Related Experiment Video
Updated: Jun 25, 2026

Standardized Hemorrhagic Shock Induction Guided by Cerebral Oximetry and Extended Hemodynamic Monitoring in Pigs
Published on: May 21, 2019
Severe methemoglobinemia detected by pulse oximetry
Emil H Annabi1, Steven J Barker
1Department of Anesthesiology, University of Arizona College of Medicine, P.O. Box 245114, Tucson, AZ 85724-5114, USA.
Abstract:
An elderly surgical patient acquired a life-threatening methemoglobinemia as a result of topical benzocaine spray to the oropharynx in preparation for awake endotracheal intubation. A new multiwavelength pulse oximeter, the Masimo Rad-57, detected this methemoglobinemia an hour before it was confirmed by laboratory CO-oximetry. The Rad-57 monitored the patient's methemoglobin levels during diagnosis and treatment with methylene blue, and the values it provided (as high as 33%) were very close to those of the laboratory CO-oximeter. The new pulse oximeter gave continuous readings of methemoglobin level at the bedside, whereas the laboratory values were delayed by up to an hour. This case demonstrates the clinical application of a multiwavelength pulse oximeter in the diagnosis and treatment of a life-threatening dyshemoglobinemia.
Related Concept Videos
Pulse Oximetry
Purpose
Average SpO2 values are greater than 95%. If the readings fall below 90%, it indicates that...
Guidelines For Measuring Vital Signs
Before taking a patient's vital signs, a nurse would consider and assess the patient's comfort level and ensure appropriate equipment is available.
Hypoxia
Types of Hypoxia
There are four primary types of hypoxia, each resulting from a different cause:
1. Anemic hypoxia: This type occurs due to insufficient oxygen delivery caused by a lack of red blood cells (RBCs) or RBCs with abnormal or...
Special considerations while measuring oxygen saturation
Ensuring accuracy in vital sign recordings while prioritizing patient comfort and minimizing anxiety is important.
Acute Respiratory Failure-IV
Acute Respiratory Failure-II
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:

