[[Redefining the Initial Endoscopy Evaluation of Esophageal Symptoms: Toward a PrecisionBased Diagnostic Paradigm]].

The noble gases, including helium, neon, argon, krypton, xenon, and radon, were chemically inert elements whose closed-shell electronic structure made them largely nonreactive under physiological conditions. Among them, xenon had been studied most extensively and had been used clinically as an inhalational anesthetic (). Beyond its anesthetic properties, xenon had attracted increasing attention because of its potential neuroprotective effects. In addition to xenon, argon and helium had also been investigated for possible neuroprotective properties in experimental models (; ; ; ). Other noble gases, such as krypton and neon, had also been explored, but the currently available evidence remained limited and lied outside the main scope of this review (; ; ). Therefore, this narrative review focused on the neuroprotective effects of xenon, argon, and helium in acquired brain injury. Acquired brain injury was a broad term that generally referred to brain damage occurring after birth as a result of traumatic or non-traumatic causes. This review focused primarily on traumatic brain injury, ischemic stroke, and post-cardiac arrest hypoxic-ischemic brain injury, which together represented major forms of acquired brain injury examined in both experimental and early clinical studies. Among the major forms of acquired brain injury, traumatic brain injury (TBI) remained an important cause of death and disability worldwide (). In China, the absolute number of TBI cases remains substantial, and TBI was reported more frequently in men than in women (). The leading cause of TBI also varied across regions. In China, common causes of TBI included traffic accidents, falls, and violence (). Neuroprotection referred to strategies that preserved neuronal structure and function and limit secondary injury after brain insult (). In acquired brain injury, secondary injury mechanisms—including excitotoxicity, oxidative stress, inflammation, apoptosis, and blood-brain barrier disruption—substantially contributed to neurological deterioration (). Accordingly, therapies capable of attenuating these secondary processes might improve histological and functional outcomes after brain injury ().