Physiologic response to varying levels of pressure support and neurally adjusted ventilatory assist in patients with acute respiratory failure

Colombo, Davide; Cammarota, Gianmaria; Bergamaschi, Valentina; Lucia, Marta De; Corte, Francesco Della; Navalesi, Paolo

doi:10.1007/s00134-008-1208-3

Cited by 214 publications

(281 citation statements)

References 29 publications

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“…Neural inspiratory time (T in ) was defined, according to previously published NAVA studies [13][14][15]19], as the time difference between the initial increase and the maximal value of EAdi (EAdi max ). Details on this point are given in the Electronic Supplementary Material.…”

Section: Measurementsmentioning

confidence: 99%

“…However, when delivering PS-NIV through a helmet, neural triggering has been shown to improve patient-ventilator synchrony compared to pneumatic triggering [11]. As neurally adjusted ventilatory assist (NAVA) [12] uses a neural signal (the diaphragm electrical activity, or EAdi, independent from airway pressure and flow signals), to trigger and cycle-off the ventilator as well as to adapt the amount of pressure delivered, and as NAVA improves patient-ventilator interaction during invasive ventilation [13][14][15][16], we hypothesized that NAVA could improve patient-ventilator synchrony during NIV. The purpose of this study was to test this hypothesis in adult intensive care patients requiring NIV because of acute respiratory failure or because of being at risk of respiratory failure after extubation [3].…”

Section: Introductionmentioning

confidence: 99%

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

Piquilloud

Tassaux

Bialais³

et al. 2012

Intensive Care Med

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Purpose: To determine if, compared to pressure support (PS), neurally adjusted ventilatory assist (NAVA) reduces patient-ventilator asynchrony in intensive care patients undergoing noninvasive ventilation with an oronasal face mask. Methods: In this prospective interventional study we compared patient-ventilator synchrony between PS (with ventilator settings determined by the clinician) and NAVA (with the level set so as to obtain the same maximal airway pressure as in PS). Two 20-min recordings of airway pressure, flow and electrical activity of the diaphragm during PS and NAVA were acquired in a randomized order. Trigger delay (T d ), the patient's neural inspiratory time (T in ), ventilator pressurization duration (T iv ), inspiratory time in excess (T iex ), number of asynchrony events per minute and asynchrony index (AI) were determined. Results: The study included 13 patients, six with COPD, and two with mixed pulmonary disease. T d was reduced with NAVA: median 35 ms (IQR 31-53 ms) versus 181 ms (122-208 ms); p = 0.0002. NAVA reduced both premature and delayed cyclings in the majority of patients, but not the median T iex value. The total number of asynchrony events tended to be reduced with NAVA: 1.0 events/min (0.5-3.1 events/min) versus 4.4 events/min (0.9-12.1 events/min); p = 0.08. AI was lower with NAVA: 4.9 % (2.5-10.5 %) versus 15.8 % (5.5-49.6 %); p = 0.03. During NAVA, there were no ineffective efforts, or late or premature cyclings. PaO 2 and PaCO 2 were not different between ventilatory modes. Conclusion: Compared to PS, NAVA improved patient ventilator synchrony during noninvasive ventilation by reducing T d and AI. Moreover, with NAVA, ineffective efforts, and late and premature cyclings were absent.

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Section: Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Piquilloud

Tassaux

Bialais³

et al. 2012

Intensive Care Med

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“…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.…”

mentioning

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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“…Compared to PS, NAVA improves patient-ventilator interaction by reducing trigger delay, improving expiratory cycling and reducing the number of asynchrony events [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…NAVA also increases respiratory variability in Vt and flow related variables compared to PS [6,9]. However, no studies make these comparisons relative to the inspiratory demand (Eadi), which may vary between modes and patients.…”

Section: Introductionmentioning

confidence: 99%

NAVA enhances tidal volume and diaphragmatic electro-myographic activity matching: a Range90 analysis of supply and demand

Moorhead

Piquilloud²,

Lambermont

et al. 2012

J Clin Monit Comput

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Physiologic response to varying levels of pressure support and neurally adjusted ventilatory assist in patients with acute respiratory failure

Abstract: Compared to PSV, NAVA averted the risk of over-assistance, avoided patient-ventilator asynchrony, and improved patient-ventilator interaction.

Cited by 214 publications

References 29 publications

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

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

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

NAVA enhances tidal volume and diaphragmatic electro-myographic activity matching: a Range90 analysis of supply and demand

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