Aims: Nowadays, the pulse oximetry is widely used to monitor the oxygen saturation constantly. In the clinical care, it is observed that the ear pulse oximetry with the finger sensor is sometimes utilized in the ICUs. The aim of the study was to determine the accuracy of the ear pulse oximetry and the fingertip with the finger sensor in the ICU patients under the mechanical ventilation. 

Materials & Methods: In the analytic comparative study, 60 hospitalized patients under the mechanical ventilation in the ICU of Moddares Hospital in Kashmar Township were studied in 2015. The subjects were selected via available convenience sampling method. One finger pulse oximetry sensor having been attached to the upper part of the ear and the other to the fingertip, the arterial blood sampling was done simultaneously. Data was analyzed by SPSS 22 software using repeated ANOVA and Spearman correlation tests. 

Findings: Mean oxygen saturation percentage and the heartbeat of ear, fingertip, and arterial blood pulse oximetry were significantly different (p<0.001). In addition, the oxygen saturation percentage of ear, fingertip, and arterial blood pulse oximetry was significantly correlated by the partial pressure of oxygen (PaO₂; p=0.001). Nevertheless, the mentioned parameters were not significantly correlated by the peripheral edema and especially, by the hand (p>0.05).   

Conclusion: The utilization of ear pulse oximetry with the finger sensor on the fingertip cannot lead to accurate results of the oxygen saturation in the hospitalized patients in the ICU under the mechanical ventilation. However, in case of any reduction in the arterial blood oxygen pressure, the accuracy of the finger pulse oximetry starts to drop out.