Hello and welcome to the Zero to Finals podcast.

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

And you can find written notes on this topic at zero tofinals.com slash arterial blood gases

or in the anesthetics and ICU section of the Zero to Finals Surgery Book.

So let's get straight into it.

Arterial blood gases or ABGs are very commonly used to assess patients with respiratory failure

and for monitoring in the intensive care unit.

An arterial blood sample is required for analysis, and this involves inserting a needle

either into the radial or the femoral artery.

Arterial lines make it very easy to obtain an arterial blood sample, and arterial lines are

very common in the intensive care unit.

ABGs give useful information about the acid-based balance, the blood gases, for example, the oxygen

and carbon dioxide in the blood, the bicarbonate, the lactate, the hemoglobin, and the electrolytes.

Let's go through some basic normal values.

The normal values for pH, or the acidity of the blood, are 7.35 to 7.45.

The normal values for the PA-O-2, or the partial pressure of oxygen, which is the oxygen that's

dissolved in the blood, are 10.7 to 13.3 KPA. The normal values for P.A. CO2, or the carbon dioxide

in the blood, are 4.7 to 6.0 KPA.

The normal values for bicarbonate or H.C.O.3 are 22 to 28 millimoles per liter.

The normal values for the base excess are minus 2 to plus 2 and the normal values for lactate are 0.5 to 1 millimol per litre.

Let's talk about respiratory failure. The first step when you're analysing an ABG is to determine if the patient is hypoxic.

Ipoxia indicates respiratory failure.

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