UK NAVA - Doctors
Quick Guide to using NAVA technology
NAVA technology -Two sides to one coin ​
Screening
Doctors on both critical care outreach; working in the Emergency Department as well as in critical care are key to identifying all potential patients who are eligible for the UK NAVA trial.
Managing patients in UK NAVA
Critical Care together with specialty doctors will be heavily involved in delivering the interventions in UK NAVA. This includes effective use of NAVA monitoring as well as safe and effective spontaneous ventilatory support with NAVA mode. furthermore, it is important that good general ventilatory practice is deployed, including high quality sedation management and daily spontaneous breathing trials.
Inserting the NAVA catheter - modified nasogastric tube
Catheter needs to be advanced
Catheter is positioned well
Monitoring the Edi - benefits of being able to see patient neural drive
Edi (Neural drive) Magnitude | Effect of Critical Care Interventions on Edi
Monitoring Asynchrony with Edi monitoring | Edi after extubation
The Edi signal from the NAVA catheter can be made to overlay over the standard pressure support breaths. It can monitor the level of neural drive the patient has ( level of 'dyspnoea') and tell you if the patient's respiratory drive is out-of-step with the support breaths- asyncrony). Note: when you are using the NAVA catheter to monitor the patient like this, nothing new is being done to the patient - the patient is NOT yet in NAVA. There are multiple forms of asyncrony.
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You will get information that you would not otherwise have known. For example, you could present this in shift handover.
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In UK NAVA we want the clinical team of the patient randomised to NAVA intervention to consider putting the patient in the NAVA pressure support mode at least daily. The presence of asyncrony may prompt this decision.
Ventilating and weaning using the NAVA mode
NAVA pressure support follows the Edi and allows the patient to select tidal volume and respiratory pattern.
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The medical team will need to work with nursing team to ensure safe placement of the NAVA catheter. This will be particularly true if placement with McGills forceps is necessary or if sedation/muscle relaxants need to be used. In general, NAVA catheters are generally as easy to place as standard NG tubes. They are pre-lubricated and the lubrication is 'activated' by immersing the catheter in water prior to insertion. Equally nurses may place the NAVA catheter uneventfully as per a normal NG tube.
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Once the NAVA catheter is in place by using the NEX measurement, the ECG series can be used to optimise the location.
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The NAVA catheter can then be used to monitor the neural drive of the patient, and be aware of the impact or effect of changes in supportive care; trajectory of neural drive; and specifically examine dysynchrony of the patient's neural drive with whatever mode the patient is in (control or support mode).
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If there is a clean Edi signal, which is usually possible to achieve in the vast majority of patients, then the patient can be transitioned to NAVA once spontaneous pressure support is felt to be clinically appropriate. The positioning tool can be used to set the appropriate level of NAVA. Alternatively, the level can be set at 1 and up- or down-titrated clinically.
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The medical team are obviously critical to weaning of NAVA to the point of liberation from ventilatory support.
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Finally, the neural drive can be used to monitor the patient after extubation eg comparison of drive in various forms of non-invasive support such as NIV, high-flow, or CPAP.
