Duration of analgesia is similar when 15, 20, 25 and 30 mL of ropivacaine 0.5% are administered via a femoral catheter

Purpose: This dose-response study was designed to determine the most appropriate dose of ropivacaine 0.5% injected via an indwelling femoral catheter for perioperative peripheral analgesia for total knee replacement (TKR). Methods: 84 patients were allocated randomly to four groups and received, via a femoral catheter, either 15, 20, 25 or 30 mL of ropivacaine 0.5% in a double-blind fashion. An anterior sciatic block with 20 mL bupivacaine 0.5% was also performed. The evolution of sensory block of femoral, obturator and lateral femoral cutaneous nerves and motor block of femoral nerve were tested every five minutes during the first 30 min. The percentage of patients with complete sensory block of both femoral and obturator nerves determined success rate. General anesthesia was then induced. After surgery, patient-controlled analgesia (PCA) with ropivacaine 0.2% was available via the femoral catheter. The interval between the initial injection and the first PCA administration determined duration of action. Results: The duration of action was not different between the four solutions tested i.e., 534 ± 379 min for 15 mL, 799 ± 364 min for 20 mL, 624 ± 342 min for 25 mL and 644 ± 266 min for 30 mL. The percentage of patients with complete sensory femoral and obturator blocks was, respectively, 60%, 95%, 85% and 70% for 15, 20, 25 and 30 mL (P = 0.008/15 mL vs 20 mL). Conclusion: Although there is no difference in duration of analgesia, because of better sensory spread, 20 mL of ropivacaine 0.5% appears to be the most appropriate dose for peripheral analgesia after TKR. Objectif: L'étude dose-réponse visait à déterminer la meilleure dose de ropivacaïne à 0,5 % injectée par cathéter fémoral à demeure pour l'analgésie périopératoire périphérique lors d'une arthroplastie totale du genou (ATG). Méthode: Nous avons réparti au hasard, en quatre groupes, 84 patients qui ont reçu par cathéter fémoral 15, 20, 25 ou 30 mL de ropivacaïne à 0,5 % en double insu. Un bloc sciatique antérieur a aussi été réalisé avec 20 mL de bupivacaïne à 0,5 %. L'évolution du bloc sensitif des nerfs fémoral, obturateur et cutané latéral de la cuisse et du bloc moteur du nerf fémoral a été vérifiée toutes les cinq minutes pendant les 30 premières minutes. Le pourcentage de patients qui présentait un bloc sensitif complet des nerfs fémoral et obturateur a déterminé le taux de succès. L'anesthésie générale a ensuite été induite. Après l'opération, l'analgésie auto-contrôlée (AAC) avec de la ropivacaïne à 0,2 % était disponible par cathéter fémoral. L'intervalle entre l'injection initiale et la première administration d'AAC a donné la durée d'action. Résultats: La durée d'action a été comparable dans tous les groupes : 534 ± 379 min avec 15 mL, 799 ± 364 min avec 20 mL, 624 ± 342 min avec 25 mL et 644 ± 266 min avec 30 mL. Le pourcentage de patients présentant un bloc sensitif complet des nerfs fémoral et obturateur a été respectivement de 60 %, 95 %, 85 % et 70 % pour les doses de 15, 20, 25 et 30 mL (P = 0,008/15 mL vs20 mL). Conclusion: Même si la durée de l'analgésie est équivalente, grâce à une meilleure diffusion sensitive, 20 mL de ropivacaïne à 0,5 % semble être la dose la plus appropriée pour l'analgésie périphérique après une AT

Levobupivacaine 0.5% provides longer analgesia after sciatic nerve block using the Labat approach than the same dose of ropivacaine in foot and ankle surgery

BACKGROUND: Levobupivacaine and ropivacaine are 2 left enantiomeric molecules frequently used for peripheral nerve blocks because of their safe clinical profile. Levobupivacaine is more lipophilic and theoretically more potent than ropivacaine, but clinical studies show conflicting results in terms of anesthetic and analgesic characteristics. We hypothesized that the pure S-enantiomer of bupivacaine provides longer-lasting analgesia than ropivacaine. METHODS: We compared the analgesic characteristics of 20 mL levobupivacaine versus 20 mL ropivacaine 0.5% in a posterior sciatic nerve block (Labat approach) for foot and ankle surgery. In a double-blind, randomized, prospective design, 80 patients received either substance. We assessed the onset, duration, and success of the block, and the need for rescue analgesia and technical or neurologic complications over 24 hours. RESULTS: The onset of sensory block (minutes) and the success rate were similar in levobupivacaine and ropivacaine groups (onset, 15 minutes [5-40 minutes] vs 15 minutes [5-60 minutes], respectively; success rate, 90% vs 92.5%). The average time for the first request of pain medication provided by 20 mL levobupivacaine 0.5% was significantly longer than with ropivacaine (1605 minutes [575-2400 minutes] vs 1035 minutes [590-1500 minutes], P < 0.001). The need for postoperative rescue analgesia was higher in the ropivacaine group (37 of 40 [92.5%] vs 30 of 40 [75%], P < 0.034). No complications were noted in either group at 24 hours. CONCLUSION: Twenty milliliters levobupivacaine 0.5% in posterior gluteal (Labat) sciatic nerve block provided longer-lasting analgesia after foot and ankle surgery compared with the same dose of ropivacaine

Clonidine combined with a long acting local anesthetic does not prolong postoperative analgesia after brachial plexus block but does induce hemodynamic changes

Clonidine in brachial plexus block prolongs analgesia of local anesthetics of short and intermediate duration. We performed a prospective randomized double-blinded study to determine the efficacy and adverse effects of clonidine mixed with a long-acting local anesthetic on postoperative analgesia. Sixty adult patients underwent elective rotator cuff repair using interscalene brachial plexus block combined with general anesthesia and were randomly divided into one of the following three groups. Placebo (n = 20): interscalene block with 40 mL of 0.5% bupivacaine with epinephrine (1/200000) and 1 mL of 0.9% saline, completed by 1 mL of 0.9% saline IM in the controlateral shoulder; Control (n = 20): interscalene block with 40 mL of 0.5% bupivacaine with epinephrine and 1 mL of 0. 9% saline, completed by 150 microg (=1 mL) of clonidine IM; Clonidine (n = 20): interscalene block with 40 mL of 0.5% bupivacaine with epinephrine and 150 microg (=1 mL) of clonidine, completed by 1 mL of 0.9% saline IM. During anesthesia hemodynamic variables and fractional expired isoflurane concentration (FeISO) were recorded. The following postoperative variables were assessed: duration of interscalene block, quality of pain relief on a visual analog scale, side effects, and consumption of morphine with a patient-controlled analgesia device over 48 h. Patient characteristics were comparable. During anesthesia mean arterial pressure, heart rate, and FeISO were significantly decreased in Clonidine and Control groups compared with Placebo group. Duration of analgesia, defined as the time elapsed from interscalene injection to the first morphine request, was 983 +/- 489 min in the Placebo, 909 +/- 160 min in the Control, and 829 +/- 159 min in the Clonidine groups. Pain scores and consumption of morphine at 24 h and 48 h showed no differences among the three groups. We conclude that adding 150 microg of clonidine in interscalene block does not prolong analgesia induced by 40 mL of bupivacaine 0.5% with epinephrine, but decreases mean arterial blood pressure and heart rate

Partial sensory and motor deficit of ipsilateral lower limb after continuous interscalene brachial plexus block

We describe a partial sensory and motor block of the ipsilateral lower limb after interscalene infusion. After and injection of 20 mL of ropivacaine through the needle, the catheter was advanced 5 cm, and an infusion of ropivacaine 0.2% 5 mL/h commenced. Six hours later, the patient reported a left sensory and motor hemisyndrome, which resolved after the infusion was discontinued. Cervical computed tomography showed the tip of the catheter close to the intervertebral foramen at the C7-T1 level and several intravertebral paramedullar air bubbles. We conclude that the neurological symptoms were caused by an injection of local anesthetic via an interscalene catheter placed in proximity to the epidural space. To avoid this complication, we recommend advancing the catheter no more than 2-3 cm and performing frequent neurological evaluation of patients

Epinephrine does not prolong the analgesia of 20 mL ropivacaine 0.5% or 0.2% in a femoral three-in-one block

We tested the effect of epinephrine added to 20 mL ropivacaine 0.5% and 0.2% on postoperative analgesia via a femoral catheter after total knee replacement. Forty-one patients undergoing total knee replacement under combined peripheral block/general anesthesia were randomly allocated to two groups. After insertion of a femoral catheter, 21 patients in the Ropivacaine-Epinephrine (ROPI-EPI) group received 20 mL ropivacaine 0.5% plus epinephrine 1:200,000, whereas 20 patients in the Ropivacaine group (ROPI) received 20 mL plain ropivacaine 0.5%. Thereafter, a sciatic block with 30 mL bupivacaine 0.5% plus epinephrine 1:200,000 was performed in all patients, followed by general anesthesia. After surgery, patient-controlled analgesia (PCA) with ropivacaine 0.2% plus epinephrine 1:200,000 for Group ROPI-EPI and plain ropivacaine 0.2% for Group ROPI was available via the femoral catheter (200 mL ropivacaine 0.2% +/- epinephrine, bolus 20 mL, lockout 120 min). The patients were instructed to use PCA when the knee pain score was >3 cm. The interval between the initial ropivacaine injection and the first PCA injection determined the duration of 20 mL ropivacaine 0.5% +/- epinephrine, whereas the interval between the first and second PCA injection determined the duration of 20 mL ropivacaine 0.2% +/- epinephrine. The average duration of ropivacaine 0.5% was 657 +/- 345 min for the ROPI-EPI group and 718 +/- 423 min for the ROPI group (NS), whereas for ropivacaine 0.2%, the average duration was 409 +/- 245 min for the ROPI-EPI group and 419 +/- 339 min for the ROPI group (not significant). We conclude that epinephrine does not influence the duration of analgesia of the ropivacaine concentrations investigated

Isobaric versus hypobaric spinal bupivacaine for total hip arthroplasty in the lateral position

Total hip arthroplasty (THA) is frequently performed under spinal anesthesia using either isobaric or hypobaric anesthetic solution. However, these two solutions have never been compared under similar surgical conditions. In the present study, we compared the anesthetic and hemodynamic effects of isobaric and hypobaric bupivacaine in 40 ASA physical status I-II patients undergoing THA in the lateral decubitus position under spinal anesthesia. With operative side up, patients randomly received, in a double-blinded manner, a spinal injection of 3.5 mL (17.5 mg) of plain bupivacaine mixed with either 1.5 mL of normal saline (isobaric group) or 1.5 mL of distilled water (hypobaric group). Sensory level and degree of motor block were evaluated on the nondependent and dependent sides until regression to L2 and total motor recovery. Hemodynamic changes during the first 45 min after spinal injection, and the time between spinal administration and first analgesic for a pain score >3 (on a 0-10 scale) were noted. Demographic characteristics of both groups were comparable. Upper sensory level and maximal degree of motor block were comparable between the operative and nonoperative sides in each group and between corresponding sides in both groups. Compared with the isobaric group, in the hypobaric group there was a prolonged time to sensory regression to L2 on the operative side (287 +/- 51 versus 242 +/- 36 min, P < 0.004) and a prolonged time to first analgesic (290 +/- 46 versus 237 +/- 39 min, P < 0.001). No difference in quality of motor block was noted at the end of surgery. Hemodynamic changes were comparable. We conclude that for THA in the lateral position, spinal hypobaric bupivacaine seems to be superior to isobaric in that it prolongs the sensory block on the operative side and delays the use of analgesics after surgery without further compromising hemodynamic stability