Minerva anestesiologica
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Minerva anestesiologica · May 2003
Review[Anesthesia for neurosurgery in children: techniques and monitoring].
Pediatric neuroanesthesia can be seen as a specific branch of anesthesia half way in between pediatric anesthesia and neuroanesthesia. As a matter of fact, we must keep well in mind the peculiarities of the pediatric patient and the different pharmadynamic and pharmacochinetic properties of the anesthetic drugs, particularly in neonates and infants. Other relevant problems are: 1) high complexity of surgical procedures implying a difficult anesthesiological management; 2) complex blood loss management either if we want to apply a blood sparing technique strategy or if we consider the problems related to diagnosis and treatment of coagulative disorders caused by intraoperative massive blood loss; 3) management of patients with latex allergy for the high incidence, in pediatric neuroanesthesia, of patients belonging to high risk groups; 4) need of repeated radiological examinations implying several anesthesiological procedures. In this article aspects related to the anesthesiological techniques and to the hemodynamic and neurophysiological monitoring of pediatric neurosurgical patients were also discussed.
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Minerva anestesiologica · May 2003
ReviewGuidelines on anticoagulants and the use of locoregional anesthesia.
Growing numbers of patients are treated with hemostasis altering drugs, as thromboembolic diseases are a major cause of mortality in our western society. The insertion of epidural or subarachnoidal needles and/or catheters in such patients carries the inherent risk of the development of a compressing vertebral canal hematoma. This is especially true in patients treated with thrombolytic agents or oral anticoagulants. ⋯ The available data do not allow making firm recommendations on the safe use of major neuraxial blocks. In contrast, the isolated use of acetyl-salicylic acid or non-steroidal anti-inflammatory drugs is no longer considered contraindicated, but their combination with of heparin remains controversial. Intraoperative heparinization, perioperative thromboprophylactic use of unfractionated heparin or low molecular weight heparins are possible if: 1) a minimum time interval between the regional anesthetic block and the administration of the previous or next dose of anticoagulant is respected and; 2) the specified dose limitations of the heparin compound used are not exceeded; and 3) indwelling catheters are removed only after the disappearance of any remaining anticoagulant effect.
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Ketamine is an NMDA receptors antagonist, with a potent anaesthetic effect. NMDA receptors are involved in nociceptive modulation, in the wind-up phenomenon, in peripheral receptive fields expansion, in primary and secondary hyperalgesia, in neuronal plasticity. Ketamine effects are well-known: it produces a state of "dissociative anaesthesia", amnesia, and, at the same time, it mantains the respiratory drive effective and supports the sistemic arterial blood pressure. ⋯ The suggested doses are: Epidural or caudal route (as an ajuvant for local anaesthetic agents, in the treatment of postoperative pain): 0.5 mg/kg. Sedative/analgesic effect (for algesic procedures): 1-2 mg/kg i.v. Continuous infusion (intensive care unit): 0.5 mg/kg/h, with a range from 20-30 microg/kg/min to 80 microg/kg/min, depending on the age of the patient.
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Microcirculatory alterations have been widely described in experimental models of sepsis, however the microcirculation have long been neglected in septic patients as traditional techniques do not allow the visualisation of the microcirculation. The Orthogonal Polarization Spectral (OPS) imaging technique allows the direct visualisation of the microcirculation at the bedside. A selected review of the articles on the microcirculation in patients with sepsis using the OPS imaging technique, is made. ⋯ The severity of these alterations is more pronounced in non survivors than in survivors, and is related with the development of multiple organ failure. These alterations can be reversed by vasodilators, either topically applied or administered intravenously. Microvascular blood flow alterations are frequently observed in patients with sepsis and can have major pathophysiological implications.
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Minerva anestesiologica · May 2003
Review[Antithrombin: prospects in clinical practice. Sespsi: anticoagulant or anti-inflammatory agents?].
Sepsis and septic shock represent a frequent cause of mortality in Intensive Care Units, despite of the progress in antibiotic therapy and in the hemodynamic and respiratory support. The most frequent cause of death is the Multi Organ Dysfunction Syndrome (MODS), which is the clinical manifestation of the irreversibile damage of the microvascular bed. During sepsis and septic shock both activation of coagulation /fibrinolysis and release of mediators of inflammation contribute to the pathogenesis of disseminated intravascular coagulation (DIC); in particular the formation of fibrin in the microvascular bed is the pathological substrate of the clinical development of MODS. ⋯ AT has a double function: anticoagulant and anti-inflammatory. The most important mechanism responsible of the anti-inflammatory properties of AT is the binding to the glycosaminoglycans of the endothelial cells and the consequent release of prostacyclin. During sepsis and septic shock, treatment with AT was able, especially in animal models but also in clinical studies, to decrease plasma levels of mediators of inflammation and in some case to preserve organ failure and to reduce mortality.