patient effort is only a small fraction of the total effort expended to overcome the inspiratory load. Similarly, advances in ventilator pressure or flow delivery and inspiratory flow termination improve patient effort or inspiratory muscle work during mechanical ventilation. Yet refinements in ventilator design do not necessarily allow optimal patient-ventilator interactions, as the clinician is key in managing patient factors and selecting appropriate ventilator factors to maintain patient-ventilator synchrony. In patient-ventilator interactions, unmatched patient flow demand by ventilator flow delivery results in flow asynchrony, whereas mismatches between mechanical inspiratory time (mechanical T I ) and neural T I produce timing asynchrony. Wasted efforts are an example of timing asynchrony. In the triggering phase, trigger thresholds that are set too high or the type of triggering methods induces wasted efforts. Wasted efforts can be aggravated by respiratory muscle weakness or other conditions that reduce respiratory drive. In the post-triggering phase, ventilator factors play an important role in patient-ventilator interaction; this role includes the assistance level, set inspiratory flow rate, T I , pressurization rate, and cycling-off threshold, and to some extent, applied PEEP. This paper proposes an algorithm that clinicians can use to adjust ventilator settings with the goal to eliminate or reduce patients' wasted efforts.

show abstract

“…17 A long inspiratory delay significantly increases the patient's work of breathing, because it reduces the amount of assistance delivered to the patient in the early stages of the breathing effort. [18][19][20] Therefore, the ventilator must have efficient triggering and pressurization capacity to promptly meet the patient's demand and reduce the work of breathing and discomfort. The sensitivity of the inspiratory trigger is a key element that depends both on the sensing technology and the sealing level of the inspiratory circuit.…”

mentioning

confidence: 99%

Leak Compensation Algorithms: The Key Remedy to Noninvasive Ventilation Failure?

Luca¹,

Sall

Khoury

2016

Respir Care

View full text Add to dashboard Cite

The effects of pressurization rate on breathing pattern, work of breathing, gas exchange and patient comfort in pressure support ventilation

Cited by 84 publications

References 29 publications

Different modes of assisted ventilation in patients with acute respiratory failure

Different modes of assisted ventilation in patients with acute respiratory failure

Triggering of the Ventilator in Patient-Ventilator Interactions

Leak Compensation Algorithms: The Key Remedy to Noninvasive Ventilation Failure?

Contact Info

Product

Resources

About