British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Spinal anaesthesia with 0.5% hyperbaric bupivacaine in elderly patients: effects of duration spent in the sitting position.
Sixty patients, aged 65-84 yr, undergoing minor urological surgery under spinal anaesthesia remained sitting for 2 (group 1, n = 15), 5 (group 2, n = 15), 10 (group 3, n = 15), or 20 (group 4, n = 15) min after completion of the subarachnoid administration of 3 ml of a 0.5% hyperbaric bupivacaine solution. They were then placed in the supine position. Analgesia levels were assessed bilaterally using pinprick. ⋯ Twenty minutes after the injection the upper analgesia levels were lower (P<0.05) in group 4 (median T9.0) than in the groups 1-3 (medians T6.6-T8.5). The highest obtained levels (medians T5.7-T8.0) did not differ between the groups, but occurred later (P<0.05) in group 4 (median 35 min) than in groups 1-3 (medians 19-24 min). There were no significant differences in the maximum degree of motor block or haemodynamic changes between the four study groups.
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Investigators in the field of depth of anaesthesia monitoring sometimes measure the auditory evoked potential (AEP) and the Bispectral Index (BIS) concurrently. However, the auditory stimuli required to generate an AEP may increase the level of consciousness, and cause an increase in the BIS. They may also alter the BIS by producing phase-locked harmonics in the surface electroencephalogram. ⋯ The second 3 epochs took place during steady-state anaesthesia. During alternate epochs, patients were subjected to the auditory stimuli generated by an AEP system. The auditory stimuli were not associated with a change in BIS values (during sedation and anaesthesia) or OAA/S scores (sedation).
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Comparative efficacy and safety of remifentanil and fentanyl in 'fast track' coronary artery bypass graft surgery: a randomized, double-blind study.
This multi-centre, parallel group, randomized, double-blind study compared the efficacy and safety of high-dose remifentanil administered by continuous infusion with an intermittent bolus fentanyl regimen, when given in combination with propofol for general anaesthesia in 321 patients undergoing elective coronary artery bypass graft surgery. A significantly lower proportion of the patients who received remifentanil had responses to maximal sternal spread (the primary efficacy endpoint) compared with those who received fentanyl (11% vs 52%; P<0.001). More patients who received remifentanil responded to tracheal intubation compared with those who received fentanyl (24% vs 9%; P<0.001). ⋯ Overall, the incidence of adverse events was similar but greater in the remifentanil group with respect to shivering (P<0.049) and hypertension (P<0.001). Significantly more drug-related adverse events were reported in the remifentanil group (P=0.016). There were no drug-related adverse cardiac outcomes and no deaths from cardiac causes before hospital discharge in either treatment group.
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Randomized Controlled Trial Clinical Trial
Cerebral effects and blood sparing efficiency of sodium nitroprusside-induced hypotension alone and in combination with acute normovolaemic haemodilution.
The combined reduction of oxygen-carrying capacity and perfusion pressure during the combination of acute normovolaemic haemodilution (ANH) and controlled hypotension (CH) raises concerns of hypoperfusion and ischaemic injury to the brain. Forty-two patients undergoing radical prostatectomy were prospectively allocated to receive CH induced by sodium nitroprusside (mean arterial pressure (MAP) 50 mm Hg), a combination of CH+ANH (post-ANH haematocrit 29%; intraoperative MAP 50 mm Hg), or standard anaesthesia (control). Serum levels of the brain-originated proteins neuron-specific enolase (NSE) and protein S-100, blood loss, transfusion requirements, adverse effects, and postoperative recovery profile were compared among the three groups. ⋯ Increased serum S-100 protein concentrations imply a disturbance in astroglial cell membrane integrity and an increased endothelial permeability of the blood-brain barrier. There were no associations between serum S-100 protein or NSE and adverse cognitive effects. Further work needs to be done to determine the prognostic importance of S-100 protein and NSE as surrogate variables of postoperative cerebral complications.