15. O2 THERAPY

Question 1

What is the equation of O2 delivery (DO2)?

Answer 1

DO2 = Q × CaO2
Where Q = cardiac output and CaO2 = arterial oxygen content and is calculated as:
CaO2 = [1.34(ml O2/g) × SaO2 (%) × Hemoglobin (g/dl)] + [PaO2(mm Hg) × 0.003 (ml O2/dl/mm Hg)]

Question 2

When is O2 supplementation recommended?

Answer 2

PaO2 less than 70 mm Hg or SaO2 less than 93% on room air or if the patient’s effort at breathing is increased and at risk of respiratory fatigue.
Cardiovascular instability or anemia in an effort to prevent tissue hypoxia

Question 3

How to place a nasal oxygen catheter?

Answer 3

the patient’s nasal passage should be anesthetized first with topical 2% lidocaine or proparacaine. Next, the tip of a 5- to 10-French (depending on patient size) red rubber or polypropylene catheter should be premeasured. To approximate the distance to advance a nasal oxygen catheter, it should be premeasured from the nose to the level of the lateral canthus of the eye and the distance marked on the tube using a permanent marker.
The tip of the tube is lubricated, and the tube is gently inserted into the ventral nasal meatus to the level of the mark on the tube. To enter the ventral meatus, it may be necessary to angle the tube ventromedially when inserted. The tube can be secured adjacent to the nostril with suture or staples

Question 4

What flow rate would you use with a nasal catheter? And what FIO2 does it provide?

Answer 4

Flow rates of 50 to 150 ml/kg/min can provide 30% to 70% FiO2

Question 5

T or F: Total oxygen flow rates provide higher tracheal FiO2 when provided through two nasal catheters.

Answer 5

F: Total oxygen flow rates provide similar tracheal FiO2 when provided through one catheter or divided between two nasal catheters.

Question 6

What is the recommended starting flow rate in clinical patients when using High-Flow?

Answer 6

0.4–2.0 L/kg/min for optimal tolerance

Question 7

2 techniques of intra-tracheal catheter are describes, have you used it?

Answer 7

They don’t talk about the procedure that we do here.

Question 8

Regarding O2 toxicity, what is the “general rule” about FiO2 levels and length of O2 treatment to avoid toxicity?

Answer 8

As a general rule, an FiO2 level of more than 50% should not be administered for longer than 24 to 72 hours to avoid pulmonary oxygen toxicity.