Blood Gas Analysis Flashcards

Comprehensive practice flashcards covering arterial, capillary, and venous blood gas collection, site selection, equipment, and acid-base disorders.

What specific parameters are measured in a blood gas analysis?

$pH$, $pO_2$, $pCO_2$, $HCO_3^-$, and $\%SatO_2$

What are the three types of blood gas samples?

Arterial blood gas (ABG), Capillary blood gas (CBG), and Venous blood gas (VBG)

Why is arterial blood preferred for testing arterial blood gases (ABGs), ammonia, and lactic acid?

Arterial blood is rich in oxygen and electrolytes and has a uniform composition throughout the body.

What do $pO_2$ and $pCO_2$ express in the context of blood gas testing?

$pO_2$ expresses the partial pressure of oxygen, and $pCO_2$ expresses the partial pressure of carbon dioxide.

What condition is indicated by a low $pO_2$ and a high $pCO_2$?

It indicates that gas exchange in the lungs is impaired and body tissues are not receiving adequate oxygen.

Which cleaning agents are used to prep an arterial puncture site to minimize the risk of infection?

Alcohol and either povidone-iodine or chlorhexidine.

What anesthetic may be used to lessen pain during arterial puncture, and in what amount?

$0.5\,mL$ of lidocaine.

What are the typical needle specifications for arterial collection?

A $21$ or $22\,g$ needle; $1$ inch for the brachial or radial artery, or $1.5$ inches for the femoral artery.

Why is a luer tip used on the syringe after an arterial collection?

To cover the syringe top once the needle is removed, preventing air from reaching the specimen and altering gas concentrations.

Why is a thermometer required for the equipment list of an arterial puncture?

The solubility of gases in blood is temperature dependent.

What is the purpose of the Modified Allen's test?

To assess collateral circulation by ensuring the hand receives blood from more than one artery.

During a Modified Allen's test, how many seconds should it take for color to return to the hand to imply adequate circulation?

Within $15$ seconds.

Identify the advantages and the main disadvantage of the radial artery site.

Advantages: easily accessible, good collateral circulation, easy to compress. Disadvantage: hard to locate due to small size.

What is the significant risk associated with puncturing the brachial artery?

Significant risk of puncturing the median nerve.

When is the femoral artery most commonly used for blood gas collection?

When cardiac output is low.

What is an arteriospasm?

A spontaneous constriction of an artery in response to pain that may prevent oxygen from reaching the site.

What are the two most significant sources of sampling error for blood gas analysis?

Failure to deliver the sample to the lab immediately and lack of storage on ice if delivery is delayed.

What is a 'flea' and how is it used in capillary blood gas (CBG) collection?

A flea is a metal filing inserted into the tube before collection, used with a magnet to mix the specimen.

What type of vacutainer is used for collecting venous blood gases (VBG)?

A lithium heparin (dark green) vacutainer.

Define Metabolic Acidosis based on $pH$ and bicarbonate levels.

$pH < 7.35$ and a bicarbonate deficit.

What characterizes Respiratory Alkalosis?

$pH > 7.45$ and an excessive loss of $CO_2$ (often caused by hyperventilation or ventilators).