RESUMEN
BACKGROUND: Arterial blood gases are important when assessing acute or critically ill patients. Capillary blood and mathematical arterialization of venous blood have been proposed as alternative methods, eliminating pain and complications of arterial puncture. OBJECTIVES: This study compares the arterial samples, arterialized venous samples, and capillary samples in ICU and pulmonary ward patients. METHOD: Ninety-one adult patients with respiratory failure were included in the analysis. Arterial, peripheral venous, and mathematically arterialized venous samples were compared in all patients using Bland-Altman analysis, with capillary samples included in 36 patients. RESULTS: Overall for pH and PCO2, arterialized venous values, and in the subset of 36 patients, capillary values, compared well to arterial values and were within the pre-defined clinically acceptable differences (pH ± 0.05 and PCO2 ± 0.88 kPa). For PO2, arterialized or capillary values describe arterial with similar precision (PO2 arterialized -0.03, LoA -1.48 to 1.42 kPa and PO2 capillary 0.82, LoA -1.36 to 3 kPa), with capillary values underestimating arterial. CONCLUSIONS: Mathematical arterialization functions well in a range of patients in an ICU and ward outside the country of development of the method. Furthermore, accuracy and precision are similar to capillary blood samples. When considering a replacement for arterial sampling in ward patients, using capillary sampling or mathematical arterialization should depend on logistic ease of implementation and use rather than improved measurements of using either technique.