[The application of combining low dose naloxone with ropivacaine in supraclavicular brachial plexus block].

To observe the effect of low dose naloxone combinewith ropivacaine for supraclavicular brachial plexus block. Seventy patients undergoing elective upper limb surgery were randomly divided into two groups, ropivacaine group (Group R, =35) and naloxone group (Group N, =35). An ultrasound guided technique was used in both two groups.The onset and duration time of sensory and motor blockade, visual analog score(VAS)of 3, 6, 12, 18, 24 h postoperatively, time of first request fordezocine, total amount of dezocine needed, incidence of nausea and vomiting postoperatively(PONV) and patients' satisfaction score for analgesia in 24 h after surgery were measured.At the same time, blood samples were taken before anesthesia, 6 h, 24 h after operation for inspecting the concentration of β-endorphin(β-EP)in plasma. The duration of sensory and motor blockade, time of first request for dezocine in Group N were 736.0(713.5, 836.5), 514.5(491.3, 572.8), 708.5(683.2, 877.0)min, which were all prolonged compared to Group R(522.0(469.5, 606.5), 401.0(370.0, 458.5), 570.0(435.0, 618.5)min)(=-6.844, -6.758, -6.700, all <0.01). The 6, 12, 18 h postoperatively VAS of Group N were 0, 5.0(3.0, 5.8), 5.0(5.0, 6.0)point. Among which the 6, 12 h postoperatively VAS of Group N were lower than that of Group R(1.0(1.0, 3.5), 6.0(6.0, 7.0)point)(=-6.596, -4.864, all <0.01), while the 18 h postoperatively VAS was higher than that of Group R (5.0(4.0, 5.0)point)(=-2.603, <0.01). Total amount of dezocine needed in Group N in 24 h after surgery was 7.5(5.0, 10.0)mg, which was lower than that of Group R(10.0(10.0, 15.0)mg)(=-3.449, <0.01). The incidence of PONV after surgery in Group N was 21.9%, which was lower than that of Group R(45.5%)(χ(2)=4.034, <0.05). Ptients' satisfaction score for analgesia in 24 h after surgery in Group N was 8.0(7.0, 8.0)point, which was higher than that of Group R(7.0(6.0, 7.0)point)(=-3.509, <0.01). At 6 h postoperatively , the concentration of plasma β-EP in Group N was(113.34±12.36)μg/L, lower than that of Group R((147.14±11.65)μg/L)(=-7.694, <0.01). Low dose naloxone combine with ropivacaine for supraclavicular brachial plexus block, prolong the duration of sensory and motor blockade without affecting the onset time.