Anesthesiology
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Acceleromyography is regularly used as an isolated test to detect residual paralysis. The performance of acceleromyography, however, has not been investigated for the setting where calibration is impossible. This study first evaluated the reliability of a single acceleromyographic train-of-four (TOF) ratio (T4/T1) to detect residual paralysis and compared it with tactile estimation of fade after double-burst stimulation and 100-Hz, 5-s tetanus. The second part of the study investigated whether uncalibrated acceleromyographic TOF ratio can predict time to complete recovery. ⋯ Acceleromyographic TOF performed better than double-burst stimulation or 100 Hz tetanus, but it did not reliably detect low degrees of residual paralysis when used as an isolated test at the end of surgery. The uncalibrated acceleromyographic TOF ratio, however, did predict the time to complete recovery.
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Comparative Study
Comparative cardiac effects of terlipressin, vasopressin, and norepinephrine on an isolated perfused rabbit heart.
Terlipressin, a synthetic analog of arginine-vasopressin (AVP), has been proposed as an effective vasopressive therapy in catecholamine-resistant vasodilatory shock. Although beneficial effects of terlipressin on systemic arterial pressure have been clearly demonstrated, its intrinsic effects on coronary circulation and myocardial performances remain unknown. ⋯ On isolated rabbit heart, terlipressin induced a coronary vasopressor effect and in turn myocardial depression only at supratherapeutic concentrations (> or =30 nM). Its effects are mainly mediated via V1a receptors. However, these potential negative side effects on the heart were less pronounced than were those of AVP.
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Propofol decreases the acute hypoxic ventilatory response in humans and depresses in vivo carotid body chemosensitivity. The mechanisms behind this impaired oxygen sensing and signaling are not understood. Cholinergic transmission is involved in oxygen signaling, and because general anesthetics such as propofol have affinity to neuronal nicotinic acetylcholine receptors, the authors hypothesized that propofol depresses carotid body chemosensitivity and cholinergic signaling. ⋯ It is concluded that propofol impairs carotid body chemosensitivity, the magnitude of depression being dependent on the severity of PO2 reduction, and that propofol causes a concentration-dependent block of cholinergic chemotransduction via the carotid sinus nerve, whereas it seems unlikely that an activation of the gamma-aminobutyric acid A receptor complex is involved in this interaction.
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To gain a better understanding of spinal cord injury (SCI)-induced central neuropathic pain, the authors investigated changes in properties of spinal dorsal horn neurons located rostrally and caudally to the lesion and their sensitivity to morphine in rats after SCI. ⋯ The findings suggest that changes in properties of spinal dorsal horn neurons after SCI are caused by different mechanisms, depending on the classification of the neurons and their segmental locations.
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Cancer-induced bone pain is a major clinical problem for which current treatments lack full efficacy. Gabapentin is licensed for use in neuropathic pain yet is also effective against inflammatory stimuli in animals. ⋯ Pain-related behavior in this rat model of cancer-induced bone pain is strongly linked to hyperexcitability of a population of superficial dorsal horn neurones. Gabapentin normalizes the cancer-induced bone pain induced dorsal horn neuronal changes and attenuates pain behavior. It may therefore provide a novel clinical treatment for cancer-induced bone pain.