BackgroundPerioperative immune function plays an important role in the prognosis of patients. Several studies have indicated that low-dose opioid receptor blockers can improve immune function.MethodsSixty-nine patients undergoing video-assisted thoracoscopic resection of the lung cancer were randomly assigned to either the naloxone group (n = 35) or the non-naloxone group (n = 34) for postoperative analgesia during the first 48 h after the operation. Both groups received sufentanil and palonosetron via postoperative analgesia pump, while 0.05 μg·kg− 1·h− 1 naloxone was added in naloxone group. The primary outcomes were the level of opioid growth factor (OGF) and immune function assessed by natural killer cells and CD4+/CD8+ T-cell ratio. Second outcomes were assessed by the intensity of postoperative pain, postoperative rescue analgesia dose, postoperative nausea and vomiting (PONV).ResultsThe level of OGF in the naloxone group increased significantly at 24 h (p<0.001) and 48 h after the operation (P < 0.01). The natural killer cells (P < 0.05) and CD4+/CD8+ T-cell ratio (P < 0.01) in the naloxone group increased significantly at 48 h after the operation. The rest VAS scores were better with naloxone at 12 and 24 h after operation(P < 0.05), and the coughing VAS scores were better with naloxone at 48 h after the operation(P < 0.05). The consumption of postoperative rescue analgesics in the naloxone group was lower (0.00(0.00–0.00) vs 25.00(0.00–62.50)), P < 0.05). Postoperative nausea scores at 24 h after operation decreased in naloxone group(0.00 (0.00–0.00) vs 1.00 (0.00–2.00), P < 0.01).ConclusionInfusion of 0.05 μg·kg− 1·h− 1 naloxone for patients undergoing sufentanil-controlled analgesia for postoperative pain can significantly increase the level of OGF, natural killer cells, and CD4+/CD8+ T-cell ratio compared with non-naloxone group, and postoperative pain intensity, request for rescue analgesics, and opioid-related side effects can also be reduced.Trial registrationThe trial was registered at the Chinese Clinical Trial Registry on January 26, 2019 (ChiCTR1900021043).

Background: Perioperative immune function plays an important role in the prognosis of patients. Several studies have indicated that low-dose opioid receptor blockers can improve immune function. Methods: Seventy patients undergoing video-assisted thoracoscopic resection of the lung cancer were randomly assigned to either the naloxone group (n=35) or the non-naloxone group (n=35) for postoperative analgesia during the first 48 hours after the operation. Both groups received sufentanil and palonosetron via postoperative analgesia pump, while 0.05μg·kg -1 ·h -1 naloxone was added in naloxone group. The primary outcomes were the level of opioid growth factor （OGF） and immune function assessed by natural killer cells and CD4 + /CD8 + . Second outcomes were assessed by the score of postoperative pain, postoperative rescue analgesia dose, postoperative nausea and vomiting (PONV). Results: The level of OGF in the naloxone group was significantly increased at 24 hours ( p ＜0.001) and 48 hours after the operation ( P <0.01). The natural killer cells ( P <0.05) and CD4+/CD8+ ( P <0.01) in the naloxone group increased significantly at 48 hours after the operation. The rest VAS score was better with naloxone at 12 and 24 hours after operation（ P <0.05）, and the coughing VAS score was better with naloxone at 48 hours after the operation（ P <0.05). The consumption of postoperative rescue analgesics in the naloxone group was lower (0.00（0.00-0.00）vs 25.00（0.00-62.50））， P <0.05). Postoperative nausea score at 24 hours after operation decreased in naloxone group（0.00 (0.00-0.00) vs 1.00 (0.00-1.00), P < 0.01). Conclusion: Infusion of 0.05μg·kg -1 ·h -1 naloxone for patients undergoing sufentanil-controlled analgesia for postoperative pain can significantly increase the level of OGF, natural killer cells, and CD4 + /CD8+ ，And also reduce the postoperative pain intensity, request for rescue analgesics, and opioid-related side effects. Trial registration: ChiCTR1900021043 on January 26, 2019.

Background : Perioperative immune function plays an important role in the prognosis of patients. Several studies have indicated that low-dose opioid receptor blockers can improve immune function. Methods: Sixty-nine patients undergoing video-assisted thoracoscopic resection of the lung cancer were randomly assigned to either the naloxone group (n=35) or the non-naloxone group (n=34) for postoperative analgesia during the first 48 hours after the operation. Both groups received sufentanil and palonosetron via postoperative analgesia pump, while 0.05μg·kg -1 ·h -1 naloxone was added in naloxone group. The primary outcomes were the level of opioid growth factor （OGF） and immune function assessed by natural killer cells and CD4 + /CD8 + T-cell ratio. Second outcomes were assessed by the intensity of postoperative pain, postoperative rescue analgesia dose, postoperative nausea and vomiting (PONV). Results: The level of OGF in the naloxone group increased significantly at 24 hours ( p ＜0.001) and 48 hours after the operation ( P <0.01). The natural killer cells ( P <0.05) and CD4 + /CD8 + T-cell ratio ( P <0.01) in the naloxone group increased significantly at 48 hours after the operation. The rest VAS scores were better with naloxone at 12 and 24 hours after operation（ P <0.05）, and the coughing VAS scores were better with naloxone at 48 hours after the operation（ P <0.05). The consumption of postoperative rescue analgesics in the naloxone group was lower (0.00（0.00-0.00）vs 25.00（0.00-62.50））， P <0.05). Postoperative nausea scores at 24 hours after operation decreased in naloxone group（0.00 (0.00-0.00) vs 1.00 (0.00-2.00), P < 0.01). Conclusion: Infusion of 0.05μg·kg -1 ·h -1 naloxone for patients undergoing sufentanil-controlled analgesia for postoperative pain can significantly increase the level of OGF, natural killer cells, and CD4+/CD8+ T-cell ratio compared with non-naloxone group ，and postoperative pain intensity, request for rescue analgesics, and opioid-related side effects can also be reduced. Trial registration: ChiCTR1900021043 on January 26, 2019. Keywords: Low-dose naloxone, Opioid growth factor, Immune function, Postoperative pain, nausea, vomiting

Background: Perioperative immune function plays an important role in the prognosis of patients. Several studies have indicated that low-dose opioid receptor blockers can improve immune function. Methods: Sixty-nine patients undergoing video-assisted thoracoscopic resection of the lung cancer were randomly assigned to either the naloxone group (n=35) or the non-naloxone group (n=34) for postoperative analgesia during the first 48 hours after the operation. Both groups received sufentanil and palonosetron via postoperative analgesia pump, while 0.05μg·kg-1·h-1 naloxone was added in naloxone group. The primary outcomes were the level of opioid growth factor（OGF）and immune function assessed by natural killer cells and CD4+/CD8+ T-cell ratio. Second outcomes were assessed by the intensity of postoperative pain, postoperative rescue analgesia dose, postoperative nausea and vomiting (PONV). Results: The level of OGF in the naloxone group increased significantly at 24 hours (p＜0.001) and 48 hours after the operation (P<0.01). The natural killer cells (P<0.05) and CD4+/CD8+ T-cell ratio (P<0.01) in the naloxone group increased significantly at 48 hours after the operation. The rest VAS scores were better with naloxone at 12 and 24 hours after operation（P<0.05）, and the coughing VAS scores were better with naloxone at 48 hours after the operation（P<0.05). The consumption of postoperative rescue analgesics in the naloxone group was lower (0.00（0.00-0.00）vs 25.00（0.00-62.50）），P<0.05). Postoperative nausea scores at 24 hours after operation decreased in naloxone group（0.00 (0.00-0.00) vs 1.00 (0.00-2.00), P < 0.01). Conclusion: Infusion of 0.05μg·kg-1·h-1 naloxone for patients undergoing sufentanil-controlled analgesia for postoperative pain can significantly increase the level of OGF, natural killer cells, and CD4+/CD8+ T-cell ratio compared with non-naloxone group，and postoperative pain intensity, request for rescue analgesics, and opioid-related side effects can also be reduced. Trial registration: ChiCTR1900021043 on January 26, 2019. Keywords: Low-dose naloxone, Opioid growth factor, Immune function, Postoperative pain, nausea, vomiting

Background: Perioperative immune function plays an important role in the prognosis of patients.Several studies have indicated that low-dose opioid receptor blockers can improve immune function.Methods: Sixty-nine patients undergoing video-assisted thoracoscopic resection of the lung cancer were randomly assigned to either the naloxone group (n=35) or the non-naloxone group (n=34) for postoperative analgesia during the first 48 hours after the operation. Both groups received sufentanil and palonosetron via postoperative analgesia pump, while 0.05μg·kg-1·h-1 naloxone was added in naloxone group. The primary outcomes were the level of opioid growth factor OGF and immune function assessed by natural killer cells and CD4+/CD8+ T-cell ratio. Second outcomes were assessed by the intensity of postoperative pain, postoperative rescue analgesia dose, postoperative nausea and vomiting (PONV). Results: The level of OGF in the naloxone group increased significantly at 24 hours (p 0.001) and 48 hours after the operation (P<0.01). The natural killer cells (P<0.05) and CD4+/CD8+ T-cell ratio (P<0.01) in the naloxone group increased significantly at 48 hours after the operation. The rest VAS scores were better with naloxone at 12 and 24 hours after operation P<0.05 , and the coughing VAS scores were better with naloxone at 48 hours after the operation P<0.05). The consumption of postoperative rescue analgesics in the naloxone group was lower (0.00 0.00-0.00 vs 25.00 0.00-62.50 P<0.05). Postoperative nausea scores at 24 hours after operation decreased in naloxone group 0.00 (0.00-0.00) vs 1.00 (0.00-2.00), P < 0.01).Conclusion: Infusion of 0.05μg·kg-1·h-1 naloxone for patients undergoing sufentanil-controlled analgesia for postoperative pain can significantly increase the level of OGF, natural killer cells, and CD4+/CD8+ T-cell ratio compared with non-naloxone group and postoperative pain intensity, request for rescue analgesics, and opioid-related side effects can also be reduced. Trial registration: The trial was registered at the Chinese