Acid base tutorial

Question 1

What is ABG?

Answer 1

ABG= Arterial Blood Gas

Question 2

How is ABG taken and What ABG info is taken from ABG?

Which part of that info will tell you that there is an ABG problem?

Answer 2

ABG is taken from the radial artery

PH/PCO2/O2/HCO3-/O2 sat is taken from ABG

PH/PCO2/HCO3- are used to determine a blood gas problem

Question 3

What is the equation for the buffering system in the body?

What represents each side of that equation?

Answer 3

H2O + CO2↔ H2CO3 ↔ H+ + HCO3-

Left Lungs (respiratory)
Right Kidneys (metabollic)

Question 4

What is the shift when there is a build up in H+ or CO2? What gets rid of the other?

Answer 4

H2O + CO2↔ H2CO3 ↔ H+ + HCO3-

H+ increase- shift left lungs responds

CO2 build up shift right kidney respond

Question 5

What is the HH equation for the buffering system?

How do HCO3 and PCO2 relate to pH?

Answer 5

pH= 6.1 + log [HCO3-]/PCO2 x 0.03

Short form pH=HCO3/PCO2

if HCO3 goes up then pH goes up/if down then pH goes down (direct relationship)

If PCO2 goes up then pH goes down/if PCO2 goes down pH goes up (inverse relationship)

Question 6

What manages HCO3 and PCO2

Answer 6

HCO3 think kidneys (metabollic)

PCO2 think lungs repiratory

Question 7

What is it called when the blood pH is above 7.4? Below 7.4?

Answer 7

Above 7.4 = alkalemic

below 7.4 = Acidemic

Question 8

What are the four situations in which your blood pH is affected and which direction will it affect you blood pH?

Answer 8

pH=HCO3/PCO2

Metabolic acidosis (kidneys) - pH goes down and HCO3 goes down

Metabolic alkalosis (kidneys)- pH goes up and HCO3 goes up

Respiratory acidosis (lungs)- pH goes down PCO2 goes up

Respiratory alkalosis (lungs)- pH goes up PCO2 goes down

Question 9

How does the lungs respond to CO2?

Answer 9

Slow breathing- high CO2, low pH (acidoses)

Fast breathing - gets rid of CO High pH

Question 10

What are the two ways to create an acidosis by bicarbonate?

Answer 10

Lose (decrease)HCO3- decrease pH (acidosis)

Use (decrease) HCO3- decrease pH (acidosis)-by the use of hydrogen ions

Question 11

How does the body respond to a metabolic acidosis (decreased HCO3- causing a decresed pH)? Metabolic alkalosis increased HCO3- causing increased pH?

Answer 11

remember pH=HCO3/PCO2

Lungs will respond to correct pH back to 7.4

metabolic acidosis (decreased HCO3- causing a decresed pH)- this will cause a decrease in CO2 by the lungs (breathing faster)

metabolic alkalosis(incresed HCO3- causing a increased pH)- this will cause a increase in CO2 by the lungs (breathing slower)

fast process

Question 12

How does the body respond in a respiratory acidosis (increased PCO2 causing a decreased pH)? Respiratory alkalosis decreased PCO2 causing a increased pH?

Answer 12

remember pH=HCO3/PCO2

Lungs will respond to correct pH back to 7.4

respiratory acidosis (increased PCO2 causing a decreased pH)- kidneys increase HCO3

Respiratory alkalosis decreased PCO2 causing a increased pH- kidneys decrease HCO3

slow process

Question 13

What is the formula of how the lungs will respond to a metabolic acidosis?

Answer 13

Winters Formula-Metabolic Acidosis:

Expected pCO2 = 1.5 * [HCO3-]+ 8 (+/- 2)

Question 14

What is the formula of how the lungs will respond to a metabolic alkalosis?

Answer 14

Metabolic Alkalosis:

Expected pCO2 = 0.7 [HCO3-] + 20 mmHg (range: +/- 5)

Question 15

What is a anion gap acidosis?

Answer 15

an anion that is introduced into the system and brings a H+ with it. H+ depletes HCO3 casing acisosis

Question 16

What are the important areas on a metabolic panel?

What does CO2 equal on the metabolic panel

Answer 16

First column is cations Na+/K+ second is anion CL-/CO2

CO2= HCO3

Question 17

How is anion gap calculates?
What is a normal anion gap?
What is normal sodium?

Answer 17

Na - (Cl + HCO3(CO2)) = AG
Normal AG = 12

Normal Na = 140

Question 18

What are the two types of metabolic acidosis? define them

Answer 18

Anion Gap metabolic acidosis (AGMA)- a anion brings in H+ and H+ is used with HCO3 this is called use. This creates a larger anion gap than normal because anion is added and H+ is being used with HCO3-

Non Anion Gap metabolic acidosis (NAGMA)- when metabolic acidosis is created because of loss of HCO3 no widened anion gap is created

Question 19

Which metabolic processes that cam happen at the same time? what you cannot have?

Answer 19

(Use) AGMA and Metabolic alkalosis (retention) of HCO3
NAGMA and AGMA (use and lose)

NAGMA (loss of HCO3) and Metabolic alkalosis(retain of HCO3) cannot happen

Question 20

What is the delta Gap? how do you calculate an delta gap?

Answer 20

Delta gap is a change Anions added to the blood

Calculated AG – Expected AG = Delta Gap

Question 21

How do you determine which type of osis is going on?

Answer 21

1) Calculate the Anion Gap (AG)
2) Calculated AG – Expected AG = Delta Gap

Delta Gap + Measured HCO3-

If higher than 24 then metabolic Alkalosis (retain HCO3) along with AGMA(USE HCO3))

If less than 24 then NAGMA(loss of HCO3) with AGMA (use of HCO3)

Question 22

Which ways in which a NAGMA (Loss of HCO3)?

Answer 22

GI
Pancreas
renal

Question 23

How is a metabolic alkalosis created?

Answer 23

Retention of HCO3 by kidneys- only way

Question 24

What are the steps to approaching acid base problems?

Answer 24

Determine if the blood is Acidemic or Alkalemic

Determine the direction in change of PCO2 and pH (up or down from normal values)

Primary Metabolic ( decrease pH decrease PCO2) vs. Primary Respiratory ( increase pH decrease PCO2)

Acidosis vs. Alkalosis

Calculate the Anion Gap

Compensation: PCO2 and HCO3; is there a mixed disorder

Winters formula: Expected pCO2 = 1.5 * HCO3- + 8 +/- 2

Metabolic Alkalosis: Expected pCO2 = 0.7 [HCO3] + 20 mmHg (range: +/- 5)

Delta Gap; Measured AG – Normal AG; then add to measured HCO3-

Map out your Differential Diagnosis

Treat underlying conditions unless pH in dangerous range, then treat with acute management.