Hello and welcome to the Zero to Finals podcast.

My name is Tom and in this episode I'm going to be talking to you about arterial blood

gases or ABGs.

And you can find written notes on this topic at zero tofinals.com slash arterial blood gases or in the respiratory section of the second

edition of the 0.2 finals medicine book. So let's get straight into it. Artereal blood gases or

ABGs are commonly used to monitor acute respiratory conditions,

especially where there's a risk of type 2 respiratory failure,

for example, chronic obstructive pulmonary disease or COPD.

ABGs give helpful information about the acid-based balance,

the blood gases, oxygen and carbon dioxide in the blood, bicarbonate,

hemoglobin and the electrolytes.

Let's start with the normal values.

On an arterial blood gas, the normal values for pH are 7.35 to 7.45.

PAO2, which is the oxygen in the blood, is from 10.7 to 13.3 KPA.

P.A.O.2, or carbon dioxide in the blood, is from 4.7 to 6.0 KPA. H.O.3, or bicarbonate, is from 22 to 26 millimoles per liter.

Base excess is from minus 2 to plus 2, and lactate is from 0.5 to 1 millimoles per liter.

Let's talk about respiratory failure.

PAO2 is the partial pressure of oxygen, which is the amount of oxygen dissolved in the blood.

A low P.A.O.2 indicates hypoxia, or low oxygen.

FI.O.2 is the fraction of inhaled oxygen.

Room air has an FI.O.2 of 21%, meaning the oxygen concentration in room air is 21%.

Venturi masks can be used to control the FI.O.2 accurately. Other masks only give an approximate FIO2.

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