Canberra Hospital and Health Services Clinical



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Guide to initial NIV-NAVA settings

Aim

To facilitate synchronised non-invasive ventilation, prevent de-recruitment and avoid increased work of breathing and apnoea.


Set up

  1. Place Edi catheter and record Edi peak and Edi min.

  2. Initial settings based on indications




Post-extubation

Escalation mode from CPAP

Backup mode to treat apnoea

NAVA Level

1.0-1.5

1.5-2.0

0

PEEP

6-8

6-8

6-8

PC above PEEP

10

10

10

IT

0.40

0.40

0.40

Apnoea Time

2-3 sec

2-3 sec

2 sec

Back up rate

40-50

50

40-50

Comments

(All settings to be tailored according to individual patient requirements)



Usually NAVA level that generates PIP of 16-18 cmH20 provides adequate support

Usually NAVA level that generates PIP of 16-18 cmH20 provides adequate support

For nasal CPAP therapy, choose NIV-NAVA mode and set NAVA to zero. Do not choose nCPAP mode.


Monitoring and optimisation of NIV-NAVA

  • Ensure Edi catheter is well positioned (refer to picture 7). Nasally inserted Edi catheter is more secure and easier to look after in comparison to oral Edi catheter. Nasal Edi catheter can be used with prongs and mask.

  • Edi catheter malposition:

  1. P wave on all lines and increasing P wave progressing from 1st to 4th lead- Push in catheter

  2. No P wave and dampened QRS on all 4 leads-Pull out catheter

  3. Larger P and QRS on 1st and 4th waveforms-Catheter curled in-Reinsert

  4. No signal- No respiratory drive

  • Review regularly and look at the efficiency of seal with the baby’s nose. Note the NAVA level and PIP and Edi’s generated, infant’s breathing effort, spontaneous respiratory rate, percentage back-up assist and any gaseous distention of abdomen.

  • Regularly review Edi peak (normal 5-15 µV), Edi min (normal <3µV) and percentage backup assist to avoid under or over- support.

  1. If Edi peak is >20 µV consistently- Ensure common causes are addressed e.g. secretions blocking nose or prongs wrongly positioned. Otherwise indicates increase work of breathing. Please increase NAVA level in increments of 0.2 until Edi is persistently below 15 µV and baby is comfortable.

  2. If Edi peak is <5 µV consistently- indicates work of breathing is low. Please decrease NAVA level by 0.1 to 0.2 after discussion with medical staff.

  3. If desaturations & periods of apnoea are worsening do a blood gas and review apnoea time. This may need to be decreased. Please consider change in baby’s condition like RDS worsening, sepsis, IVH, Pneumothorax, abdomen distention, etc.

  4. If Edi peak & Fio2 is increasing and work of breathing worsening- It indicates under-support, increase NAVA level. Other changes could be: Increasing PEEP if Edi min is high and increasing Fio2 or reassessing the infants need for invasive respiratory support

  5. If Edi peak and Edi min are low, Fio2 is decreasing and work of breathing is improving- decrease NAVA level. Other proposed changes can be reducing PEEP (if Edi min is low)

  • If there is abdominal distention or feed intolerance place another gastric tube into the stomach to vent air out. Use the Edi catheter for feeding and keep the spare gastric tube open.



Weaning from NIV-NAVA


  • Infant can be transferred to bubble CPAP or High Flow Therapy once the NAVA level is <0.5 and Fio2 <0.30 with Edi peak< 15 µV and Edi min <3 µV.

  • Review frequency of backup ventilation (Back up PC %) on the trends page and time spent in back up/min. If back-up is frequent consider increasing apnoea time and reducing back up PC rate &/or pressure control to encourage an increase in spontaneous respiratory drive.

  • There is no recommended weaning of NAVA level and it is based on individual experience. Once infant’s respiratory distress improves, weaning of NAVA level can be quicker. Usually NAVA level is weaned by 0.1-0.2 at a time. If baby does not tolerate weaning return to previous settings.


Troubleshooting on NIV-NAVA

Problem/Alarm

Response

Edi Catheter won’t aspirate

Aspirating Edi catheter may collapse the lumen. They are however designed to be aspirated so gentle adjustment should allow aspiration in case of aspirate measurement.

Edi catheter blocked

As the Edi catheter is incorporated with an electrical probe, the lumen is smaller than a usual nasogastric tube. Therefore it can get blocked by thick viscous medications or thickened feeds. In this case it may be necessary to pass a second nasogastric or orogastric tube.

Excessive leak/Low PEEP disconnection alarm

Means the leak is >15L/min. Review circuit for disconnections, interface and connections to interface. (Most common cause being mouth open, inappropriate interface seal and secretions)

Volume delivery restricted

It means that upper high pressure alarm limit is set low. The pressure is limited to 5cmH2O below the set upper pressure limit, which restricts the volume delivery. Check the ventilator alarm pressure setting. Might need to increase the alarm limits.

No patient effort

Ensure Edi is correctly positioned, if so then patient may be apnoeic in which case back up rate will begin. Consider reducing apnoea time if patient is not adequately supported in back up mode. Both oversedation and overventilation can lead to this alarm. Reduce sedation or backup rate

Desaturations/Bradycardia

Consider:

  • Suitability of mode of ventilation

  • Changing NAVA level (increase)

  • Insufficient Back Up Ventilation seen in extreme prems: may see reduced Edi activity-> can reduce Apnoea time down as low as 1 sec in 0.2 sec increments to give more Backup PC & Resp. Rate

  • Air in stomach (Aspirate Edi Catheter/OG tube & check positions are correct)

  • Clinical change in baby’s condition- RDS, Sepsis, IVH, Pneumothorax


Difference between Conventional and NAVA ventilation

Controls

Conventional ventilation

NAVA ventilation

Trigger

Flow trigger

Neural diaphragm (Edi) Trigger

Ventilator controls

  • PEEP

  • Fio2

  • Peak pressure or tidal volume

  • Inspiratory Time

  • Minimum Rate

  • Breath termination




Synchrony

Initiation of breath

Initiation of breath

Size of breath

Termination of breath



Back to Table of Contents

Section 11 - Care of Muscle Relaxed Infant



Purpose

The purpose of this section is to outline the management of the Infant who is Muscle Relaxed.


Muscle relaxation eliminates spontaneous respiratory effort therefore the infant must have artificial respiratory support prior to administration of medication. The drugs used for prolonged muscle relaxation are the non-depolarising agents such as Vecuronium bromide or Pancuronium bromide.

This group of drugs block the binding of acetylcholine at the nicotinic receptors preventing an influx of sodium into muscle cells hence depolarisation is prevented, calcium ions are not released and muscle contraction does not occur.


Equipment

  • Alcohol Based Hand Rub (ABHR)

  • Neopuff and Laerdal bag with appropriate sized mask

  • Cardio-respiratory and pulse oximetry monitors

  • Suction equipment

  • Pressure relieving devices such as sheepskin or gel mattress

  • Extra linen for nesting infant

  • Lanoline, swab sticks and sterile water

  • Artificial tears or ophthalmic lubricant, cotton swabs and sterile saline

  • Ears muffs

  • Urinary catheter


Procedure

  1. Ensure infants respirations are controlled via a ventilator

  2. Ensure ETT is in the correct position and taped securely

  3. Set Neopuff parameters according to ventilator settings

  4. Attach cardio-respiratory and pulse oximetry monitoring

  5. Check alarm limits as per protocols

  6. Check drug and dosage against medication order

  7. Ensure infant is nursed one-to-one at all times

  8. Perform hourly assessment of infants pain level to ensure adequate pain relief, utilising Premature Pain Profile (PIPP) parameters of heart rate and oxygen saturation only

  9. Neuromuscular depolarising agents do not have any pain relieving qualities, so it is imperative that the neonate also receives appropriate pain relief and sedation

  10. Perform continuous observations and assessments for signs of returning muscle activities

Observe for:

    1. Movement of diaphragm including spontaneous respiratory effort or hiccup

    2. Movement of limbs, eyelids or digits

    3. Increase in jaw tone

    4. Notify RMO if signs of spontaneous muscle activity are noted

  1. Minimal handling:

    1. Ensure pain relief and muscle relaxation is adequate prior to performing care and or procedures

    2. Cluster all cares

    3. Provide rest periods

  2. Positioning:

    1. Ensure correct body alignment

    2. Support all limbs

    3. Nesting to increase infant security

    4. Pressure area care attended regularly

  3. Pressure area care – risks involved in the use of neuromuscular blockade include: skin breakdown, peripheral oedema and muscle atrophy

    1. Use soft bedding such as a sheepskin or gel mattress to facilitate comfort and minimal handling

    2. Implement side to side positioning if not contraindicated

    3. Regular skin inspection

  4. Joint mobility – prolonged neuromuscular relaxation may cause joint contractures, muscle weakness and atrophy:

    1. Implement gentle extension and flexion of the joints if not contraindicated

    2. Maintain joints in the position of function

  5. Oral care – muscle relaxation results in an absent swallow reflex and accumulation of secretions. A side effect of muscle relaxants can be increased production of saliva

    1. Suction should be performed as necessary

    2. Moisten lips and tongue with water or EBM using swab sticks

    3. Lanolin to lips if not under radiant heater

  6. Eye care – neuromuscular blockers eliminate the blink reflex leading to corneal drying with potential for abrasion, ulceration, scaring and infection

    1. Keep eye closed at all times

    2. Avoid pressure on the lower eye when head is turned to the side

    3. Inspection of eyes for signs of infection

    4. Cleanse eyes with cotton swabs and normal saline

    5. Bilateral instillation of artificial tears/ophthalmic lubricant every four hours

  7. Ear protection – neuromuscular blockers produce muscular relaxation of all skeletal muscles including the tensor tynpani and the stapedius. Loud sounds may damage the hearing receptors

    1. Application of earmuffs to one or both ears depending on infant’s position

    2. Reduction of noise in infant’s immediate environment

  8. Urine retention – accumulation of urine can occur, leading to bladder distension and decreased urine output

    1. Urinary catheterisation as per Neonatologist recommendations

  9. The following are recommended

    1. Transcutaneous monitor or

    2. End tidal CO2 monitor


Alert

Consider bedside aEEG for babies who are muscle relaxed if there is a medical indication


Outcome

  • The neuromuscular blocking agent has been administered correctly and safely.

  • The desired level of muscle relaxation has been achieved

  • No adverse effects have been reported


Back to Table of Contents

Section 12 - Nitric Oxide (NO) Administration



Purpose

The purpose of this section is to outline the care of an Infant while receiving inhaled Nitric Oxide (NO).


Inhaled nitric oxide is a selective pulmonary vasodilator used to treat persistent hypertension of the newborn (PPHN).
Background

  • Persistent pulmonary hypertension of the newborn is a cardiopulmonary disorder characterized by systemic arterial hypoxemia secondary to elevated pulmonary vascular resistance with resultant shunting of pulmonary blood flow to the systemic circulation:

  • Diversion of blood through fetal shunts (R→L shunts)

  • Foramen ovale

  • Ductus arteriosus

  • Systemic arterial hypoxemia and hypercapnia

  • Acidosis

  • Shock


NOTE

Prior to commencing Nitric Oxide preductal oxygen saturations should be targeted >90% and PaO2 between 50-80 mmHg


Equipment

  • Alcohol based hand rub (ABHR)

  • Inovent® unit

  • Flow injector

  • Nitric (NO) delivery line

  • NO sampling line

  • Ventilator

  • Ventilator circuit

  • Connector for sampling port

  • Scavenger and tubing Identification bands


Procedures

  1. Assemble nitric oxide delivery system and scavenging system (optional)

  2. Check that monthly high and low calibrations have been performed by equipment technician – recorded in book on side of Inovent® machine

  3. If the monthly calibration has not been performed within the last 4 weeks arrange for this to be done by the equipment technician or biomedical engineer

  4. Purge Inovent® system as per this SOP, Section 12 -Nitric Oxide Setup

  5. Connect emergency resuscitation equipment i.e. Neopuff to nitric oxide/oxygen outlet on Inovent®

Alert

If the baby requires resuscitation it must be done with the Neopuff and NO with a set flow of 15 litres per minute (this administers 10ppm).


Perform cranial ultrasound if possible prior to commencement of NO therapy in infants <32 weeks gestation to exclude IVH


  1. NO therapy maybe contraindicated in the presence of haemorrhagic brain injury

  2. Perform cardiac echocardiogram if possible, prior to commencement of nitric oxide therapy to confirm the presence of pulmonary hypertension and exclude duct dependent lesions

  3. Nitric oxide should not be administered to neonates with congenital heart disease who depend on a right-to-left shunt or have severe left heart failure



Alert

Commence nitric oxide therapy when echo evidence of PPHN and FiO2 >0.4 or oxygenation index exceeds 25 (OI=mean airway pressure x FiO2 x 10/PaO2).


Seek advice from a second consultant neonatologist before commencing nitric oxide therapy on infants < 32 weeks gestation since nitric oxide therapy is less effective in this group and may increase the incidence of severe intracranial haemorrhage.


  1. Commence nitric oxide therapy at 20ppm (Inspired Oxygen (FiO2) 100%)or as directed by consultant

  2. Obtain an arterial blood gas sample 30 minutes after initiation of therapy

  3. If oxygenation improved, continue nitric oxide at 20ppm and wean oxygen slowly as tolerated as per consultants orders which must be written in notes

  4. Once oxygen below 40% NO may be weaned as clinically indicated

  5. Minimise disconnection times to maintain continuity of nitric oxide delivery and maintain therapeutic vasodilatory effects, as nitric oxide has a rapid half life

  6. Use a closed suction system for endotracheal suction in order to minimize disconnection time

  7. Monitor methaemoglobin levels 12 hourly and platelet levels and coagulation profile 24-48 hourly

  8. Nitric oxide concentration should be reduced or discontinued if methaemoglobin levels exceed 5-7 percent

  9. Perform daily low calibration of nitric oxide unit as per instructions in Inovent® manual

  10. Record both NO and NO2 levels on observation chart

  11. NO2 levels above 3 are considered toxic to the neonate and may require nitric oxide therapy to be weaned or discontinued.


Outcome

  • Calibration has been performed prior to commencement of NO

  • Cranial ultrasound and echogram has been performed if required

  • Arterial Blood Gases have been analysed 30 minutes after commencement or according to clinical direction

  • Resuscitation has been performed using NO and Neopuff

  • Weaning from NO has occurred according to clinical condition

  • Met Hb has been monitored 12 hourly and action taken


Back to Table of Contents

Section 13 - Nitric Oxide-INOvent® Operation



Purpose

The purpose of this section is to go step by step through the process of setting up the Inovent Unit, including calibration and purging prior to commencing delivery of Nitric Oxide to the infant.


Equipment

  • Inovent® unit

  • Flow injector

  • Neopuff resuscitator

  • Delivery tubing

  • Sampling port line

  • One way valve

  • Ventilator


Procedure

  1. Assemble equipment

  2. Connect Inovent to oxygen outlets and power points

  3. Ensure that monthly high and low calibrations have been performed by the equipment technician or biomedical engineer (see book on side of Inovent®)

  4. Perform a pre-use purge


Pre-use Purge

  1. Turn the Inovent® delivery system on

  2. Check that the cylinder has adequate gas (pressure gauge at front of monitor) wait 30 seconds and then check that the cylinder pressure gauge remains static and has not fallen


Alert

If gauge falls this indicates a leak in the system. Do not use machine until the source of the leak has been identified.




  1. Ensure that the purge has been completed within 5 minutes of the start of therapy. If more than 5 minutes has elapsed, repeat the procedure

  2. Ensure NO2 value is less than 1.5

  3. Connect purging circuit to machine

  4. Turn suction unit on full and O2 flow metre to 15 litres

  5. Perform a low range calibration

  6. Push the calibration button to display the first calibration menu

  7. The low range (room air) NO, NO2 and O2 option is highlighted

  8. Push the control wheel to start the low range calibration

  9. When calibration successful turn control wheel to “Exit Normal Display”

  10. Turn nitric cylinder to OFF

  11. Ensure that the O2 flow continues to run at 15L/min

  12. Set the NO at its MAXIMUM setting and run. This will pull the old gases through

  13. Ensure the cylinder pressure gauge returns to zero. This will take a few minutes

  14. Ensure the NO2 values are higher than 0.2ppm to verify the NO2 monitor is functional

  15. Ensure the following alarms occur

    1. “Low NO/N2” pressure

    2. “Delivery Failure”-this will take a few minutes

  16. Turn the NO cylinder ON to start therapy

  17. Leaving O2 flow at 15L/min-set NO to 40ppm

  18. Wait 3 minutes or until monitor readings are stable

  19. Ensure the readings are within acceptable range as per chart on p5.2 of manual

  20. An appropriate level of NO2 is below 1.5

  21. Inovent® may now be connected to patient

  22. Press pause, remove the purge circuit and replace with the patient circuit






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