Anesthesia and analgesia
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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)
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Anesthesia and analgesia · Apr 1985
Vecuronium infusion dose requirements during fentanyl and halothane anesthesia in humans.
Steady-state infusion rate requirements of vecuronium were determined in 29 patients during either halothane-nitrous oxide or fentanyl-nitrous oxide anesthesia at different levels of neuromuscular block. During N2O-halothane anesthesia (end-tidal concentration, 0.5%), the infusion rate necessary for a steady-state (defined as unchanging twitch height and infusion rate for at least 20 min) 50% depression of twitch force was 28.8 +/- 5.4 (mean +/- SD) (n = 8) and 47.6 +/- 9.7 micrograms . kg-1 . hr-1 (n = 6) at 90% reduction of twitch force. ⋯ The variances of vecuronium steady-state infusion dose requirements were smaller in the halothane groups than in the fentanyl anesthesia groups. The steady-state vecuronium infusion dose requirements during fentanyl anesthesia were greater than the mean infusion dose requirements during halothane anesthesia at equivalent levels of twitch depression.
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The safety of etomidate for induction of anesthesia in malignant hyperthermia-susceptible (MHS) pigs was evaluated in a two-phase experiment. Two litters of Purebred Poland China pigs, one MHS (n = 4) and the other malignant hyperthermia-resistant (MHR) (n = 4) were used. Phase I compared MHS vs MHR animals in terms of cardiovascular, metabolic, and skeletal muscle rigidity responses to etomidate and fentanyl anesthesia and to a subsequent malignant hyperthermia (MH) challenge with halothane-succinylcholine. ⋯ Heart rate and bicarbonate levels were lower in MHS than in MHR pigs during etomidate infusion. With discontinuation of etomidate and a subsequent challenge with halothane-succinylcholine, all four pigs developed the MH syndrome within 15-30 min. Thiopental replacement of etomidate in the phase II experiment resulted in a twofold greater time (45-75 min) for halothane-succinylcholine to trigger MH in the susceptible pigs.(ABSTRACT TRUNCATED AT 250 WORDS)