Arterial Blood Gases

Question 1

What does an ABG look at?

Answer 1

Blood test which evaluates acid base balances

Question 2

What artery is an ABG typically taken from?

Answer 2

Radial artery → or special monitoring cath (arterial line)

Question 3

How do you perform an Allen’s test?

Answer 3

Occlude both radial and ulnar arteries and instruct patient to repeat a fist motion. First let go of ulnar artery and watch for perfusion of blood to the hand (should turn from white back to normal color)

Question 4

What does Allen’s test check?

Answer 4

Patency of the artery

Question 5

What angle should the needle be inserted when performing an ABG?

Answer 5

45 degree angle until you get a flashback of blood into the needle

Question 6

Case study 1:

AJ, 28, comes to the ED with acute shortness of breath and pain on her right side. She smokes and recently started taking birth control pills. The blood pressure is 140/90; pulse is 120 bpm; & respiratory rate is 40 rpm. Her ABG values are as follows → pH: 7.55; PaCO2: 27 mmHg; PaO2: 60 mmHg; HCO3: 24 mmHg; SaO2: 88%. What is her acid base imbalance?

Answer 6

Respiratory Alkalosis

Question 7

Case Study 2:

MK, 22, is brought to the ED for an overdose of Diazepam. They are unconscious and have a respiratory rate of 5 to 8 rpm. The ABG are as follows: pH: 7.25; PaCO2: 61 mmHg; PaO2: 76 mmHg; HCO3: 26 mmHg; SaO2: 89%. What is the acid base imbalance? Why is it occurring?

Answer 7

Respiratory Acidosis → occurring as a result of the drug overdose & the hypoventilation the patient is experiencing. The diazepam is a CNS depressant so they are not blowing off their CO2 instead they are retaining it leading to respiratory acidosis.

Question 8

Case Study 3:

KB, 26 y/o with type 1 DM and hasn’t been feeling well for the last 3 days and hasn’t eaten or taken any insulin. KB is confused and lethargic. The respiratory rate is 32 rpm, & there is a fruity odor to the breath. The serum glucose level is 620 mg/dL.
While receiving 40% O2, ABG values: pH: 7.15; PaCO2: 36 mmHg; PaO2: 130 mmHg; HCO3: 10 mmHg; SaO2: 99%. What is the acid base imbalance? Why is it occurring?

Answer 8

Metabolic Acidosis → This occurs because of the type 1 diabetic experiencing symptoms of DKA. The patient is using fats for energy which is causing ketones to be produced & results in the blood becoming acidic