Case Studies

Medical

Gas

Therapy

Case Study #1

Mr. Johnson arrives in the ER after a car accident. He is 25 years old and has no Hx of lung disease. His RR is 12 bpm and his Vt is approximately 1L/min. Mr. Johnson is on a non-rebreathing mask at approximately 70% FiO2. You obtain an ABG and the results are:

pH 7.39

pCO2 34

HCO3- 20

PaO2 200

To obtain a PaO2 of 100 mmHg on Mr. Johnson, what FiO2 would you need to put him on??

Formula

PaO2 (current) = PaO2 (desired)

FiO2(current) new FiO2 (X)

200 mmHg = 100 mmHg

.70 X

SOLVE FOR X

X = 35%

What device do I put him on to achieve approximately 35% FiO2??

Cannula – what flow?

4 LPM

Why??

4 lpm X 4% = 16%

16% + RA (21%) = 37%

What other device would work?

Simple Mask – delivers

35% to 50%

Partial Rebreather delivers

35% to 60%

Air Entrainment Mask (venti mask) delivers 24% - 50%

If I put Mr. Johnson on a venti mask, on the above FiO2 (35%), with a flow of 6 lpm, what would his total flow be??

Do the Magic Box to Obtain your Air:Oxygen Ratio

21 X

35

100 X

Do the Magic Box to Obtain your Air:Oxygen Ratio

21 65

35

100 14

Air:Oxygen Ratio

65:14 AIR O2

Air:Oxygen Ratio (Simplify)

5:1 AIR O2

Add them together:

5+1 = 6

Multiply by lpm at the flowmeter:

6X6=36

TOTAL FLOW AT THE PATIENT’S AIRWAY IS:

36 LPM

What is Mr. Johnson’s Ve?

Formula:

Ve = RR X Vt

Formula:

Ve = 12 X 1 (lpm)

Formula:

Ve = 12 lpm

CASE STUDY

#2

MRS.

WADE

Mrs. Wade is admitted to the ER with SOB. She has a Hx of smoking 4 packs of cigarettes a day for 40 years. She has been diagnosed with exacerbation of COPD.

What is Mrs. Wade’s pack year HX?

Pack Year HX Formula:

# of packs/day X #of years smoked

Mrs. Wade’s Pack Year HX:

4 X 40 = 160 pack years

With Mrs. Wade being SOB and considering her Hx, what would you do to relieve her SOB?

Put her on O2…

What kind of O2 device would you use?

Nasal Cannula (NC) at what flow??

Be safe with 2 lpm…

What will happen to Mrs. Wade if you put her on 100% FiO2 ??

She will lose her Respiratory Drive

What do you recommend now??

ABG??

Her ABG results are:

pH 7.35

PCO2 80

HCO3 33

PaO2 55

Why is her PaO2 so

low? What is the normal range for a patient who has COPD?

55-65 mmHg

Mrs. Wade is still short of breath. She said she needs more air. What is a safe FiO2 range for her??

To obtain a PaO2 of 65 on her, what do I need to increase my FiO2 to??

She is currently on 2 lpm NC.

What is her current FiO2??

4% X 2 lpm =8%

8% + RA (21%)=29%

She is on 29% FiO2 with a PaO2 of 55 mmHg.

Formula

PaO2 (current) = PaO2 (desired)

FiO2(current) new FiO2 (X)

55 mmHg = 65 mmHg

.29 X

SOLVE FOR X

X = 34%

Since we don’t want to go over 34%

FiO2, what device do we need to use?

We would put her on a venti mask to supply her with more flow at an FiO2 of 30% and a 3lpm from the flowmeter.

WHY??

What is her total flow??

Do the Magic Box to Obtain your Air:Oxygen Ratio

21 X

30

100 X

Do the Magic Box to Obtain your Air:Oxygen Ratio

21 70

30

100 9

AIR:O2 RATIO IS:

70:9OR

8:1

8 + 1 = 9

9 x 3 lpm = 18

Her total flow is

18 lpm

Pictures of Oxygen Devices and Patients…

THE

END