Comparison and agreement between venous and arterial gas analysis in cardiopulmonary patients in Kashmir valley of the Indian subcontinent

BACKGROUND: Arterial blood gas (ABG) analysis is routinely performed for sick patients but is fraught with complications, is painful, and is technically demanding. OBJECTIVE: To ascertain agreement between the arterial and peripheral venous measurement of pH, pCO(2), pO(2), and bicarbonate levels in sick patients with cardiopulmonary disorders in the valley of Kashmir in the Indian subcontinent, so as to use venous gas analysis instead of arterial for assessment of patients. SETTING: Sher-i-Kashmir Institute of Medical Sciences, Srinagar, Kashmir, a 650-bedded tertiary care hospital in North India located at an altitude of 1584 m. METHODS: One hundred patients who required ABG analysis were admitted. Peripheral venous blood was drawn within 5 min of an ABG measurement, and the samples analyzed immediately on a point of care automated ABG analyzer. Finger pulse oximetry was used to obtain oxygen (SpO(2)) saturation. Data were analyzed using Pearson correlation and bias (Bland Altman) methods. RESULTS: The venous measurements of pH, pCO(2), pO(2) and bicarbonate, and the digital oxygen saturation were highly correlated with their corresponding arterial measurements. Bland Altman plots demonstrated a high degree of agreement between the two corresponding sets of measurements with clinically acceptable differences. The difference in pO(2) measurements was, however, higher (−22.34 ± 15.23) although the arterial saturation and finger oximetry revealed a good degree of agreement with clinically acceptable bias. CONCLUSION: Peripheral venous blood gas assessment in conjunction with finger pulse oximetry can obviate the routine use of arterial puncture in patients requiring ABG analysis.