Validation of Polar Elixir™ Pulse Oximeter against Arterial Blood Gases during Stepwise Steady-State Inspired Hypoxia.

PURPOSE: The purpose of this study was to evaluate the accuracy of peripheral oxygen saturation (SpO 2 ) measurements from Polar Elixir™ pulse oximetry technology compared with arterial oxygen saturation (SaO 2 ) measurements during acute stepwise steady-state inspired hypoxia at rest. A post hoc objective was to determine if SpO 2 measurements could be improved by recalibrating the Polar Elixir™ algorithm with SaO 2 values from a random subset of participants. METHODS: The International Organization for Standardization (ISO) protocol (ISO 80601-2-61:2017) for evaluating the SpO 2 accuracy of pulse oximeter equipment was followed whereby five plateaus of SaO 2 between 70% and 100% were achieved using stepwise reductions in inspired O 2 during supine rest. Blood samples drawn through a radial arterial catheter from 25 participants were first used to compare SaO 2 with SpO 2 measurements from Polar Elixir™. Then the Polar Elixir™ algorithm was recalibrated using SaO 2 data from 13 random participants, and SpO 2 estimates were recalculated for the other 12 participants. For SaO 2 values between 70% and 100%, root mean square error, intraclass correlation coefficients (ICC), Pearson correlations, and Bland-Altman plots were used to assess the accuracy, agreement, and strength of relationship between SaO 2 values and SpO 2 values from Polar Elixir™. RESULTS: The initial root mean square error for Polar Elixir™ was 4.13%. After recalibrating the algorithm, the RMSE was improved to 2.67%. The ICC revealed excellent levels of agreement between SaO 2 and Polar Elixir™ SpO 2 values both before (ICC(1,3) = 0.837, df = 574, P < 0.001) and after (ICC(1,3) = 0.942, df = 287, P < 0.001) recalibration. CONCLUSIONS: Relative to ISO standards, Polar Elixir™ yielded accurate SpO 2 measurements during stepwise inspired hypoxia at rest when compared with SaO 2 values, which were improved by recalibrating the algorithm using a subset of the SaO 2 data.

The effect of axillary crutch length on upper limb kinematics during swing-through gait.

BACKGROUND: Axillary crutches are commonly used in rehabilitation. Inappropriately fit crutches may result in upper limb pain or injury. OBJECTIVE: To investigate the effects of axillary crutch length on upper limb kinematics to better understand potential injury mechanisms. It was hypothesized that crutches that were longer or shorter than standard-fit crutches would alter upper limb kinematics. DESIGN: Cross-sectional. SETTING: Gait laboratory. PARTICIPANTS: Fifteen healthy males with no prior crutch experience. INTERVENTIONS: Participants were fit with axillary crutches using standardized methods, as well as with crutches that were 5 cm longer and 5 cm shorter. Participants performed swing-through gait (1.20 ± 0.07 ms-1 ) with all crutch lengths in randomized order. Kinematics were recorded using an optical motion-tracking system and joint angles for the scapula, shoulder, elbow, and wrist were computed. MAIN OUTCOME MEASURES: The effects of crutch length on joint range of motion (ROM) and joint angles at initial crutch contact were analyzed using multivariate analysis (Hotelling's T2 ; α = .025) and simultaneous confidence intervals (CI). RESULTS: The long-standard crutch fit comparison showed effects across all joints (ROM p = .009; initial contact p < .001). Longer crutches resulted in greater scapular upward rotation (mean difference [95% CI] ROM: 1.0 [-0.2 to 2.2]; initial contact: -2.7 [-4.4, -1.1]) and shoulder abduction (ROM: 0.8 [-0.1 to 1.8]; initial contact: -1.9 [-4.1 to 0.3]). Crutch length also had effects across all joints for the short-standard fit comparison (ROM p = .004; initial contact p = .016). Shorter crutches resulted in greater scapula downward rotation (2.2 [-0.4 to 4.8]) and greater shoulder adduction (2.5 [-0.6 to 5.6]) at initial contact. Shorter crutches also reduced shoulder flexion/extension ROM (-2.5 [-4.4 to -0.6]). CONCLUSIONS: Altered crutch length results in scapular and shoulder kinematic deviations that may present risk factors for upper limb injury with crutch-walking. This may underline the importance of appropriate device fitting to reduce injury risk in crutch users.

Creating a racial justice plan in a school of nursing: A journey of discovery and learning.

While there are many individuals and instances which illustrate the injustices experienced by people of color at the hands of police in the United States, the video which documented the murder of George Floyd by a law enforcement officer graphically illustrated our long and sad history of racial injustices. This and other events in 2020 forced our society to look at racism and systemic injustices that are embedded so deeply within our policies and practices that differentially advantage or disadvantage certain faculty, students and staff within higher education. This paper will describe the infrastructure and processes used to examine and address individual and systemic racism and white supremacy-based practices and policies at a School of Nursing. We describe the initial phases of racial justice work and infrastructure used to engage and support the efforts of committed faculty, staff and students aspiring to achieve racial equity. We share our challenges as well as immediate outcomes with the hope of stimulating thinking and dialogue in other schools around eliminating racial injustices in nursing education programs so the profession can achieve its' vision of preparing a diverse nursing workforce for the future who will work to improve the health of all.