The groups were compared according to the parameters such as analgesic efficacy ( VAS ) , respiratory function tests ( forced expiratory volume in 1s ( FEV ( 1 ) ) , peak expiratory flow rate ( PEFR ) and arterial blood gases ) , stress response ( serum cortisol and glucose levels ) , adverse effects , necessity for additional analgesia , duration of catheter application procedure , mean hospital stay and postoperative follow-up .
