Human bone marrow biochemical function and megaloblastic hematopoiesis after nitrous oxide anesthesia

Area of Science:

• Anesthesiology
• Hematology
• Toxicology

Background:

• Nitrous oxide (N2O) is known to inhibit bone marrow function.
• The duration of N2O exposure causing these effects and their permanence are not well-established.
• The potential protective role of folinic acid against N2O-induced bone marrow toxicity has not been previously investigated.

Purpose of the Study:

• To determine the duration of nitrous oxide exposure that induces bone marrow dysfunction.
• To assess the reversibility of N2O-induced bone marrow changes.
• To evaluate the prophylactic effect of folinic acid on N2O-related bone marrow toxicity.

Main Methods:

• Bone marrow function was assessed using the deoxyuridine (dU) suppression test.
• Morphological examination of bone marrow was performed.
• Patients were divided into groups based on nitrous oxide exposure duration: <6 hours, 12-24 hours, and a control group.

Main Results:

• Short N2O exposure (<6 hours) did not cause bone marrow abnormalities.
• Prolonged N2O exposure (12-24 hours) resulted in abnormal dU suppression tests and megaloblastic hematopoiesis.
• Observed bone marrow changes resolved within 12 hours after discontinuing N2O.
• Preoperative administration of folinic acid prevented the development of N2O-induced bone marrow abnormalities.

Conclusions:

• N2O anesthesia is safe for procedures under 6 hours, as it does not cause significant bone marrow dysfunction.
• Prolonged N2O exposure leads to temporary bone marrow impairment.
• Folinic acid administration can effectively prevent nitrous oxide-induced bone marrow toxicity.