British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Sevoflurane requirements for tracheal intubation with and without fentanyl.
We studied 80 healthy ASA 1 patients (aged 20-52 yr) to determine if fentanyl affects sevoflurane requirements for achieving 50% probability of no movement in response to laryngoscopy and tracheal intubation (MAC-TI). Patients were allocated randomly to one of four fentanyl dose groups (0, 1, 2 and 4 micrograms kg-1). Patients in each group received sevoflurane at a pre-selected end-tidal concentration according to an 'up-down' technique. ⋯ The MAC-TI of sevoflurane was 3.55% (95% confidence intervals 3.32-3.78%), and this was reduced markedly to 2.07%, 1.45% and 1.37% by addition of fentanyl 1, 2 and 4 micrograms kg-1, with no significant difference in the reduction between 2 and 4 micrograms kg-1, showing a ceiling effect. Fentanyl attenuated haemodynamic responses (HR and MAP) to tracheal intubation in a dose-dependent manner, even with decreasing concomitant sevoflurane concentration. Fentanyl 4 micrograms kg-1 suppressed the changes in HR and MAP more effectively than fentanyl 1 or 2 micrograms kg-1 at sevoflurane concentrations close to MAC-TI.
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Tissue deposits occur after administration of plasma substitutes. After hydroxyethyl starch (HES), deposits may last for months, causing pruritus and impairment of function. Because elimination of HES deposits has not been demonstrated in humans, we studied 26 patients, for up to 7 yr after HES administration, to assess HES storage. ⋯ Biopsies of the liver, muscle, spleen, intestine or skin were studied using light and electron microscopy and immunohistochemistry. HES storage was dose-dependent, decreased in all organs with time and was greater in patients suffering from pruritus. We conclude that tissue deposition of HES is transitory and dose-dependent, with differences between subjects in severity and duration.
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Randomized Controlled Trial Clinical Trial
Stability of the interstitial matrix after crystalloid fluid loading studied by volume kinetic analysis.
To investigate if fluid therapy changes the prerequisites for the development of oedema, four i.v. infusions of Ringer's solution 25 ml kg-1 were given over 15 or 30 min in a randomized crossover study to 10 healthy male volunteers, aged 28-40 (mean 31) yr. Blood haemoglobin concentration, measured every 5 min for 90 min, and urinary excretion were used as input data for volume kinetic analysis. ⋯ However, the size of V2 and the rate constant for the exchange of fluid between V1 and V2 were similar during all infusions. We conclude that a fluid challenge makes elimination of further infused fluid more effective but does not change compliance with volume expansion in healthy volunteers.
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Comparative Study Clinical Trial Controlled Clinical Trial
Oral mucosal blood flow, plasma epinephrine and haemodynamic responses after injection of lidocaine with epinephrine during midazolam sedation and isoflurane anaesthesia.
We have investigated the relationship between oral mucosal blood flow and plasma epinephrine concentration, and the effects of conscious sedation vs general anaesthesia on haemodynamic responses after submucosal epinephrine injection in 14 subjects. The same seven patients were studied both as controls and after sedation. For sedation, midazolam i.v. was used. ⋯ There were no differences in haemodynamic changes except for heart rate, between the three groups. These results suggest that plasma epinephrine concentration after submucosal injection depends on the initial mucosal blood flow in the injected area. Haemodynamic changes, except heart rate, in the sedation and general anaesthesia groups were similar despite different changes in maximum plasma epinephrine concentration.
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Clinical Trial
Patient-controlled sedation using propofol in elderly patients in day-case cataract surgery.
Patient-controlled sedation (PCS) with propofol has been used successfully as an adjunct to local anaesthetic procedures. We studied a group of elderly patients (mean age 75.4 yr) undergoing cataract surgery and attempted to increase patient acceptability and comfort of local anaesthesia. Propofol was self-administered in a dose of 0.25 mg kg-1 for patients more than 60 yr of age, with a lockout period of 3 min. ⋯ However, while it is possible to administer PCS successfully to elderly patients undergoing cataract surgery and produce a decrease in the level of anxiety, we found it unacceptable because of head movement in two patients. These patients received only two and three divided doses, to a maximum of 29 and 30 mg, respectively. There were no other adverse events.