Objective To investigate the influence of subanesthetic doses of esketamine administered through different routes on postoperative fatigue syndrome in patients treated with thoracoscopic radical resection of lung cancer.

Methods The patients scheduled by single-port thoracoscopic radical resection of lung cancer were selected as the research subjects. They were randomly divided into the intravenous injection group (group EV), nerve block group (group EN) and control group (group N), with 33 cases in each group. In the group EV, 20 mL of 0.375% ropivacaine was used for modified intercostal nerve block. In the group EN, 20 mL of a mixed solution of 0.375% ropivacaine and 0.25 mg/kg esketamine was used for modified intercostal nerve block. In the group N, 20 mL of 0.375% ropivacaine was used for modified intercostal nerve block. The subjective fatigue degree of patients was evaluated by using the fatigue scale-14 (FS-14) and 15-item quality of recovery scale (QoR-15) score. The scale was evaluated before 1 day of operation (T₁) to uniformly incorporate the baseline of the patients' scale scores, and the differences of fatigue levels after 24 hours (T₂) and 48 hours (T₃) of operation were compared. Simultaneously the immune-inflammatory indicators, such as CD4⁺, CD8⁺, interleukin-6 (IL-6), C-reactive protein (CRP) and white blood cells(WBC) at T₁, T₂ and T₃ were monitored. The occurrence of adverse reactions in patients after surgery were recorded.

Results After 30 minutes and six hours of extubation, the postoperative VAS scores of the group EN and group EV were significantly lower than those of group N, and those in the group EN were lower than those in group EV (P < 0.05). When comparing among groups at T₂ and T₃, the FS-14 scores in the group EN and group EV were lower, which the score of the group EN was lower than that of group EV. The levels of CD4⁺, CD8⁺, IL-6, CRP and WBC in the group EN and group EV were all significantly lower than those in group N (P < 0.05). The number of spontaneous compressions of the analgesic pump in the group EN was significantly reduced (P < 0.05), and the time of the first compression in the group EN was significantly prolonged (P < 0.05). There was no statistical significance in the occurrence of adverse reactions among three groups (P>0.05).

Conclusions Esketamine-assisted modified intercostal nerve block can relieve the postoperative fatigue, improve the postoperative recovery quality, and improve immune inflammatory indicators without increasing adverse reactions in patients undergoing thoracoscopic radical resection of lung cancer.