METHODS	Six hours after the initial block , patients received for 48 h either a continuous infusion of 0.2 % ropivacaine through the interscalene catheter at a rate of 5 ml/h plus a bolus dose of 3 or 4 ml with a lockout time of 20 min ( PCIA group ) or a continuous intravenous infusion of nicomorphine at a rate or 0.5 mg/h plus a bolus dose of 2 or 3 mg with a lockout time of 20 min ( PCIVA group ) .\