Oxygenation“Part of the Dumb-It-Down Lecture Series”

How do we support a patient’s pulmonary function?• Oxygenation• Nasal Cannula• Mask/Venti-Mask• Partial Non-Rebreather/Full Non-Rebreather• Supplemental O2 given through a device helping maintain

ventilation• Ventilation• Ambu-bag• Mouth to Mouth• BiPAP/CPAP• Invasive Mechanical Ventilation

The Most Misunderstood Equipment in the Hospital…

What is the FiO2 of a Nasal Cannula?

Guess-ta-mation

Why isn’t 100% FiO2 Achieved?

Why isn’t 100% FiO2 Achieved?• Normal Flow Rate is 25L/min, so if a nasal cannula is delivering

2L/min…

FiO2 = [(% of flow from NC) + (% of flow from RA)]/ total flow

FiO2 = [(2)(1) + (23)(0.21)]/25 = 0.27

Why isn’t 100% FiO2 Achieved?

But the percent of flow obtained from the nasal cannula is variable…

Monitoring Oxygenation

Pulse Oximetry

When is Pulse Oximetry Wrong?• Carbon Dioxide/Cyanide (falsely high)• Nail Polish (falsely low)• Methemoglobinemia (falsely low)• Hypoxia (falsely low)• Hypotension (wont pick up arterial pulsations)

Pulse Oximetry is not PaO2

The 40-50-60, 70-80-90 Rule:

PaO2 SaO2

40 70

50 80

60 90

Pulse Oximetry is not PaO2

Pulse Oximetry is not PaO2