Unit 4.1: Supplemental Unit 4.1: Supplemental Oxygen Therapy Case Oxygen Therapy Case studiesstudies by Elizabeth Kelley Buzbee AAS, by Elizabeth Kelley Buzbee AAS, RRT-NPS, RCPRRT-NPS, RCP

Case study #1 Case study #1

Mr. Hall is a 45 year old WM who Mr. Hall is a 45 year old WM who presents in the ER with rapid shallow presents in the ER with rapid shallow breathing. He was standing in his breathing. He was standing in his backyard when the chemical plant backyard when the chemical plant exploded and started to burn. exploded and started to burn.

How do you want to assess this person?How do you want to assess this person?

Answer:Answer:

1.1. Do vital signs for s/s of respiratory Do vital signs for s/s of respiratory distressdistress

2.2. Check his state of consciousnessCheck his state of consciousness3.3. Check his work of breathingCheck his work of breathing4.4. Listen to breath soundsListen to breath sounds5.5. Perform pulse oximetry but remember Perform pulse oximetry but remember

that it will not pick up HbC0that it will not pick up HbC06.6. Do a co-oximetry readingDo a co-oximetry reading

1.1. vital signs : HR 140 respiratory rate: 33 bpmvital signs : HR 140 respiratory rate: 33 bpm

2.2. He is anxious but understands your questionsHe is anxious but understands your questions

3.3. He is retracting and has nasal flaringHe is retracting and has nasal flaring

4.4. His breath sounds show diffuse crackles in all His breath sounds show diffuse crackles in all lobes consistent with chemical pneumonitislobes consistent with chemical pneumonitis

5.5. Sp02 is 88%Sp02 is 88%

6.6. HbC0 is wnlHbC0 is wnl

What do you want to do with this patient?What do you want to do with this patient?

answeranswer

Start him on supplementary 02 to treat Start him on supplementary 02 to treat the s/s of hypoxemia the s/s of hypoxemia

What 02 device do you select?What 02 device do you select?

Answer:Answer:

Without any history, it would be safe to Without any history, it would be safe to start him on 1-2 lpm nasal cannula start him on 1-2 lpm nasal cannula

Before you place this patient on 2 lpm Before you place this patient on 2 lpm nasal cannula, to make sure the device is nasal cannula, to make sure the device is working correctly you do what? working correctly you do what?

Answer:Answer: You look at the flow meter; is the flow indicator You look at the flow meter; is the flow indicator

in the middle of the ball?in the middle of the ball? You feel the flow coming out of the device on You feel the flow coming out of the device on

the back of your handthe back of your hand You look at the bubbles coming from the You look at the bubbles coming from the

humidifier humidifier You check the connections:You check the connections:

Between the wall connection and the flow meterBetween the wall connection and the flow meter between the humidifier and flow meter. between the humidifier and flow meter. Between the humidifier and the 02 lineBetween the humidifier and the 02 line

You put the nasal cannula in Mr. Hall’s You put the nasal cannula in Mr. Hall’s nose and warn him about what?nose and warn him about what?

Answer:Answer:

1.1. Fire hazards of 02Fire hazards of 02

2.2. Calling you if he feels the 02 is Calling you if he feels the 02 is disconnected or that he feels short of disconnected or that he feels short of breathbreath

What is the approximate Fi02 of this What is the approximate Fi02 of this device at this flow rate?device at this flow rate?

Answer:Answer:

Fi02 of nasal cannula can be Fi02 of nasal cannula can be estimatedestimated by adding 4% per each liter of flow to by adding 4% per each liter of flow to base line of 20%. base line of 20%.

2 lpm = [2 x 4] + 20%2 lpm = [2 x 4] + 20% 2 lpm = 28% Fi022 lpm = 28% Fi02

If he starts breathing any faster, what If he starts breathing any faster, what might happen to this estimated Fi02?might happen to this estimated Fi02?

Answer:Answer:

The Fi02 will drop as his respiratory rate The Fi02 will drop as his respiratory rate rises and more air is entrained.rises and more air is entrained.

How do you assess the effectiveness of How do you assess the effectiveness of this device?this device?

Answer:Answer:

1.1. Redo vital signsRedo vital signs

2.2. Redo pulse oximetryRedo pulse oximetry

3.3. Reassess him for increased work of Reassess him for increased work of breathingbreathing

Is this patient at risk for 02 toxicity?Is this patient at risk for 02 toxicity?

Answer:Answer:

Not at this flow rateNot at this flow rate

Is this patient at risk for 02 induced Is this patient at risk for 02 induced hypoventilation?hypoventilation?

Answer:Answer:

He have no history that indicated he has He have no history that indicated he has chronic hypoxemia nor that he breathes chronic hypoxemia nor that he breathes on a hypoxic drive, but at this flow rate, on a hypoxic drive, but at this flow rate, he is safe enoughhe is safe enough

After 10 minute on 2 lpm nasal cannula, After 10 minute on 2 lpm nasal cannula, Mr. Hall still is breathing at a rate of 33 Mr. Hall still is breathing at a rate of 33 bpm.bpm.

His Sp02 is still 88% and his HR is still His Sp02 is still 88% and his HR is still 130 bpm130 bpm

He is still retracting and flaring on 2 lpm He is still retracting and flaring on 2 lpm nasal cannulanasal cannula

What do you do?What do you do?

Answer:Answer:

Increase his 02 from 2 lpm to 3 lpmIncrease his 02 from 2 lpm to 3 lpm

How do you assess the effectiveness of 3 How do you assess the effectiveness of 3 lpm nasal cannula?lpm nasal cannula?

Answer:Answer:

1.1. Repeat Sp02Repeat Sp02

2.2. Reassess the vital signsReassess the vital signs

3.3. Reassess the work of breathingReassess the work of breathing

You have increased Mr. Hall’s nasal You have increased Mr. Hall’s nasal cannula from 5 lpm to 6 lpm without any cannula from 5 lpm to 6 lpm without any change in his appearance. change in his appearance.

What do you suggest now?What do you suggest now?

Answer:Answer:

Do an arterial blood gas to make sure Do an arterial blood gas to make sure that he doesn’t need more than 02that he doesn’t need more than 02

From the blood gas, calculate the Fi02 he From the blood gas, calculate the Fi02 he needsneeds

You increase the flow rate a few times You increase the flow rate a few times and when you get to 6 lpm you switch to and when you get to 6 lpm you switch to a simple mask.a simple mask.

Why?Why?

Answer:Answer:

1.1. The flow rate at 6 lpm via the cannula The flow rate at 6 lpm via the cannula may not be that comfortablemay not be that comfortable

2.2. The mask holds the 02 in the reservoir The mask holds the 02 in the reservoir so that the patient gets more 02 and so that the patient gets more 02 and less entrained air. less entrained air.

What is the Fi02 of this device?What is the Fi02 of this device?

answeranswer

30% - 60% at flow rates of 5-12 lpm30% - 60% at flow rates of 5-12 lpm

The doctor looks at the Sp02 of 89% and The doctor looks at the Sp02 of 89% and orders him placed on 50% entrainment orders him placed on 50% entrainment mask.mask.

What is the total flow rate if the flow What is the total flow rate if the flow meter is set at 6 lpm? meter is set at 6 lpm?

Answer:Answer:

Based on the magic box at 50% there is Based on the magic box at 50% there is 1.6 lpm air entrained per liter of 021.6 lpm air entrained per liter of 02

6 lpm 02 + [ 6 x 1.6] = 6 lpm 02 + [ 6 x 1.6] =

6 + 9.6 =6 + 9.6 =

15.5 lpm is the total flow going to this 15.5 lpm is the total flow going to this patientpatient

If Mr. Hall’s Ve is 14 lpm, is this flow rate If Mr. Hall’s Ve is 14 lpm, is this flow rate adequate for him?adequate for him?

Answer:Answer:

No, for a high flow system, he needs his No, for a high flow system, he needs his Ve x [i+e] usual I:E breathing Ve x [i+e] usual I:E breathing spontaneously is 1:1 or 1:1.5 spontaneously is 1:1 or 1:1.5

So 14 x [1+1] = 28 lpmSo 14 x [1+1] = 28 lpm He needs a total flow of 28 lpmHe needs a total flow of 28 lpm What can we do?What can we do?

Answer:Answer:

Increase the flow meter from 6 lpm to 12 Increase the flow meter from 6 lpm to 12 lpm to increase the total flow rate going lpm to increase the total flow rate going to this patientto this patient

You get an ABG on 12 lpm 50% You get an ABG on 12 lpm 50% entrainment mask and the Pa02 is 45 entrainment mask and the Pa02 is 45 mmHg.mmHg.

What do you do?What do you do?

Answer:Answer: Based on the Pa02:Fi02 formula, you need to Based on the Pa02:Fi02 formula, you need to

increase the Fi02 from 6 lpm simple mask to increase the Fi02 from 6 lpm simple mask to 88%88%

Pa02 : Fi02 as Pa02 Pa02 : Fi02 as Pa02 you wantyou want :Fi02 :Fi02 you needyou need 45: 50% as 80 : x45: 50% as 80 : x

45 x45 x = = .5 x 80.5 x 804545 4545

X = .88X = .88Or 88% Fi02 needed is to get Pa02 about 80 Or 88% Fi02 needed is to get Pa02 about 80

mmHg mmHg

Identify the supplementary 02 device you Identify the supplementary 02 device you need to deliver 88%need to deliver 88%

Answer:Answer:

To get an Fi02 of 88% you need to switch To get an Fi02 of 88% you need to switch to a non-rebreather maskto a non-rebreather mask

How long can this patient stay on this How long can this patient stay on this device without suffering side effects?device without suffering side effects?

Answer:Answer:

He is at risk of getting 02 toxicity if he He is at risk of getting 02 toxicity if he wears Fi02 100% for 24 hourswears Fi02 100% for 24 hours

And he can get into trouble with Fi02 And he can get into trouble with Fi02 70% within 2 days so he’s got about a 70% within 2 days so he’s got about a day to get off this 02.day to get off this 02.

What can you do under these What can you do under these circumstances to get him off NRM?circumstances to get him off NRM?

Answer:Answer:

He is in refractory hypoxemia. We need He is in refractory hypoxemia. We need to wean his Fi02 back down to less than to wean his Fi02 back down to less than 50%. If we cannot do this-- then we need 50%. If we cannot do this-- then we need to consider other options such as to consider other options such as mechanical ventilation or CPAP. For mechanical ventilation or CPAP. For example we might put him on CPAP so example we might put him on CPAP so that we can decrease his Fi02 below that we can decrease his Fi02 below 50%50%

What might we have done in the What might we have done in the beginning of this case study that would beginning of this case study that would have avoided a lot of changes in have avoided a lot of changes in therapy?therapy?

Answer:Answer:

1.1. We probably needed to get the ABG We probably needed to get the ABG after the first 2 lpm nasal cannula didn’t after the first 2 lpm nasal cannula didn’t work.work.

2.2. Also, in smoke inhalation, going straight Also, in smoke inhalation, going straight to a NRM is frequently the first choice to a NRM is frequently the first choice because [1] the patient may have CO because [1] the patient may have CO poisoning [2] persons in chemical poisoning [2] persons in chemical pneumonitis are frequently in refractory pneumonitis are frequently in refractory hypoxemiahypoxemia