Anesthesiology
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Anesthesia care for the patients undergoing ophthalmologic surgical procedures during local/regional anesthesia balances goals of patient comfort with safety and an optimal outcome in a highly cost-conscious environment. This article discusses current practices and trends in anesthesia care with respect to sedation for eye surgery during local/regional anesthesia. Although there is no evidence that one local/regional anesthesia technique or sedation analgesia regimen is superior to the others, this review highlights important differences between these varied approaches. ⋯ Changes in surgical techniques have increased the popularity of topical anesthesia, which reduces the need for sedation analgesia and may lessen the need for an anesthesia practitioner. The involvement of an anesthesia practitioner in eye surgery varies from facility to facility based on costs, anesthesiologist availability, and local standards. Anesthesia care choices are often made based on surgeon skill and anesthesiologist comfort, as well as the expectations and needs of the patient.
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The gamma-aminobutyric acid type A receptor (GABAA-R) beta subunits are critical targets for the actions for several intravenous general anesthetics, but the precise nature of the anesthetic binding sites are unknown. In addition, little is known about the role the fourth transmembrane (M4) segment of the receptor plays in receptor function. The aim of this study was to better define the propofol binding site on the GABAA-R by conducting a tryptophan scan in the M4 segment of the beta2 subunit. ⋯ This is the first report of a mutation that selectively reduces propofol sensitivity without altering the action of etomidate. The reduction in propofol sensitivity is consistent with the loss of a hydrogen bond within the propofol binding site. These results also suggest a possible orientation of the propofol molecule within its binding site.
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Clonidine can effectively reduce pain and/or hypersensitivity. However, the antihypersensitivity effects of clonidine topically applied in cream (CC) have not been investigated. The authors evaluated effects of topical application of CC on pain behaviors and spinal Fos-like immunoreactivity in rats with hypersensitivity. ⋯ Topical CC in concentrations examined significantly reduced hypersensitivity and lumbar spinal Fos-like immunoreactivity in rats with neuropathic pain, probably through activation of peripherally located alpha2 adrenoceptors. However, CC was only partially effective and totally ineffective in rats with postoperative pain and inflammatory pain, respectively.
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Mechanical ventilation (MV) may activate the innate immune system, causing the release of cytokines. The resulting proinflammatory state is a risk factor for ventilator-induced lung injury. Cytokine increase results from direct cellular injury but may also result from cyclic stretch alone as demonstrated in vitro: mechanotransduction. To study mechanotransduction in vivo, the authors used an animal MV model with clinically relevant ventilator settings, avoiding alveolar damage. ⋯ Mechanical ventilation induces reversible cytokine increase and leukocyte influx with preserved tissue integrity. This model offers opportunities to study the pathophysiologic mechanisms behind ventilator-induced lung injury and the contribution of MV to the "multiple-hit" concept.