Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1986
Epidural anesthesia with lidocaine and bupivacaine: effects of epinephrine on the plasma concentration profiles.
The effects of epinephrine on the plasma concentrations and derived pharmacokinetic parameters were studied after epidural administration of lidocaine and bupivacaine. Addition of epinephrine to the local anesthetic solutions reduced the mean peak plasma concentrations of lidocaine and bupivacaine from 2.2 to 1.7 micrograms/ml (23%) and from 0.73 to 0.53 microgram/ml (28%), respectively, but did not alter the times at which the peak concentrations were reached. Epinephrine also did not alter the terminal half-lives or the total plasma clearances. The results suggest that addition of epinephrine to minimize plasma concentrations is as relevant with bupivacaine as it is with lidocaine.
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Anesthesia and analgesia · Dec 1986
Priming with atracurium: improving intubating conditions with additional doses of thiopental.
The effects of different intubating doses of atracurium on the time of onset, and the effect of an additional dose of thiopental on intubating conditions, were studied in 72 patients divided into six groups (n = 12 in each). Stratified sampling was used to obtain an even sex distribution. Groups I, III, and V (controls) received atracurium as a single bolus dose of 0.4, 0.5 or 0.6 mg/kg respectively. ⋯ When divided doses of atracurium were given, administration of 2 mg/kg thiopental (in addition to the 5 mg/kg used for induction) before the injection of the intubating dose resulted in improvement of intubating conditions as reflected by statistically significant changes in intubating scores. This result was probably due to the increase by thiopental in the depth of anesthesia. Therefore, when thiopental is given as supplement, the priming technique can be made to provide better conditions for tracheal intubation in less than 90 sec.
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Anesthesia and analgesia · Dec 1986
Halothane metabolism in acyanotic and cyanotic patients undergoing open heart surgery.
The metabolism of halothane was examined in patients with acyanotic and cyanotic congenital heart disease undergoing open heart surgery. Statistically significant (P less than 0.05) pre-surgical differences between acyanotic and cyanotic groups included pH (7.46 +/- 0.02 vs 7.36 +/- 0.02), PaO2 (277 +/- 58 vs 51 +/- 3 torr), O2 saturation (97 +/- 1 vs 74 +/- 4%), and hematocrit (45 +/- 3 vs 58 +/- 2%). Serum fluoride levels were significantly greater in cyanotic than in acyanotic groups 2-4 hours after initial exposure to halothane. ⋯ The cyanotic group also had higher total and direct serum bilirubin levels than the acyanotic group. Therefore, patients with cyanotic congenital heart disease had greater reductive metabolism of halothane than acyanotics. However, cyanotic and acyanotic patients had essentially similar postoperative derangements in hepatic and renal function.
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Anesthesia and analgesia · Dec 1986
Pulse oximetry and circulatory kinetics associated with pulse volume amplitude measured by photoelectric plethysmography.
Through a catheter placed in a superficial vein on the finger, we observed a pulsatile venous pressure. To delineate the relationship between the pulsatile venous pressure and the pulse volume amplitude (PVA) recorded by photoelectric plethysmography (PEPG), both tracings were simultaneously recorded. When the PVA changed acutely or gradually, the venous pulse pressure and mean venous pressure simultaneously followed the same trend. ⋯ Also, the PVA detected by the pulse oximeter followed the same trend as %SaO2. This finding was explained by venous congestion in the dependent finger. On the basis of the high venous pressure, the behavioral trends between the PVA and venous pressure, the high PVO2, and the low %SaO2 and PVA in the dependent finger, we conclude that the PVA of the PEPG is determined mainly by venous pulse volume generated by shunting of arterial pulse via open arteriovenous (AV) anastomoses in the cutaneous circulation.