Anesthesiology
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Multicenter Study
Postoperative cognitive dysfunction in patients with preoperative cognitive impairment: which domains are most vulnerable?
The authors explored the database of the first International Study of Postoperative Cognitive Dysfunction study to specify the domains of cognitive function that were most vulnerable and to determine the pattern of deterioration in patients with preoperative cognitive impairment. ⋯ Postoperative cognitive deterioration was seen in all tests, although most commonly in attention and cognitive speed at 1 week. Deterioration in memory was difficult to detect after surgery in patients with preoperative cognitive impairment.
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Clinical Trial
Gabapentin activates spinal noradrenergic activity in rats and humans and reduces hypersensitivity after surgery.
Gabapentin has been reported to inhibit various acute and chronic pain conditions in animals and humans. Although the efficacy of gabapentin depends on the alpha2delta subunit of voltage-gated calcium channels, its analgesic mechanisms in vivo are still unknown. Here, the authors tested the role of spinal noradrenergic inhibition in gabapentin's analgesia for postoperative pain. ⋯ These data suggest that gabapentin activates the descending noradrenergic system and induces spinal norepinephrine release, which produces analgesia via spinal alpha2-adrenoceptor stimulation, followed by activation of G protein-coupled inwardly rectifying potassium channels. The authors' clinical data suggest that gabapentin activates the descending noradrenergic system after preoperative oral administration at the time of surgery. These data support a central mechanism of oral gabapentin to reduce postoperative pain and suggest that this effect could be magnified by treatments that augment the effect of norepinephrine release.
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Previous studies documented that near-infrared spectroscopy values were affected by factors related to optical path length, such as hemoglobin concentration, the differential path length factor, skull thickness (t-skull), and the area of the cerebrospinal fluid layer (a-CSFL). Lately, the NIRO-100 (Hamamatsu Photonics, Hamamatsu, Japan) has provided a tissue oxygen index (TOI) that theoretically is not supposed to be affected by optical path length. Therefore, the authors hypothesized that TOI is not influenced by the above-described individual factors. ⋯ rSO2 values were affected by hemoglobin concentration, a-CSFL, and t-skull, but TOI values were not affected by individual factors.
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Clinical Trial
Measurement of pressure-time product during spontaneous assisted breathing by rapid interrupter technique.
Measuring the work of breathing of patients undergoing spontaneous assisted ventilation can be useful to monitor and titrate ventilatory support. The aim of this study was to obtain measurements of the pressure generated by the respiratory muscles (PMUSC) and the derived pressure-time product (PTP; a good indicator of the metabolic work of breathing), performing the rapid interrupter technique with a commercial ventilator. ⋯ The rapid interrupter technique can be performed by means of a commercial ventilator, providing reliable measurement of PMUSC and PTP.
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A single dose of the macrolide antibiotic erythromycin can induce tolerance against cerebral ischemia in vivo (pharmacologic preconditioning). This study identified potential mechanisms of tolerance induction by assessing effects of erythromycin preconditioning on the cerebral transcriptional response to transient global cerebral ischemia. ⋯ These findings present a new molecular correlate for the induction of ischemic tolerance achieved by erythromycin preconditioning and will further the understanding of this clinically important new regimen of preemptive neuroprotection.