Accuracy of Oximeters With Hypoxia and Methemoglobin or Carboxyhemoglobin

This pilot study is designed to calibrate and validate the Mespere VA Oximeter against a CO-Oximeter on healthy volunteers.

Mespere VA (Venous and Arterial) Oximeter is a novel non-invasive medical device for simultaneous monitoring of venous blood oxygenation through the right external jugular vein and arterial blood oxygenation through the finger tip (SpO2).

The conventional pulse oximeter has been a standard in clinical care for non-invasive hemodynamic monitoring, which only measures the arterial blood oxygenation. There are many clinical situations where tissue hypoxia may exist despite normal values obtained by conventional pulse oximeter. This can be cause by inadequate monitoring of oxygen demand (i.e. venous oxygen saturation) of the tissues. The aim of monitoring tissue hypoxia can be achieved by monitoring the balance between oxygen supply (via arterial oxygen saturation) and oxygen demand (via venous oxygen saturation).

The existing method for venous blood oxygenation monitored is either through an invasive fiber optic catheter, or intermittently by blood sampling and CO-oximetry. However, catheterization can be costly and can include inherent risks. Furthermore, there is the need for catheter recalibration against a CO-oximeter every 4- 6 hours. Therefore, due to the inherent risks of catheterization, venous oximetry is limited only to those critically ill patients. The clinical application of venous oximetry is numerous, including severe sepsis and septic shock, severe trauma and hemorrhagic shock, and heart failure and cardiac arrest.

By non-invasively monitoring both venous and arterial blood oxygenation, Mespere VA Oximeter provides more complete information on patient hemodynamics and has clear advantages over conventional pulse oximeters.

Healthy volunteers between the ages of 21 and 49 years of either gender, and a range of skin tones

• Device: Mespere VA Oximeter
  Mespere VA oximeter provides non-invasive measurement of the oxygenation of the venous and arterial blood simultaneously. In the measurement, the venous adhesive patch is placed on top the right external jugular vein and the pulse oximeter probe is placed on the right index finger. The monitor simultaneously displays the oxygenations and plethysmographic waveforms of venous blood and arterial blood.
• Device: Radiometer OSM-3 Co-Oximeter
  OSM-3, a Radiometer manufactured hemoximeter, is intended for the photometric determination of hemoglobin. Using a small sample of 35ul, the Radiometer OSM-3 hemoximeter is capable of measuring 6 parameters such as sO2, ctHb, FO2Hb, FCOHb, FMetHb, and FHHb.

Inclusion Criteria:

• Healthy volunteers between the ages of 21 and 49 years of either gender

Exclusion Criteria:

• smokers
• pregnancy
• any chronic medical condition including heart disease, hypertension, pulmonary disease, liver or kidney disease
• obesity
• evidence of abnormal neck vein anatomy