Objective To investigate the effects of low-dose ketamine combined with fentanyl or sulfentanyl in postoperative patient-controlled intravenous analgesia.Methods Two hundred cases with ASA Ⅰ~Ⅱ undergoing elective orthopedic operations were randomly allocated into four groups(50 cases for each group): 0.4?g/(kg?h) fentanyl(group F);0.2?g/(kg?h) fentanyl+120?g/(kg?h) ketamine(group FK);0.04?g/(kg?h) sulfentanyl(group S);and 0.02?g/(kg?h) sulfentanyl+120 ?g/(kg?h) ketamine(group SK).8mg of ondansetron was added to each recipe,and then diluted into 100ml with normal saline.The loading doses of all the patient-controlled-analgesics were 2ml administered 30min before the end of the operation.The background infusion doses were 2ml/h,while the pressing doses were 2ml,with intervals of 30min.Heart rate(HR),blood pressure(BP),respiration rate(RR),pulse O2 saturation and visual analogue scales(VAS),sedation score(SS) with adverse effects and the total times of pressing PCA pump button were observed and recorded in all patients respectively for 48h after operations.Results No statistically significant differences were found in HR,BP and RR among the four groups.VAS and the total pressing times in group F were higher than that in the other groups significantly(P

Experiments were performed on spontaneously breathing rabbits anesthetized with urethan. The diaphragmatic fatigue (DiF) was reproduced by the phrenic nerve stimulation (30 Hz, 10 V,0. 2 ms). The transdiaphragmatic pressure (Pdi) and diaphragm evoked potential (DEP) were measured before injury and after injury 30, 60, 90, and 120 min. Pdimax and the amplitude of DEP obviously decreased and the latency of DEP obviously delayed after injury 30min. The amplitude of Pdi and DEP were quickly promoted by introvenous injection of neostig-mine after DiF. The latency of DEP was partially recovered by introvenous injection of neostig-mine. It is concluded that neostigmine can improve the generation of the fatigued diaphragm. and promote its recovery.