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:

pH7.39 pCO 2 34 HCO PaO 2 200

To obtain a PaO 2 of 100 mmHg on Mr. Johnson, what FiO2 would you need to put him on??

Formula PaO 2 ( current ) = PaO 2 (desired) FiO 2(current) new FiO 2 (X )

200 mmHg = 100 mmHg.70 X SOLVE FOR X

X = 35%

What device do I put him on to achieve approximately 35% FiO 2 ??

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 FiO 2 (35%), with a flow of 6 lpm, what would his total flow be??

Do the Magic Box to Obtain your Air:Oxygen Ratio 21X X

Do the Magic Box to Obtain your Air:Oxygen Ratio

Air:Oxygen Ratio 65:14 AIRO 2

Air:Oxygen Ratio (Simplify) 5:1 AIRO 2

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 O 2…

What kind of O 2 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% FiO 2 ??

She will lose her Respiratory Drive

What do you recommend now??

ABG??

H er ABG results are: pH 7.35 PCO 2 80 HCO 3 33 PaO255

Why is her PaO 2 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 PaO 2 of 65 on her, what do I need to increase my FiO 2 to??

She is currently on 2 lpm NC. What is her current FiO 2 ??

4% X 2 lpm =8% 8% + RA (21%)=29% She is on 29% FiO 2 with a PaO 2 of 55 mmHg.

Formula PaO 2 ( current ) = PaO 2 (desired) FiO 2(current) new FiO 2 (X )

55 mmHg = 65 mmHg.29 X SOLVE FOR X

X = 34%

Since we don’t want to go over 34% FiO 2, 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 21X X

Do the Magic Box to Obtain your Air:Oxygen Ratio

AIR:O 2 RATIO IS: 70:9 OR 8:1

8 + 1 = 9 9 x 3 lpm = 18

Her total flow is 18 lpm

Pictures of Oxygen Devices and Patients…

THE END