Transcript Unit 4.1: Supplemental Oxygen Therapy Case studies

Unit 4.1: Supplemental
Oxygen Therapy Case
studies
by Elizabeth Kelley Buzbee AAS,
RRT-NPS, RCP
Case study #1
 Mr. Hall is a 45 year old WM who
presents in the ER with rapid shallow
breathing. He was standing in his
backyard when the chemical plant
exploded and started to burn.
 How do you want to assess this person?
Answer:
1. Do vital signs for s/s of respiratory
distress
2. Check his state of consciousness
3. Check his work of breathing
4. Listen to breath sounds
5. Perform pulse oximetry but remember
that it will not pick up HbC0
6. Do a co-oximetry reading
1.
2.
3.
4.
vital signs : HR 140 respiratory rate: 33 bpm
He is anxious but understands your questions
He is retracting and has nasal flaring
His breath sounds show diffuse crackles in all
lobes consistent with chemical pneumonitis
5. Sp02 is 88%
6. HbC0 is wnl
What do you want to do with this patient?
answer
 Start him on supplementary 02 to treat
the s/s of hypoxemia
 What 02 device do you select?
Answer:
 Without any history, it would be safe to
start him on 1-2 lpm nasal cannula
 Before you place this patient on 2 lpm
nasal cannula, to make sure the device is
working correctly you do what?
Answer:
 You look at the flow meter; is the flow indicator
in the middle of the ball?
 You feel the flow coming out of the device on
the back of your hand
 You look at the bubbles coming from the
humidifier
 You check the connections:
 Between the wall connection and the flow meter
 between the humidifier and flow meter.
 Between the humidifier and the 02 line
 You put the nasal cannula in Mr. Hall’s
nose and warn him about what?
Answer:
1. Fire hazards of 02
2. Calling you if he feels the 02 is
disconnected or that he feels short of
breath
 What is the approximate Fi02 of this
device at this flow rate?
Answer:
 Fi02 of nasal cannula can be estimated
by adding 4% per each liter of flow to
base line of 20%.
 2 lpm = [2 x 4] + 20%
 2 lpm = 28% Fi02
 If he starts breathing any faster, what
might happen to this estimated Fi02?
Answer:
 The Fi02 will drop as his respiratory rate
rises and more air is entrained.
 How do you assess the effectiveness of
this device?
Answer:
1. Redo vital signs
2. Redo pulse oximetry
3. Reassess him for increased work of
breathing
 Is this patient at risk for 02 toxicity?
Answer:
 Not at this flow rate
 Is this patient at risk for 02 induced
hypoventilation?
Answer:
 He have no history that indicated he has
chronic hypoxemia nor that he breathes
on a hypoxic drive, but at this flow rate,
he is safe enough
 After 10 minute on 2 lpm nasal cannula,
Mr. Hall still is breathing at a rate of 33
bpm.
 His Sp02 is still 88% and his HR is still
130 bpm
 He is still retracting and flaring on 2 lpm
nasal cannula
 What do you do?
Answer:
 Increase his 02 from 2 lpm to 3 lpm
 How do you assess the effectiveness of 3
lpm nasal cannula?
Answer:
1. Repeat Sp02
2. Reassess the vital signs
3. Reassess the work of breathing
 You have increased Mr. Hall’s nasal
cannula from 5 lpm to 6 lpm without any
change in his appearance.
 What do you suggest now?
Answer:
 Do an arterial blood gas to make sure
that he doesn’t need more than 02
 From the blood gas, calculate the Fi02 he
needs
 You increase the flow rate a few times
and when you get to 6 lpm you switch to
a simple mask.
 Why?
Answer:
1. The flow rate at 6 lpm via the cannula
may not be that comfortable
2. The mask holds the 02 in the reservoir
so that the patient gets more 02 and
less entrained air.
 What is the Fi02 of this device?
answer
 30% - 60% at flow rates of 5-12 lpm
 The doctor looks at the Sp02 of 89% and
orders him placed on 50% entrainment
mask.
 What is the total flow rate if the flow
meter is set at 6 lpm?
Answer:
 Based on the magic box at 50% there is
1.6 lpm air entrained per liter of 02
6 lpm 02 + [ 6 x 1.6] =
6 + 9.6 =
15.5 lpm is the total flow going to this
patient
 If Mr. Hall’s Ve is 14 lpm, is this flow rate
adequate for him?
Answer:
 No, for a high flow system, he needs his
Ve x [i+e] usual I:E breathing
spontaneously is 1:1 or 1:1.5
 So 14 x [1+1] = 28 lpm
 He needs a total flow of 28 lpm
 What can we do?
Answer:
 Increase the flow meter from 6 lpm to 12
lpm to increase the total flow rate going
to this patient
 You get an ABG on 12 lpm 50%
entrainment mask and the Pa02 is 45
mmHg.
 What do you do?
Answer:

Based on the Pa02:Fi02 formula, you need to
increase the Fi02 from 6 lpm simple mask to
88%
Pa02 : Fi02 as Pa02 you want :Fi02 you need
45: 50% as 80 : x
45 x = .5 x 80
45
45
X = .88
Or 88% Fi02 needed is to get Pa02 about 80
mmHg
 Identify the supplementary 02 device you
need to deliver 88%
Answer:
 To get an Fi02 of 88% you need to switch
to a non-rebreather mask
 How long can this patient stay on this
device without suffering side effects?
Answer:
 He is at risk of getting 02 toxicity if he
wears Fi02 100% for 24 hours
 And he can get into trouble with Fi02
70% within 2 days so he’s got about a
day to get off this 02.
 What can you do under these
circumstances to get him off NRM?
Answer:
 He is in refractory hypoxemia. We need
to wean his Fi02 back down to less than
50%. If we cannot do this-- then we need
to consider other options such as
mechanical ventilation or CPAP. For
example we might put him on CPAP so
that we can decrease his Fi02 below
50%
 What might we have done in the
beginning of this case study that would
have avoided a lot of changes in
therapy?
Answer:
1. We probably needed to get the ABG
after the first 2 lpm nasal cannula didn’t
work.
2. Also, in smoke inhalation, going straight
to a NRM is frequently the first choice
because [1] the patient may have CO
poisoning [2] persons in chemical
pneumonitis are frequently in refractory
hypoxemia