Site(s) mediating sympathetic activation with desflurane

Area of Science:

• Anesthesiology
• Neurophysiology

Background:

• Desflurane's neurocirculatory activation mechanism requires precise identification of afferent pathways.
• Understanding these pathways is crucial for safe anesthetic administration.

Purpose of the Study:

• To delineate the specific afferent sites responsible for desflurane-induced neurocirculatory activation.
• To investigate the role of upper airway and pulmonary receptors in this response.

Main Methods:

• Three studies in healthy volunteers (aged 19-28) monitored cardiovascular and sympathetic responses.
• Desflurane was selectively delivered to upper/lower airways or lungs using double-lumen tubes.
• Lidocaine or placebo was administered to assess its effect on desflurane's neurocirculatory activation.

Main Results:

• Desflurane directed to the upper airway caused significant increases in heart rate, blood pressure, and sympathetic activity.
• Delivery to the lungs induced even greater neurocirculatory responses, independent of systemic desflurane levels.
• Lidocaine administration did not attenuate the observed desflurane-induced neurocirculatory activation.

Conclusions:

• Both upper airway (laryngeal) and pulmonary sites initiate sympathetic activation during desflurane administration.
• These responses are partly independent of systemic anesthetic concentrations.
• The findings suggest direct airway mucosal irritation and distinct pulmonary reflexes contribute to desflurane's effects.