Abstract

Arterial blood gas (ABG) analysis is routinely performed for sick patients but is fraught with complications, is painful, and is technically demanding. As there is a huge requirement of performing ABG analysis, an alternative to the arterial puncture would be quite helpful in this setting, and the current study was aimed to determine the extent of correlation of arterial and venous blood gas (VBG) analysis with a view to identifying whether the venous samples can be used as an alternative to arterial values in clinical management of patients presenting with various acute respiratory illness. This prospective observational study was conducted on 90 patients who presented with acute respiratory illness in in-patient Department of Medicine and Pulmonology, Mata Chanan Devi Hospital, after applying specific inclusion & exclusion criteria. Pregnant ladies, patients having age less than 20 years and those who were having respiratory symptoms due to non-respiratory causes were excluded from this study. Arterial sample was drawn via an arterial puncture into a heparinized syringe in all patients and at the same time, venous blood was also taken, without application of tourniquet via antecubital vein into another heparinized syringe. Venous and arterial blood samples were taken within 5-minutes of each other and in addition to this, the measurement of oxygen saturation (SpO2) was obtained from finger pulse oximeter. In order to access the agreement between values of two samples, the paired t-test and Pearson correlation coefficient was used. The mean age of the patient in the present study was 62.4 ± 14.75 years and gender distribution was 54 males and 36 females out of total 90 patients. After statistical evaluation, the present study shows minimal difference and good correlation between arterial and venous samples for the values of pH, bicarbonates, pCO2 ( r > 0.9 ). Although the correlation of pO2 measurement was fair  ( r = 0.615 ) , but there was good correlation between values of finger pulse oximeter and arterial oxygen saturation( r > 0.9 ).  Thus, venous blood may be a useful alternative to arterial blood during blood gas analysis in the management of patients with acute respiratory illnesses. However, further large scale studies are needed to accurately assess whether VBG analysis can always replace ABG analysis.

Keywords: Arterial blood gas analysis,venous blood gas analysis.

Shobhit Shah

Department of Medicine and Pulmonology

Mata Chanan Devi Hospital, Janakpuri, New Delhi