Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2003
Clinical TrialEchocardiographic monitoring during induction of general anesthesia with a miniaturized esophageal probe.
Standard transesophageal echocardiography (TEE) does not allow cardiac monitoring during the induction of anesthesia because standard probes would limit the oropharyngeal space and impair mask ventilation and tracheal intubation. We hypothesized that a prototype, miniaturized TEE probe could be safely introduced transnasally in awake patients and that mask ventilation and orotracheal intubation could be performed while continuously monitoring left ventricular (LV) function during the induction of anesthesia. Forty-five patients were studied prospectively. The transnasal TEE probe was introduced through one of the nares and advanced until a transverse plane image of the LV at the level of the papillary muscles was seen. Anesthesia was induced, and the patients were ventilated with a mask that had previously been threaded over the TEE probe via a central perforation. Probe insertion was successful in 12 patients under local anesthesia alone and in an additional 31 patients with a combination of local anesthesia and mild sedation. In two cases, probe placement was unsuccessful. Overall, hemodynamic variables did not change significantly during insertion. No case of significant mucosal bleeding was seen. In one patient, regurgitation of gastric contents occurred without affecting the perioperative outcome. The two-dimensional echocardiogram image quality of the LV during the induction of anesthesia was good or acceptable in 95% of patients. We conclude that transnasal TEE can effectively be used for cardiac monitoring during the induction of general anesthesia. ⋯ This study demonstrates that it is feasible and generally safe to introduce a miniaturized transesophageal echocardiography probe transnasally in awake cardiac risk patients to monitor cardiac performance during the induction of general anesthesia.
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Anesthesia and analgesia · Jan 2003
Case ReportsSpinal cord injury in a child caused by an accidental dural puncture with a single-shot thoracic epidural needle.
A child experienced a spinal cord injury by an accidental dural puncture during thoracic epidural anesthesia. A magnetic resonance image was used for diagnosis and treatment.
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Anesthesia and analgesia · Jan 2003
Oral tramadol for the treatment of pain of 7-30 days' duration in children.
This open-label, multicenter trial was designed to determine the safety profile and analgesic efficacy of tramadol for the treatment of painful conditions lasting 7-30 days in 7-16-yr-old children. We found that tramadol 1-2 mg/kg per os every 4-6 h (maximal dose = 8 mg x kg(-1). d(-1), not to exceed 400 mg/d) is a safe and effective analgesic in this patient population.
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Anesthesia and analgesia · Jan 2003
Glycine receptors mediate part of the immobility produced by inhaled anesthetics.
Many inhaled anesthetics potentiate the effect of glycine on inhibitory strychnine-sensitive glycine receptors in vitro, supporting the view that this receptor could mediate the immobility produced by inhaled anesthetics during noxious stimulation (i.e., would underlie minimum alveolar anesthetic concentration [MAC]). There are quantitative differences between anesthetics in their capacity to potentiate glycine's effect in receptor expression systems: halothane (most potentiation), isoflurane (intermediate), and cyclopropane (minimal). If glycine receptors mediate MAC, then their blockade in the spinal cord should increase the MAC of halothane more than that of isoflurane and isoflurane MAC more than cyclopropane MAC; the increases in MAC should be proportional to the receptor potentiation produced in vitro. Rats with chronically implanted intrathecal catheters were anesthetized with halothane, isoflurane, or cyclopropane. During intrathecal infusion of artificial cerebrospinal fluid, MAC was determined. Then MAC was re-determined during an infusion of 3, 12, 24, or 48 (isoflurane only) micro g/min of strychnine (strychnine blocks glycine receptors) in artificial cerebrospinal fluid. Strychnine infusion increased MAC in proportion to the enhancement of glycine receptors found in vitro. The maximum effect was with an infusion of 12 micro g/min. For the combined results at 12 and 24 micro g/min of strychnine, the increase in MAC correlated with the extent of in vitro potentiation (r(2) = 0.82). These results support the hypothesis that glycine receptors mediate part of the immobilization produced by inhaled anesthetics. ⋯ In vitro, halothane potentiates glycine's effect on strychnine-sensitive glycine receptors more than isoflurane and isoflurane more than cyclopropane. The present in vivo work indicates that antagonism of the glycine receptor with strychnine increases minimum alveolar anesthetic concentration for halothane more than isoflurane and isoflurane more than cyclopropane. Such results support the notion that glycine receptors may mediate part of the immobility produced by inhaled anesthetics.