[In vivo blood histamine during anesthesia]

Area of Science:

• Anesthesiology and Pharmacology

Background:

• Histamine release is a known side effect of certain anesthetic agents.
• Understanding histamine dynamics is crucial for patient safety during anesthesia.

Purpose of the Study:

• To quantify histamine variations in plasma and whole blood.
• To compare histamine release induced by different anesthetic agents.
• To evaluate the clinical correlation of histamine levels with adverse effects.

Main Methods:

• Intravenous administration of histamine, thiopental, methohexital, and propanidide to volunteers.
• Measurement of plasma and whole blood histamine concentrations.
• Monitoring of clinical signs such as tachycardia and hypotension.

Main Results:

• Mean plasma histamine: 0.69 +/- 0.26 ng/ml; whole blood histamine: 54 +/- 18 ng/ml.
• Propanidide caused a 350% increase in plasma histamine, but clinical signs were inconsistent.
• Thiopental and methohexital also induced histamine release and associated symptoms.
• Estomidate, a new hypnotic, did not cause histamine liberation.

Conclusions:

• Thiopental, methohexital, and propanidide are histamine-releasing agents.
• Clinical manifestations of histamine release may not directly correlate with measured histamine levels.
• Estomidate represents a safer alternative due to its lack of histamine liberation.