Articles: nerve-block.
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Anaesthetists who manage acute and chronic pain need to be familiar with current research and practice guidelines in these areas. New local anaesthetics and new routes of administration for opioids and adjuvants may further improve our management of acute pain. ⋯ The limitations of nerve blocks are acknowledged and guidelines for managing chronic pain and opioids are available. Anaesthetists must recognize psychological difficulties as a significant perpetuating factor in chronic pain.
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Acta Anaesthesiol Scand · Aug 1998
Case ReportsAn unusual toxic reaction to axillary block by mepivacaine with adrenaline.
An increase in blood pressure, accompanied by atrial fibrillation, agitation, incomprehensible shouts and loss of consciousness, was observed in an elderly, ASA classification group II, cardiovascularly medicated male, 12 min after performance of axillary block with mepivacaine 850 mg containing adrenaline 0.225 mg, for correction of Dupuytren's contracture. After intravenous administration of labetalol, metoprolol and midazolam the patient's condition improved, and 15 min later he woke up. ⋯ Postoperatively, the patient refused DC cardioversion and was treated medically. Both the temporal relationship of events and the response to treatment suggest that a rapid systemic absorption of mepivacaine with adrenaline and/or interaction of these drugs with the patient's cardiovascular medications were responsible for the perioperative complications.
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Anaesth Intensive Care · Aug 1998
Incidence of phrenic nerve block and hypercapnia in patients undergoing carotid endarterectomy under cervical plexus block.
Deep cervical plexus blockade blocks the second, third and fourth cervical nerve roots. The phrenic nerve arises from C3, C4, C5 and should therefore be commonly blocked with cervical plexus blockade. The aim of this study was to report the incidence of phrenic nerve block and to assess the effect of this on arterial carbon dioxide tension (PaCO2) in premedicated and sedated patients. ⋯ Fluoroscopy showed that 22 patients (55%) had evidence of phrenic nerve block (Group A), 18 patients showed no change (Group B). PaCO2 levels increased in both groups following premedication, from 41 +/- 5 mmHg (mean +/- SD) to 46 +/- 5 mmHg in Group A, and 41 +/- 4 mmHg in Group B; twenty minutes after cervical plexus block the PaCO2 rose to 49 +/- 6 mmHg in Group A, and 48 +/- 6 mmHg in Group B. These changes were not statistically significantly different when the two groups were compared.
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Anesthesia and analgesia · Aug 1998
The effect of thoracic paravertebral blockade on intercostal somatosensory evoked potentials.
The paravertebral nerve blocks used in upper abdominal or thoracic surgery provide excellent pain relief and can inhibit some aspects of the neuroendocrine stress response to surgical trauma, which suggests that a very high-quality afferent block can be effected. To confirm this, we evaluated intercostal somatosensory evoked potentials (SSEPs) in 10 patients undergoing paravertebral nerve blocks as a treatment for chronic pain. SSEPs were recorded before and after ipsilateral thoracic paravertebral deposition of 1.5 mg/kg bupivacaine 0.5%. Sensory loss to temperature was demonstrated in all patients at the level of injection and had a mean superior spread of 1.4 (range 0-4) dermatomes and a mean inferior spread of 2.8 (range 0-7) dermatomes. SSEPs were abolished (the normal waveform was rendered unrecognizable with unmeasurable latencies and a mean amplitude of zero) in all patients at the level of injection. In addition, a two-dermatome SSEP abolition was found in four patients and a three-dermatome abolition was found in two patients. SSEPs were modified, but not significantly, at all other test points. We conclude that cortical responses to thoracic dermatomal stimulation can be abolished at the block level and adjacent dermatomes by thoracic paravertebral nerve blockade. Equivalent results have not been demonstrated with more central forms of afferent blockade, which suggests that thoracic paravertebral nerve blocks may be uniquely effective. ⋯ To improve outcomes after major surgery, as much nociceptive information as possible should be prevented from entering the central nervous and neuroendocrine systems. We have shown that local anesthetics alongside the vertebral column can abolish the usual brain recordings that follow intercostal nerve stimulation, which suggests that paravertebral nerve blocks may be uniquely effective.