Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1988
Randomized Controlled Trial Comparative Study Clinical TrialLumbar plexus block in children: a comparison of two procedures in 50 patients.
Two techniques for blocking the lumbar plexus were prospectively evaluated in 50 children undergoing surgery in the hip region and randomly allocated to one of two equal groups. A variant of the "psoas compartment block" and the classic technique were used in groups 1 (n = 25) and 2 (n = 25), respectively. All procedures were carried out under light general anesthesia with the patients in the lateral position using insulated needles and electrical stimulation. ⋯ However, the distribution of analgesia differed: 23 (ipsilateral) lumbar and sacral plexus blocks and 2 (ipsilateral) lumbar blocks alone were produced in group 2, compared to 22 areas of anesthesia comparable to those that might be associated with a lumbar epidural block and two ipsilateral lumbar plexus blocks in group 1. The two techniques are not, therefore, mere variants of the same basic approach to the lumbar plexus. The procedure described by Winnie et al. (Anesthesiol Rev 1974;1:11-6) was more suitable for providing unilateral blockade than the "psoas compartment block."
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Anesthesia and analgesia · Aug 1988
Comparative StudyThe roles of acute and chronic pain in regression of sensory analgesia during continuous epidural bupivacaine infusion.
The purpose of this study was to investigate whether regression of sensory analgesia during constant epidural bupivacaine infusion was different in postoperative patients with acute pain than in patients with chronic nonsurgical pain. Sensory levels of analgesia (to pinprick) and pain (on a five-point scale) were assessed hourly for 16 hours during continuous epidural infusion of 0.5% plain bupivacaine (8 ml/hr) in 12 patients with chronic nonsurgical pain and in 30 patients after major abdominal surgery performed under combined bupivacaine and halothane--N2O general anesthesia. No opiates were given. ⋯ Mean duration of sensory blockade was significantly longer (P less than 0.005) in the patients with chronic pain than in surgical patients (13.1 +/- 1.2 and 8.5 +/- 0.7 hours, respectively). Thus, surgical injury hastens regression of sensory analgesia during continuous epidural bupivacaine infusion. The underlying mechanism remains to be determined.
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Anesthesia and analgesia · Aug 1988
Prolongation of the QT interval by volatile anesthetics in chronically instrumented dogs.
The influence of volatile anesthetics on ventricular repolarization in vivo (QT interval) has not been studied in a systematic fashion. The purpose of this investigation was to characterize the electrocardiographic and hemodynamic actions of the volatile anesthetics halothane, isoflurane, and enflurane in chronically instrumented dogs. Because autonomic nervous system tone may influence ECG findings, experiments were completed with and without concomitant pharmacologic autonomic nervous system blockade. ⋯ The results demonstrate that ventricular repolarization is directly altered by the volatile anesthetics independent of changes in autonomic nervous tone. Whether or not such effects are additive with other congenital or acquired forms of QTc prolongation has yet to be examined. The present results indicate that caution should be used during the administration of volatile anesthetics to patients with abnormalities of the QT interval.
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Anesthesia and analgesia · Aug 1988
Cardiovascular effects of fentanyl reversal by naloxone at varying arterial carbon dioxide tensions in dogs.
Clinical reports, as well as animal studies, have described cardiovascular and sympathetic stimulation after the administration of naloxone (NX) to reverse opioid-induced respiratory depression. This investigation examines the effect of PaCO2 on hemodynamic and adrenergic responses to NX, by means of 24 experiments carried out in six dogs. Each dog underwent NX reversal of fentanyl (FEN) at three different PaCO2 levels: 20, 35, and 60 mm Hg. ⋯ NE levels were greater in hypercapnic dogs at all time periods after NX. In blocked dogs, neither F nor NX had any effects on hemodynamic functions or plasma CA levels; the institution of hypercapnia caused significant decreases in HR, MAP, and systemic vascular resistance. This direct circulatory depressant action of an elevated PCO2 may have attenuated the indirectly mediated excitatory hemodynamic effects of NX in intact dogs, thus explaining the relatively greater effect of hypercapnia on adrenergic than on hemodynamic responses to reversal.(ABSTRACT TRUNCATED AT 250 WORDS)