Assessment of xenon effect on postoperative pain syndrome severity in oncological patients: a randomized study

Introduction. The present study was designed to evaluate analgetic effect of xenon-oxygen mixture inhalations in oncological patients with abdominal tumors in postoperative period. Materials and methods. It was randomized blind placebo-controlled clinical trial, which was performed in 60 patients: 31 of them were in the main group and received xenon-oxygen mixture containing 25 ± 5 % xenon and other 29 were in the placebo group and received oxygen-air mixture. Results. According to the visual-analogical scale of pain, significant decreasing of the pain level was found in the main group after the inhalation and 30 minutes later in 90.3 % (p < 0.01) and 80.6 % of patients (p < 0.05) accordingly. The same result was found in the placebo group in 37.9 % of patients after oxygen-air mixture inhalation and 30 minutes later in 27.4 % of patients. The pain threshold measured with transcutaneal electroneurostimulation significantly increased in the xenon group after the inhalation (p < 0.01) and 30 minutes later (p < 0.05). In the placebo group no difference between the measurements was found. Conclusions. Xenon-oxygen mixture inhalation leads to the postoperative pain level reduction and increases the pain threshold in oncological patients.