Delirium, as per the diagnostic criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders, Delirium, is characterized by an acute onset of attention and awareness disturbances, involving cognitive impairments, such as memory deficits, disorientation, and language or perception issues [1]. Delirium is often a complication of post-cardiac surgery [2]. Postoperative delirium (POD) has been linked with increased morbidity and related complications [3]. Evidence suggests that the analgesia and sedative of choice may play a part in the incidence of POD and may affect short- and long-term outcomes [4] (see Fig. 9).

Anesthetic agents such as sevoflurane and propofol are commonly used and have shown notable effects on POD [5]. Several studies have suggested that volatile anesthetics may have cardioprotective effects, an important aspect of postoperative cardiac complications [6,7]. However, the data on their role in preventing POD remains inconclusive [8].

Xenon interacts with the N-methyl-d-aspartate (NMDA) receptor which results in neuroprotective effects, due to the suppression of ischemia-induced neurotransmitter release, and may increase synthesis of pro-survival proteins and decrease apoptosis [9]. Xenon can also activate plasmalemma ATP-sensitive potassium channels thereby reducing neuronal excitability, and providing protection against ischemic injury. In this context, xenon has appeared as a possible substitute owing to its pharmacological profile. Compared to conventional anesthetics, Xenon has been described as having minimal hemodynamic complications and a promising safety profile [10]. Additionally, both clinical and experimental research have established its cardioprotective and neuroprotective properties [11,12].

Xenon may be beneficial in terms of morbidity and mortality, as well as for the left ventricular function, compared to propofol or sevoflurane anesthesia [13,14]. Thus, its usefulness in cardiac surgery due to its cardiovascular stabilization properties may be evident [17,18]. In non-cardiac surgery, it may provide good blood flow within blood vessels, and may assist in maintaining the tone of the autonomic nervous system [13,14], and enhance the recovery of myocardial tissue while limiting the occurrence of infarction [15,16]. However, there are not enough studies in children to confirm whether its effect is as striking as its effect in older patients. Although the Devroe study (2018) showed that all children in the study who used xenon-enhanced sevoflurane anesthesia had better neurocognitive performance after surgery than the control group, statistically significant differences were not observed.

Given this, the applicability of xenon in the prevention of POD and other complications in cardiac surgeries continues to be an area of current research. Currently, there are several randomized controlled trials (RCTs) and observational studies to evaluate the safety and efficacy of xenon anesthesia in cardiac surgeries, but a synthesis of the body of evidence is deficient. Considering the effects of POD on patient outcomes, there is a current need for a systematic review and meta-analysis that can clarify the role of Xenon in anesthesia.

Thus, this systematic review aims to compile and analyze the current literature to evaluate whether xenon is an effective method for preventing postoperative delirium in cardiac surgeries.