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Ep1: Hierarchy of O2 Delivery

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This podcast covers oxygen delivery methods available for our patients.  Methods are listed in order of least support to highest support.

 

CLICK HERE: To Download Chart

PODCAST TRANSCRIPT:

Hey everybody. This is Jon with Nrsng.com. Today I just want to talk about a couple of the different methods of oxygen delivery systems that we have available for our patients.

 

There will be a chart available for this at Nrsng.com/1. So basically when a patient comes in and is in need of oxygen delivery, we have a choice about how invasive we want to be with that delivery and how much oxygen a patient is going to need.

 

Delivery needs and everything is going to depend on the patient condition, how acidotic they may be, if they’re COPD and various other things that could determine the amount of oxygen that that patient might need. But today we’re just going to talk about the different kinds of oxygen delivery systems and just kind of the basics behind that.

 

So patient comes in, is in need of oxygen. The least invasive method of oxygen delivery is going to be the basic nasal cannula. Now, the nasal cannula is going to deliver just a very minimal amount more of FiO2 than basic atmospheric air. So we know that FiO2 in the basic atmospheric air, if you go outside today, the FiO2 is going to be about 23 percent.

 

Now if you give a patient a nasal cannula at one liter per minute, they’re going to get about 24 percent oxygen. Give them the two liters and they’re going to get about 28 percent.

 

Now with the nasal cannula, you can go all the way up to about six liters per minute and you wouldn’t want to go much above that just for damage to the nasal airways and everything. At six liters per minute, they’re going to get about 44 percent FiO2.

 

So really at one liter per minute, they’re starting at 24 percent and it goes up kind of four percent per liter and the most you want to give a patient on nasal cannula is six liters per minute.

 

After nasal cannula, the next option for a patient would be a simple face mask and all the simple face mask does, it really kind of just covers the nose and the mouth and you can start – if you have a patient who needs five liters per minute, that would be a good time to start the simple face mask.

 

You can go up to eight liters per minute with the simple face mask. With that, at eight liters per minute, they’re going to get about 60 percent FiO2. So the patient really just isn’t cutting it on a simple face mask.

 

There are kind of two options here. You’ve got a non-rebreather mask or a venturi mask. With a non-rebreather mask, it’s a face mask that is the one that has the bag at the end as well. What the non-rebreather does differently from the simple face mask is it prevents the patient from breathing in some of that expired CO2. So this would help the patient who’s really just not setting [0:03:15] [Phonetic] well despite being on a simple face mask.

 

So if they’re really just not setting [Phonetic] well even though they’re on a simple face mask, you would – you could throw them a non-rebreather, prevent them from taking any of that expired CO2 and you would start that at about six liters per minute. That would be 60percent FiO2. You can go all the way up to 10 liters per minute and at 10 liters per minute they’re going to be getting close to 100 percent.

 

So from there, you can do a venturi mask and the venturi mask is a simple face mask but it also has – on the oxygen delivery port, you also have a dial that allows you to provide a set rate of FiO2. So you can definitely get very precise FiO2 using the venturi mask.

 

So it’s kind of just a simple face mask and coming off on oxygen delivery portion. You can dial in a very precise set rate of FiO2.

 

Now there are a couple of non-invasive – from there, so the patient still just isn’t doing well. You’re most likely going to need some positive pressure ventilation.

 

The patient is awake and doing decently well. You have a couple of options for non-invasive positive pressure ventilation. So what positive pressure does is if they’re just really not able to get that air into the lungs and to oxygenate themselves, you can add pressure to the ventilation.

 

What this is going to do is it’s going to kind of force those alveoli open and in some ways keep the alveoli open on expiration as well. So if you are not wanting to intubate or trache the patient, then you have a couple of options for non-invasive pressure, positive pressure ventilation.

 

There are two options with that. There’s CPAP and BIPAP. So what CPAP does is it provides positive pressure during spontaneous press. So as the patient takes spontaneous press on their own, it’s going to provide just a small amount of positive pressure to make sure that they’re getting the alveoli open.

 

So with BIPAP, it’s biphasic, positive pressure. So on inspiration and expiration, it’s going to provide them with a positive pressure. So it’s going to provide that little bit of peep to make sure that they keep those alveoli open.

 

Now if neither of these are working, there are non-invasive methods. You can go to invasive methods for mechanical – to ventilate the patient. You have a couple of different options with that. There are many options. The two that we’re going to discus are basically SIMV and assist-control.

 

So if your patient just really – despite all these other efforts or the patient – so really the number one criteria for if your patient needs to be mechanically ventilated is if the physician and if you as the nurse assess that the patient needs to be mechanically ventilated.

 

If they’re not protecting their airway, if they’re somnolent, if they have a drastic acid-base imbalance, then these are all reasons to mechanically ventilate the patient.

 

So you have a couple of different settings. So mechanical ventilation just means that you are providing airway assistance inside the airway and there are many different modes for that. We’re going to discuss SIMV and assist-control.

 

So with SIMV ventilation, you have a preset title volume and rate. But between the ventilator and the patient, there’s a circuit that either allows the patient to take their own breaths and expire – or prevents them from kind of taking their own breaths.

 

With SIMV, the circuit remains open between mandatory breaths, so the patient can take additional breaths on their own. When the patient takes spontaneous breaths, it triggers the ventilator to not deliver one of its required – one of its [0:07:32] [Indiscernible]. So the patient’s tidal volume varies with those. So, basically anytime the patient takes a spontaneous breath, the ventilator is not going to deliver a breath and the patient can – and due to that, the ventilator is not going to deliver its tidal volume.

 

So this is usually recommended for patients who – as a weaning method for patients who are maybe trying to get off the ventilator or for patients who are doing a little bit better respiratory-wise, because it allows patients to kind of take their own breath.

 

So a lot of times what we do on our floor for example is we will start patients on a rate of about 12 on SIMV and as we see that they’re breathing over the vent or that they’re taking more breaths than the required breaths, then we will start to decrease the rate and it kind of allows the patient to take breaths on their own and manage their own tidal volumes, which is the amount of volume that they’re bringing in, the amount of volume that they’re bringing out.

 

If the patient is doing well with that, then we assume that we can start thinking about weaning from the ventilator. So above that, kind of is the assist control method.

 

So there’s – with the assist control, you have a preset tidal volume and rate and inspiratory effort is required to assist with spontaneous breaths. So if the patient does take a spontaneous breath, it’s going to deliver a set tidal volume no matter what.

 

So rather than allowing them to kind of determine their own tidal volumes, we’re pushing a specific amount of air in every time. It’s going to be at that set rate. So it’s not going to say, “OK, well, you’re breathing on your own. I’m not going to deliver a breath.” It’s going to set that rate no matter what.

 

So whether they’re taking breaths on their own or not, we’re going to push our set amount of tidal volume. We don’t want to keep our patients on a ventilator for too long. This kind of depends by the physician. Some physicians don’t want to keep the patient on for more than a couple of days. Others will go to two weeks, sometimes more.

 

From mechanical ventilation, from being intubated, what can happen next is that a patient can get trached.

Podcast Transcription

Hey everybody, this is Jon with NRSNG.com.

Today I just want to talk about a couple of the different methods of oxygen delivery

systems that we have available for our patients. There will be a chart available for this at

www.NRSNG.com/1.

Basically when a patient comes in and is in need of oxygen delivery, we have a choice

about how invasive we want to be with that delivery and how much oxygen a patient is

going to need. Delivery needs and everything is going to depend on the patient condition

– how acidotic they may be, if they’re COPD and various other things that can determine

the amount of oxygen that patient might need. But today we’re just going to talk about

the different kinds of oxygen delivery systems and just the basics behind that.

So a patient comes in and is in need of oxygen. The least invasive method of oxygen

delivery is going to be the basic nasal cannula. The nasal cannula is just going to deliver

a very minimal amount more FiO2 than basic atmospheric air. So we know that FiO2 in

the basic atmospheric air if you go outside today, the FiO2 is going to be about 23%. If

you give a patient nasal cannula at 1 liter per minute, they’re going to get about 24%

oxygen. If you bump that up to 2 liters they’re going to get about 28%. With nasal

cannula you can get all the way up to about 6 liters per minute – you wouldn’t want to go

much above that just for damage to the nasal airways and everything. At 6 liters per

minute, they’re going to get about 44% of FiO2. So really, at 1 liter per minute they’re

starting at 24% and it goes up 4% per liter. At the most you want to give a patient of

nasal cannula is 6 liters per minute.

After nasal cannula, the next option for a patient would be a simple facemask. All the

simple face mask does is really cover the nose and the mouth and you can start – if you

have a patient who needs 5 liters per minute, that would be a good time to start the

simple face mask. You can go up to 8 liters per minute with the simple facemask. With 8

liters per minute they’re going to get about 60% in FiO2. If a patient really isn’t cutting it

on a simple facemask, there are 2 options here: you got non-rebreather mask or venturi

mask. With the non-rebreather mask, it’s a facemask that has a bag at the end as well.

What the non-rebreather does differently from the simple facemask is it prevents the

patient from breathing in some of that expired CO 2 . So this would help the patient who is

really just not satin well [3:13], despite being on simple facemask. So if they’re really just

not satin well, even though they’re on a simple facemask, you could throw them on a

non-rebreather, prevent them from taking any of that expired CO 2 and you would start

that at about 6 liters per minute and that would be 60% FiO2. You can go all the way up

to 10 liters per minute and they’re going to be getting close to 100%. From there you can

do a venture mask. The venture mask is a simple facemask but it also has an oxygen

delivery port. You also have a dial that allows you to provide a set rate of FiO2 so you

can definitely get very precise FiO2 using the venture mask. It’s kind of just a simple

facemask and coming off of the oxygen delivery portion, you can dial in a very precise

set rate of FiO2.

From there, if a patient still isn’t doing well, you’re most likely going to need some

positive pressure ventilation. If the patient is awake and doing decently well, you have a

couple options for non-invasive positive pressure ventilation. What positive pressure

does is if they’re really not able to get that air into the lungs and to oxygenate

themselves, you can add pressure to the ventilation. What this is going to do is force

those alveoli open and in some ways keep the alveoli open on expiration as well. If you

are not want to intubate or trach the patient, then you have a couple options for non-

invasive positive pressure ventilation. There are two options with that: there’s CPAP and

BiPAP.

What CPAP does is it provides positive pressure during spontaneous breaths. So as a

patient takes spontaneous breaths on their own, it’s going to provide just a small amount

of positive pressure to make sure they’re getting the alveoli open. With BiPAP (biphasic

positive pressure) – on inspiration and expiration it’s going to provide them with a

positive pressure. So it’s going to provide that little bit of peep to make sure that they

keep those alveoli open.

If neither of these are working as non-invasive methods, you can go to invasive methods

to ventilate the patient. You have a couple different options with that. There are many

options; the two we’re going to discuss are basically SIMV and assist control. If your

patient despite all these other efforts – what really the number 1 criteria for if your patient

needs to be mechanically ventilated is if the physician and if you as the nurse asses that

the patient needs to be mechanically ventilated. If they’re not protecting their airway, if

they’re somnolent, if they have a drastic acid-base imbalance, then these are all reasons

to mechanically ventilate the patient.

You have a couple different settings. Mechanical ventilation just means that you are

providing airway assistance inside the airway and there are many different modes for

that. We’re going to discuss SIMV and assist control.

With SIMV ventilation, you have a preset title volume and rate but between the ventilator

and the patient is a circuit that either allows the patient to take their own breaths or

prevents them from taking their own breaths. With SIMV, the circuit remains open

between mandatory breaths so the patient can take additional breaths on their own.

When the patient takes spontaneous breaths, it triggers the ventilator to not deliver one

of it’s edits rate [7:32]. So the patient’s title volume varies with those. Basically anytime

the patient takes a spontaneous breath, the ventilator is not going to delivery a breath

and due to that, the ventilator is not going to deliver its title volume. This is usually

recommended for patients as a weaning method for patients who you are trying to get off

a ventilator or patients who are doing a little bit better respiratory wise because it allows

patients to take their own breaths. A lot of times what we do on our floor for example, is

we’ll start patients on rate of about 12 on SIMV and as we see that they’re breathing

over the vent or they’re taking more breaths than the required breaths, then we’ll start to

decrease the rate and it allows the patient to take breaths on their own and manage their

own title volumes which is the amount of volume that they’re bringing in and amount of

volume that they’re bringing out. And if the patient is doing well with that, then we

assume that we can start thinking about weaning from the ventilator.

Above that, is the assist control method. With assist control, you have a preset title

volume and rate and inspiratory effort is required to assist with spontaneous breaths. So

if the patient does take a spontaneous breath, it’s going to deliver a set title volume no

matter what. Rather than allowing them to determine their own title volumes, we’re

pushing a specific amount of air in every time and it’s going to be at that set rate. It’s not

going to say ‘okay, you’re breathing on your own, I’m not going to deliver breath’, it’s

going to set that rate no matter what. Whether they are taking breaths on their own or

not we’re going to push our set amount of title volume. And we don’t want to keep our

patients on a ventilator for too long. This depends on the physician – some physicians

don’t want to keep the patient on for more than a couple of days, others will go to two

weeks sometimes more. From mechanical ventilation, from being intubated, what can

happen next is that the patient can get trached. With being trached, what they do is they

insert an airway through the trachea, externally into the trachea and use a cannula to

access the airway. With that, you have TPs that can be connected to the ventilator so

you can still be mechanically ventilated with a trach. So the TPs can be connected to the

ventilator, you can put it on CPAP, you can put it on BiPAP, you can put it on SIMV,

assist control, anything, and you can achieve that access to the trachea that you need.

From that, the patient can go down to what is called a trach collar. So rather than then

being hooked to the ventilator or anything, they just have that open trachea access and

on top of that generally you put a kind of facemask just to deliver oxygen at a set liter

rate rather than connecting them to the ventilator and providing pressure support or

anything like that.

Those are the basics of some of the options available with oxygen delivery for our

patients. There’s a lot more involved with this – that just kind of gives you an overview of

some of the basics of the delivery methods.

Some terms to know in order to start understanding mechanical ventilation and

everything a little bit better, we’ll go over some of these real quick. Some terms to know

are going to be:

Pressure support: What is pressure support? Pressure support is a preset inspiratory

support level so when the patient is being delivered a breath or when a patient is taking

a breath we can deliver a support level. That can be set and that can be adjusted but

usually its very minimal amount of support – maybe 5-15 up to 20 of pressure support to

kind of push the air into their lungs.

PEEP: Another term to know is going to be PEEP, which is positive and expiratory

pressure. So pressure support is pressure delivered on inspiration. PEEP is pressure

delivered on expiration. As the patient begins to expire, that breath we can deliver a

small amount of pressure to kind of keep the alveoli open and usually that’s just set at 5

or so, so it’s much lower than what we’re delivering on our pressure support but it’s also

keeping the alveoli open. This is a great tool to make sure that the alveoli stay open but

it can also cause damage to the alveoli open by keeping that pressure in there all the

time and it requires that patients have to overcome that little bit of peep when they’re

trying to wean from the ventilator.

Peak inspiratory Pressure (P IP ): Another term is peak inspiratory pressure. That is the

airway pressure at the peak of inspiration. A lot of times when your ventilator is setting a

high pressure alarm, it’s setting off that high peak inspiratory pressure alarm. That can

be due to pinched tube or the patient holding volumes or the patient’s mucus in the

airway and things like that.

Minute Ventilation (VE): Another term to know is going to be minute ventilation and

that’s termed in VE; on your ventilator you’ll see it is VE. That’s going to be your title

volume [x] your rate. That’s going to be the amount of air being exchanged per minute.

There’s a couple of parameters were going to want to monitor as we are mechanically

ventilating our patients and we draw our blood gas. With these numbers we can kind of

determine how/what changes to make to the ventilator settings and things like that. You

got your PaCO2, SaO2, and PaO2. So these are all arterial measurements of gas

distribution within the blood. Basically, oxygen is going to be found in the blood in two

different ways – you’re going to have an amount of oxygen that is dissolved in plasma,

and that’s going to be about 3% of the total oxygen volume within the body and you’re

going to have the remainder of oxygen is going to be bound to hemoglobin.

SaO2 is a percent of oxygen that is saturated with hemoglobin, and you want that to be

between 95% and 100%. You want your oxygen to be saturated 95% to 100% with

hemoglobin as it’s being delivered to the tissues.

Then you have your PaO2, which is the amount of oxygen dissolved in the plasma. This

is oxygen – the partial pressure of oxygen within the blood plasma and you want that to

be between 80-100. Generally, when a patient is ventilated, your PaO2 is going to be a

bit higher, possibly closer to 200 or more and that makes sense because we’re giving

them an amount of an FiO2 that is generally double what they’re receiving from

atmospheric air, so they’re going to have a bit more oxygen dissolved within the plasma.

Then you have your PaCO2, which is the amount of CO 2 that’s dissolved in the plasma.

It’s the partial pressure of arterial CO 2 and that number is going to be 35-45. This is a

good way to determine respiratory status. Now, obviously, the CO 2 is much higher than

45 or if it’s higher than 45 at all generally, in very layman’s terms we’re basically looking

at a respiratory acidosis state depending on where the PH is and everything. If the CO 2

is lower than 35 then we’re looking at a respiratory alkalosis state assuming that we’re

not dealing with some sort of metabolic compensation. So if your PH is low and your CO 2

is greater than 45, we’re dealing with respiratory acidosis and we are looking at patient

that is retaining CO 2 and that is generally a good indicator that you need to adjust your

rate on your ventilator or the patient possibly needs to be mechanically ventilated to help

get rid of that CO 2 . So the patient possibly isn’t breathing at a high enough rate or we’re

delivering at a setting that they are not able to get rid of that CO 2 .

Those are kind of just a basic introduction to oxygen delivery and some of the terms that

are important to know with your ventilator and with your oxygen delivery systems. This

will be available on NRSNG.com/1, there will be a chart that you can download and

make notes on regarding some of the oxygen delivery systems and their advantages

and disadvantages.

Thanks for listening, and we’ll talk to you soon.

Date Published - Oct 24, 2014
Date Modified - Feb 16, 2018

Jon Haws RN

Written by Jon Haws RN

Jon Haws RN began his nursing career at a Level I Trauma ICU in DFW working as a code team nurse, charge nurse, and preceptor. Frustrated with the nursing education process, Jon started NRSNG in 2014 with a desire to provide tools and confidence to nursing students around the globe. When he's not busting out content for NRSNG, Jon enjoys spending time with his two kids and wife.

6 Comments

  1. Yana

    Thank you! But there is no chart anywhere. Not at Nrsng.com/1 and no at “CLICK HERE: To Download Chart”.

    Reply
  2. Fayne

    Hi, Thanks for this podcast. But when I looked for the chart in nrsng.com/1, it directed me to the EKG Interpretation.

    Reply
  3. BJ

    Hey Jon,
    I am a pediatric RN in ED. Do you have any access or contacts for study guide for the Emergency Pediatric Nurse Certification. I already have the book. But need stream video,or dvd’s visual study material.

    Reply
    • Jon RN CCRN

      Jon RN CCRN

      I don’t have anything tailored specifically to that test. We are beginning to put together more videos but they may not be available until after you have taken your test!

      Reply