Placement of finger oximeter on the ear: comparison with oxygen saturation values taken from the finger

Abstract

Pulse oximetry is widely used to assess oxygen saturation (SpO2) in order to guide patient care and monitor the response to treatment. However, inappropriate oximeter probe placement has been shown to affect the measured oximetry values in healthy and normoxic outpatients. This study evaluated how treatment decisions might be impacted by SpO2 values obtained using a finger probe placed on the pinna of the ear in a cohort of 46 patients receiving non-invasive ventilation compared with values obtained from a probe on the finger and the results of arterial blood gas (ABG) (SaO2) analysis. Bland-Altman analysis was performed to evaluate agreement between the methods. Finger probe saturation was not statistically different from SaO2, with a mean difference of -0.66% (P>0.05). Saturation from the ear was significantly different (-4.29%; P<0.001). Subgroup analysis in hypoxic patients (SaO2<90%) showed a significant difference between ABG SaO2, and finger and ear SpO2. The study provides evidence that placement of a finger probe on the ear is unsafe clinical practice, potentially leading to patient mismanagement.

Improving Patient Safety by Increasing Staff Knowledge of Evidence-Based Pulse Oximetry Practices

“…The limited literature available suggested that off-label placement could potentially give erroneous readings and negatively impact decisions about managing oxygen therapy. 10,11 No evidence supported the use of off-label placement. To evaluate the scope of the local problem, we assessed resources, the frequency of off-label use, and health care staff members' knowledge.…”

“…10 Furthermore, the limited literature that exists suggests that off-label placement, such as placement of a finger-or toe-designated sensor on an earlobe, may lead to overestimation of a patient's oxygenation status. 10,11 Although 3 studies have assessed this specific practice, only 2 studies compared off-label sensor placement with the reference standard, arterial blood gas measurement. [10][11][12] These studies have limitations; neither reported using power analysis and both relied upon small sample sizes.…”

“…10,11 Although 3 studies have assessed this specific practice, only 2 studies compared off-label sensor placement with the reference standard, arterial blood gas measurement. [10][11][12] These studies have limitations; neither reported using power analysis and both relied upon small sample sizes. 10,11 In addition, one of the previously published studies used finger clip pulse oximetry sensors, which are not commonly used in the clinical setting for continuous pulse oximetry monitoring.…”

“…[10][11][12] These studies have limitations; neither reported using power analysis and both relied upon small sample sizes. 10,11 In addition, one of the previously published studies used finger clip pulse oximetry sensors, which are not commonly used in the clinical setting for continuous pulse oximetry monitoring. 10 Without high-quality evidence to support the practice of off-label placement, accepted practice should include only on-label placement because potential overestimation of a patient's oxygen saturation could lead to reduced detection of hypoxemia and underuse of appropriate oxygen therapy.…”

Everything About Pulse Oximetry—Part 2: Clinical Applications, Portable/Wearable Pulse Oximeters, Remote Patient Monitoring, and Recent Advances

“…Despite this knowledge, clinicians continue to place finger probes on patients’ ears when readings from the finger are not feasible or appear too low. 17…”