Intranasal perfluorochemical spray for preferential brain cooling in sheep

Area of Science:

• Neuroscience
• Medical Devices
• Thermoregulation

Background:

• Hypothermic brain protection effectiveness depends on rapid and uniform cooling to the therapeutic hypothermic zone (THZ).
• The nasopharyngeal (NP) route offers anatomical advantages for preferential brain cooling due to its proximity to cerebral vasculature.
• This study investigates a new NP cooling method utilizing aerosolized perfluorochemical (PFC).

Purpose of the Study:

• To evaluate a novel NP cooling approach using aerosolized PFC for rapid and preferential brain cooling.
• To compare the efficacy of NP-PFC cooling with whole body surface (WBS) cooling in reaching the brain THZ.
• To assess the safety and physiological effects of the NP-PFC method.

Main Methods:

• Anesthetized sheep (n=30) were randomized to NP-PFC (n=24) or WBS (n=6) cooling.
• Temperature probes and vascular catheters monitored regional temperatures and vital signs.
• Cooling rates and time to reach brain THZ (< or =-3.5°C below baseline) were analyzed.

Main Results:

• NP-PFC cooling resulted in significantly faster brain cooling compared to WBS (P < 0.001).
• The NP-PFC method achieved brain THZ within 15 minutes, maintaining brain-to-systemic temperature gradients.
• WBS cooling did not achieve significant brain cooling or reach THZ within 2 hours; NP epithelium remained intact.

Conclusions:

• The NP-PFC procedure significantly accelerated preferential brain cooling compared to WBS.
• This novel NP cooling method effectively and safely induced therapeutic hypothermia in the brain.
• The NP-PFC approach demonstrates potential for improved neuroprotection strategies.