Inhaled Carbon Monoxide: From Toxin to Therapy

Area of Science:

• Biochemistry
• Physiology
• Toxicology

Background:

• Carbon monoxide (CO) is primarily known as a toxic gas, interfering with hemoglobin function and leading to carboxyhemoglobin (HbCO) formation.
• Clinical assessments of CO poisoning often show poor correlation between HbCO levels and patient presentation or improvement.
• Standard treatments for CO poisoning include 100% oxygen, with hyperbaric oxygen as a potential but debated alternative.

Purpose of the Study:

• To review the dual nature of carbon monoxide, encompassing its toxicity and emerging physiological roles.
• To highlight the limitations of current methods for assessing CO poisoning, such as pulse oximetry.
• To explore the potential therapeutic applications of endogenous CO production.

Main Methods:

• Literature review of carbon monoxide's toxicological and physiological effects.
• Analysis of clinical correlations in carbon monoxide poisoning.
• Examination of endogenous CO production via heme oxygenase activity.

Main Results:

• Blood HbCO levels do not consistently correlate with clinical symptoms or recovery in CO poisoning.
• Measurement of exhaled CO may offer insights for smoking cessation programs but pulse oximetry can be unreliable for HbCO assessment.
• Endogenous CO, produced by heme oxygenase, demonstrates significant physiological functions in vascular health, inflammation, apoptosis, and cell signaling.

Conclusions:

• Despite its toxicity, carbon monoxide exhibits crucial physiological functions.
• Further clinical trials are warranted to investigate the therapeutic potential of CO based on extensive basic science research.