• SpO₂, arterial oxygen saturation measured by noninvasive pulse oximetry, is unable to assess in the hyperoxic range (higher than normal oxygenation) due to the flattening of the oxyhaemoglobin dissociation curve (as seen in figure 1).
• PaO₂, the partial pressure of oxygen measured by arterial blood gas, can be used as an indication of oxygenation throughout all ranges. However, results are both intermittent and delayed.
• Between invasive samples, changes in PaO₂ cannot be assessed and therefore unexpected hypoxia or unintended hyperoxia can occur.

• ORi is a noninvasive and continuous parameter intended to provide insight into a patient’s oxygen status in the moderate hyperoxic range (PaO₂ >100 and ≤200 mm Hg), defined as a patient’s oxygen “reserve”.
• ORi is an index with a unit-less scale between 0.00 and 1.00.
• ORi can be trended and has optional alarms to notify clinicians of changes in a patient’s oxygen reserve.
• When utilised in conjunction with SpO₂ monitoring (as demonstrated in figure 2), ORi may noninvasively and continuously extend the visibility of a patient’s oxygen status into ranges previously unmonitored in this fashion.
• ORi is an index that is intended to supplement, not replace, SaO₂/SpO₂ and PaO2 measurements.

ORi with Masimo SET^® pulse oximetry may provide:

• Expanded visibility during preoxygenation prior to intubation.
• Potential advanced warning of impending desaturation, helping clinicians intervene sooner.
• Insight into oxygen reserve when titrating patients who are receiving supplemental oxygen.

Masimo rainbow SET is a noninvasive monitoring platform featuring Masimo SET^® Measure-through Motion and Low Perfusion™ pulse oximetry with the option to measure multiple additional parameters.