Incidence of diaphragmatic paralysis following supraclavicular brachial plexus block and its effect on pulmonary function

Thirty unpremedicated ASA physical status 1-3 patients aged between 18 and 69 years, scheduled for upper limb surgery, received a conventional supracl avicular brachial plexus block using a nerve stimulator and bupivacaine 0.3 75% 0.5 ml.kg(-1). Spirometric measurements of pulmonary function and ultra sonographic assessments of diaphragmatic function were made before the bloc k and at 10-min intervals after injection until full motor block of the bra chial plexus had developed. Complete paralysis of the ipsilateral hemidiaph ragm occurred in 50% of patients. Seventeen per cent of patients had reduce d diaphragmatic movement and the rest (33%) had no change in diaphragmatic movement. Those with complete paralysis all showed significant decreases in pulmonary function, whereas those with reduced or normal movement had mini mal change. All patients remained asymptomatic throughout, with normal oxyg en saturation on room air.