ABG presentation for medical student .

1. AB
G
S U B M I T T E D B Y : K H A L I D A . A L - H A R B I .

2. What IS ABG ?
- Arterial Blood Gasses
*the purpose of collecting ABG ?
- To measures the acidity (PH) and the
levels of oxygen and carbon
dioxide in.the blood from an artery

3. *WHAT ARE THE SITES BLOOD CAN BE DRAWN
FOR BLOOD GAS ANALYSIS ?
- Usually from peripheral art. (Radial, Brachial,
Femoral or Dorsalis pedis)
- Arterialised capillary sample.
.- Rare cases venous blood is used

4. How arterialised capillary sample is taken
* Site – Finger, toe, heel or ear lobe
* Wrapping in warm pad (40-430 C) for 10 minutes
* Massage ear lobe for 2-3 minutes
* Heparinised capillary tube should be sealed after
collecting sample with clay at one end
•* Short steel wire is inserted then other end is sealed
* Steel wire is moved with magnet to mix the sample

5. EQUIPMENT
Gloves
Heparin
Medical Swap
Cotton
Plaster
Syringe 1-3 CC

6. Procedure of ABG Sample Collection
Prepare Collect Send to Lab

7. *WHAT IS THE DIFFERENCE BETWEEN :
BLOOD GAS MONITORING
&
BLOOD GAS ANALYSIS
?
- Blood gas monitor is a patient dedicated device
that measures arterial pH, PaCO2 and
PaO2without permanently removing
blood.
- For blood gas analysis – Blood is removed from
Patient .

8. * BLOOD GAS ANALYSIS?
- Acid-base status.
.- Oxygenation

10. Blood Gas Norms
pH pCO2 pO2 HCO3 BE
Arterial 7.35-7.45 35-45 80-100 22-26 -2 to +2
Venous 7.30-7.40 43-50 ~45 22-26 -2 to +2

11. * What are indications & contraindications of
arterial blood gas analysis ?
Indications:
- To evaluate the adequacy of ventilation
- To Quantitate patient’s response to therapeutic intervention
Contraindications:
- -ve result of Allen’s test
- Coagulopathy or medium to high dose anticoagulation therapy
(Heparin, Coumadin, streptokinase, Caprostat)
- Femoral puncture avoided outside hospital
- Arterial puncture not performed distal to surgical shunt

12. * What are the complications of Arterial Puncture?
- Arteriospasm, Haematoma, Emboli (Air or clotted blood),
Anaphylaxis if LA is used, Haemorrhage, Trauma to vessel
, Arterial occlusion, Vasovagal response and Pain

13. - PH in ABG?
1- Determine if pH is acidotic or
alkalotic
2-Determine cause:
A-Respiratory
B-Metabolic
C-Mixed
3. Check oxygenation

14. Acid-Base Regulation
* Three mechanisms to maintain pH
- Respiratory (CO2)
- Buffer (in the blood: carbonic acid/bicarbonate,
phosphate buffers, Hgb)
- Renal (HCO3
-)

15. CO2 + H2O H2CO3 HCO3- +
H+
Respiratory component Acid Blood/renal component Base
Acid-Base Equation: the carbonic acid/bicarbonate
- Every change in CO2 of 10 mEq/L causes pH to change by 0.08
(or Δ1 = 0.007)
- Increased CO2 causes a decreases in pH
- Decreased CO2 causes an increase in pH

16. Acid vs. Alkaline Blood pH
Venous pH = 7.35 Arterial pH = 7.40
6.9 7.00 7.1 7.2 7.3 7.4 7.5
Acidosis Neutral pH Alkalosis

17. Respiratory Acidosis
- Hypercarbia from hypoventilation
Findings:
-pCO2 increased therefore… pH decreases
---------Example:----------
ABG : 7.32

18. Respiratory Alkalosis
-Hypercarbia from hypoventilation
Findings:
-pCO2 decreased… therefore pH increases
--------------------Example:
ABG – 7.45

19. Metabolic Changes
-Remember normal HCO3
- is 22-26
Rule #2
Every change in HCO3
- of 10 mEq/L causes pH to change by 0.15
Increased HCO3
- causes an increase in pH
Decreased HCO3
- causes a decrease in pH