There were several outliers on individual patients, with SpO2 readings varying from control as much as 23%. Note that there were 2 missing measurements in the OxyWatch group (N = 198). The mean difference between the device readings and controls for the entire population was narrow–between 1% and 1.87% for all 3 devices (Table 2). The Bland‐Altman plots also show this visually with fewer outliers in SpO2 readings for Onyx (Figures 3– 5).
![onyx 2 9550 onyx 2 9550](https://i.ebayimg.com/images/g/hyUAAOSwQWhgbDEj/s-l1600.jpg)
The more expensive, medical‐grade Onyx device showed a narrower distribution of SpO2 readings that more closely mirrored the control values (Figure 2). This study was approved by the UAB Institutional Review Board.īland‐Altman plots for Santa Medical SM‐165 All analysis was performed using SAS software, version 9.4 (SAS Institute). The sample size was chosen based on a convenience sample of patients and authors' availability to perform enrollment. McNemar's test was performed to evaluate the diagnostic characteristics for sensitivity of hypoxia. Sensitivity analysis using an SpO2 of 92% as a cutoff value to hypoxia was performed post hoc and is provided as a supplemental table. Sensitivities, specificities, positive predictive values, and negative predictive values were calculated. A cutoff value of ≤ 94% was chosen to define hypoxia a priori. Subgroup analysis of hypoxic patients was performed and planned a priori. Pearson's correlation was performed between each test group and the control. Bland‐Altman plots were created to evaluate agreement between the 3 tested devices and control. Mean SpO2s were compared across groups using an analysis of variance test. Differences between control and test groups SpO2 were calculated and presented with 95% confidence intervals (CIs). Counts with percentages, means with SDs and medians with interquartile ranges were calculated and presented, as appropriate. We found in our previous study that a variety of iPhone apps that purported to measure pulse oximetry were inaccurate and should not be used-even in austere conditions.ĭescriptive statistics were performed.
#ONYX 2 9550 PROFESSIONAL#
Determining the accuracy of affordable, consumer pulse oximetry devices could allow for a cost‐effective addition to the wilderness medicine field kit for both the professional and layperson.
![onyx 2 9550 onyx 2 9550](https://images-na.ssl-images-amazon.com/images/I/61l7pWzhZ2L._SL1200_.jpg)
These devices may also be useful in austere conditions or when the supply of medical‐grade pulse oximeters is exhausted.
#ONYX 2 9550 PORTABLE#
Pulse oximetry has several limitations that can cause inaccuracies in measurement: light‐emitting diode (LED) integrity, motion, hypotension, methemoglobinemia, carboxyhemoglobiemia, and anemia.Ī variety of portable pulse oximetry devices exist and range from inexpensive, commercially available to more expensive, health‐care‐oriented models (ranging from ∼$25 to over $300). The consensus in the literature is that portable pulse oximeters are acceptable for use but may experience inaccuracies as a patient becomes increasingly hypoxemic. Small, portable pulse ox devices allow measurement of oxygen saturation in resource‐limited environments. More recently, portable finger probes have been developed, and these allow oxygen saturation measurements to be obtained in a variety of environments and situations. The use of pulse oximetry has been shown to reduce the need for more invasive measurements, such as an arterial blood gas. This tool can be placed on multiple spots on the body to obtain noninvasively an accurate measure of blood oxygenation and easily detect hypoxemia.Ī finger probe is commonly used for measurements, but multiple other sites can be used with varying accuracy. This difference is measured by the diodes on the device and is used to calculate the SpO2.
![onyx 2 9550 onyx 2 9550](https://cdn.mysagestore.com/e795745c6a03d6dde051c5f1393dbe3d/contents/EM95099560/EM95099560.jpg)
![onyx 2 9550 onyx 2 9550](https://www.picclickimg.com/d/l400/pict/194502898298_/Nonin-Onyx-II-9550-Military-Wireless-Fingertip-Pulse.jpg)
Oxygenated hemoglobin absorbs more infrared light, and deoxygenated hemoglobin absorbs more red light. Pulse oximeters measure peripheral capillary oxygen saturation (SpO2) by measuring the difference in absorption of oxygenated versus deoxygenated blood at 2 different wavelengths (typically red light at 660 nm and infrared light at 940 nm). The term “oximetry” is attributable to him. It was developed during World War II by Glenn Allan Millikan, an American physiologist and mountaineer. Pulse oximetry (pulse ox) is an expedient and accurate tool to measure noninvasively the oxygenation status of any patient in whom this might be a clinical concern.