Élisabeth Van Gessel

BACKGROUND: The usefulness of peripheral nerve blockade in the anesthetic management of hip surgery has not been clearly established. Because sensory afferents from the hip include several branches of the lumbar plexus, the authors hypothesized that a lumbar plexus block could reduce pain from a major hip procedure. METHODS: In a double-blind prospective trial, 60 patients undergoing total hip arthroplasty were randomized to receive general anesthesia with (plexus group, n = 30) or without (control group, n = 30) a posterior lumbar plexus block. The block was performed after induction using a nerve stimulator, and 0.4 ml/kg bupivacaine, 0.5%, with epinephrine was injected. General anesthesia was standardized, and supplemental fentanyl was administered per hemodynamic guidelines. Postoperative pain and patient-controlled intravenous morphine use were serially assessed for 48 h. RESULTS: The proportion of patients receiving supplemental fentanyl intraoperatively was more than 3 times greater in the control group (20 of 30 vs. 6 of 29, P = 0.001). In the postanesthesia care unit, a greater than fourfold reduction in pain scores was observed in the plexus group (visual analogue scale [VAS] pain score at arrival 1.3 +/- 2 vs. 5.6 +/- 3, P < 0.001), and "rescue" morphine boluses (administered if VAS > 3) were administered 10 times less frequently (in 2 of 28 vs. in 22 of 29 patients, P < 0.0001). Pain scores and morphine consumption remained significantly lower in the plexus group until 6 h after randomization (VAS at 6 h, 1.4 +/- 1.3 vs. 2.4 +/- 1.4, P = 0.007; cumulative morphine at 6 h, 5.6 +/- 4.7 vs. 12.6 +/- 7.5 mg, P < 0.0001). Operative and postoperative (48 h) blood loss was modestly decreased in the treated group. Epidural-like distribution of anesthesia occurred in 3 of 28 plexus group patients, but no other side-effects were noted. CONCLUSIONS: Posterior lumbar plexus block provides effective analgesia for total hip arthroplasty, reducing intra- and postoperative opioid requirements. Moreover, blood loss during and after the procedure is diminished. Epidural anesthetic distribution should be anticipated in a minority of cases.

UNLABELLED: 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. IMPLICATIONS: Clonidine in brachial plexus block does not improve postoperative analgesia when mixed with a long-lasting anesthetic. Nevertheless, with or without clonidine, bupivacaine in interscalene block provides a long-lasting analgesia of approximately 15 h.

BACKGROUND: To facilitate students' transition from basic, science-oriented, problem-based learning (PBL) to clinical reasoning-oriented PBL, the University of Geneva School of Medicine introduced a 12-week unit of Introduction to Clinical Reasoning (ICR) at the beginning of its fourth or clerkship year. PURPOSE: The aims of the present study were to determine, after 12 weeks in the ICR unit, to what extent students had: (1) identified the learning content set by the faculty while adapting to the hypothetico-deductive reasoning approach; (2) familiarised themselves with the clinical reasoning-oriented learning process, and (3) transferred and further developed this process during the clinical years. METHOD: Students' derived objectives from the problems were compared to the objectives preset by the faculty to determine acquisition of intended learning content. To assess their adaptation to the clinical reasoning-oriented PBL approach, students (n = 124) were asked to list and freely comment on aspects of the unit they felt most at ease with or had difficulty with, and to complete a questionnaire on the clinical reasoning process (CRP). The same questionnaire was administered 6 and 12 months later to assess the evolution of the students' self-perception during clerkships. RESULTS: On average, student objectives matched 62% of faculty objectives. Half of the missed (38%) objectives were in basic sciences. Students generated 16% additional objectives, also predominantly in the basic sciences category (41%). Free comments indicated that the difficulties perceived by students were very similar to those previously reported in studies on reasoning and errors, such as difficulty in gathering, interpreting and weighting relevant data, synthesising information, and organising it hierarchically. These results were confirmed with the CRP questionnaire administered at the end of the unit. For most of the competencies assessed on the CRP questionnaire, a gradual improvement was seen to have occurred by 6 and 12 months after the unit. CONCLUSIONS: To ease students' transition from the preclinical to clinical years, a learning unit should give them the opportunity to train their clinical reasoning processes on standardised and prototypical problems, before encountering real patients with more ill-structured problems during clerkships. Such a transitional structure should particularly emphasise a developed repertoire of problem representations, recognition of key findings and a hierarchical classification of working hypotheses. It should foster the creation of links between the acquired basic clinical knowledge and the diagnostic, management and therapy steps of problem solving.