Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2003
Randomized Controlled Trial Clinical TrialHyperbaric bupivacaine 2.5 mg prolongs analgesia compared with plain bupivacaine when added to intrathecal fentanyl 25 microg in advanced labor.
We investigated the effect of sequential administration of intrathecal (IT) hyperbaric bupivacaine (after the initial administration of IT hypobaric fentanyl) on the duration of spinal analgesia. Thirty-seven nulliparous parturients with a cervical dilation >/= 5 cm were randomized to receive either IT fentanyl 25 micro g and plain bupivacaine 2.5 mg (group P; n = 19) or IT fentanyl 25 micro g and hyperbaric (with 8% glucose) bupivacaine 2.5 mg (group H; n = 18). The two components of the IT injectate were administered sequentially (fentanyl 25 micro g diluted in 2 mL of normal saline, immediately followed by 0.5 mL of 0.5% bupivacaine). ⋯ Group H also had a more limited dermatomal spread (median highest sensory level of T8 versus T4 in group P; P < 0.05). The side-effect profile was similar. Under these circumstances, hyperbaric bupivacaine conferred an increased duration of IT analgesia compared with plain bupivacaine.
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Anesthesia and analgesia · Sep 2003
Randomized Controlled Trial Clinical TrialThe effect of nitrous oxide on cerebrovascular reactivity to carbon dioxide in children during propofol anesthesia.
Nitrous oxide (N(2)O) increases cerebral blood flow when used alone and in combination with propofol. We investigated the effects of N(2)O on cerebrovascular CO(2) reactivity (CCO(2)R) during propofol anesthesia in 10 healthy children undergoing elective urological surgery. Anesthesia consisted of a steady-state propofol infusion and a continuous caudal epidural block. ⋯ We conclude that N(2)O does not affect CCO(2)R during propofol anesthesia in children. When preservation of CCO(2)R is required, the combination of N(2)O with propofol anesthesia in children would seem suitable. The cerebral vasoconstriction caused by propofol would imply that hyperventilation to ETCO(2) values less than 35 mm Hg may not be required because no further reduction in cerebral blood flow velocity would be achieved.
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Anesthesia and analgesia · Sep 2003
Clinical TrialPatient-controlled sedation using propofol for dressing changes in burn patients: a dose-finding study.
The first change of dressings after skin grafting in burn patients is a source of great anxiety because of pain anticipation and the immediate and first confrontation with the result of skin grafting. We designed this dose-finding study to determine the feasibility and safety of patient-controlled sedation (PCS) using propofol during these procedures. Twenty patients were familiarized with the PCS and asked to use PCS whenever they felt uncomfortable or anxious. ⋯ The second group of patients showed a more effective sedation, with respiratory and hemodynamic variables being not significantly different from the first group of patients. PCS with propofol is feasible in burn patients and can be used safely. To provide an optimal sedation, we suggest to initially titrate the bolus to achieve a significant decrease of BIS or a clinically effective state of sedation and to abolish the lockout interval.
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Anesthesia and analgesia · Sep 2003
The effect of lidocaine on the globule size distribution of propofol emulsions.
In this study, we sought to determine the globule size distribution of a propofol/lidocaine mixture as a function of lidocaine concentration and time elapsed after mixing in a standard formulation of propofol emulsion (Diprivan) and in a new formulation containing L-lysine to improve stability. The globule size was measured with a laser diffraction technique. The median diameter of the globule size in 20 mL of Diprivan immediately after the addition of 0, 10, 20, 30, 40, and 50 mg of lidocaine was similar to that of chylomicrons, ranging from 0.28 +/- 0.01 micro m to 0.30 +/- 0.02 micro m, over the whole range of lidocaine concentration. ⋯ The maximum globule diameter in the propofol emulsion to which L-lysine was added as a stabilizer did not exceed 3.0 micro m even when the largest amount of lidocaine was added. This study demonstrated that when 30 mg of lidocaine was added to 20 mL of Diprivan and the solution was left for a period of time, the globule size increased. Its increase was minimized by the addition of L-lysine to the propofol emulsion.
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Anesthesia and analgesia · Sep 2003
Comparative StudyAntinociceptive properties of neurosteroids: a comparison of alphadolone and alphaxalone in potentiation of opioid antinociception.
In this study, we investigated the antinociceptive and sedative effects of the opioids fentanyl, morphine, and oxycodone given alone and in combination with two neurosteroids: alphadolone and alphaxalone. An open-field activity monitor and rotarod apparatus were used to define the sedative effects caused by opioid and neurosteroid compounds given alone intraperitoneally to male Wistar rats. Dose-response curves for antinociception were constructed using only nonsedative doses of these drugs. ⋯ Alphaxalone given alone had no antinociceptive effects at nonsedative doses and it had no effect on opioid antinociception. Neither neurosteroid caused sedative effects when combined with opioids. We conclude that coadministration of alphadolone, but not alphaxalone, with morphine, fentanyl, or oxycodone potentiates antinociception and that this effect is not caused by an increase in sedation.