Anesthesia and analgesia
-
Anesthesia and analgesia · May 1985
Clinical Trial Controlled Clinical TrialAtracurium infusion requirements in children during halothane, isoflurane, and narcotic anesthesia.
We were interested in determining the dose-response relationship of atracurium in children (2-10 yr) during nitrous oxide-isoflurane anesthesia (1%) and the atracurium infusion rate required to maintain about 95% neuromuscular blockade during nitrous oxide-halothane (0.8%), nitrous oxide-isoflurane (1%), or nitrous oxide-narcotic anesthesia. Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation at the ulnar nerve at 2 Hz for 2 sec at 10-sec intervals. To estimate dose-response relationships, three groups of five children received 80, 100, 150 micrograms/kg atracurium, respectively. ⋯ At equipotent concentrations, halothane and isoflurane augment atracurium neuromuscular block to the same extent, compared to narcotic anesthesia. Atracurium steady-state infusion requirements averaged 6.3 +/- 0.6 micrograms . kg-1 . min-1 during halothane or isoflurane anesthesia; the requirements during balanced anesthesia were 9.3 +/- 0.8 micrograms . kg-1 . min-1 (P less than 0.05). There was no evidence of cumulation during prolonged atracurium infusion.
-
Vecuronium was studied in eight malignant hyperthermia (MH) susceptible pigs for its potential to either trigger or prevent MH. Two sets of experiments were performed in the same animals: 1-hr total neuromuscular blockade by vecuronium infusion with thiopental anesthesia in the absence of invasive monitoring and halothane; and 1-hr infusion of vecuronium with thiopental anesthesia with invasive monitoring in the absence of and then, followed by 30-min infusion in the presence of halothane, followed in turn by exposure to halothane alone. ⋯ In view of the results of control experiments, the development of MH during vecuronium neuromuscular blockade before exposure to halothane was attributed to surgical stress rather than to vecuronium itself. It is concluded that vecuronium is not a trigger to MH in susceptible pigs.
-
Anesthesia and analgesia · May 1985
Acid and alkaline solutions of local anesthetics: duration of nerve block and tissue pH.
The effect of solution pH on the duration of rat infraorbital nerve blocks produced by 1% lidocaine or 0.25% bupivacaine at pH 5.0 and 7.4, with and without epinephrine was investigated in a double-blind study. The time course of tissue pH changes subsequent to infections into the infraorbital area or abdominal musculature of rats was measured with a tissue pH microelectrode. Injectable pH had little or no effect upon the duration of block. Tissue pH was minimally changed by the injection of solutions at pH 7.4, but decreased appreciably with injections of solutions at pH 5.0, or if the injectate contained epinephrine.
-
Anesthesia and analgesia · May 1985
In vitro study of the effect of epidural blood patch on leakage through a dural puncture.
Pressure resistance of an experimental epidural blood patch was studied in vitro. Pieces of canine lumbar dura were perforated with a 19-gauge needle (n = 12) or a 25-gauge needle (n = 6) and kept between the intercommunicating chambers of a plexiglass apparatus. One chamber (epidural side) was filled with autologous blood and the other chamber (subdural side) was filled with autologous cerebrospinal fluid. ⋯ Four blood-treated specimens showed some leakage at 20 mm Hg. All dura specimens perforated with a 19-gauge needle leaked at 40 mm Hg, five of them only at the lowest score rate, 1-4 drops/5 min. One blood-patched dura perforated with a 25-gauge needle did not leak until the pressure reached 50 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)