Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2003
Comparative StudyCatheter-associated masses in patients receiving intrathecal analgesic therapy.
A cohort of seven patients receiving intrathecal analgesic drug therapy for chronic intractable pain underwent radiocontrast myelography and computed tomography (CT) scanning to screen for catheter-associated intrathecal masses. Three of seven patients examined had intraspinal masses associated with the tip of the drug infusion catheter after a total of 118 mo of therapy. The index case presented with exacerbation of neuropathic pain and paralysis of the left lower extremity. The two additional cases detected by CT myelography were asymptomatic at the time the catheter-associated mass was assessed. The mean duration of therapy before diagnosis of the catheter-associated mass was 19.6 mo, with a range of 16-25 mo. An intergroup comparison of demographic and treatment variables between patients, with and without catheter-associated masses, demonstrated that patients with masses were younger and were receiving a larger morphine dose than patients without masses. The differences were statistically significant (P = 0.05). In one patient with an asymptomatic catheter-associated intrathecal mass, regression of the mass was observed after cessation of therapy. In a second asymptomatic patient, the mass remained stable over 1 yr of continued treatment after substitution of hydromorphone for morphine without interruption of therapy. Neither asymptomatic patient has subsequently developed additional neurologic findings or injury after detection of occult catheter-associated intrathecal masses and clinical intervention. We suggest that all patients receiving long-term intrathecal analgesia should undergo periodic radiographic surveillance to further define their risk of developing occult catheter-associated masses and to allow intervention before neurologic injury can develop. ⋯ Catheter-associated intrathecal masses were detected in three of seven patients receiving long-term intrathecal analgesia. In the two asymptomatic patients, timely clinical intervention was associated with the avoidance of subsequent neurologic injury and spontaneous resolution of one of the occult masses.
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Anesthesia and analgesia · Jan 2003
Case ReportsCompression of the pulmonary artery during transesophageal echocardiography in a pediatric cardiac patient.
Hemodynamic compromise caused by the insertion of the probe for transesophageal echocardiography in a patient with severe stenosis of the main pulmonary artery is reported for the first time. The first symptom of the impending problem was a rapid decrease of end-tidal CO(2).
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Anesthesia and analgesia · Jan 2003
Case ReportsDelayed onset of malignant hyperthermia in desflurane anesthesia.
Animal-experimental studies demonstrate desflurane's trigger effect for malignant hyperthermia (MH). In contrast to other anesthetics, the time interval from exposure to the occurrence of symptoms is much longer with desflurane. This case report focuses on MH induced by desflurane alone.
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Anesthesia and analgesia · Jan 2003
Extending the skeletal muscle viability period in the malignant hyperthermia test.
The caffeine halothane contracture test (CHCT) is the only validated test for diagnosing malignant hyperthermia (MH) susceptibility (MHS) and phenotyping MHS families. Although most diagnostic laboratory tests can check intra- and interlaboratory consistency through the use of standard control samples, there has been no practical way to achieve this goal for the CHCT. The distances between diagnostic centers and time constraints of the CHCT protocol (5 h) prohibit centers from sharing tissue samples. In this study, we investigated varying storage conditions to extend the standard viability period of skeletal muscle to 24 h. Twenty MHS patients were tested according to the North America protocol. After standard CHCT, the surplus muscle samples were placed in one of the following four treatment groups. In Groups 1 and 2, muscles remained under tension and were stored in Krebs buffer (pH 7.4) at 23 degrees C-25 degrees C (clamped-warm) and 4 degrees C (clamped-cold), respectively. In Groups 3 and 4, muscle strips were dissected, and the ends were tied with silk sutures, cut from the clamp, and placed in Krebs buffer at 23 degrees C-25 degrees C (free-warm) and 4 degrees C (free-cold), respectively. The responses of the treatment groups to halothane (3%) and caffeine (0.5-32 mM) were tested at 22-26 h after excision. The clamped-warm storage group correctly diagnosed MHS in all patients. ⋯ Varying conditions for storage of muscle were investigated to extend the viability period of muscle in the malignant hyperthermia (MH) test from 5 to 24 h. Muscles stored for 24 h under tension at room temperature remained viable and correctly diagnosed MH susceptibility in all patients.
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Anesthesia and analgesia · Jan 2003
Validity of arterial and mixed venous oxygen saturation measurements in a canine hemorrhage model after resuscitation with varying concentrations of hemoglobin-based oxygen carrier.
In this study, we evaluated the validity of saturation measurements in mixed venous and arterial blood during posthemorrhagic anemia and resuscitation with varying levels of hemoglobin-based oxygen carrier (Hemoglobin glutamer-200 [bovine]; Oxyglobin [Hb-200]). Nineteen anesthetized, splenectomized, mixed-breed dogs were anesthetized (two were excluded from the data because they did not survive the exsanguination, supporting the validity of the model). Their pulmonary arteries were cannulated with the Abbott QVUE Oximetrix 3 catheter. An 18-gauge catheter was placed in the femoral artery, and a reusable Nellcor probe was applied to the tongue. Mixed venous and arterial samples were drawn at baseline, after 40% hemorrhage (to keep arterial pressure at 50 mm Hg), and postresuscitation with 30 mL/kg of 6% hetastarch in lactated Ringer's solution (n = 4), 10 mL/kg of Hb-200, 20 mL/kg of hetastarch (n = 6), 20 mL/kg of Hb-200, and 10 mL/kg of hetastarch (n = 7). Samples were compared with oxygen content from the LEXO2CON-K oxygen analyzer, and oxygen content was calculated for all values from the monitors. Results were compared by using analysis of variance. There was good correlation (0.97 > or = r > or = 0.92) for the measured versus calculated hemoglobin oxygen saturation values at baseline. After resuscitation, the correlation between calculated and measured values of oxygen content was significantly smaller for all tested instruments. The values of oxygen content calculated from the oxygen saturation monitor and from the oximetric pulmonary artery can deviate by as much as 20% from directly measured values. We conclude that the administration of this oxygen therapeutic may interfere with the values of some monitors. ⋯ This study evaluated oxygen saturation monitors in a canine model of acute blood loss and resuscitation with a blood substitute and found that these may interfere with the monitors' results in a dose-dependent way.