Discussion
anemia
ANEMIA
This study adds to the existing body of evidence on pulse oximeter performance under conditions of motion and low perfusion. We believe this is the first study to induce significant levels of low perfusion using an ice bath test method.The non-motion test results showing the measurements of the control hand versus SaOAn ongoing concern is the potential impact of skin pigmentation levels on SpOThe finding of two oximeters (Nellcor and GE) having reduced bias during motion versus non-motion conditions for the SaOA study by Louie et al., found the ARMS error greater than 3% in motion test conditions in all devices except for Nihon Kohden [The low perfusion test conditions resulted in greater performance degradation and larger mean bias and ARMS values. The normal PI of ≥ 1.0 is associated with mean bias levels less than one, but ARMS values ranged from 1.78 (Nellcor) to 2.14 (GE). In this study normal PI is defined as ≥ 1.0, while in a previous study PI values < 2 were considered representative of poor perfusion [In the low and ultra low PI ranges, significant differences in mean bias were observed across devices. In the very low PI range, no significant differences were evident. At ultra low levels of perfusion, Masimo (N = 9) and Nellcor (N = 10) experienced a number of missing values while GE had no missing values. The increase in proportion of missing values with ultra low PI, suggests that a threshold for pulse oximeter performance may have been reached although additional study is required to evaluate further. However, due to the low number of low and ultra low PI samples, no conclusions can be reached regarding relative pulse oximeter performance. Additional studies using larger patient populations and data sets which include more low and ultra low PI samples are required compare performance across different SpOLoss of pulse oximetry signals due to low perfusion is a clinical challenge requiring additional actions to estimate arterial oxygen levels and hemoglobin saturation. If the signal is lost from a finger, probes may be applied on alternative anatomic locations such as toes, ears, buccal mucosa, or nares. Invasive measurement via arterial blood gas is a clinical option when the pulse oximetry signal is not reliable. However, invasive measurement is associated with increased risk of patient morbidity due to line placement, line dislodgement, repeated blood sampling, delays due to the requirement to transport and run samples, anemia if repeated measurement is required, and costs from supplies and equipment use [The motion testing group assessed pulse oximetry performance over a wide range of clinically relevant conditions. Findings demonstrated similar performance of all three SpO