Incidence of Hemidiaphragmatic Palsy After Interscalene Block

Primary objective of this study is to find out the incidence of hemi-diaphragmatic palsy associated with interscalene block done under ultrasound guidance. Primary hypothesis: • There is an incidence of hemidiaphragmatic palsy ranging fron 33-100 % after an interscalene block. Secondary hypothesis * The incidence of hemidiaphragmatic palsy is much less than 33% when the block is done using ultrasound. * The incidence of hemi-diaphragmatic palsy is directly proportional to volume of local anaesthetic injected. * The incidence of hemi-diaphragmatic palsy is directly proportional to concentration of local anaesthetic injected.