Comparison of Two Oxygenation Targets With Two Different Oximeters - Impact on Oxygen Flow Rates and Oxygenation

The oximeters to be evaluated will be the Nonin (Plymouth, MN), and the Philips (Eindhoven, Netherlands). The sensors used will be digital reusable sensors for all oximeters. Because of the impact of the fingers used for SpO2 measurement, each oximeter will be randomly assigned a different finger to each patient (digit 2 and 3 on the hand opposite to the arterial catheter).

Two SpO2 targets will be assessed: 90% and 94%. A total of four 10-minute periods will be performed in randomized order: Nonin 90, Nonin 94, Philips 90, and Philips 94.

At the end of each 10-minute period, arterial gas will be collected through the arterial catheter.

The adjustment of the oxygen flow rates will be performed manually. The average oxygen flow of the last 2 minutes of the period will be considered.

Inclusion criteria

• ≥ 18 years of age
• Patients admitted to postoperative cardiac surgery intensive care unit
• Presence of an arterial catheter Specific for the extubate patient
• Ongoing on conventional oxygen therapy at moderate flow (up to a maximum of 5L/min) with SpO2 between 88 and 100% with the usual oximeter and nasal cannula.
• SpO2 < 92% ambient air Specific for the intubate patient FiO2 <= 0.60 with SpO2 between 88 and 100% with usual oximeter SpO2 < 92% with FiO2 0.21

Exclusion criteria

• No SpO2 signal with oximeter in use
• False nails or nail polish
• Methemoglobinemia >0.015 on last available arterial gas
• Patient in isolation (multi-resistant bacteria, C-Difficile, SARS-CoV-2 ...) Specific for the extubate patient
• Expected to use another respiratory support within one hour of inclusion (NIV or nasal high flow oxygen) Planned extubation within one hour of inclusion