Podcast 813: Pulse Oximetry

<p><strong>Contributor: Travis Barlock, MD</strong></p> <p><strong>Educational Pearls:</strong></p> <ul> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">Most oxygen in the body is bound to hemoglobin, forming oxyhemoglobin. Less than 1% of the oxygen in the body is dissolved in plasma. </span></li> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">Pulse Oximeters (Pulse Ox) function by emitting wavelengths of light from one side, and capturing the amount absorbed on the opposite side. A calculation determined the amount of saturation. </span></li> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">Pulse Ox relies on pulsations in arterial flow to create a photoplethysmogram (pleth) for measurements </span></li> <li style="list-style: none; display: inline"> <ul> <li style="font-weight: 400;" aria-level="2"><span style= "font-weight: 400;">Patients with poor peripheral perfusion may have unreliable pulse ox.</span></li> <li style="font-weight: 400;" aria-level="2"><span style= "font-weight: 400;">Patient with an LVAD have constant flow and also unreliable pulse ox. </span></li> </ul> </li> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">Pulse Ox is a useful tool when pacing to determine mechanical capture. If there is disparity between the electrical wave pulse and the rate on pulse ox, there is likely no mechanical capture leading to poor distal flow. </span></li> </ul> <p> </p> <p><strong>References</strong></p> <p><span style="font-weight: 400;">Eecen CMW, Kooter AJJ. Pulsoximeters: werking, valkuilen en praktische tips [Pulse oximetry: principles, limitations and practical applications].</span> <em><span style="font-weight: 400;">Ned Tijdschr Geneeskd</span></em><span style="font-weight: 400;">. 2021;165:D5891. Published 2021 May 11.</span></p> <p><span style="font-weight: 400;">Elgendi M. On the analysis of fingertip photoplethysmogram signals.</span> <em><span style= "font-weight: 400;">Curr Car