pH OF THE BLOOD:
A
CID-BASE BALANCE


MICHAEL J. BOOKALLIL
M.B., B.S., F.F.A.R.C.S., F.F.A.R.A.C.S.

Senior Lecturer in Anaesthetics
Royal Prince Alfred Hospital
THE UNIVERSITY OF SYDNEY


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CONTENTS:

1. Introduction

2. Definitions

2.1 Balance and Status
2.2 Acid and Base
2.3
pH and Acid Base
2.4
Buffer Solution
2.5
Distinction Between Buffer and Base
2.6 Respiratory, Non-Respiratory, Metabolic
2.7
Acidosis and Alkalosis
2.8
Nanoequivalents H+/ litre
2.9
Abbreviations

3. Control of pH

3.1 Normal pH
3.2 Buffer Control
   3.2.1 Normal Acid Load
   3.2.2 Abnormal Acid Balance
   3.2.3 Low Buffer States
3.3 Respiratory Control
   3.3.1 Normal
   3.3.2 Effect of Control of PCO2 in Minimising pH Changes
   3.3.3 Compensation of Non-Respiratory Disturbances.
3.4 Renal Control
   3.4.1 Normal
   3.4.2 Excess Acid or Base (Non-respiratory)
   3.4.3 Deficiency of Acid or Base (Non-respiratory)
   3.4.4 Changes in CO2
   3.4.5 Limitation of Acidity of Urine
3.5 Compensation and Correction

4. Description of pH or Acid-Base Status in Blood

4.1 Direct Analysis
4.2 Actual pH, PaCO2, Non-Respiratory pH
4.3 Other Methods of quantitating Non-Respiratory pH Changes
   4.3.1 Standard HCO3
   4.3.2
Base Excess
   4.3.3
Anion Gap.

5. Techniques for Measuring pH Status

5.1 pH electrode, Blood sampling
5.2 Astrup
5.3 pH and PCO2 Electrode Systems

6. Causes, Diagnosis and Effects of Abnormal pH

6.1 Introduction
6.2 Chemical Classification of Changes in Blood pH
6.3 Clinical Classification of Causes of Changes in Blood pH
   5.3.1 Respiratory Acidosis
   6.3.2
Respiratory Alkalosis
   6.3.3
Non-Respiratory (metabolic) Acidosis
   6.3.4
Non-Respiratory (metabolic) Alkalosis
6.4 Clinical Diagnosis of Disturbances in Blood pH
6.5 Physiological Effects of pH Disturbances

7. Treatment

7.1 Respiratory Acidosis
7.2 Respiratory Alkalosis
7.3 Metabolic Acidosis
   7.3.1 Cardiac Arrest
   7.3.2
Shock
   7.3.3
Ketoacidosis
   7.3.4
Neonatal Resuscitation
7.4 Metabolic Alkalosis

8. Relationship Between Potassium and pH

9. pH and Temperature

10. References

11. Footnotes