Abstract:Objective To assess the effects of ultrasound-guided nerve block analgesia on immune microenvironment in patients with rectal cancer (RC) during perioperative period. Methods Sixty patients with rectal cancer were selected as the study subjects and randomly divided into two groups: control group ［general anesthesia (GA)+patient-controlled intravenous analgesia (PCIA)scheme］ and test group (GA+PCIA+NB scheme). The total dosage of opioids during and after operation was recorded. The levels of NK, CD4⁺, CD4⁺/CD8⁺cells and IL-6 were measured 24 hours before, during and 6, 12 and 24 hours after operation. Results The amount of sufentanil during and after operation in the two groups was significantly increased (P＜0.01), and the amount of sufentanil in the control group was 4.6 μg more than that in the test group every 6 h (P＜0.01)。 The remedial analgesia rate in test group was significantly lower than that in the control group (16.7% vs 46.7%, P=0.012). In the two groups, except for the slight increase of IL-6 in the 24 h before and during the operation, the four indexes of NK, CD4⁺, CD4⁺/CD8⁺ and IL-6 showed a trend of first inhibition and then recovery, and the inhibition of IL-6 lasted the longest, followed by NK cells, while CD4⁺and CD4⁺/CD8⁺cells recovered earlier. Comparing CD4⁺and CD4⁺/CD8⁺cells, it was found that the inhibition lasted longer in the control group than in the test group (P＜0.05). Conclusion Ultrasound-guided NB technology can reduce the consumption of opioids during and after radical resection of rectal cancer, and reduce the inhibition of immune function.