This document provides information on interpreting arterial blood gases (ABGs), including: 1) How to identify acidosis or alkalosis based on pH levels. 2) The Rome method for determining if a pH change is due to respiratory or metabolic causes based on pCO2 and HCO3 levels. 3) Examples of respiratory acidosis, respiratory alkalosis, and metabolic alkalosis and how they may present on ABGs. 4) How the body can partially or fully compensate for acid-base imbalances through changes in HCO3 or pCO2. 5) Formulas like Winter's formula and the Anion Gap that can help evaluate compensation and identify causes of metabolic acidosis

1. INTERPRETATION OF
ABGS

2. 1. Iidentify Acidosis or alkalosis
2. PH 7.35 to 7.45
3. Ph <7.35 Acidosis
4. Ph >7.45 Alkalosis
5. Ph =7.40 absolute
6. Ph 7.35 to 7.40 Acidosis Range
7. Ph 7.40 to 7.45 Alkalosis range

3. METABOLIC OR RESPIRATORY
• Rome Method
• Ph decreased, pco2 Increased =respiratory disorder
• Ph decreased pco2 decreased = metabolic disorder
• 2. More co2 more H+ Acidosis ph will be less
• More hco3 alkalosis more ph
• Tic tac toe mathod

4. EXAMPLES
• 1. Ph 7.25
• paco2 50
• HCo3 24
• Acidosis Normal alkalosis
• ph hco3
• Co2
• Respiratory Acidosis

5. • Ph 7. 5 pco2 28 Hco3 22
• Acidosis Normal Alkalosis
• hco3. , ph Pco2
• RESPiratory alkalosis

6. METABOLIC OR RESPIRATORY
• Rome Method
• Ph

7. COMPENSATION
• Partially or fully compensated
• In case of respiratory Acidosis hco3 will inc to compensate
• In case of respiratory alkalosis Hco3 will dec
In case of metabolic Acidosis co2 will decrease
In case of metabolic alkalosis co2 will increase

8. EXAMPLE
• Ph 7.30 co2 50 hco3 49
• ph dec Acidosis
• Co2 inc.. Leading to increase in H+
• Hco3 inc to compensate
• respiratory Acidosis partially compensated

9. • PH 7. 5. Pco2 51 hco3 41
• ph Aalkalosis
• Pco2 compensation
• hco3 METABOLIC
• METABOLIC ALKALOSIS PARTIALLY COMPENSATED

10. FULLY COMPENSATED
• PH shoull be i with in normal range
• e. G
• ph7.44 Pco2 48 hco3 35
• Ph is normal but more in alkalosis range so alkalosis
• hco3 s increased. So it’s metabolic
• Co2 inc
• Metabolic alkalosis fully compensated

11. • Ph 7.35 co2 49 hco3 30
• respiratory Acidosis fully compensated

12. WINTERS FORMULA
• Pco2 )(1.5 * hco3) +8 +- 2
• Eg if hco3 is 10
• Pco2 21 to 25. So.
• Co2 21 to 25 = adequate compensation
• Co2 < normal range = associated respiratory alkalosis
• Co2 > normal range = associated respiratory Acidosis

13. • Or pco2 = hco3 +15

14. METABOLIC ACIDOSIS AND AG
• Ag is unmeasured anions

15. ANION GAP METABOLIC ACIDOSIS
• Anion gap = NA – (HCO3 +CL)
• NORMAL RANGE - 6 12
• NORMAL AG METABOLIC ACIDOSIS
• LOOS OF NAHCO3 OR GAIN HCL
• EG NS DIARRHEA Rta CAI

16. • Inc anion gap metabolic Acidosis
• HA ~H+ A-
• Dka Lactic Acidosis toxins
• Dec anion gap metabolic Acidosis
• Mm / HYPERPARATHYRIDISm

17. DELTA DELTA GAP
• Diff in AG / diff in Hco3 = Ag – 12/ 24-hco3
• HA~ H+. A-
• H+ + HCO3 = H2CO3
• SO,.
• DIFF IN AG / DIFF IN HCO3 =1 ~~ PROPTIONAL LOSS OF HCO3 FOR EVERY
H+ ( PURE ANION GAP METABOLIC ACIDOSIS)

18. • Diff in AG /diff in Hco3 >1 less loss of hco3 than h+ generated (Superimposed
metabolic alkalosis)
• Diff in AG!/ diff in Hco3 < 1 more hco3 lost than h generated (Superimposed
metabolic Acidosis)

19. CORRECTION FIR ALBUMIN
• Corrected alb = Ag = 2.5*(4-alb)

20. • Osmolar gap 2*(NA+k)+urea/2.8 + glucose /18