Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1997
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of multiport and uniport epidural catheters in laboring patients.
The relative incidence of technical difficulties associated with multiport (three lateral ports) and uniport (single distal port) epidural catheters remains controversial. As part of a continuing institutional evaluation of epidural catheter insertion, 500 parturients were randomized to have either a multiport or a uniport epidural catheter inserted 6 cm into the epidural space. ⋯ No multiport epidural catheter was associated with multicompartment placement. We conclude that multiport epidural catheters are preferable for use in laboring patients since they reduce the incidence of inadequate epidural analgesia.
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Anesthesia and analgesia · Jun 1997
Clinical TrialDynamic ventilatory characteristics during weaning in postoperative critically ill patients.
Postoperative patients occasionally require more than 48 h of mechanical ventilation. This study examined whether there were distinct differences in dynamic respiratory variables between patients who successfully weaned from mechanical ventilation and those who failed. Forty general and thoracic surgery patients underwent a standardized weaning sequence: 25 min of synchronous intermittent mandatory ventilation (SIMV) at 8 bpm plus 5 cm H2O pressure support ventilation (PSV), then SIMV at 4 bpm plus 5 cm H2O PSV, followed by continuous positive airway pressure (CPAP) plus 5 cm H2O PSV and, finally, CPAP without PSV. ⋯ P0.1 (threshold 4.5 cm H2O, sensitivity 1.00, specificity 1.00), patient work of breathing (threshold 1.3 J/L, sensitivity 0.92, and specificity 0.98), and the sRR/sV(T) ratio (threshold 65 bpm/L, sensitivity 0.90, specificity 0.80) were distinctive. Most unique was the analysis of spontaneous breaths during low SIMV rates. This appears to permit an early determination of whether weaning would succeed.
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Anesthesia and analgesia · Jun 1997
The effects of sevoflurane anesthesia on insulin secretion and glucose metabolism in pigs.
We investigated the effects of two different concentrations of sevoflurane, 0.4 minimum alveolar anesthetic concentration (MAC) and 1.0 MAC, on insulin secretion before, during, and after sevoflurane anesthesia using three successive intravenous glucose tolerance tests (IVGTT) in pigs with indwelling catheters. We also investigated changes in the levels of plasma glucose, catecholamines (epinephrine [E], norepinephrine [NE]), and cortisol (Cor). The pigs were grouped as awake, 0.4 MAC, or 1.0 MAC. ⋯ These decreases were quickly reversible (control levels were regained within 2 h of the end of anesthesia), were probably dose-related, appeared not to be mediated by E, NE, or Cor. In addition, the INS/GLU ratio 2.5-4 h after the end of anesthesia was significantly higher in the anesthetized groups than in the awake group. We conclude that sevoflurane anesthesia has a rapidly reversible inhibitory effect on basal and glucose-stimulated insulin secretion, as do other inhaled anesthetics, and might induce insulin resistance.
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Anesthesia and analgesia · Jun 1997
Comparative StudyThe effect of xenon on spinal dorsal horn neurons: a comparison with nitrous oxide.
We compared the effects of xenon (Xe) on the spinal cord dorsal horn neurons with those of nitrous oxide (N2O) in cats anesthetized with chrolarose and urethane. We assessed the potency of both anesthetics by the inhibition of wide dynamic range neuron responses evoked by cutaneous noxious (pinch) stimulation to a hindpaw. During 70% Xe inhalation, the responses of 7 of 11 neurons to pinch stimulation were suppressed. ⋯ After 20 min of Xe inhalation, the response to pinch was suppressed to 49.5% +/- 8.2% (mean +/- SE), while N2O, 70% in oxygen, suppressed it to 45.9% +/- 7.9%. The difference between N2O and Xe was not significant. We conclude that Xe and N2O suppress the spinal cord dorsal horn neurons to a similar degree.