Introduction: Various approaches are available but only few graphical methods are there for Arterial Blood Gas(ABG) interpretation. A novel four quadrant graphical tool was developed by the current author.The calculated hydrogen ion concentration equivalent of standard bicarbonate is called the 'non-respiratory' hydrogen ion concentration. Novel acid base balance theory states that the net changes in total pH are due to both the changes in respiratory and non-respiratory (metabolic) component affecting the pH.Using this concept, an innovative ABG interpretation method was developed  by the current author.

Aim & Objectives:

1. To construct a Novel four quadrant graphical tool for ABG interpretation
2. To develop a Novel pH based ABG interpretation method
3. To apply a newer equation to understand and identify hidden and mixed acid base disorders
4. To create a 7 Step approach for ABG interpretation integrating various approaches.

Methods: A four quadrant graphical tool applies Standard Base Excess (SBE), modified ratio 2 (derived using HCO₃,Std HCO₃ & H₂CO₃) and  (pCO₂ - 40 mm of Hg). The SBE is positive for metabolic alkalosis and negative for metabolic acidosis. Modified ratio 2 and  (pCO₂ - 40 mm of Hg) are greater positive for respiratory acidosis and greater negative for respiratory alkalosis.  The net changes in total pH are due to both the changes in respiratory [ΔRpH] and non-respiratory (metabolic) component [ΔNRpH] affecting the pH.  A newer equation that correlates delta gap with other metabolic and respiratory components was developed.

Results: Each acid base disorder will occupy any of the four quadrants.The changes in respiratory [ΔRpH] and non-respiratory (metabolic) component [ΔNRpH] affecting the pH values are negative for acidic effect and positive for alkaline effect. The newer relation integrated with delta gap  helps to identify the hidden acid base disorders. 

Conclusion: These novel interpretation methods to identify the acid base disorders can be integrated by developing a mobile application or upgrading the software in the ABG analyzer itself. The implementation of this 7 steps approach will help to overcome the arduous task of ABG interpretation.

Keywords: 4 Quadrant graph, Novel pH based method, Hidden acid base disorders