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Abstract:
Arterial Blood Gas analyser is one of the most important point of care testing in intensive care unit that has immense clinical value in the management of critically ill patients. The technological innovations in Point-of-care devices offer rapid analysis at the patient bed side which produce quick and accurate results. The advancement in...
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Acid-base disturbances in patients with cardiopulmonary or other disorders are common and are often misinterpreted or interpreted incompletely. Treating acid-base disorders in greater detail facilitates pathophysiologic understanding and improved therapeutic planning. Understanding the ratiometric relationship between the lungs, which excrete volat...
Citations
... introduction Arterial blood gas (ABG) interpretation plays an indispensable role in emergency medicine and intensive care patients yet its interpretation is challenging. 1 Bicarbonate is highly influenced by pCO 2 values and it is rectified by standard bicarbonate (Std HCO 3 ) which is the plasma bicarbonate concentration from blood equilibrated with pCO 2 of 40 mm Hg. [2][3][4][5] The hydrogen ion concentration calculated using Std HCO 3 is known as the nonrespiratory hydrogen ion concentration (NRH + ) and it denotes the hydrogen ion concentration at non-respiratory pH (NRpH). 6,7 The net changes in blood pH reflect the sum total alterations in the hydrogen ion concentration in the blood. ...
Background
Arterial blood gas (ABG) interpretation plays an indispensable role in health care. The total changes in hydrogen ion concentration or actual pH are due to both the changes in respiratory and non-respiratory (metabolic) components affecting the hydrogen ion concentration or pH in the acid–base homeostasis. Using this concept, an innovative ABG interpretation method was developed and published by the current author. The aim of this study is to apply the compensation rules and to develop a stepwise approach in this novel method to interpret various acid–base disorders.
Methods
The total change in pH (ΔpH), non-respiratory hydrogen ion concentration (NRH⁺), changes in non-respiratory pH (ΔNRpH), and respiratory change in pH (ΔRpH) were calculated for 232 ABG samples. The expected pCO2 (Exp pCO2) or expected bicarbonate (Exp HCO3⁻) values were calculated using the compensation rules and compared with their actual given values.
Results
Few acid–base disorder cases were shown as examples comparing the physiological, standard base excess (Std BE) and parameters such as ΔpH, ΔRpH, and ΔNRpH values of novel ABG interpretation method which change in different acid–base disorders.
Conclusion
The stepwise approach in this novel method appears to be much user-friendly providing interpretation of various acid–base disorders easily and quickly.
Clinical significance
This innovative method may help to overcome the challenging task of ABG interpretation.
How to cite this article
Samuel R. Application of Boston Compensation Rules in the Development of a Stepwise Approach for Novel Diagnostic Arterial Blood Gas Interpretation Method. Indian J Crit Care Med 2023;27(10):717–723.
... The graphical representation for the diagnosis of acid base disorders may make its interpretation simpler and easier but the available methods are few (1)(2)(3)(4). Davenport diagram uses the relationship of pH, pCO2 and bicarbonate to diagnose the acid-base disorder which is not routinely utilized in practice (5)(6)(7)(8). The technological development in blood gas analyser during the previous years has not resulted in corresponding development in the field of its graphical tools and diagnosis (9). ...
... Siggaard-Andersen chart is considered as the standard diagrammatic method for acid-base disturbances which plots pH as a linear function of logp CO2 but the drawback of this method is that it cannot diagnose many acid base disorders. Grogono diagram represents a particular acid-base balance disorder using pCO2 representing the respiratory and the standard basedenoting the metabolic component of the acid base disorders (7,9,10). ...
... A newer four quadrant graph method for ABG interpretation was published by Rajini Samuel (7,8). The standard base excess denotes the metabolic component, a positive value above 2 mmol/L indicates metabolic alkalosis and a negative value below 2 mmol/L denotes metabolic acidosis (7,11). ...
Introduction and Aim: The advancement in the field of diagrammatic representation for diagnosis of acid base disturbances is not significant. A graphical tool was published by Rajini Samuel for ABG interpretation using standard base excess, the ratio (HCO3 - Std HCO3) / H2CO3 and parameter (pCO2- 40 mm of Hg) in a four quadrant graph. In the present study this diagrammatic representation is constructed and utilized for the diagnosis of acid base disorders. Materials and Methods:One hundred and fifty arterial blood gas samples were classified into various acid base disturbances and the respiratory and metabolic disorders are again subdivided into uncompensated, partially compensated and fully compensated based on compensatory mechanisms. A four quadrant graph was constructed to analyse the various acid base disorders. Results:This diagrammatic representation appears to be easier and much simpler to be widely utilized at the bed side in clinical practice. Conclusion: ABG interpretation plays an essential role for aquicker and easier interpretation may help in saving the life of the patients. This diagrammatic representation method may serve as an useful diagnostic tool to interpret the results easily.
... Hg and for bicarbonate is 22-26 mEq/L or mmol/L.[10] The measured pH, pCO , and bicarbonate values are noted. ...
ABSTRACT:
Arterial blood gas analysis plays an indispensable role in the management of critically ill patients. The interpretation of the arterial blood gas (ABG) report is an essential skill required in the emergency and intensive care unit but the accuracy of the report also depends on the knowledge of pre-analytical and analytical errors. In ABG analysis, the pH and pCO2 are measured parameters but HCO3 values are calculated using the Modified Henderson Equation. The consistency of the ABG report can be easily checked using this Modified Henderson Equation. The hydrogen ion concentration is calculated using this equation and then the pH is calculated by two methods. In one method, pH is calculated by using the logarithm relationship of pH and hydrogen ion concentration. In the other method, the pH is calculated without logarithm by using the relationship of changes in hydrogen ion concentration that results in changes in pH. The concentration of hydrogen ion is 40 nanomoles/litre at a pH of 7.4 and for every 1 nanomole/litre change in hydrogen ion concentration, the pH changes by 0.01 unit. The pH calculated using these two methods is then compared with the measured pH. The Modified Henderson Equation is applied for a total of 150 arterial blood gas sample data’s and the various parameters are analysed using graphical methods. The similarity and the deviation in the measured and calculated pH values are clearly depicted from the graphical figures. The aim of this study is to assess the consistency of the ABG report using the deviation noted in the measured and calculated pH values.
Key words: Modified Henderson Equation, Measured pH, Calculated pH
