JMIR Publications

ABSTRACT

Background:

Abstract- Background- Pulse oximeters work with red- infrared wavelengths. These oximeters give erratic results in dark skinned subjects and also in subjects with cold extremities. Pulse oximetry is done routinely in all those with fever. With an elevation in body temperature, the affinity of hemoglobin for oxygen is decreased causing a drop in O2 saturation or decrease in oxyhemoglobin concentrations.

Objective:

Objectives- We wanted to know if our new investigational device ‘SH1’ can detect this drop in O2 saturation or decrease in oxyhemoglobin concentrations.

Methods:

Methods and design - Phase-1 observational studies were done in two groups separately, for validation of measurements of hemoglobin and oxygen concentrations. Only current students and members of the staff between the ages of 20 to 40 years were allowed to participate. There were a total of 39 participants in both studies. All 39 volunteers completed visit-1 or baseline readings using our new device -sH1- and the commercially available FDA approved pulse oximeter-Masimo. Later 16 subjects completed ‘Heat jacket study’, and others went for ‘Blood donation study’. The pulse oximeter Masimo was used in comparison on the finger. Melanin was accounted for using VLS Scale or Von Luschan Skin Scale and a specially designed algorithm. We are discussing data and results of heat jacket study here. This new device ‘SH1’ uses two Light Emitting Diodes [LED]. The emitted wavelengths matched with absorption peaks of oxyhemoglobin and deoxy or reduced hemoglobin [hemoglobin combined with oxygen is oxyhemoglobin and hemoglobin without oxygen is termed here as deoxy or reduced hemoglobin. Total hemoglobin means sum of oxyhemoglobin and deoxy or reduced hemoglobin or simply hemoglobin]. The device measures the reflection ratio of oxyhemoglobin [E1] and deoxyhemoglobin [E2]. E1+E2 is a measure of total hemoglobin [Patent US 11191460].

Results:

Results- The mean age of the study population was 24.1 (+/- 0.8) years. The skin tone varied from 12 to 36 on VLS Scale. The sample population had a uniform distribution with one third with fair skin, brown skin, and dark skin. Using a specific algorithm and software, results of reflection ratio for oxyhemoglobin may be displayed on screen and direct hemoglobin values as well. In ‘heat jacket study’ we expected a slight drop in oxyhemoglobin concentrations in heating phase at tissue level. Our device could pick up minor changes in oxyhemoglobin levels after a change in body temperature in heat jacket study as against the pulse oximeter. The maximum drop in oxyhemoglobin concentrations picked up by our device was 6.5% compared to 2.54% by the pulse oximeter.

Conclusions:

Conclusion- Our new investigational device ‘SH1’ measures oxygen saturation at tissue level, by reflectance spectroscopy and using green wavelengths. This device fared well not just in subjects with dark skin but in subjects with light skin as well. This eliminates racial disparity in these key biomarker assessments. Secondly, the light is shone on wrist of the individual and is then measured. So, futuristically this device can be miniaturized into a wearable. Clinical Trial: [STU-2021-0150, 02/23/2021, and 5/11/2021].