The Accuracy of Smartphone Pulse Oximetry in Patients Visiting an Outpatient Pulmonary Function Lab for a 6-Minute Walk Test
Conditions: Oximetry
Sponsor: Rush University Medical Center

 
 
 
 
Study Title:  
The Accuracy of Smartphone Pulse Oximetry in Patients Visiting an Outpatient Pulmonary 
Function Lab for a 6-Minute Walk Test 
 
 
Primary Investigator: 
Jonathan Brady Scott, MSc, RRT-ACCS, AE- 
C, FAARC, FCCP 
Director of Clinical Education  
Assistant Professor 
Rush University, Department of Respiratory Care 
 
Co-Investigator: 
Aashna Modi 
M.S. in Respiratory Care | Class of 2018 
Department of Respiratory Care 
Rush University Medical Center 
 
 
Renee Kiourkas, MS, RRT, RPFT 
Pulmonary Function Lab 
Rush University Medical Center 
 
October 13, 2019 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
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Aim of the Study 
The primary aim of this research is to determine the accuracy of smartphone pulse 
oximeters in detecting blood oxygen saturations, episodes of desaturations, and heart rate by 
comparing results to a Masimo© hospital-grade pulse oximeter.  
 
Introduction 
Digital innovations have made it possible for consumers to use mobile devices for 
medical purposes. They can be used to monitor physiological parameters such as blood pressure, 
heart rate, blood oxygen saturation, and body temperature. They can also be used to conduct 
diagnostic tests, request prescription refills, and relay medical information to physicians.1 
Consequently, the healthcare sector is being profoundly affected by this emerging technology.1,2 
A frequent reliance on mobile devices has been reported among healthcare practitioners (HCPs) 
and students, with 85% reporting the use of a mobile device at least once daily for clinical 
purposes. The most common use was for information, time management, or communication 
relating to education and patient care.3 In 2010, approximately 50 percent of physicians used a 
mobile phone or a smart mobile device as a part of his or her practice. In 2015, that number 
increased to approximately 70 percent. The overall growth of applications (apps) was 38.1 
percent, compounded annually over the past five years; in regards to medical apps, the growth 
was documented at 41.9 percent.4   
 
Various cell phone companies have created and embedded pulse oximetry apps in smart 
phones that enable individuals to monitor their oxygen saturation and vital signs. Samsung, 
Apple, and various other companies have designed cellular devices that are capable of providing 
health-related apps. Other developers have created apps that are compatible with Android and 
iOS technologies. Some companies, including Lionsgate Technologies and Masimo, have 
developed external pulse oximeters that are compatible with smartphones. While these features 
seem promising for use of home monitoring of blood oxygen saturation levels, the accuracy of 
many of these features and devices have not yet been established. 
 
Smartphone pulse oximeters and other mobile health (mHealth) apps are examples of 
new and evolving technology, which if developed accurately and used correctly, may make a 
difference in the lives of many individuals. A study conducted by Petersen et al suggests that if 
pulse oximeters could be available on mobile phones many global infectious diseases, such as 
pneumonia in children, could be treated faster and mortality rate would thus decrease due to 
prompt detection of changes in vital signs alongside quicker treatments.5, 6 Studies from both 
Canada and Uganda regarding the Phone Oximeter prototype (a device interfacing pulse 
oximeters and smartphones) provide an overall usability scores of 82 percent and 78 percent 
respectively, indicative that a phone could be a functional oximeter interface.7 A usability score 
of  > 75% is considered appropriate as a functional interface. Additionally, a blinded randomized 
control trial in Australia, revealed that self-monitoring of oxygen saturation via a telehealth app 
Breathe-easy© reduced exacerbations of asthma in pregnant women.8 Since the severity of 
asthma increases during pregnancy commonly, Zairaina et al studied monitoring in pregnant 
women and found that it improved quality of life, although it did not impact lung function.8 
 

 
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Alexander et al compared four different smartphone application-based monitors: Instant 
Blood Pressure, Instant Blood Pressure Pro, Pulse Oximeter, and Pulse Oximeter Pro. Three 
different parameters were measured using these four devices: heart rate, blood pressure, and 
SpO2. The comparison revealed a large degree of variance in the values between the Instant 
Blood Pressure, the Instant Blood Pressure Pro, the Pulse Oximeter, and the Pulse Oximeter 
Pro.9 Another study by Petersen and Dumont was conducted that compared the response of 
motion artifact of three different mobile pulse oximeter devices, all interfaced to Apple iPod 
Touch devices: the Nonin Xpod, the Masimo OEM inline module, and an Audio Phone Oximeter 
prototype. The study showed that there was more motion artifact at lower saturations for all three 
of the devices. The most valid measurements was found with Masimo’s mobile device at 
readable values of approximately 85 to 87 percent.10  
 
While the technology to detect SpO2 and heartrates on smartphones is emerging and 
widely available, there is no evidence supporting its use in patients with lung disease. 
Smartphone pulse oximetry could be useful in individuals with acute or chronic lung disease; 
however, device inaccuracies could be harmful if desaturations are not detected immediately. It 
is not known how accurately these devices detect oxygen saturation/desaturation in patients with 
acute or chronic lung conditions. This study will be used to evaluate the accuracy of smartphone 
pulse oximeters in patients that will be undergoing a six-minute walk test in a pulmonary 
function lab.   
 
Experimental Design and Methods 
This is a prospective, observational study conducted at the pulmonary function laboratory at 
Rush University Medical Center. Subjects (n=48) will be selected if they are of 18 years of age 
or older, ambulatory, scheduled for a six-minute walk test, and agree to participate. The 
following information will be collected:  
 First name 
 Last name 
 Date of Birth 
 Age 
 Height 
 Gender 
 Race/Ethnicity 
 Oxygen use and frequency (if they are already on oxygen) 
 Pulmonary Disorders 
 Borg’s Dyspnea Scale  
 Heart rate (hospital-grade pulse oximeter and external and built-in smartphone pulse 
oximeter; pre- and post- test) 
 SpO2 (hospital-grade pulse oximeter and external and built-in smartphone pulse oximeter; 
pre- and post- test) 
 
Procedures 
For every patient that meets inclusion criteria, demographic information such as: age, 
race, and gender will be collected. Weight will be measured in the pulmonary function clinic by 
the designated respiratory therapist. Heart rate and SpO2 measurements will be taken per normal 
routine during the six-minute walk test (before and after the test). Parameters will be measured 

 
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using an iPhone attached external pulse oximeter (Kenek Edge, LionsGate Technologies, 
Vancouver, Canada), a Samsung S8 (Samsung Electronics Co. Inc., Seoul, South Korea) built-in 
pulse oximeter, and a Masimo© (Masimo Corporation, Irvine, California) hospital-grade pulse 
oximeter. Readings will be obtained before and after the test. All three devices will be used to 
obtain readings from a single arm, consecutively. Each reading will be recorded manually by 
persons involved in the research. Each reading will be recorded using RedCap software and later 
transferred to SPSS software for data analysis. All data placed on the RedCap software and SPSS 
will only be accessible by the primary investigators. 
 
Subject Population 
Inclusion criteria 
Ambulatory patients, 18 years and older, visiting the pulmonary function laboratory at Rush 
University Medical Center for a 6-minute walk test (n = 30) that agree to participate.  
Exclusion criteria  
 
Patients who are under the age of 18 years or patients with high blood pressure above 
180/90 mm Hg or pressure below 70/50 mm Hg will be excluded. Patients who are dizzy, light-
headed or have severe headaches, if SpO2 at or below 85% on supplemental oxygen or if patients 
are on oxygen greater than 4 liters per minute will be excluded. Gait issues that may result in a 
fall or patient walks with a walker and did not bring the device to this visit will be excluded. 
 
Consent and Recruitment Procedure 
Recruitment will be based on inclusion and exclusion criterion. Study subjects will be 
recruited through convenience sampling of patients attending the pulmonary function lab for a 6-
minute walk test at Rush University Medical Center. Verbal consent will be obtained during the 
time of subject interaction. Waiver of written consent will be requested since no invasive 
procedures are involved or procedures that would potentially be harmful to the participants. 
 
Compensation 
There is no compensation provided in this study. The participant is not required any other 
follow up after obtaining this initial data. 
 
Special Precautions 
There are no special precautions needed in this study. Standard disinfection policies 
apply. Personal protective equipment and standard protocol should be followed at all times. 
Patient safety and privacy will be addressed at all times. 
 
Confidentiality 
Persons who are primary investigators and secondary investigators, along with the IRB, 
will have access to patient records. To protect patient privacy and confidentiality, each patient 
will be assigned a subject identification number. Names will not be included in the data analysis. 
The investigators will strictly adhere to HIPAA and IRB guidelines to ensure that patient 
confidentiality is maintained.  
Plans for Data Analysis 
Data for each subject will be recorded in RedCap which will only be accessed by study 
investigators. Means and standard deviation will be calculated for age, gender, race, heart rate, 

 
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and pulse oximeter reading from hospital-grade and smartphone pulse oximeters. A t-test will be 
used to determine any significant association between age, gender, diagnosis, weight, and 
oxygen use (p< .05). Alpha will be used as 0.05 and beta will be used as 0.20. It can be predicted 
that these tests will be parametric. A scatter plot will be used to assess bias and validity.  
 
Independent variables: Type of pulse oximeter 
 
Dependent variables: SpO2 and heart rate 
Co-variables: body mass index, admitting diagnosis, age, site of measurement, oxygenation 
status, skin pigmentation, nail color, and pulmonary disorders.  
 
 

 
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References 
 
1. Topol E. How technology is transforming healthcare. 2013;2017(08/02). Web. 
2. Huston C. The impact of emerging technology on nursing care: warp speed ahead. Online 
J Issues Nurs 2013;18(2):1. 
3. Ventola CL. Mobile Devices and Apps for Health Care Professionals: Uses and Benefits. 
P T 2014;39(5):356-364. 
4. Heath S. mHealth App Market Sees $400 Million Growth in Five Years. 
2015;2017(08/03). Web. 
5. Petersen CL, Chen TP, Ansermino JM, Dumont GA. Design and Evaluation of a Low-
Cost Smartphone Pulse Oximeter. Sensors (Basel, Switzerland). 2013;13(12):16882-
16893.  
6. Bickler PE, Feiner JR, Severinghaus JW. Effects of skin pigmentation on pulse oximeter 
accuracy at low saturation. Anesthesiology 2005;102(4):715-719. 
7. Hudson J, Nguku SM, Sleiman J, Karlen W, Dumont GA, Petersen CL, et al. Usability 
testing of a prototype Phone Oximeter with healthcare providers in high- and low-
medical resource environments. Anaesthesia 2012;67(9):957-967. 
8. E. Zairina, M. J. Abramson, C. F. McDonald, J. Li, T. Dharmasiri, K. et. Al. 2016. 
Telehealth to improve asthma control in pregnancy: A randomized controlled trial. 
Respirology 21 (5): 867-874. 
9. Alexander JC, Minhajuddin A, Joshi GP. Comparison of smartphone application-based 
vital sign monitors without external hardware versus those used in clinical practice: a 
prospective trial. J Clin Monit Comput 2017;31(4):825-831 
10. Petersen C, Gan H, Görges M, Ansermino M, Dumont G. Comparison of Motion Artifact 
Response in Three Mobile Pulse Oximeters; 2014. 

 
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Appendix 
 
Subject ID __________________________________ 
 
Gender  
Male  
Female 
Transgendered 
 
Ethnicity  
White/Caucasian 
Hispanic/Latino 
Black/African American  
Asian 
Other (specify) ___________ 
 
Age __________________________________ 
 
Weight (lbs) __________________________________ 
 
Diagnosis  
 
Asthma 
Congestive obstructive pulmonary disorder (COPD) 
Cystic Fibrosis 
Pulmonary Fibrosis 
Chronic Bronchitis 
Bronchiectasis 
Congestive Heart Failure 
Stroke 
Heart Attack/Failure 
Pulmonary Hypertension 
Cancer 
Renal Disease 
Other (specify) 
 
Oxygen use?   
Yes  
No 
 
If yes, indicate the amount of oxygen used 
 
๐ 
 
๐ 
 
 
๐ 
 
๐ 
 
 
๐ 
< 2L/min flow      2-6 L/min flow  
6-10 L/min flow     As needed    Only after physical activity 
 
 
 
Pre-test Vital Signs 
Post-test Vital Signs 
 
Masimo 
Kenek/Apple Samsung 
Masimo 
Kenek/Apple Samsung 
Heart Rate 
 
 
 
 
 
 
SpO2 
 
 
 
 
 
 
Blood Pressure 
 
 
RR 
 
 
Borg Dyspnea 
Scale 
 
 

 
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