Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Pre-emptive analgesia from intravenous administration of opioids. No effect with alfentanil.
Forty patients undergoing total abdominal hysterectomy were randomly allocated to receive either 40 micrograms.kg-1 of alfentanil on induction of anaesthesia or 40 micrograms.kg-1 of alfentanil after the skin incision. Postoperative pain relief was provided with morphine from a patient-controlled analgesia system. ⋯ There were no differences found between the two groups for morphine consumption but the 'pre-emptive' group had significantly higher pain scores at rest. We conclude that there is no clinically useful pre-emptive analgesic effect with this dose of alfentanil and that therefore systemic opioid premedication is unlikely to decrease postoperative analgesic requirements through the mechanism of pre-emptive analgesia.
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Randomized Controlled Trial Clinical Trial
Effects of surgical stimulation on midlatency auditory evoked potentials during general anaesthesia with propofol/fentanyl, isoflurane/fentanyl and flunitrazepam/fentanyl.
During general anaesthesia, midlatency auditory evoked potentials are suppressed in a dose dependent manner by a number of general anaesthetics. The activating effects of surgical stimuli on midlatency auditory evoked potentials have been demonstrated during light inhalational anaesthesia, and indicate that midlatency auditory evoked potentials reflect the activity of the central nervous system and not only anaesthetic concentrations. We investigated the effect of surgical stimulation (skin incision, sternotomy) on midlatency auditory evoked potentials under high dose opioid analgesia in 30 patients undergoing elective cardiac surgery. ⋯ The latencies of the early cortical potentials were similar to those in the awake state. After skin incision as well as after sternotomy no significant changes of midlatency auditory evoked potentials could be observed in any of the experimental groups. These results indicate that activation of the auditory pathway by surgical stimuli may be blocked when analgesia is provided by high dose fentanyl.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Analgesic effect of intra-articular morphine after arthroscopic meniscectomy.
A study was performed to assess the analgesic effect of intra-articular morphine 2 mg in 33 patients undergoing elective arthroscopic meniscectomy. Patients were randomly allocated to receive either 2 mg of morphine hydrochloride in 40 ml of normal saline intra-articularly and 1 ml of normal saline intramuscularly (n = 18), or 40 ml of normal saline intra-articularly and 2 mg of morphine hydrochloride intramuscularly (n = 15). The latter group was to act as a control for any potential systemic effects of the morphine. ⋯ No significant differences between the groups were found in pain scores at rest or during active flexion of the knee at 1-6 h postoperatively, or during walking at 6 h postoperatively (p > 0.05). Six and two patients in the intra-articular and intramuscular morphine group, respectively, requested supplemental morphine given intravenously (p > 0.05). In conclusion, no significant differences in pain scores or in requirements for supplemental morphine were observed between patients receiving intra-articular versus intramuscular morphine 2 mg after elective arthroscopic meniscectomy and consequently no specific local analgesic effect of intra-articular morphine could be demonstrated.
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Randomized Controlled Trial Clinical Trial
The effect of parenteral diclofenac and morphine on duration and height of blockade of continuous epidural infusion of bupivacaine 0.5%.
Twenty-six patients undergoing abdominal hysterectomy (ASA 1-2) were entered into a double-blind randomised trial to determine: (a) whether diclofenac given intravenously could influence the effective duration of a continuous epidural infusion of bupivacaine 0.5%, and (b) whether morphine given intravenously altered the height of the regressing block. A block to T4 was established pre-operatively and a continuous infusion of 0.5% bupivacaine 8 ml.h-1 ran for 14 h. Thirteen patients received 50 mg diclofenac intramuscularly before surgery repeated at 4 and 10 h later and 13 patients received saline intramuscularly. ⋯ Duration of blockade was not significantly prolonged (p > 0.05), but pain scores were significantly reduced with diclofenac (p < 0.01). Morphine did not alter blockade height. It is concluded that epidural bupivacaine and diclofenac act additively on postoperative pain.
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A safe and predictable method by which an epidural infusion sufficient for pain control in labour can be rapidly converted to a more intense block adequate for emergency Caesarean section continues to present a challenge. A prospective study was undertaken. ⋯ This produced an adequate block in 11 out of 18 patients. There were no significant differences in duration of infusion, cumulative local anaesthetic dose or pre-existing block height in these patients when compared with the remaining seven patients who required an additional top-up.