There are a number of performance limitations of pulse oximetry that should be understood by all clinicians who use these devices. Motion of the probe and high intensity ambient light can produce inaccurate readings. Motion artefact can be lessened by attaching the probe to an alternate site (such as the ear or toe rather than the finger), and interference by light can be minimized by wrapping the probe with a light barrier. Both carboxyhemoglobin and methemoglobin produce significant inaccuracy, and pulse oximetry should not be used when elevated levels of these are present. Vascular dyes also affect the accuracy of pulse oximetry, with methylene blue producing the greatest effect.
Because pulse oximeters require a pulsating vascular bed, they are unreliable with low peripheral perfusion. Nail polish can affect accuracy and it should be removed before pulse oximetry is used. The accuracy and performance of pulse oximetry may also be affected by deeply pigmented skin. The accuracy of pulse oximetry is not affected by hyperbilirubinemia or fetal hemoglobin. Although pulse oximetry is generally considered safe, burns from defective probes and pressure necrosis may occur during monitoring by pulse oximetry. Visiting an online pharmacy has never been easier and safer, since now you have the one you can call your favorite one: buy alesse birth control at the pharmacy that always takes care of its customers and always pay less money.