Methemoglobinemia: A Novel Way to Noninvasively Measure It by Pulse Oximetry

Abstract

Listen

Translate article

To the Editor: We read with interest the article by Linz et al1 regarding methemoglobinemia in rubber molding workers exposed to an adhesive containing dinitrobenzene. Prompt diagnosis and treatment is dependent on a high index of suspicion and an infrastructure that facilitates prompt confirmation of the diagnosis. Blood testing for methemoglobin by cooximetry from arterial or venous samples is not readily available in medical clinics or hospitals and is not available at most workplaces where exposure to substances known to cause methemoglobinemia occurs. A new pulse oximeter is available that measures methemoglobin noninvasively using a finger probe. It uses eight wavelengths and signal extraction technology to accurately measure methemoglobin,2 carboxyhemoglobin,3 and arterial blood oxygenation in a few seconds. The Rad-57 pulse cooximeter has been developed by Masimo (Masimo Corp., www.Masimo.com) and can be a cheap, noninvasive way to screen for methemoglobin, but also carboxyhemoglobin, in the workplace. In addition to being used for quickly identifying workers toxic from exposure to substances causing methemoglobinemia and toxic exposure to carbon monoxide in confined spaces, it may be used to identify smokers as part of an employee wellness program. Prompt diagnosis of dyshemoglobinemias can be achieved using pulse cooximetry in a noninvasive manner in the field or workplace. This can be lifesaving and decrease the burden of life-threatening toxicities. Mamatha P. Reddy, MD Wayne State University Detroit, Michigan Sridhar P. Reddy, MD, MPH St. Clair Pulmonary and Critical Care St. Clair, Michigan