Résumé
Ultrasound-guided peripheral nerve blocks may expose patients to procedural pain (transcutaneous punction, local anesthetics injection). Predict pain intensity might allow to adopt a personalized attitude of sedation, anxiolysis or reassurance. The aim of our study was to establish a correlation between the level of pain at peripheral venous catheter (PVC) installation and pain during the locoregional anesthesia procedure (primary endpoint) and to explore associated factors (medical history, technical data, catastrophism). Material & methods: this monocentric prospective observation al study consecutively included adult patients receiving troncular nerve blocks or catheters for ambulatory orthopedic surgery. Pre-operatively, chronic pain history was recorded, and a catastrophizing pain score (PCS) was realized. Our primary endpoint was the correlation between pain intensity (Numerical Rating Scale from 0 to 10) at venous catheterization and during nerve block procedure. Number of punctures, time from puncture to end of injection, and venous cannulation difficulty (very easy, easy, difficult, very difficult) were also recorded. Statistical analyses: descriptive, comparative non-parametric tests. Results: over study period, 100 patients were analyzed: age 59 (39-67) years, BMI 26 (22-29) kg/T-2, ASA status II (I-III). PVC pain was 1 (0-3) /10 with a median number of punctures of 1 (1-1). 90% of them were judged as easy or very easy. Nerve block pain was 2 (1-3) /10. A score > 3/10 was recorded for 25% of the patients (maximum 8/10). Median number of puncture was 1 with a procedure duration of 6 (4-8) min. There was a correlation between pain scores at PVC insertion and during block puncture (T > 0; r=0.53, CI: 0.36-0.66). Similar results were observed for patients reporting pain scores > 3/10 during blocks (T > 0; r=0.54, CI: 0.17-0.78), and for axillary (n=22) and popliteal blocks (n=52) subgroups. Pre-operative PCS did not interfere with prediction (p > 0.05). Conclusion: pain during nerve block was low for 75% of patients and was correlated with venous cannulation pain. Type of block did not impact the results. High pain score at cannulation may be a warning to anticipate pain over block procedure and try to reduce it using intravenous sedatives or nonpharmacologic methods.