scholarly journals Absence of inspiratory laryngeal constrictor muscle activity during nasal neurally adjusted ventilatory assist in newborn lambs

2012 ◽  
Vol 113 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Mohamed Amine Hadj-Ahmed ◽  
Nathalie Samson ◽  
Marie Bussières ◽  
Jennifer Beck ◽  
Jean-Paul Praud
Keyword(s):  
Electrical Activity ◽  
Lung Ventilation ◽  
Random Order ◽  
Volume Control ◽  
Neurally Adjusted Ventilatory Assist ◽  
Glottal Closure ◽  
Respiratory Inductive Plethysmography ◽  
Diaphragm Electrical Activity ◽  
Tracheal Pressure ◽  
Ventilatory Assist

In nonsedated newborn lambs, nasal pressure support ventilation (nPSV) can lead to an active glottal closure in early inspiration, which can limit lung ventilation and divert air into the digestive system, with potentially deleterious consequences. During volume control ventilation (nVC), glottal closure is delayed to the end of inspiration, suggesting that it is reflexly linked to the maximum value of inspiratory pressure. Accordingly, the aim of the present study was to test whether inspiratory glottal closure develops at the end of inspiration during nasal neurally adjusted ventilatory assist (nNAVA), an increasingly used ventilatory mode where maximal pressure is also reached at the end of inspiration. Polysomnographic recordings were performed in eight nonsedated, chronically instrumented lambs, which were ventilated with progressively increasing levels of nPSV and nNAVA in random order. States of alertness, diaphragm, and glottal muscle electrical activity, tracheal pressure, Spo2, tracheal PetCO2, and respiratory inductive plethysmography were continuously recorded. Although phasic inspiratory glottal constrictor electrical activity appeared during nPSV in 5 of 8 lambs, it was never observed at any nNAVA level in any lamb, even at maximal achievable nNAVA levels. In addition, a decrease in Pco2 was neither necessary nor sufficient for the development of inspiratory glottal constrictor activity. In conclusion, nNAVA does not induce active inspiratory glottal closure, in contrast to nPSV and nVC. We hypothesize that this absence of inspiratory activity is related to the more physiological airway pressurization during nNAVA, which tightly follows diaphragm electrical activity throughout inspiration.

scholarly journals Feasibility of neurally adjusted positive end-expiratory pressure in rabbits with early experimental lung injury

2021 ◽  
Author(s):  
Ling Liu ◽  
Daijiro Takahashi ◽  
Haibo Qui ◽  
Arthur S. Slutsky ◽  
Christer Sinderby ◽  
...  
Keyword(s):  
Lung Injury ◽  
Electrical Activity ◽  
Esophageal Pressure ◽  
Neurally Adjusted Ventilatory Assist ◽  
Diaphragm Electrical Activity ◽  
New Zealand White Rabbits ◽  
Ventilatory Assist ◽  
Resistive Loading ◽  
Inspiratory Activity ◽  
The Mean

Background During conventional Neurally Adjusted Ventilatory Assist (NAVA), the electrical activity of the diaphragm (EAdi) is used for triggering and cycling-off inspiratory assist, with a fixed PEEP (so called “Triggered Neurally Adjusted Ventilatory Assist” or “tNAVA”). However, significant post-inspiratory activity of the diaphragm can occur, believed to play a role in maintaining end-expiratory lung volume. Adjusting pressure continuously, in proportion to both inspiratory and expiratory EAdi (Continuous NAVA, or cNAVA), would not only offer inspiratory assist for tidal breathing, but also may aid in delivering a “neurally adjusted PEEP”, and more specific breath-by-breath unloading. Methods Nine adult New Zealand white rabbits were ventilated during independent conditions of: resistive loading (RES1 or RES2), CO2 load (CO2) and acute lung injury (ALI), either via tracheotomy (INV) or non-invasively (NIV). There were a total of six conditions, applied in a non-randomized fashion: INV-RES1, INV-CO2, NIV-CO2, NIV-RES2, NIV-ALI, INV-ALI. For each condition, tNAVA was applied first (3 min), followed by 3 min of cNAVA. This comparison was repeated 3 times (repeated cross-over design). The NAVA level was always the same for both modes, but was newly titrated for each condition. PEEP was manually set to zero during tNAVA. During cNAVA, the assist during expiration was proportional to the EAdi. During all runs and conditions, ventilator-delivered pressure (Pvent), esophageal pressure (Pes), and diaphragm electrical activity (EAdi) were measured continuously. The tracings were analyzed breath-by-breath to obtain peak inspiratory and mean expiratory values. Results For the same peak Pvent, the distribution of inspiratory and expiratory pressure differed between tNAVA and cNAVA. For each condition, the mean expiratory Pvent was always higher (for all conditions 4.0 ± 1.1 vs. 1.1 ± 0.5 cmH2O, P < 0.01) in cNAVA than in tNAVA. Relative to tNAVA, mean inspiratory EAdi was reduced on average (for all conditions) by 19 % (range 14 %–25 %), p < 0.05. Mean expiratory EAdi was also lower during cNAVA (during INV-RES1, INV-CO2, INV-ALI, NIV-CO2 and NIV-ALI respectively, P < 0.05). The inspiratory Pes was reduced during cNAVA all 6 conditions (p < 0.05). Unlike tNAVA, during cNAVA the expiratory pressure was comparable with that predicted mathematically (mean difference of 0.2 ± 0.8 cmH2O). Conclusion Continuous NAVA was able to apply neurally adjusted PEEP, which led to a reduction in inspiratory effort compared to triggered NAVA.

Daily titration of neurally adjusted ventilatory assist using the diaphragm electrical activity

2011 ◽  
Vol 37 (7) ◽  
pp. 1087-1094 ◽  
Author(s):  
Hadrien Rozé ◽  
Abdelghani Lafrikh ◽  
Virginie Perrier ◽  
Arnaud Germain ◽  
Antoine Dewitte ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Neurally Adjusted Ventilatory Assist ◽  
Diaphragm Electrical Activity ◽  
Ventilatory Assist

scholarly journals Feasibility of neurally adjusted positive end-expiratory pressure in rabbits with early experimental lung injury

2021 ◽  
Author(s):  
Ling Liu ◽  
Daijiro Takahashi ◽  
Haibo Qui ◽  
Arthur S. Slutsky ◽  
Christer Sinderby ◽  
...  
Keyword(s):  
Lung Injury ◽  
Electrical Activity ◽  
Esophageal Pressure ◽  
Neurally Adjusted Ventilatory Assist ◽  
Diaphragm Electrical Activity ◽  
New Zealand White Rabbits ◽  
Ventilatory Assist ◽  
Resistive Loading ◽  
Inspiratory Activity ◽  
The Mean

Background During conventional Neurally Adjusted Ventilatory Assist (NAVA), the electrical activity of the diaphragm (EAdi) is used for triggering and cycling-off inspiratory assist, with a fixed PEEP (so called “Triggered Neurally Adjusted Ventilatory Assist” or “tNAVA”). However, significant post-inspiratory activity of the diaphragm can occur, believed to play a role in maintaining end-expiratory lung volume. Adjusting pressure continuously, in proportion to both inspiratory and expiratory EAdi (Continuous NAVA, or cNAVA), would not only offer inspiratory assist for tidal breathing, but also may aid in delivering a “neurally adjusted PEEP”, and more specific breath-by-breath unloading. Methods Nine adult New Zealand white rabbits were ventilated during independent conditions of: resistive loading (RES1 or RES2), CO2 load (CO2) and acute lung injury (ALI), either via tracheotomy (INV) or non-invasively (NIV). There were a total of six conditions, applied in a non-randomized fashion: INV-RES1, INV-CO2, NIV-CO2, NIV-RES2, NIV-ALI, INV-ALI. For each condition, tNAVA was applied first (3 min), followed by 3 min of cNAVA. This comparison was repeated 3 times (repeated cross-over design). The NAVA level was always the same for both modes, but was newly titrated for each condition. PEEP was manually set to zero during tNAVA. During cNAVA, the assist during expiration was proportional to the EAdi. During all runs and conditions, ventilator-delivered pressure (Pvent), esophageal pressure (Pes), and diaphragm electrical activity (EAdi) were measured continuously. The tracings were analyzed breath-by-breath to obtain peak inspiratory and mean expiratory values. Results For the same peak Pvent, the distribution of inspiratory and expiratory pressure differed between tNAVA and cNAVA. For each condition, the mean expiratory Pvent was always higher (for all conditions 4.0 ± 1.1 vs. 1.1 ± 0.5 cmH2O, P < 0.01) in cNAVA than in tNAVA. Relative to tNAVA, mean inspiratory EAdi was reduced on average (for all conditions) by 19 % (range 14 %–25 %), p < 0.05. Mean expiratory EAdi was also lower during cNAVA (during INV-RES1, INV-CO2, INV-ALI, NIV-CO2 and NIV-ALI respectively, P < 0.05). The inspiratory Pes was reduced during cNAVA all 6 conditions (p < 0.05). Unlike tNAVA, during cNAVA the expiratory pressure was comparable with that predicted mathematically (mean difference of 0.2 ± 0.8 cmH2O). Conclusion Continuous NAVA was able to apply neurally adjusted PEEP, which led to a reduction in inspiratory effort compared to triggered NAVA.

Standardized Unloading of Respiratory Muscles during Neurally Adjusted Ventilatory Assist

2018 ◽  
Vol 129 (4) ◽  
pp. 769-777 ◽  
Author(s):  
Francesca Campoccia Jalde ◽  
Fredrik Jalde ◽  
Mats K. E. B. Wallin ◽  
Fernando Suarez-Sipmann ◽  
Peter J. Radell ◽  
...  
Keyword(s):  
Pressure Support ◽  
Respiratory Muscles ◽  
Lung Ventilation ◽  
Interquartile Range ◽  
Secondary Outcome ◽  
Neurally Adjusted Ventilatory Assist ◽  
Impedance Tomography ◽  
Respiratory Parameters ◽  
Ventilatory Parameters ◽  
Ventilatory Assist

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Currently, there is no standardized method to set the support level in neurally adjusted ventilatory assist (NAVA). The primary aim was to explore the feasibility of titrating NAVA to specific diaphragm unloading targets, based on the neuroventilatory efficiency (NVE) index. The secondary outcome was to investigate the effect of reduced diaphragm unloading on distribution of lung ventilation. Methods This is a randomized crossover study between pressure support and NAVA at different diaphragm unloading at a single neurointensive care unit. Ten adult patients who had started weaning from mechanical ventilation completed the study. Two unloading targets were used: 40 and 60%. The NVE index was used to guide the titration of the assist in NAVA. Electrical impedance tomography data, blood-gas samples, and ventilatory parameters were collected. Results The median unloading was 43% (interquartile range 32, 60) for 40% unloading target and 60% (interquartile range 47, 69) for 60% unloading target. NAVA with 40% unloading led to more dorsal ventilation (center of ventilation at 55% [51, 56]) compared with pressure support (52% [49, 56]; P = 0.019). No differences were found in oxygenation, CO2, and respiratory parameters. The electrical activity of the diaphragm was higher during NAVA with 40% unloading than in pressure support. Conclusions In this pilot study, NAVA could be titrated to different diaphragm unloading levels based on the NVE index. Less unloading was associated with greater diaphragm activity and improved ventilation of the dependent lung regions.

scholarly journals Reference values for diaphragm electrical activity (Edi) in newborn infants

2021 ◽  
Author(s):  
Varappriyangga Gurumahan ◽  
Sriganesh Thavalingam ◽  
Tim Schindler ◽  
John Smyth ◽  
Kei Lui ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Reference Values ◽  
Newborn Infants ◽  
Feeding Tube ◽  
Respiratory Support ◽  
Neurally Adjusted Ventilatory Assist ◽  
Term Infants ◽  
Term Neonates ◽  
Diaphragm Electrical Activity ◽  
The Mean

Background: Neurally adjusted ventilatory assist (NAVA) is an emerging mode of respiratory support that uses the electrical activity of the diaphragm (Edi) to provide synchronised inspiratory pressure support, proportional to an infant’s changing inspiratory effort. Data on Edi reference values for neonates are limited. The objective of this study was to establish reference Edi values for preterm and term neonates. Methods: This was a prospective observational study of newborn infants breathing spontaneously in room air. The Edi signal was monitored by a specialised intragastric feeding tube with embedded electrodes positioned at the level of the diaphragm. Edi minimums and peaks were recorded continuously for four hours. Results: 24 newborn infants (16 preterm [<37 weeks’ gestation]; 8 term) were studied. All infants were breathing comfortably in room air at the time of study. Edi data were successfully captured in all infants. The mean (±SD) Edi minimum was 3.02 (±0.94) µV and the mean Edi peak was 10.13 (±3.50) µV. In preterm infants the mean (±SD) Edi minimum was 3.05 (±0.91) µV and the mean Edi peak was 9.36 (±2.13) µV. In term infants the mean (±SD) Edi minimum was 2.97 (±1.05) µV and the mean Edi peak was 11.66 (±5.14) µV. Conclusion: Reference Edi values were established for both preterm and term neonates. These values can be used as a guide when using diaphragm-triggered modes on respiratory support in newborn infants.

scholarly journals Laryngeal response to nasal ventilation in nonsedated newborn lambs

2007 ◽  
Vol 102 (6) ◽  
pp. 2149-2157 ◽  
Author(s):  
François Moreau-Bussière ◽  
Nathalie Samson ◽  
Marie St-Hilaire ◽  
Philippe Reix ◽  
Joëlle Rouillard Lafond ◽  
...  
Keyword(s):  
Upper Airway ◽  
Lung Ventilation ◽  
Intermittent Positive Pressure Ventilation ◽  
Volume Control ◽  
Positive Pressure ◽  
Quiet Sleep ◽  
Subsequent Increase ◽  
Glottal Closure ◽  
Adult Humans ◽  
In Trans

Although endoscopic studies in adult humans have suggested that laryngeal closure can limit alveolar ventilation during nasal intermittent positive pressure ventilation (nIPPV), there are no available data regarding glottal muscle activity during nIPPV. In addition, laryngeal behavior during nIPPV has not been investigated in neonates. The aim of the present study was to assess laryngeal muscle response to nIPPV in nonsedated newborn lambs. Nine newborn lambs were instrumented for recording states of alertness, electrical activity [electromyograph (EMG)] of glottal constrictor (thyroarytenoid, TA) and dilator (cricothyroid, CT) muscles, EMG of the diaphragm (Dia), and mask and tracheal pressures. nIPPV in pressure support (PS) and volume control (VC) modes was delivered to the lambs via a nasal mask. Results show that increasing nIPPV during wakefulness and quiet sleep led to a progressive disappearance of Dia and CT EMG and to the appearance and subsequent increase in TA EMG during inspiration, together with an increase in trans-upper airway pressure (TUAP). On rare occasions, transmission of nIPPV through the glottis was prevented by complete, active glottal closure, a phenomenon more frequent during active sleep epochs, when irregular bursts of TA EMG were observed. In conclusion, results of the present study suggest that active glottal closure develops with nIPPV in nonsedated lambs, especially in the VC mode. Our observations further suggest that such closure can limit lung ventilation when raising nIPPV in neonates.

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