Effects of propofol and halothane on long-term potentiation in the rat hippocampus after transient cerebral ischaemia.

BACKGROUND: Propofol is reported to have protective effects on cerebral ischaemia-induced neuronal death. The aim of this study was to explore whether propofol and halothane can protect hippocampal neuronal function from ischaemic injury during general anaesthesia in rats. METHODS: Rats were divided into 2-vessel occlusion (incomplete cerebral ischaemia) and 4-vessel occlusion (complete cerebral ischaemia) groups consisting of three subgroups each (sham-operated, propofol and halothane groups). One hour after starting propofol 1 mg kg(-1) min(-1) with 30% O2 and N2 or halothane 0.8% in 30% O2 and N2 rats with or without bilateral vertebral artery occlusion had bilateral common carotid arteries occluded by vessel clips for 10 min. Anaesthesia was maintained for another 1 h. Seven days after ischaemia-reperfusion, hippocampal long-term potentiation in the perforant path-dentate gyrus synapse was determined as an index of cerebral outcome. RESULTS: In the propofol groups, the formation of long-term potentiation was significantly impaired in the 2-vessel and 4-vessel occlusion groups compared to the respective sham-operated groups (P < 0.01 and P < 0.05, respectively). Impaired formation of long-term potentiation in propofol groups was comparable to that in halothane groups. The formation of long-team potentiation in the propofol and halothane 2-vessel group was not significantly different from that in the awake 2-vessel group. CONCLUSIONS: Propofol and halothane administered during ischaemia do not possess protective effects against hippocampal neuronal dysfunction induced by cerebral ischaemia-reperfusion as evaluated by our transient ischaemic rat models.

[Efficacy of patient-controlled epidural analgesia using a disposable PCA device].

We evaluated efficacy of patient-controlled epidural analgesia (PCEA) using a disposable PCA device (3.0 ml type). Twenty-two patients for elective gynecological surgery were randomized into two groups. Patients of the continuous epidural group received epidural fentanyl (15 micrograms.ml-1) with bupivacaine (1.25 mg.ml-1) from a disposable infusion pump (infusion rate: 2.1 ml.hr-1). Patients of the PCEA group received the same anesthetic solution from the same infusion pump serially connected to the disposable PCA device. There were no significant differences in postoperative visual analogue scale (VAS) scores at rest and with movement between the two groups. However, VAS scores significantly decreased from 6.8 +/- 1.6 to 1.0 +/- 1.3 when the PCA device was used for severe pain. This suggests that segmental analgesic effect might be obtained by diffusion of anesthetic solution in the epidural space after 3.0 ml PCEA bolus administration. The incidences of side effects were similar in both groups. Respiratory depression and sedative effects were not observed in both groups. We conclude that PCEA using a disposable PCA device (3.0 ml type) seems to be effective for postoperative pain relief.

[Delayed rupture of a balloon reservoir in a disposable infusion pump].

We experienced delayed rupture of a balloon reservoir in a disposable infusion pump 3 hours after filling. The investigation revealed a sharp scratch in the reservoir. Furthermore, as we did not filtrate the drugs before filling, we speculate that ampule fragments could have provoked the rupture. When filling a disposable infusion pump with ampule solution, filtration against glass contamination is recommended.

[Postoperative pain relief by preanesthetic administration of buprenorphine suppository in elective mastectomy].

Seventy female patients scheduled for elective mastectomy were divided into three groups: Buprenorphine suppository (BPS) 0.4 mg group (n = 29); BPS 0.2 mg (n = 23) group; and control (scopolia extract and tannic acid suppository) group (n = 18). Suppositories were administered rectally to patients of each group one hour before induction of anesthesia. Plasma buprenorphine concentrations, sedation scores at entering the operating room, postoperative pain scores and side effects were evaluated. There were no significant differences in sedation effects of suppository among the three groups. Although there were significant differences in pain scores except at the time when patients left the operating room between BPS 0.2 mg group and the control group, postoperative pain relief in BPS 0.2 mg group was judged not enough. However, postoperative pain relief was more satisfactory in the BPS 0.4 mg group. Plasma concentrations of the BPS 0.4 mg group were higher than those of the BPS 0.2 mg group. Although nausea and vomiting were observed in 5 patients (17.2%) of the BPS 0.4 mg group and 4 patients (17.4%) of the BPS 0.2 mg group, respiratory depression and changes in blood pressure and heart rate were not observed in all groups. In conclusion, preanesthetic administration of the BPS 0.4 mg seemed to be useful for postoperative pain relief after elective mastectomy.