The effects of interscalene brachial plexus block on humeral arterial blood flow: a Doppler ultrasound study.

In this study we investigated and quantified the effects of interscalene block (ISB) on humeral arterial blood flow (HBF). Eleven patients scheduled for shoulder arthroscopic surgery under ISB were prospectively studied. A Doppler ultrasound of the humeral artery was performed before, and 30 min after, the ISB. The resistance index and the HBF were measured at the level of the midpoint of the upper arm. The median (interquartile range) of resistance index decreased from 0.98 (0.95-1.00) to 0.81 (0.77-0.91) (P < 0.01). The median HBF increased from 32 (18-46) to 88 (59-98) mL/min (P < 0.01). We conclude that ISB enhances arterial blood flow and decreases arterial resistance.

Femoral block provides superior analgesia compared with intra-articular ropivacaine after anterior cruciate ligament reconstruction.

BACKGROUND AND OBJECTIVES: Arthroscopic anterior cruciate ligament (ACL) reconstruction of the knee is a painful procedure requiring intensive postoperative pain management. This prospective study investigates analgesic quality after a femoral block as compared with intra-articular injection of local anesthetic. METHODS: Eighty patients scheduled for elective ACL repair under general anesthesia were included in our study. Upon completion of surgery, the patients were randomly assigned into 1 of 2 groups: femoral group (n = 40) received a femoral block with 20 mL 1% ropivacaine; intra-articular group (n = 40) received 20 mL 1% ropivacaine injected intra-articularly. During the first 24 hours after surgery, all patients received 2 g propacetamol and 100 mg ketoprofen, intravenously. Additional postoperative analgesia was available with parenteral morphine if required. Analgesic duration was defined as the time from end of surgery to the first requirement for a supplemental analgesic. Data collection included patient demographics, visual analog scale (VAS) scores, analgesic duration, and morphine use. Analysis of variance (ANOVA) test was used to compare the 2 groups. RESULTS: VAS score in the recovery room and during rehabilitation was higher in the intra-articular group than in the femoral group (P <.001). Morphine use was lower in the femoral group than in the intra-articular group (P <.001). Similarly, analgesic duration was longer in the femoral group than the intra-articular group (P <.0001). CONCLUSIONS: Compared with intra-articular injection of local anesthetic, femoral nerve block (FNB) provides better analgesia and allows a significant morphine-sparing effect after ACL repair.

The analgesic effect of interscalene block using clonidine as an analgesic for shoulder arthroscopy.

UNLABELLED: Used as the sole analgesic, clonidine produces analgesia after central neural blockade and intraarticular injection but not after axillary block. In this study, we sought to determine whether interscalene clonidine induces analgesia for shoulder arthroscopy. Forty patients scheduled for shoulder arthroscopy were prospectively included in this double-blinded study. Using a nerve stimulator technique, an interscalene catheter was inserted. The patients were randomly divided into two groups. The interscalene group (n = 20) received clonidine 150 micro g in 15 mL of saline through the catheter and 1 mL of subcutaneous saline, and the systemic group (n = 20) received 15 mL of saline through the catheter and clonidine 150 micro g (1 mL) subcutaneously. All patients underwent general anesthesia for surgery. On completion of arthroscopy, all patients received, via a patient-controlled analgesia, on demand a bolus of 8 mL of ropivacaine 0.2% through the catheter with a 1-h lockout period. Postoperative pain was measured every 4 h using the visual analog scale (VAS) for 24 h. Additional postoperative analgesia was available with parenteral nalbuphine if required until VAS < 3. VAS scores in the recovery room were significantly higher in the systemic group compared with the interscalene group (P < 0.0001). Analgesic duration was significantly longer in the interscalene group (P < 0.00001), and ropivacaine consumption was significantly less than in the systemic group (P < 0.0001). No significant difference was observed between groups for nalbuphine consumption. Side effects were comparable in the two groups. IMPLICATIONS: Clonidine administered via an interscalene catheter enhanced analgesia compared with systemic administration. Nevertheless, the adverse effect of clonidine at this dose limits its use for routine management for postoperative analgesia.