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.

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.

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.

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 Clinical Assessment of Auto-positive End-expiratory Pressure by Diaphragmatic Electrical Activity during Pressure Support and Neurally Adjusted Ventilatory Assist

2014 ◽  
Vol 121 (3) ◽  
pp. 563-571 ◽  
Author(s):  
Giacomo Bellani ◽  
Andrea Coppadoro ◽  
Nicolò Patroniti ◽  
Marta Turella ◽  
Stefano Arrigoni Marocco ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Pressure Support Ventilation ◽  
Pressure Support ◽  
Esophageal Pressure ◽  
Inspiratory Flow ◽  
Neurally Adjusted Ventilatory Assist ◽  
Positive End Expiratory Pressure ◽  
Assisted Mechanical Ventilation ◽  
Support Ventilation ◽  
Ventilatory Assist

Abstract Background: Auto-positive end-expiratory pressure (auto-PEEP) may substantially increase the inspiratory effort during assisted mechanical ventilation. Purpose of this study was to assess whether the electrical activity of the diaphragm (EAdi) signal can be reliably used to estimate auto-PEEP in patients undergoing pressure support ventilation and neurally adjusted ventilatory assist (NAVA) and whether NAVA was beneficial in comparison with pressure support ventilation in patients affected by auto-PEEP. Methods: In 10 patients with a clinical suspicion of auto-PEEP, the authors simultaneously recorded EAdi, airway, esophageal pressure, and flow during pressure support and NAVA, whereas external PEEP was increased from 2 to 14 cm H2O. Tracings were analyzed to measure apparent “dynamic” auto-PEEP (decrease in esophageal pressure to generate inspiratory flow), auto-EAdi (EAdi value at the onset of inspiratory flow), and IDEAdi (inspiratory delay between the onset of EAdi and the inspiratory flow). Results: The pressure necessary to overcome auto-PEEP, auto-EAdi, and IDEAdi was significantly lower in NAVA as compared with pressure support ventilation, decreased with increase in external PEEP, although the effect of external PEEP was less pronounced in NAVA. Both auto-EAdi and IDEAdi were tightly correlated with auto-PEEP (r2 = 0.94 and r2 = 0.75, respectively). In the presence of auto-PEEP at lower external PEEP levels, NAVA was characterized by a characteristic shape of the airway pressure. Conclusions: In patients with auto-PEEP, NAVA, compared with pressure support ventilation, led to a decrease in the pressure necessary to overcome auto-PEEP, which could be reliably monitored by the electrical activity of the diaphragm before inspiratory flow onset (auto-EAdi).

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 Backup ventilation during neurally adjusted ventilatory assist in preterm infants

2021 ◽  
Author(s):  
JUYOUNG LEE ◽  
Vilhelmiina Parikka ◽  
Liisa Lehtonen ◽  
Hanna Soukka
Keyword(s):  
Respiratory Rate ◽  
Preterm Infants ◽  
Prospective Observational Study ◽  
Clinical Deterioration ◽  
Neurally Adjusted Ventilatory Assist ◽  
Mean Values ◽  
Ventilatory Assist ◽  
Postmenstrual Age ◽  
Acute Increase ◽  
The Mean

Objective: To analyze the proportion of backup ventilation during neurally adjusted ventilatory assist (NAVA) in preterm infants at different gestational ages and to analyze the trends in backup ventilation in relation to clinical deteriorations. Methods: A prospective observational study was conducted in 18 preterm infants born at a median (range) 27 (23–34) weeks of gestation with a median (range) birth weight of 1,100 (460–2,820) g, who received respiratory support with either invasive or noninvasive NAVA. Data on ventilator settings and respiratory variables were collected daily; the mean values of each 24-hour recording were computed for each respiratory variable. For clinical deterioration, ventilator data were reviewed at 6-hour intervals for 30 hours prior to the event. Results: A total of 354 ventilator days were included: 269 and 85 days during invasive and noninvasive NAVA, respectively. The time on backup ventilation (%/min) significantly decreased, and the neural respiratory rate increased with increasing postmenstrual age during both invasive and noninvasive NAVA. The median time on backup ventilation was less than 15%/min, and the median neural respiratory rate was more than 45 breaths/min for infants above 26 weeks of gestation during invasive NAVA. The relative backup ventilation significantly increased prior to the episode of clinical deterioration. Conclusion: The proportion of backup ventilation during NAVA showed how the control of breathing matured with increasing gestational age. Even the most immature infants triggered most of their breaths by their own respiratory effort. An acute increase in the proportion of backup ventilation anticipated clinical deterioration.

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