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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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)
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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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Anesthesia and analgesia · Mar 1985
Large volume crystalloid resuscitation does not increase extravascular lung water.
The purpose of this study was to determine whether Ringer's lactate solution increases extravascular lung water (EVLW) during resuscitation after hemorrhagic shock. Ten sheep anesthetized with thiamylal were bled to a mean arterial pressure (MAP) of 50 mm Hg; further bleeding maintained that pressure for 30 min. Resuscitation fluid consisted of Ringer's lactate solution in volumes necessary to restore and maintain for 1 hr MAP, pulmonary capillary wedge pressure (PCWP), and cardiac index at levels equal to those measured before bleeding. ⋯ After volume restoration, COP decreased from 19 +/- 8 mm Hg to 12 +/- 2 mm Hg (P less than 0.001). Despite the large volume of fluid administered, EVLW did not increase. Crystalloid resuscitation does not necessarily increase EVLW despite significant decreases in COP and COP - PCWP gradient.