carboxyhemoglobin

Introduction

Hemoglobin with carbon monoxide (CO) bound to heme.

Pathology

• CO competively binds to heme
• it also shifts the oxygen dissociation curve to the left (diminished release of O2)
• the 1/2 life of carboxyhemoglobin is 5 hours on room air
• susceptible organs include brain, heart & to a lesser extent kidney
• see carbon monoxide poisoning

Laboratory

• may cause falsely elevated SaO2 on pulse oximetry
• arterial blood gas with blood carboxyhemoglobin levels

Complications

• up to 1 year later, patients may develop neurologic evidence of CO poisoning

Management

• levels < 25%, 100% O2
• levels > 25%: hyperbaric O2
• levels > 40%, risk of anoxic brain damage
• rule out myocardial infarction

More general terms

• hemoglobin

Additional terms

• carbon monoxide poisoning
• carboxyhemoglobin in blood