Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2011
Activated charcoal effectively removes inhaled anesthetics from modern anesthesia machines.
If a malignant hyperthermia-susceptible patient is to receive an anesthetic, an anesthesia machine that has been used previously to deliver volatile anesthetics should be flushed with a high fresh gas flow. Conflicting results from previous studies recommend flush times that vary from 10 to 104 minutes. In a previously proposed alternative decontamination technique, other investigators placed an activated charcoal filter in the inspired limb of the breathing circuit. ⋯ Activated charcoal filters provide an alternative approach to the 10 to 104 minutes of flushing that are normally required to prepare a machine that has been used previously to deliver a volatile anesthetic.
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Anesthesia and analgesia · Jun 2011
The effect of antihypertensive class on intraoperative pressor requirements during carotid endarterectomy.
Certain classes of antihypertensive drugs have been associated with intraoperative hypotension, and frequently, patients are receiving multiple classes of antihypertensive medications. We sought to determine whether one class of antihypertensive medication either alone, or in combination with other classes of antihypertensive medications, increased the probability of intraoperative hypotension, determined by the amount of vasopressor required during carotid endarterectomy (CEA) performed under general anesthesia with specific arterial blood pressure management. ⋯ Diuretics are associated with increased vasopressor requirements in patients having a CEA under general anesthesia in the preclamp period, which is likely true for any patient having a general anesthetic.
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The arterial pulse oximeter, which was introduced clinically in the 1970s, is a convenient, useful, and now ubiquitous anesthesia monitor. Unfortunately, although percent saturation of arterial hemoglobin is, along with cardiac output and concentration of hemoglobin, one of 3 components of oxygen delivery, it does not indicate whether oxygen delivery to a region of interest is adequate. Knowledge of peripheral or regional venous oxygen saturation (Sxvo₂) may lend insight into analysis of regional oxygen supply and demand. Our goal was to assess the suitability of 3 anatomic sites for the transcutaneous assessment of Sxvo₂. ⋯ Validation and subsequent improvement of this technique requires correlation of our results with venous blood gas measurements, followed by incorporation of technologies from related fields in oximetry (fetal reflectance oximetry and near-infrared spectroscopy), as well as the development of advanced signal processing techniques.
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Anesthesia and analgesia · Jun 2011
Suppression of cautery-induced electromagnetic interference of cardiac implantable electrical devices by closely spaced bipolar sensing.
Electromagnetic interference (EMI) induced by electrocautery during surgery in patients with cardiac pacemakers or implanted cardioverter-defibrillators (ICDs) may inhibit pacing and cause inappropriate tachyarrhythmia oversensing. In particular, susceptibility to EMI may be enhanced in ICDs by frequently used wide interelectrode sensing (i.e., integrated bipolar sensing). Consequently, ICD function is usually disabled preoperatively and restored later by noninvasive programming. Because sensing by closely spaced electrodes (i.e., true bipolar) may be less susceptible to EMI, preoperative programming to a true bipolar mode may minimize the need for perioperative programming while preserving device function. ⋯ Closely spaced bipolar sensing (i.e., true bipolar) appropriately rejects electrocautery-induced EMI. Programming implanted devices to closely spaced bipolar sensing may minimize the need for perioperative reprogramming while preserving intraoperative device operation.
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Anesthesia and analgesia · Jun 2011
Adenosine triphosphate-sensitive potassium channel blockers attenuate the antiallodynic effect of R-PIA in neuropathic rats.
Nerve injury can generate neuropathic pain. The accompanying mechanical allodynia may be reduced by the intrathecal administration of adenosine. The neuroprotective effects of adenosine are mediated by the adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channel. We assessed the relationship between the adenosine A1 receptor agonist, N⁶-(R)-phenylisopropyl adenosine (R-PIA), and K(ATP) channels to determine whether the antiallodynic effects of R-PIA are also mediated through K(ATP) channels in a rat nerve ligation injury model of neuropathic pain. ⋯ The antiallodynic effects of adenosine A1 receptor stimulation may be related to K(ATP) channel activity in a rat model of nerve ligation injury.