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Ventilators: Why, What, How, When?

Made by UK Paramedics, this video demonstrates how to use the PneuPac ParaPac ventilator.

Read more:

How do I get the ventilator off the racks?

What is the relief pressure dial on the ventilator?

What is positive pressure breathing?

What is Negative Pressure Breathing?

The Discovery of Negative and Positive Pressure Ventilation – Fast Fact

Disclaimer

You must read the full disclaimer at www.article999.co.uk/about/ (disclaimer tab) before putting into place anything you see here. Useful information is available in the text on this video, so if you only listen to the narration you will miss important facts. The ventilation settings mentioned in this video are what is recommended by Smiths Medical, current guidelines and some articles – however, as with all topics, there is always varying information available online & alternative expert advice, and no video can cater for all of that. Similarly, this video is intended to demonstrate how to use equipment & to introduce or remind you to the Why, What and When of ventilators – not to tell you that you should or shouldn’t be using it. That is dependent on local guidelines, your research & your choice as a clinician. This video merely highlights the varying advice regarding tidal volume settings, and in the text points out the potential problems with some of the figures. No specific volume is recommended.


Transcript

Article 999. Ventilators: Why, What, How, When?

This video has been made by UK Paramedics following guidelines. It is not endorsed by any author, organisation or Ambulance Trust. You must read the full disclaimer at www.article999.co.uk/about/ and refer to your local guidelines before putting into place anything you see here. This video is intended to demonstrate how to use the ventilator according to use guides and guidelines – not to tell you that you should or shouldn’t use it. That decision is up to you and should be dependent on local guidelines and your own research. This is what the textbooks, the manufacturer and a few articles say & is not intended to represent the expert opinions or experience of others within healthcare.

Remember hand hygiene, bare below the elbows and gloves in real life.

Why use the ventilator?

Research suggests that mechanical ventilators can reduce the variability of breath timings & as a result, capnography readings. They can also increase the likelihood of ‘effective ventilation’ (Owen and Castle, 2006)

To quote from Gregory & Mursell (2010: 47) ‘A high flow rate over a short inflation time inevitably produces a high peak airway pressure in an unprotected airway [as with BVM technique]. High peak airway pressure overcomes the pressure of the lower oesophageal sphincter and causes gastric inflation. […] Use of […] mechanical ventilation may help to overcome the high pressures involved. […] In an intubated patient or a patient with an LMA in situ, use of a mechanical ventilator has been shown to allow paramedics to accomplish extra tasks, document better, and provide better patient care’ (Gregory & Mursell, 2010: 47)

What?

This is a time-cycled, volume preset flow generator (Baker, 2012). In other words, the pressure can vary, volume is always the same, and the air must be delivered within a preset time, which helps to control the tidal volume.

There are many different types. One of the most common ones in UK ambulances at this time (Gregory & Mursell, 2010: 44) is the Pneupac paraPAC (Smiths Medical, 2017) but the ParaPac Plus may soon replace it.

Here are the useful parts:

The supply gas failure alarm
The inlet connection
The relief pressure control
The ‘main pneumatic switch’
Air mix control
Inflation pressure monitor
Frequency control
Tidal volume control
(Pilbery and Lethbridge, 2016: 189)

How?

  1. To remove the ventilator from the racks, pull the flap to the side and push the ventilator up. To put it back in, simply push it down and pull the flap to the side again.
  2. To connect to the gas supply, push the hose into the socket and twist. It’s the same when connecting to a portable oxygen cylinder.
  3. When you turn it on, the ventilator should complete a self check. The alarm lights should flash in sequence, there should be one burst of the high pressure audible alarm, and the orange indicator should flash for 60 seconds.
  4. Next, check the indicator shows white for O2.
  5. Connect the patient circuit [shown in video].
  6. Next on the list, adjust the ventilation parameters. Set the air mix control to no air mix for respiratory arrest or CPR. Set the relief pressure control to 40. Set the respiratory rate to 12. As for the tidal volume, it varies massively as you can see on the screen. It depends on whether you opt for an average value or base it on the patient’s weight. Smiths Medical (2017) advise 800-900ml on their training video, [but this may not be advisable] but don’t worry too much about the slight differences in tidal volume because the PneuPac features a high pressure alarm that we’ll discuss shortly. The alarm will help you identify if the tidal volume is too high for your patient.

(Gregory & Mursell, 2010: 44; Pilbery & Lethbridge, 2016: 189; Baker, 2012; Smiths Medical, 2017)

The following demonstrate the variance in researched texts and guidelines – not necessarily the advised settings:

400-600ml Baskett, 1996
500-600ml Perkins et al, 2015
600ml Baker, 2016
800-900ml Smiths Medical, 2017 – may not be advisable due to risks of barotrauma. See below
6-8ml/kg Bocklage & Balk, 2017; Frakes, 2007
10ml/kg or 5-8ml/kg Baker, 2012 – depending on the extent of the risk of barotrauma

7. Next, temporarily occlude the patient connection. The relief pressure monitor should go to the maximum setting – i.e. 40cmh20.

(Gregory & Mursell, 2010: 44; Pilbery & Lethbridge, 2016: 189; Baker, 2012; Smiths Medical, 2017)

 

What do the audible warnings mean?

  • Top left is the high pressure alarm
  • Top right is low pressure
  • Bottom left is the battery indicator
  • The middle one tells you when breathing is detected by the ventilator

(Smiths Medical, 2017)

High pressure = excessive tidal volume, incorrect airway position, kinked ET tube, or incorrect ventilation settings.
If the pressure is reaching it’s max, there may be something wrong with the circuit.

If you’ve checked the above and the alarm is still sounding, Smiths Medical (2017) advise that your tidal volume setting might simply be too high.

Low pressure = leakage or insufficient tidal volume/settings, faulty valve in the patient’s circuit
This alarm tends to occur when pressure drops below 10cmh20

Earlier, I pointed out the alarm in the middle, at the bottom. This is SMMV. It’s an indicator that will flash green if the patient is breathing for themselves. The ventilator will assist if the patient breathes with less than 150ml of tidal volume. Between 150-400ml the ventilator will extent the exhalation time to allow the patient to complete their own breath, and above 400ml the ventilator will allow the patient to breathe and will not assist, but may still assist on the next breath if required (Smiths Medical, 2017; Baker, 2012).

When?

– AACE (2016) recommend considering ventilation if a ptn’s o2 sats <90 on high con o2,
if the RR is <10 or >30 bpm or if there is ‘inadequate chest expansion’ (p42) but the mechanical ventilator is to be used …
– for ’emergency and transport ventilation’ in 5kg + patients (Smiths Medical, 2017)

Extra facts:

McCarty et al (2012) found that ‘ventilation rates and tidal volumes commonly exceeded Guideline recommendations. This resulted in […] excessive mean airway pressure’

Smiths Medical (2017) advise that peak inflation pressure should be below 20cmh20 when using a mask to ventilate due to the issues of too high pressure

Inspiration to Expiration should be 1:2 (Smiths Medical, 2017; Baker, 2012)

 

References

Baker, D. 2012. Emergency and Transport Ventilation, an introductory guide, Smiths Medical International Limited: Luton

Baker, D.J. 2016. Artificial Ventilation: A Basic Clinical Guide. Springer International: Switzerland

Baskett, P. et al. 1996. ‘Tidal volumes which are perceived to be adequate for resuscitation’, Resuscitation, 31 (3), pp. 231-4

Bocklage, T. & Balk, R.A. 2017. Setting the Tidal Volume In Adults Receiving Mechanical Ventilation: Lessons

Learned From Recent Investigations, Available Online: https://www.nbrc.org/wp-content/uploads/2017/07/Setting-the-Tidal-Volume.pdf (Accessed 17/12/17)

Frakes, M. 2007. Ventilation Modes and Monitoring, Available Online: http://www.rtmagazine.com/2007/02/ventilation-modes-and-monitoring/ (Accessed 17/12/17)

Gregory, P. and Mursell, I. 2010. Manual of Clinical Paramedic Procedures, West Sussex: John Wiley & Sons

McCarty, K. et al, 2012. Ventilation rates and tidal volume during emergency department cardiac resuscitation, Resuscitation, 83: 4, p45

Owen, R. and Castle, M. 2006. ‘EtCO2: the key to effective prehospital ventilation’, Emergency Medical Journal, 23 (7), pp. 578-579

Perkins, G.D. 2015. European Resuscitation Council Guidelines for Resuscitation 2015: Section 2. Adult basic life support and automated external defibrillation, Available Online: https://ercguidelines.elsevierresource.com/european-resuscitation-council-guidelines-resuscitation-2015-section-2-adult-basic-life-support-and/fulltext#back-bib0760 (Accessed 17/12/17)

Pilbery, R. & Lethbridge, K. 2016. Ambulance Care Practice, Bridgwater: Class Professional Publishing

Smiths Medical, 2017. ‘Pneupac – ParaPAC’, Pneupac Transport Ventilators – Breathe Easy, Available Online: https://www.smiths-medical.com/resources/pneupac-transport–ventilators—breathe-easy¬†(Accessed 27/10/17)

With thanks to Smiths Medical for their correspondence and information

Music:
Dobroide, 2010. 20091229.ambulance.siren.wav. Available Online: https://freesound.org/people/dobroide/sounds/8713/ (Accessed 21/08/17)

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