Optimizing the dose of intrathecal morphine when combined with continuous 3-in-1 nerve block after total knee replacement

Abstract

Background: Continuous femoral 3-in-1 block alone is insufficient for the treatment of severe pain after total knee replacement (TKR). Intrathecal (IT) morphine provides effective postoperative analgesia but may result in many side effects. The optimal dose of spinal morphine when combined with continuous 3-in-1 block after TKR is not known.Methods: Patients were randomized to receive IT morphine in five groups (n = 20 per group): 1) 0.0 mg, 2) 0.05 mg, 3) 0.1 mg, 4) 0.15 mg, and 5) 0.2 mg. All patients received continuous 3-in-1 block performed with 20 ml of 0.25% bupivacaine, followed by a continuous infusion of 0.125% bupivacaine at the rate of 2 ml/h plus PCA boluses of 1 ml with a lockout of 10 minutes. The intensity of pain at rest and on movement of the knee was assessed by using a visual analog scale for the first two postoperative days.Results: All treatment groups produced effective pain relief and decreased cumulative femoral PCA bolus use of 0.125% bupivacaine compared with control, respectively (P ＜ 0.05); however, there were no significant differences among the treatment groups. The incidence of vomiting was significantly more frequent with 0.1−0.2 mg IT morphine groups compared with control, respectively (P ＜ 0.05). The rate of administration of antipruritic medication was increased as IT morphine dose increased (P ＜ 0.05).Conclusions: Use of 0.05 mg IT morphine would appear to provide the optimal balance between pain relief and adverse effects following TKR.

Efficacy and safety of intrathecal morphine for analgesia after lower joint arthroplasty: a systematic review and meta‐analysis with meta‐regression and trial sequential analysis

“…Most trials used bupivacaine for spinal anaesthesia, except in three studies where levobupivacaine [51] or tetracaine [30,48] analgesia was used in one study [25]. In patients scheduled for knee arthroplasty, additional analgesic techniques employed were local infiltration analgesia [26,43,49]; local infiltration analgesia with adductor canal block [27]; femoral nerve block [39,40,46,47]; continuous femoral nerve block [51]; and epidural analgesia [38]. Finally, four studies reported the use of a multimodal analgesic regimen in the postoperative period [25][26][27]46].…”

“…We identified 1198 trials, with 29 different trials published in 29 distinct manuscripts, including a total of 1814 patients, meeting the inclusion criteria [25–53] (see also Supporting Information Fig. S1).…”

“…We identified 1198 trials, with 29 different trials published in 29 distinct manuscripts, including a total of 1814 patients, meeting the inclusion criteria [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ] (see also Supporting Information Fig. S1).…”

“…The risk of bias of the different trials is summarised in Figure 1 . Fourteen authors were contacted [ 27 , 31 , 34 , 39 , 40 , 43 , 44 , 45 , 46 , 47 , 49 , 50 , 51 , 52 ] and five provided additional data [ 27 , 31 , 39 , 44 , 51 ].…”

“…Table 1 shows the trial characteristics. In eight and 14 trials, authors included patients undergoing hip [ 25 , 32 , 36 , 37 , 41 , 42 , 44 , 53 ] or knee arthroplasty [ 26 , 27 , 28 , 29 , 38 , 39 , 40 , 43 , 46 , 47 , 49 , 50 , 51 , 52 ], respectively, while seven trials included both [ 30 , 31 , 33 , 34 , 35 , 45 , 48 ]. One trial presented separate results for hip and knee arthroplasties [ 48 ].…”