Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1988
The pharmacokinetics of bupivacaine when injected intra-articularly after knee arthroscopy.
Bupivacaine pharmacokinetics were determined in 11 patients receiving the drug intra-articularly after knee arthroscopy performed under general anesthesia. Forty ml 0.25% bupivacaine was given at the end of surgery and the thigh tourniquet was released 2 to 3 minutes after injection. ⋯ Results indicate that injections of 100 mg bupivacaine intra-articularly after knee arthroscopy produce peak blood concentrations within the first hour after surgery, and that these will be well below concentrations associated with toxic reactions. Peak concentrations can be minimized with shorter tourniquet inflation times and with longer intervals between injection and tourniquet release.
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Anesthesia and analgesia · Sep 1988
Pain scores and ventilatory and circulatory sequelae of epidural morphine in cancer patients with and without prior narcotic therapy.
Pain scores and respiratory and circulatory sequelae of epidural morphine were studied in 25 patients with cancer, classified into two groups: 15 with and 10 without a history of previous narcotic analgesic therapy. Morphine, 2.5 mg initially and 5.0 mg 12 hours later, was given through an indwelling lumbar epidural catheter. ⋯ Statistically significant dose-dependent hypoventilation and concomitant respiratory acidosis were seen in both groups, the changes being significantly greater in opiate-naive patients. These results demonstrate that the ventilatory depressant actions of opioids are attenuated but not eliminated in narcotic-familiar cancer patients and that epidural narcotics are as effective in relieving pain in narcotic-naive patients as in patients previously exposed to narcotics for relief of cancer pain.
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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.