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Neurally Adjusted Ventilatory Assist

NAVA, Neurally adjusted ventilator assist. Achieve faster personalized weaning with lung and diaphragm protective ventilation

Neurally Adjusted Ventilatory Assist

It’s not mindreading, but close.[1],[2]

Imagine being able to see and deliver what your patients want, while their own natural respiratory drive controls the ventilator. We call it Neurally Adjusted Ventilatory Assist (NAVA). It is based on close monitoring of the output of the patient’s respiratory center, by capturing the electrical signal that activates the diaphragm (Edi), using a dedicated gastric feeding tube (Edi catheter). NAVA shortens the time of mechanical ventilation[3] and increases the number of ventilator-free days[3] [4] [5] by providing personalized ventilation that is both lung- and diaphragm-protective.

Overview

Achieve faster personalized weaning with lung- and diaphragm-protective ventilation

Monitor Edi – the vital sign of respiration, from day zero

1. Monitor Edi – the vital sign of respiration, from day zero

Protect and activate the diaphragm to wean earlier

2. Protect and activate the diaphragm to wean earlier

Protect the lungs in synchrony with the patient

3. Protect the lungs in synchrony with the patient

Improve the patient’s overall ICU experience

4. Improve the patient’s overall ICU experience

Monitor Edi – the vital sign of respiration

In addition to monitoring the impact of mechanical ventilation on lung function, it is also imperative to monitor patient respiratory drive and effort from day zero. Edi monitoring facilitates earlier and more informed decision-making. With this vital sign in your lower screen, you can detect diaphragm inactivity, over-sedation, patient-ventilator asynchrony as well as over- and under-assist. You can also monitor increased work-of-breathing during weaning trials and post-extubation[5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15].

Learn more about Edi monitoring

Diaphragm-protective ventilation

Suboptimal mechanical ventilation can rapidly cause acute diaphragm atrophy or load-induced injury associated with poor clinical outcomes [16] [17]. The key physiological benefits of NAVA are that pressure is always delivered in proportion to and in synchrony with the patient’s own respiratory drive, and that Edi is readily available as a bedside diagnostic tool [1] [2]. NAVA shortens the duration of weaning and increases the proportion of patients with successful weaning[3][4].

Learn more about diaphragm-protective ventilation

Lung-protective ventilation

A key difference between NAVA and conventional support modes is that tidal volume (VT) is controlled via neuro-electrical output from the patient’s respiratory center. Lung over-distension is thus prevented thanks to the Hering-Breuer reflex, which down-regulates the respiratory drive at higher tidal volumes to avoid hyperinflation. As a result, it is possible to achieve lung-protective spontaneous breathing within the protective range of 6-8 ml/kg [1] [2] [18] PBW.

Learn more about lung-protective ventilation with NAVA

Improved patient experience

NAVA has been shown to improve the patient’s overall ICU experience, helping clinicians to potentially reduce sedation with improved comfort and sleep quality [19] [20] [21] [22] [23]. Together, Edi and NAVA assure that the breathing efforts from all patient categories are effectively assessed and responded to. For patients with acute exacerbation of COPD, our non-invasive, leakage-independent NIV NAVA mode can be helpful effective in managing their status and avoiding intubation [14] [24] [25] [26] [27] [28].

Learn more about improved patient experience with NAVA

Key benefits

How will your hospital benefit from NAVA with Edi monitoring?

Key benefits in brief:

Personalized support

Personalized support throughout the treatment

illustration nava

Invasive NAVA

Synchronized assist, weaning and sedation management, supporting early diaphragm activation.

Illustation non-invasive nava

Non-invasive NAVA

Synchronized assist, independent of leakages allowing a gentler mask application.

illustration monitoring

Edi monitoring

Monitor diaphragm activity  and breathing effort after extubation. Can be used with High Flow therapy if needed.

 

Personalized ventilation

See and deliver what your patient wants

In most intensive care units, 20% of the patients consume 80% of ventilation resources, which may lead to increased complications and unwanted outcomes. [31] For these patients, conventional ventilation simply isn’t enough. By using the NAVA mode on Servo ventilators, which works regardless of patient category or size, the ventilator shows you what the patient wants. Together with other personalized ventilation tools, this can help you reduced complications [9] [10] [29] [30], monitor and reduce sedation [5] [19] [20] [21], achieve earlier and more successful weaning [3] [4] [8] [13] [14] and shorten the time of mechanical ventilation [3] [20] [21].

Learn how NAVA neurally adjusted ventilator assist delivers a more personalized level of ventilation to your patient

How NAVA delivers a more personalized level of ventilation in three easy steps.

  1. The brain directs our breathing. The exact size and timing of every breath we take is controlled by the brain’s respiratory center. When the brain has processed multiple sensory input, it sends a signal via the phrenic nerve that electrically activates the diaphragm, leading to muscle contraction. The diaphragm then contracts into the abdominal cavity, which leads to a descending movement, creating chestwall and lung expansion and an inflow of air. The signal that excites the diaphragm is proportional to the integrated output of the respiratory center in the brain and controls the depth and timing of each breath.

  2. Micro-electrodes detect the vital sign of respiration (Edi). The electrical discharge of the diaphragm is captured by a special nasogastric feeding tube fitted with an array of micro-electrodes (the Edi catheter). Like an ordinary enteral feeding tube, the Edi catheter passes through the esophagus, where it measures the electrical activity of the diaphragm. The electrodes in the Edi catheter also monitor electrocardiographic (ECG) signals, which are used to guide and validate correct positioning in relation to the diaphragm.

  3. Your Servo ventilator user interface presents it all. The lower part of the screen shows the Edi signal at all times, even if the patient ventilation mode is not switched to NAVA. When you switch on the NAVA mode, the Edi signal automatically guides the ventilator to deliver support in time with and proportion to the diaphragm. The ventilator acts as a second inspiratory muscle – in perfect synchrony with the patients.

The diaphragm is the "heart" of the respiratory system and is designed to be continuously active. [26] The Edi is a bedside diagnostic tool that allows you to monitor and safeguard the patients diaphragm activity. [27] [28] The Edi guides weaning [29] and helps you prevent muscular exhaustion during weaning trials, even after extubation. [30]

Getting started with NAVA on the Servo-u ventilator

Educational training video on how to get started using NAVA on the Servo-u ventilator.

Training

Improve your knowledge with our eLearning courses

The basic concept of NAVA and Edi
NAVA module 1 (10 min)

  • Breathing regulation
  • Conventional ventilatory treatment
  • Edi and NAVA treatment

English (voice over) | Dutch | French | German | Italian | Spanish | Swedish

The basic concept of NAVA and Edi
NAVA module 2 (10 min)

  • Breathing regulation
  • Conventional ventilatory treatment
  • Edi and NAVA treatment

English (voice over) | Dutch | French | German | Italian | Spanish | Swedish

Servo-u NAVA (10 min)

  • Servo-u NAVA screen layout
  • NAVA workflow

English (voice over) | Dutch | French | German | Italian | Spanish | Swedish

Downloads

All references

  1. Sinderby C, et al. Neural control of mechanical ventilation in respiratory failure. Nat Med. 1999 Dec;5(12):1433-6.

  2. Jonkmann A, et al. Proportional modes of ventilation: technology to assist physiology Intensive Care Med. 2020 Aug 11;1-13.

  3. Kacmarek R, et al. Neurally adjusted ventilatory assist in acute respiratory failure: a randomized controlled trial. Intensive Care Med 2020. Sep 6 : 1–11.

  4. Liu L, et al. Neurally Adjusted Ventilatory Assist versus Pressure Support Ventilation in Difficult Weaning. A Randomized Trial. Anesthesiology. 2020 Jun;132(6):1482-1493.

  5. Hadfield D, et al Neurally adjusted ventilatory assist versus pressure support ventilation: a randomized controlled feasibility trial performed in patients at risk of prolonged mechanical ventilation Critical Care 2020 May 14;24(1):220.

  6. ATS/ERS Statement on Respiratory Muscle Testing. American Journal of Respiratory and Critical Care Medicine, 2002166(4), pp. 518-624.

  7. Ducharme-Crevier L, et al. Interest of Monitoring Diaphragmatic Electrical Activity in the Pediatric Intensive Care Unit. Crit Care Res Pract. 2013;2013:384210.

  8. Emeriaud G, et al. Evolution of inspiratory diaphragm activity in children over the course of the PICU stay. Intensive Care Med. 2014 Nov;40(11):1718-26.

  9. Piquilloud L, et al. Neurally adjusted ventilatory assist improves patient-ventilator interaction. Intensive Care Med. 2011 Feb;37(2):263-71.

  10. Yonis H, et al. Patient-ventilator synchrony in Neurally Adjusted Ventilatory Assist (NAVA) and Pressure Support Ventilation (PSV). BMC Anesthesiol. 2015 Aug 8;15:117.

  11. Cecchini J, et al. Increased diaphragmatic contribution to inspiratory effort during neurally adjusted ventilatory assistance versus pressure support: an electromyographic study. Anesthesiology. 2014 Nov;121(5):1028-36.

  12. Di Mussi R, et al. Impact of prolonged assisted ventilation on diaphragmatic efficiency: NAVA versus PSV. Crit Care. 2016 Jan 5;20(1):1.

  13. Barwing J, et al. Electrical activity of the diaphragm (EAdi) as a monitoring parameter in difficult weaning from respirator: a pilot study. Crit Care. 2013 Aug 28;17(4):R182.

  14. Bellani G, Pesenti A. Assessing effort and work of breathing. Curr Opin Crit Care. 2014 Jun;20(3):352-8.

  15. Bellani G, et al. Clinical assessment of autopositive end-expiratory pressure by diaphragmatic electrical activity during pressure support and neurally adjusted ventilatory assist. Anesthesiology. 2014 Sep;121(3):563-71.

  16. Dres M, Goligher EC, Heunks LMA, Brochard LJ. Critical illness-associated diaphragm weakness. Intensive Care Med. 2017 Oct;43(10):1441-1452.

  17. Goligher EC, Hodgson CL, Adhikari NKJ, et al. Lung recruitment maneuvers for adult patients with acute respiratory distress syndrome. Ann Am Thorac Soc 2017;14:S304-11.

  18. Patroniti N, et al. Respiratory pattern during neurally adjusted ventilatory assist in acute respiratory failure patients. Intensive Care Med. 2012 Feb;38(2):230-9.

  19. De la Oliva P, et al. Asynchrony, neural drive, ventilatory variability and COMFORT: NAVA versus pressure support in pediatric patients. Intensive Care Med. 2012 May;38(5):838-46.

  20. Piastra M, et al. Neurally adjusted ventilatory assist vs pressure support ventilation in infants recovering from severe acute respiratory distress syndrome: nested study. J Crit Care. 2014 Apr;29(2):312.e1-5.

  21. Kallio M, et al. Neurally adjusted ventilatory assist (NAVA) in pediatric intensive care – a randomized controlled trial. Pediatr Pulmonol. 2015 Jan;50(1):55-62.

  22. Delisle S, et al. Sleep quality in mechanically ventilated patients: comparison between NAVA and PSV modes. Ann Intensive Care. 2011 Sep 28;1(1):42.

  23. Delisle S, et al. Effect of ventilatory variability on occurrence of central apneas. Respir Care. 2013 May;58(5):745-53.

  24. Doorduin J, et al. Automated patient-ventilator interaction analysis during neurally adjusted noninvasive ventilation and pressure support ventilation in chronic obstructive pulmonary disease. Crit Care. 2014 Oct 13;18(5):550.

  25. Kuo NY, et al. A randomized clinical trial of neurally adjusted ventilatory assist versus conventional weaning mode in patients with COPD and prolonged mechanical ventilation. International Journal of COPD. 2016 11;11:945-51.

  26. Sun Q, et al. Effects of neurally adjusted ventilatory assist on air distribution and dead space in patients with acute exacerbation of chronic obstructive pulmonary disease. Crit Care 2017 2;21(1):126.

  27. Karagiannidis C, et al. Control of respiratory drive by extracorporeal CO 2 removal in acute exacerbation of COPD breathing on non-invasive NAVA. Crit Care 2019 Apr 23;23(1):135.

  28. Prasad KT, et al. Comparing Noninvasive Ventilation Delivered Using Neurally-Adjusted Ventilatory Assist or Pressure Support in Acute Respiratory Failure. Resp Care 2020 Sep 1;respcare.07952.

  29. Blankman P, et al. Ventilation distribution measured with EIT at varying levels of PS and NAVA in Patient with ALI. Intensive Care Med. 2013 Jun;39(6):1057-62.

  30. Patroniti N, et al. Respiratory pattern during neurally adjusted ventilatory assist in acute respiratory failure patients. Intensive Care Med. 2012 Feb;38(2):230-9.

  31. Icuregswe.org. (2016). Start - SIR-Svenska Intensivvardsregistret. [online] Available at: http://www.icuregswe.org/en/ [Accessed Dec 2. 2015].