Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1982
Comparative StudyA comparative in vivo study of local neurotoxicity of lidocaine, bupivacaine, 2-chloroprocaine, and a mixture of 2-chloroprocaine and bupivacaine.
This study was undertaken because of several recent reports of adverse neurologic reactions following the use of 2-chloroprocaine. Carotid sheaths containing undisturbed vagus nerve were surgically exposed in rabbits and bathed in situ for up to 1 hour in one of the following-isotonic solutions: physiologic salt solution, lidocaine 2%, bupivacaine 0.75%, 2-chloroprocaine 3%, or a mixture of 2-chloroprocaine 1.5% and bupivacaine 0.375%. Each solution contained epinephrine, 5 micrograms/ml, (1:200,000). ⋯ Histologic sections revealed the presence of epineurial cellular infiltration and fibrosis, perineurial fibrosis, and axonal degeneration in nerves that had been exposed to 2-chloroprocaine or the mixture of 2-chloroprocaine and bupivacaine. Histologic abnormalities were minor or absent following exposure to lidocaine, to bupivacaine, or to physiologic salt solution. These findings suggest that, under the conditions of the experiments, 2-chloroprocaine is more neurotoxic than lidocaine or bupivacaine.
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Anesthesia and analgesia · Nov 1982
Criteria for selection of ambulatory surgical patients and guidelines for anesthetic management: a retrospective study of 1553 cases.
The charts of 1553 patients who were anesthetized for ambulatory surgery were analyzed retrospectively to determine the effect of the type of surgery, the age of the patient, the use of premedication, the duration of anesthesia, and the anesthetic technique on the duration of recovery and the rate of complications. In a 4-month period in 1979, 1073 patients were treated, and another 480 patients were treated during a 2-month period in 1980. Aside from patients undergoing dental surgery, the surgical procedure and the extremes of age affected neither the duration of recovery (193 +/- 97 minutes) nor the rate of complications (2.45%). ⋯ There was no relationship between anesthesia time and the duration of recovery. Patients who received local anesthesia had a significantly shorter recovery period than the whole population, and significantly fewer patients receiving local anesthesia had to be admitted to the hospital. Thus, arbitrary limits placed on the type of surgery, age of the patient, the duration of the procedure, and the use of certain premedication appear to be unwarranted.
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Concentrations of halogenated anesthetics produced by contemporary vaporizers vary from vaporizer dial settings when carrier gas is not 100% oxygen. This effect is most marked when carrier gas changes from 100% O2 to 100% nitrous oxide (N2O). ⋯ Steady-state outputs of halothane and enflurane in 100% N2O were 10% below dial settings. The significance of these changes in administration of closed-circuit anesthesia with an out-of-circuit vaporizer is discussed.
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Anesthesia and analgesia · Oct 1982
Prophylactic intravenous ephedrine infusion during spinal anesthesia for cesarean section.
Ephedrine sulfate was administered to 44 healthy parturients undergoing elective repeat cesarean section under spinal anesthesia. Twenty patients received ephedrine infusion (0.01% solution, beginning with approximately 5 mg/min) immediately after induction of spinal anesthesia to maintain maternal systolic blood pressure between 90% and 100% of the base line systolic blood pressure (mean dose of ephedrine 31.6 mg). Twenty-four patients (control group) received 20 mg of ephedrine as an intravenous bolus, and additional 10-mg increments, if necessary when systolic blood pressure decreased to 80% of the base line systolic blood pressure (mean dose of ephedrine 26.8 mg). ⋯ Nausea and/or vomiting occurred in nine women in the control group and one patient in the infusion group (p less than 0.01). Apgar scores, fetal blood gas tensions, and time for onset of respiration were comparable in the two groups. The results suggest that prophylactic ephedrine infusion is safe and desirable in healthy parturients undergoing cesarean section under spinal anesthesia.