Accuracy of Peripheral and Central Venous Blood Gas Analysis in Evaluating Patients with Respiratory Failure

Objectives: Arterial blood samples are the gold standard test but these are more difficult to get than venous samples. In this study we assessed the possibility of utilization of venous (peripheral and central) blood gas samples in evaluation of subjects with respiratory failure instead of arterial samples. Methods: critically ill subjects with respiratory failure had paired venous (peripheral and central) and arterial samples taken. Assessment of agreement between blood gas samples (arterial and venous) as regard PH, Pco2 and HCO3 was done using Bland–Altman analyses. The spearmen correlation and linear regression tests were also performed to assess the degree of association between arterial and venous samples. Results: 100subjects were included. A good agreement was found between venous (peripheral and central) and arterial values of pHand HCO3.The agreements between peripheral venous and arterial PH and HCO3 values is higher than agreements between arterial and central venous measures. Conclusions: venous blood gas analysis (mainly peripheral samples) could replace arterial blood gas analysis in the evaluation of acid base balance in subjects with respiratory failure