Optimizing dose infusion of 0.125% bupivacaine for continuous femoral nerve block after total knee replacement

Abstract

BackgroundThe optimal dose infusion of 0.125% bupivacaine via a femoral catheter after total knee replacement (TKR) has not been defined. This study examined various dose infusions of bupivacaine to determine the analgesic quality in patients receiving a continuous femoral nerve block (CFNB).MethodsPatients were randomized to receive a single-injection femoral nerve block (SFNB) or CFNB performed with 20 ml of 0.125% bupivacaine, followed by a continuous infusion of 0.125% bupivacaine in four groups (n = 20 per group): 1) 0 ml/h (SFNB), 2) 2 ml/h, 3) 4 ml/h, and 4) 6 ml/h. The pain intensity at rest and on knee movement was assessed using a visual analog scale (VAS) for the first 2 postoperative days. The cumulative bolus use of IV patientcontrolled analgesia (PCA) with a morphine-ketorolac combination was evaluated.ResultsA lower cumulative bolus of IV PCA was noted in all CFNB groups compared to SFNB on postoperative days (PODs) 1 and 2, respectively (P < 0.05). Lower VAS scores at rest were observed in the 4 ml/h and 6 ml/h groups than in the SFNB group on PODs 1 and 2, respectively, but only on POD 2 in the 2 ml/h group (P < 0.05). Lower VAS scores on movement were noted in the 4 ml/h than the SFNB group on PODs 1 and 2, but only on POD 1 in 6 ml/h (P < 0.05).ConclusionsThe minimum effective infusion rate of 0.125% bupivacaine for CFNB after TKR appears to be 4 ml/h according to the VAS pain scores.

Dexamethasone as adjuvant for femoral nerve block following knee arthroplasty: a randomized, controlled study

“…The aim of the bupivacaine infusion was to incorporate a multimodal analgesic strategy to ameliorate pain and to decrease the use of opioids and their side effects . The 4 ml/h dose was chosen based on the study of Park and colleagues who demonstrated that this rate was the lowest effective analgesic dose …”

Eficacia analgésica de una dosis única de dexametasona perineural en el bloqueo ecoguiado del nervio femoral en cirugía de prótesis total de rodilla

“…Los eventos adversos graves son raros con el bloqueo femoral, sin haberse descrito complicaciones importantes derivados del mismo en PTR. Sin embargo, el bloqueo femoral continuo no está recomendado actualmente, según la evidencia científica, para cirugía de PTR (recomendación G, evidencia 4) debido a la gran heterogeneidad de los resultados obtenidos en las últimas revisiones [102][103][104] .…”

The efficacy of continuous versus single-injection femoral nerve block in Total knee Arthroplasty: a systematic review and meta-analysis

“…Multimodal pain management in total joint arthroplasty involves a combination of modalities that act on different regions of the pain pathway to achieve better pain relief [2][3][4]. In the setting of multimodal analgesic protocols, a few studies reported a lower VAS score in the cFNB group [10,11,17], while other studies did not find a difference [9,12,18,19]. Since many studies employed spinal anesthesia (or subarachnoid block), PCA and/or sciatic nerve block as part of their regimen, it could have greatly alleviated pain and may masked the efficacy of femoral nerve blocks.…”

“…To manage postoperative pain and facilitate early mobilization and rehabilitation, the concept of multimodal analgesic protocol has been employed [2][3][4]. Femoral nerve block is a regional nerve block frequently performed after TKAs as part of a multimodal analgesia regimen [5][6][7][8][9][10][11]. Currently, there are two commonly used methods to administer femoral nerve blocks, the continuous femoral nerve block (cFNB) and single-shot femoral nerve block (sFNB).…”

“…FNB has been proven to have a beneficial effect on pain management but it remains uncertain whether cFNB can lead to additional benefits compared with that of sFNB in the setting of multimodal analgesic protocols (eg. pain scores at different time points, amount of opioid consumption, adverse effects of opioids, length of hospital stay and functional outcomes) [9][10][11][12][13][14]. Due to the mixed results in current literature, it is undetermined whether the additional benefits of cFNB over sFNB are worthy of its extra cost and time involved.…”