EMS A-Z Series by Jim Hoffman, Paramedic

Jim Hoffman covers a wide range of  EMS topics in his column EMS from A - Z.  About the columnist: Jim Hoffman, Paramedic, is a contributor to EMS Solutions.  EMS Solutions sells low cost online EMS and fire training resources, pocket field guides, customized guides and more.

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EMS A-Z Series "V" Ventilations, Ventilators, Very Basic.

  If you recall back in the "A" installment I resisted the temptation to cover the very basic topic of airway. In this installment I have chosen ventilations as part of the article not so much because it fits in this part of the alphabet, but because in keeping with the theme of the A-Z series, I want to stress the very basics of what we do.

 Ventilations. You would think that this is a pretty mundane topic and I am not going to go into gas exchange, tidal volume etc. What I do want to discuss is the ventilation rate.

I have found many providers do not ventilate during CPR at the correct rate according the 2005 AHA Guidelines.  

By now I am sure you have recertified your CPR card and are aware of the primary changes 30:2 vs. 15:2 etc. But what I want to focus on is the ventilations when a patient has an advanced airway.

 Once a patient has the advanced airway in place there are no pauses for ventilations. The provider giving ventilations should do so at a rate of 8-10 per minute. This is only 1 breath every 6-8 seconds. Compared to the way you may be used to doing it coupled with the excitement of performing CPR and that may seem like next to nothing. Add that to some providers desire to appear like they are doing something (even subconsciously) and it is very hard to keep that rate at 8-10 per minute.

 I don't want to make this into a CPR refresher course so I am not going to start giving all the rates, changes and reason why's, but The Highlights of the AHA 2005 Cardiopulmonary Resuscitation states " … rescuers should be particularly careful to avoid delivery of an excessive number of breaths. Several studies of actual CPR by healthcare providers showed that many victims receive too many breaths, breaths with too large a volume, or both. Rescuers should practice delivering the correct number of breaths during CPR. During CPR a lower than normal respiratory rate will maintain adequate oxygenation and carbon dioxide elimination because blood flow to the lungs is much lower than normal. Rescuers should avoid over ventilation because it increases intra-thoracic pressure, interferes with venous return of blood to the heart (so it prevents adequate refilling of the heart), and therefore decreases the cardiac output generated by subsequent chest compressions."¹

If you have taken a recertification class lately you most likely were exposed to this new method. But reading it and doing it is a bit different. Next time you perform ventilations during CPR really try and count in your head the seconds between each ventilation. It will seem like forever.

 My point here is that there has been a lot of research and design to make these changes and there is a reason why it is taught this way. We as providers have to adapt to these changes and although they became effective in 2005, we must make the effort to stop doing it the way we want in the field and do it the way it will benefit the patient most.  

Ventilators. While I am not an expert in using pre hospital ventilators or with long inter facility transports with patients on ventilators. I do want to touch on a few basic ideas.

 Physicians will tailor a ventilators settings to a specific patient and it will depend on factors that are too vast for me to go into in this short article. I have posted a picture below to give you an idea on varied settings you may see according to patient condition.

  You as the transport provider must be aware of the settings and monitor the patient. Many ventilators will give alarms and these may be unimportant or can be a sign of something going on with the patient that may need to be addressed. Don't be the one that turns off the alarm settings during transport only to find your patient has died during transport. Remember, the ventilator will still keep doing its job, even if the patient has no pulse.

 So as with everything else I try and stress in this series. Remember the basics and treat the patient, not the machine. You may have to use the ole BVM if the ventilator fails or the patient condition worsens.

 I personally feel that mechanical ventilation should be more understood by all pre hospital care providers. Both BLS and ALS alike are bound to come in contact with a vent patient sometime in their career. Maybe someday ventilators will be adopted as the preferred method of all pre hospital care respiratory assistance. Giving us a free set of hands during patient treatment. Think about it. In an ill or injured patient, variations in the CO2 level and blood chemistry can affect mortality and morbidity. It would be much better if patients receiving ventilatory support were ventilated at a controlled rate and volume. With a manual device, this is not possible. If you had a choice, the ability to control rate and volume of gases delivered would benefit your patient and improve their outcome.

 Someday.

 Very Basic. Well I know I have been drumming along with the "basics" theme in this article. I know that ventilations and ventilator use are basic.  Keep in mind that there are so many levels of providers out there, basic, advanced and everything in between. This along with experience levels makes it vital that we all try and remember the basics and follow the guidelines of research driven treatment modalities and manufacturer equipment use.  

Don't forget, not everyone in the field today did CPR back in 2003 and some of us used ventilators when they weighed as much as the stretcher. But I’m not mentioning any names.

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References

1 - Currents in Emergency Cardiovascular Care Volume 16 Number 4 Winter 2005-2006

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