Accuracy of Pulse Oximeters With Profound Hypoxia
Condition: Oximetry, Pulse
MeSH terms: Hypoxia
Study type: Observational

Summary: 
      The aim of this project is to test the accuracy of pulse oximeters during mild, moderate and
      severe hypoxia. This is done by comparing the reading of the pulse oximeter during brief,
      steady state hypoxia with a gold-standard measurement of blood oxyhemoglobin saturation
      (arterial blood sample processed in a laboratory hemoximeter). The data obtained is submitted
      by pulse oximeter manufacturers to the FDA for device approval.
    

Detailed description: 
      Overall design:

      Studies normally involve 6-12 normal adult volunteer paid subjects, with 20-25 1-2 ml
      arterial blood samples from each subject obtained at different steady-state levels of hypoxia
      from 70-100%. Blood samples obtained from an arterial line are measured in a hemoximeter to
      determine true saturation value. Some sponsors may not require any blood sampling. Some
      sponsors may require additional blood samples, up to 35 samples may be drawn.

      Readings from the test pulse oximeters are recorded and compared to these "gold-standard"
      blood values. The pulse oximeter probes may be located at a variety of sites on the subjects,
      including fingers, toes, ears, forehead, scalp and bridge of the nose. These detector-probes
      are all non-invasive. The level of hypoxia is measured and controlled by the investigator. A
      computer program that displays a prediction, breath by breath, the arterial oxygen
      saturation, (SaO2) of the study subject. SaO2 is computed from end-expired Po2 and Pco2 as
      determined by mass spectrometer gas analysis. This information permits the inspired gas
      mixture of air, plus CO2 and nitrogen, to be adjusted by an operator watching the value
      computed after each expiration on an analog meter. This computer-estimated saturation is
      adjusted by the operator to one of 6 levels of predicted saturation, and is held stable for
      about 30 seconds at each level. Two or three "runs" are conducted per subject. Each "run"
      lasts 8-12 min and 4 to 5 plateaus are tested per run. The manufacturer may choose the target
      values. Plateaus are typically sought at 92%, 86%, 80%, 74%, 68% and 62%. Other manufacturers
      have asked for an equal number of data points but with all points between 70% and 100%. Some
      sponsors may also request additional variables to be measured during testing including high
      or low Carbon Dioxide (CO2), where subjects will be asked to hyperventilate; low perfusion,
      where subjects will be asked to lay flat, or with their head up or down; testing pulse
      oximeters during motion, with the subject's hand fixed to a motion machine; or measure
      eye-tracking during hypoxia. The subject's will be informed by the study staff and in the
      consent form if any of these additional procedures apply.

      .
    

Intervention name(s): Surveyor S4
Intervention type(s): Device
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        10-12 healthy volunteers