Interrelationship of breath components in neighboring breaths of normal eupneic subjects.

Tobin, Martin J.; Yang, Ki Yeon; Jubran, Amal; Lodato, Robert F.

doi:10.1164/ajrccm.152.6.8520764

Cited by 51 publications

(47 citation statements)

References 32 publications

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“…Breath-to-breath variability is a normal characteristic of ventilation that reflects the degree of freedom-and therefore the adaptability-of the ventilatory control system (6,27,28). A decreased variability is associated with respiratory disease in adults (29) and in infants (22), and a lower variability is a predictor of weaning failure (30).…”

Section: Respiratory Variabilitymentioning

confidence: 99%

Neurally adjusted ventilatory assist improves patient–ventilator interaction in infants as compared with conventional ventilation

et al. 2012

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Background: Neurally adjusted ventilatory assist (NaVa) is a mode of ventilation controlled by the electrical activity of the diaphragm (edi). The aim was to evaluate patient-ventilator interaction in infants during NaVa as compared with conventional ventilation. Methods: Infants were successively ventilated with NaVa, pressure control ventilation (PcV), and pressure support ventilation (PsV). edi and ventilator pressure (Pvent) waveforms were compared and their variability was assessed by coefficients of variation. results: Ten patients (mean age 4.3 ± 2.4 mo and weight 5.9 ± 2.2 kg) were studied. In PcV and PsV, 4 ± 4.6% and 6.5 ± 7.7% of the neural efforts failed to trigger the ventilator. This did not occur during NaVa. Trigger delays were shorter with NaVa as compared with PcV and PsV (93 ± 20 ms vs. 193 ± 87 ms and 135 ± 29 ms). During PcV and PsV, the ventilator cycled off before the end of neural inspiration in 12 ± 13% and 21 ± 19% of the breaths (0 ± 0% during NaVa). During PcV and PsV, 24 ± 11% and 25 ± 9% of the neural breath cycle was asynchronous with the ventilator as compared with 11 ± 3% with NaVa. a large variability was observed for edi in all modes, which was transmitted into Pvent during NaVa (coefficient of variation: 24 ± 8%) and not in PcV (coefficient of variation 2 ± 1%) or PsV (2 ± 2%). conclusion: NaVa improves patient-ventilator interaction and delivers adequate ventilation with variable pressure in infants.c onventional modes of mechanical ventilation are clearly limited in their ability to provide synchrony between the patient and the assist delivered, as demonstrated repeatedly in adults (1,2) and more recently in children (3). Patientventilator asynchrony has been associated with poor clinical outcome (1,2,4). Despite the attempt to improve synchrony with "patient-triggered" modes such as pressure control ventilation (PCV) or pressure support ventilation (PSV), 25% of adult patients show more than 10% asynchrony with the ventilator (1,2,5). In pediatric patients, synchrony is particularly difficult to achieve because of the small tidal volumes, high respiratory rates, and weak airway flows and pressures. Ironically, during synchronized intermittent mandatory ventilation, more than half of the patient's breathing cycle is spent in asynchrony (3) with the ventilator.Besides the poor timing between the patient and the ventilator, patient-ventilator asynchrony also includes the inability of the ventilator to respond to patient demand and the natural breath-to-breath variability. Respiratory variability is a sign of a well functioning respiratory system (6). By definition, PCV and PSV deliver fixed levels of assist, thereby offering no possibility to respond to the patient's respiratory demand and variability.Neurally adjusted ventilatory assist (NAVA) is a mode of mechanical ventilation that delivers assist in time and in proportion to the electrical activity of the diaphragm (Edi) on a breath-by-breath basis (7). Numerous studies have shown that NAVA efficiently unloads the respirat...

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Section: Respiratory Variabilitymentioning

confidence: 99%

Neurally adjusted ventilatory assist improves patient–ventilator interaction in infants as compared with conventional ventilation

et al. 2012

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“…Thus, PSV may adapt to breath-to-breath variability [27] more precisely than APCV, where the mechanical inflation stops after a preset time. However, the present authors found no differences in the patient/ ventilator interaction [28] (e.g.…”

Section: Pressure Support Ventilation and Assist Pressure Control Venmentioning

confidence: 99%

Different modes of assisted ventilation in patients with acute respiratory failure

Chiumello¹,

Pelosi²,

Calvi³

et al. 2002

European Respiratory Journal

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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...

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“…Since variability in complex living systems is not only an artefact of biological noise but also an intrinsic property of various control mechanisms, different types of deterministic (nonrandom) variability have been described in the pattern of breathing. These types include correlated and oscillatory fractions [12][13][14].…”

Section: Linear Methodsmentioning

confidence: 99%

Fractal Physiology, Breath-to-Breath Variability and Respiratory Diseases: An Introduction to Complex Systems Theory Application in Pulmonary and Critical Care Medicine

Papaioannou¹,

Pneumatikos²

2013

Practical Applications in Biomedical Engineering

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Interrelationship of breath components in neighboring breaths of normal eupneic subjects.

Cited by 51 publications

References 32 publications

Neurally adjusted ventilatory assist improves patient–ventilator interaction in infants as compared with conventional ventilation

Neurally adjusted ventilatory assist improves patient–ventilator interaction in infants as compared with conventional ventilation

Different modes of assisted ventilation in patients with acute respiratory failure

Fractal Physiology, Breath-to-Breath Variability and Respiratory Diseases: An Introduction to Complex Systems Theory Application in Pulmonary and Critical Care Medicine

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