Smartphone Application-Based Vital Sign Monitors
Condition: Signs and Symptoms
Study type: Observational

Summary: 
      Health-related applications for smartphones represent a new and popular market for consumer
      oriented products. These applications are generally not considered medical devices and, as
      such, are not under the purview of the Federal Drug Administration. Some of these
      applications purport to measure vital signs, but do not have any published data to confirm
      accuracy of such measurements and their developers have not been willing to divulge the
      methods by which vital sign readings are produced.

      Use of unvalidated application derived data may contribute to patient harm as patients may
      make healthcare decisions based on the results these applications provide. This study aims to
      assess the accuracy of several such applications by comparing their findings to those of
      clinical vital sign monitors commonly used in the perioperative setting.
    

Detailed description: 
      Recruitment of volunteers take place via announcement at the Anesthesiology Departmental
      Grand Rounds as well as by flyers posted in the UT Southwestern Department of Anesthesiology
      & Pain Management.

      After verbal consent is obtained, each volunteer will be placed in the seated position.
      Upper-arm non-invasive blood pressure will be measured using WelchAllyn Propaq CS via a
      standard size cuff placed in the standard fashion between the elbow and shoulder. Pulse
      oximetry measurement will be obtained using the WelchAllyn Propaq CS via the 4th digit of the
      hand.

      The smart phone applications are Instant Blood Pressure, Instant Blood Pressure Pro, Pulse
      Oximeter and Pulse Oximeter Pro and purchased by the principal investigator and downloaded
      via the iTunes App Store onto an iPhone 5S with iOS 7.1.2 owned by the principal
      investigator. The application-based measurements will be performed by the volunteer according
      to the instructions from the application to the user without explanation from the
      investigators.

      Systolic blood pressure (SBP), diastolic blood pressure (SBP), pulse (P) and peripheral
      capillary oxygen saturation (SpO2) will be collected from 100 volunteers. Serial measurements
      will be taken in the following fashion: right upper extremity, smartphone application
      measurements, left upper extremity and repeat smartphone application measurements. Thus, for
      each volunteer each data point referenced above will be recorded six times: two times using
      standard equipment readings (one per extremity) and four times with application-based
      readings (two times per application).

      The two applications to measure blood pressure (Instant Blood Pressure and Instant Blood
      Pressure Pro) both utilize the camera and flashlight on the iPhone. In addition, the Instant
      Blood Pressure application also utilizes the microphone and instructs the user to hold the
      iPhone against the chest in a specific fashion to complete its measurement. Both applications
      also request the user to input certain demographic data: Gender, Age, Height and Weight. In
      addition, one application (Instant Blood Pressure Pro) also instructs the user to input data
      on "Body Condition" and provides the following options: Poor, Below Average, Average, Above
      Average, Good, Excellent and Athlete. The application does not provide any direction on how
      one is to distinguish between these options. If these applications measure data based on some
      yet unexplained function using the iPhone's onboard technology, then changing the demographic
      data should not alter the result of the measurement. In the same way, a sphygmomanometer or
      pulse oximeter does not need to know one's gender, height, weight or age to accurately
      measure blood pressure or pulse.

      The application based vital sign readings may change in concert with changes to demographic
      variables even though clinical vital sign monitors remain relatively consistent. To test this
      hypothesis, in a subgroup (n=20), serial measurements using both clinical vital sign and
      application based vital sign readings will be evaluated by changing demographic variables in
      the application based vital sign monitors.

      For this subgroup the volunteer will perform serial measurements with the following changes
      in demographic data for each application: Correct data, Age + 10, Age + 20, Age - 10, Age -
      20, Weight - 10%, Weight - 25%, Weight + 10% and Weight +25%. Additionally, for the Instant
      Blood Pressure Pro application additional readings will be taken changing the "Body
      Condition" demographic as follows: Poor, Average, Good and Athlete. For each measurement
      taken using the applications another will be taken using the clinical monitor, or thirteen
      total readings per volunteer.
    

Observational model: Other
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Volunteers from the UT Southwestern Department of Anesthesiology & Pain Management