Resuscitation from experimental heatstroke by hyperbaric oxygen therapy.

Area of Science:

• Physiology
• Toxicology
• Emergency Medicine

Background:

• Heatstroke is a life-threatening condition characterized by hyperthermia, vasoplegic shock, and cerebral ischemia/hypoxia.
• Hyperbaric oxygen (HBO) has shown promise in mitigating brain ischemia and dysfunction in other conditions.
• The effectiveness of HBO for heatstroke resuscitation requires laboratory investigation.

Purpose of the Study:

• To determine the efficacy of hyperbaric oxygen (HBO) therapy in the resuscitation of experimental heatstroke in rats.
• To evaluate the impact of various hyperbaric and normobaric oxygenation strategies on heatstroke outcomes.

Main Methods:

• Male Sprague-Dawley rats were subjected to heatstroke by exposure to 43°C.
• Rats were randomized to receive different resuscitation protocols: normobaric air, HBO (100% O2 at 253 kPa), cyclic HBO, hyperbaric air, normobaric hyperoxia, or 8% HBO.
• Physiological parameters, blood markers (pH, gases, TNF-α), and cortical neuronal damage were assessed.

Main Results:

• HBO for 1 hour and cyclic HBO significantly increased survival time compared to controls.
• Heatstroke induced hypotension, bradycardia, altered blood gases, elevated TNF-α, and increased cellular damage markers.
• HBO treatments effectively reduced neuronal damage scores in the cerebral cortex.

Conclusions:

• Hyperbaric oxygen (HBO) therapy is beneficial for resuscitating rats from experimental heatstroke.
• HBO effectively counteracted heatstroke-induced hypotension, hypoxia, inflammation (TNF-α), and cerebral injury.
• Various hyperbaric and hyperoxic interventions showed some benefit, but HBO demonstrated the most significant improvements in survival and neurological outcomes.