Oxygen changes may not be detected by the pulse oximeter until

Oxygen changes may not be detected by the pulse oximeter until

• A. 15-30 seconds
• B. 30-90 seconds
• C. 2-3 minutes
• D. 0-15 seconds

Answer: (B)

Oxygen changes don’t show up on the pulse oximeter immediately because the reading depends on arterial blood that has to circulate from the lungs to the peripheral site and because the device commonly averages the signal to reduce noise. After you alter inspired oxygen or the patient’s oxygenation state changes, it takes time for the new arterial saturation to equilibrate and for that change to be reflected at the skin where the sensor sits. In patients with adequate perfusion, this adjustment typically becomes evident within about 30 to 90 seconds. Shorter intervals (0–15 seconds or 15–30 seconds) are usually too quick for full equilibration and averaging, while much longer durations (2–3 minutes) exceed what is normally expected for a resuscitation-quality change.

Oxygen changes don’t show up on the pulse oximeter immediately because the reading depends on arterial blood that has to circulate from the lungs to the peripheral site and because the device commonly averages the signal to reduce noise. After you alter inspired oxygen or the patient’s oxygenation state changes, it takes time for the new arterial saturation to equilibrate and for that change to be reflected at the skin where the sensor sits. In patients with adequate perfusion, this adjustment typically becomes evident within about 30 to 90 seconds. Shorter intervals (0–15 seconds or 15–30 seconds) are usually too quick for full equilibration and averaging, while much longer durations (2–3 minutes) exceed what is normally expected for a resuscitation-quality change.