AN ATTEMPT TO PREVENT SPREAD OF LOCAL-ANESTHETIC TO THE PHRENIC-NERVEBY COMPRESSION ABOVE THE INJECTION SITE DURING THE INTERSCALENE BRACHIAL-PLEXUS BLOCK

The brachial plexus was identified by electrical stimulation before in terscalene block with 30 mt 0.5% bupivacaine and adrenaline 1:200 000. During injection, compresion was applied with a finger proximal to th e injection site. Spirometric measurements were made before the block, and then at 5 min, 10 min, 20 min and 4h after the injection. Diaphra gmatic excursion was measured radiographically before the block, and a t 15 min and 4 h afterwards. In 25 patients studied, spirometric measu rements decreased. Twenty minutes after the injection, the forced vita l capacity was 27% less, forced expiratory volume at 1 s 34% less and peak expiratory flow rate 15% less (all P<0.05). Right diaphragmatic e xcursion decreased from 4.5 cm (SD 1.2 cm) to 1.8 cm (0.6 cm) at 15 mi ns and to 1.1 cm (0.6 cm) at 4 h (P<0.05). Identification of the plexu s by electric stimulation combined with finger compression above the i njection site did not prevent diaphragmatic paresis.