Agreement and Correlation Between Arterial and Venous Blood pH, PO2, PCO2, Lactate, and HCO3

The aim of this study is to assess the correlation and agreement between venous blood gas (VBG) values and arterial blood gas (ABG) values in patients presented in the emergency department of the Indus Hospital, Karachi. This study also included the evaluation of specificity and sensitivity of VBGs values for the identification of abnormal ABG values.

It was a retrospective, observational study conducted at the Indus Hospital and Health Network, Karachi, Pakistan. All VBG and ABG values in the same patient which were collected at the same time from April 2020 to May 2021 were included in the study.  Results: The study involved 377 patients; 52.8% of patients were female, while 47.2% were male. The mean age of patients was 53.4 years (±17.2). There is an acceptable agreement between the arterial and venous values of pH, bicarbonate (mEq/l), and lactate (mEq/l), respectively, and poor agreement in PCO₂ (mmHg) and PO₂.

The study found that analysis of VBG has the potential to be used in the emergency setting in general. Blood gas values of Lactate, HCO₃, and pH have shown acceptable association and significant correlation, and they can be considered clinically interchangeable with ABGs values. However, venous PCO₂ and PO₂ were found to be different between the two.