FP-C Prep: ABGs UPDATED ACTUAL
Exam Questions and CORRECT Answers
Normal range for pH - CORRECT ANSWER - 7.35-7.45
(*below is acidic; above is alkaline*)
Normal range for CO2 - CORRECT ANSWER - 35-45 mmHg
Normal range for HCO3 - CORRECT ANSWER - 22-26 mEq/L
What is base deficit/excess? - CORRECT ANSWER - When looking at an acid/base
buffering system, you must have a balance of acid and base available to cancel each other out
and maintain homeostasis. Base Excess/deficit is the value that represents either an increase or
decrease in the amount of base available when compared to the amount of acid present.
Bicarb Replacement Formula - CORRECT ANSWER - Formula: 0.1 x (-BE) x kg =
Bicarb needed
Ex. 220lbs pt, with BE of -5.
0.1 x (-5) x 100kg = 50 mEqs of sodium bicarb needed to be infused.
What is PaO2? - CORRECT ANSWER - The concentration of oxygen dissolved in the
plasma, expressed in millimeters of mercury (mm Hg).
Think of it as the amount of oxygen that is dissolved and available in the plasma for the
hemoglobin to pick up.
What is SaO2? - CORRECT ANSWER - The concentration of oxygen bound to the
hemoglobin. This is expressed as a percentage, and correlates with SpO2 if you have an accurate
pulse ox.
, 4,5,6 - 7,8,9 Rule - CORRECT ANSWER - A tool to help remember the correlation
between PaO2 and SaO2. 4,5,6 - 7,8,9
PaO2 SaO2
40 mmHG 70%
50 mmHG 80%
60 mmHG 90%
What is the oxyhemoglobin dissociation curve? - CORRECT ANSWER - A graph
displaying hemoglobin saturation and desaturation resulting in a distinct S curve (variables:
SaO2 and PaO2). The curve displays the anticipated association between SaO2 and PaO2.
The curve may shift to the left or to the right, based on the patients condition.
The oxyhemoglobin disassociation curve allows us to better predict how our patients may react
to our interventions, if they are able to maintain their compensatory mechanisms, and ultimately
maintain end organ perfusion/oxygenation.
What does a right shift mean on the oxyhemoglobin disassociation curve? - CORRECT
ANSWER - RIght shifts are caused by high metabolic states.
1.) Decreased affinity for oxygen to bind to hemoglobin.
2.) Increased H+ (causing decreased pH and acidosis)
3.) Increased temperatures
4.) Increased 2-3DPG (2-3DPG is the compound that allows oxygen to unbind from hemoglobin,
in order to disperse to the tissue where its needed.) Increased 2-3DPG causes oxygen to offload
too quickly for it to reach its destination.
5.) Increased PCO2
Exam Questions and CORRECT Answers
Normal range for pH - CORRECT ANSWER - 7.35-7.45
(*below is acidic; above is alkaline*)
Normal range for CO2 - CORRECT ANSWER - 35-45 mmHg
Normal range for HCO3 - CORRECT ANSWER - 22-26 mEq/L
What is base deficit/excess? - CORRECT ANSWER - When looking at an acid/base
buffering system, you must have a balance of acid and base available to cancel each other out
and maintain homeostasis. Base Excess/deficit is the value that represents either an increase or
decrease in the amount of base available when compared to the amount of acid present.
Bicarb Replacement Formula - CORRECT ANSWER - Formula: 0.1 x (-BE) x kg =
Bicarb needed
Ex. 220lbs pt, with BE of -5.
0.1 x (-5) x 100kg = 50 mEqs of sodium bicarb needed to be infused.
What is PaO2? - CORRECT ANSWER - The concentration of oxygen dissolved in the
plasma, expressed in millimeters of mercury (mm Hg).
Think of it as the amount of oxygen that is dissolved and available in the plasma for the
hemoglobin to pick up.
What is SaO2? - CORRECT ANSWER - The concentration of oxygen bound to the
hemoglobin. This is expressed as a percentage, and correlates with SpO2 if you have an accurate
pulse ox.
, 4,5,6 - 7,8,9 Rule - CORRECT ANSWER - A tool to help remember the correlation
between PaO2 and SaO2. 4,5,6 - 7,8,9
PaO2 SaO2
40 mmHG 70%
50 mmHG 80%
60 mmHG 90%
What is the oxyhemoglobin dissociation curve? - CORRECT ANSWER - A graph
displaying hemoglobin saturation and desaturation resulting in a distinct S curve (variables:
SaO2 and PaO2). The curve displays the anticipated association between SaO2 and PaO2.
The curve may shift to the left or to the right, based on the patients condition.
The oxyhemoglobin disassociation curve allows us to better predict how our patients may react
to our interventions, if they are able to maintain their compensatory mechanisms, and ultimately
maintain end organ perfusion/oxygenation.
What does a right shift mean on the oxyhemoglobin disassociation curve? - CORRECT
ANSWER - RIght shifts are caused by high metabolic states.
1.) Decreased affinity for oxygen to bind to hemoglobin.
2.) Increased H+ (causing decreased pH and acidosis)
3.) Increased temperatures
4.) Increased 2-3DPG (2-3DPG is the compound that allows oxygen to unbind from hemoglobin,
in order to disperse to the tissue where its needed.) Increased 2-3DPG causes oxygen to offload
too quickly for it to reach its destination.
5.) Increased PCO2
