Accuracy of Pulse Oximetry in the Detection of Hypoxia in Liver Transplant Candidates

Abstract

Hypoxia is common in patients with chronic liver disease. Screening guidelines for detecting the presence of arterial hypoxemia do not exist. The aim of this study was to investigate the accuracy and utility of pulse oxymetry in the detection of hypoxemia (PaO2<65) in a group of patients with liver cirrhosis who were candidate for liver transplantation. Two hundred and ninety-five transplant candidates enrolled in this study. Arterial oxyhemoglobin saturation was obtained by pulse oxymetry (SpO2) and compared with simultaneous arterial blood gas (ABG) oxyhemoglobin values (SaO2). Bias, the overestimation or underestimation of one method compared with another, is defined as the difference between SpO2 and SaO2. SpO2 overestimated SaO2 in 78.3% (n=231) and underestimated in 18.6% (n=54) cases. The bias was over 4% or less than -4% (Bias4) in 11.6% (n=34) of the cases and significantly different between the patients with SaO2 =94%. PaO2 =65 mmHg (p=0.000) and SpO2 =94% (p=0.003). Also, when we used the cut-off level of A-a O2 gradient =20 and =15, the bias was significantly different between the patients (p=0.000). Pulse oximetry is a useful screening test to detect hypoxemia in patients with liver disease.