we have compared analgesic requirements , perceived pain , and self-assessment of 'health locus of control ' for 72 h in 88 subjects after cholecystectomy , randomized to either a standard technique of self-administration of meperidine ( patient-controlled analgesia , pca ) or to intramuscular injections on demand ( i.m . ) .
C0030193
pain
C0025376
meperidine