Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2009
Airway stenosis-related increase of pulmonary pressure during high-frequency jet ventilation depends on injector's position.
High-frequency jet ventilation (HFJV) can lead to high-airway pressures under certain conditions. In this laboratory study, we evaluated the influence of the injector's position relative to a fixed airway obstruction on peak pressures in a tracheal-lung model. ⋯ This study in a lung model suggests that placing an injector more than 8 cm proximal to a laryngotracheal stenosis will prevent changes in intrapulmonary pressure related to the degree of stenosis or driving pressure during HFJV. The location of the injector chosen for clinical care should balance the need for effective ventilation with the risk of barotrauma.
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Anesthesia and analgesia · Aug 2009
Long-term pain vulnerability after surgery in rats: prevention by nefopam, an analgesic with antihyperalgesic properties.
Tissue damage associated with surgery often produces peripheral and central sensitization that may outlast the stimuli, leading to exaggerated postoperative pain. Paradoxically, the use of opioid analgesia, which is essential for surgical pain management may induce pain sensitization leading to enhanced postoperative pain and an increased risk of developing chronic pain. We studied whether a surgical incision in the rat hindpaw may favor the development of long-term pain vulnerability by estimating hyperalgesia induced by an inflammatory stimulation of the unlesioned contralateral hindpaw 3 wk later. We also evaluated the ability of nefopam, an analgesic drug commonly used in postoperative pain management, to prevent not only exaggerated postoperative pain but also long-term pain vulnerability. The efficacy of morphine was assessed 1 day after surgical incision. ⋯ Given preemptively, nefopam may be effective at improving postoperative pain management and at reducing the risk of developing postoperative chronic pain, because the drug has both analgesic and antihyperalgesic properties.
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Anesthesia and analgesia · Aug 2009
The influence of hemorrhagic shock on the electroencephalographic and immobilizing effects of propofol in a swine model.
Hemorrhagic shock increases the hypnotic effect of propofol, but the influence of hemorrhagic shock on the immobilizing effect of propofol is not fully defined. ⋯ The results show that hemorrhagic shock increases both the hypnotic and immobilizing effects of propofol due to pharmacokinetic and pharmacodynamic alterations, with the changes in pharmacodynamics occurring to a similar extent for both effects.
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Anesthesia and analgesia · Aug 2009
A closed-circuit neonatal xenon delivery system: a technical and practical neuroprotection feasibility study in newborn pigs.
Asphyxia accounts for 23% of the 4 million annual global neonatal deaths. In developed countries, the incidence of death or severe disability after hypoxic-ischemic (HI) encephalopathy is 1-2/1000 infants born at term. Hypothermia (HT) benefits newborns post-HI and is rapidly entering clinical use. Xenon (Xe), a scarce and expensive anesthetic, combined with HT markedly increases neuroprotection in small animal HI models. The low-Xe uptake of the patient favors the use of closed-circuit breathing system for efficiency and economy. We developed a system for delivering Xe to mechanically ventilated neonates, then investigated its technical and practical feasibility in a previously described neonatal pig model approximating the clinical scenario of global HI injury, prolonged Xe delivery with and without HT as a potential therapy, subsequent neonatal intensive care unit management, and tracheal extubation. ⋯ We describe a closed-circuit Xe delivery system with automatic mechanical oxygen replenishment, which could be developed as a single use device. Gas exchange was maintained while Xe consumption was minimal (<$2/h at $10/L*). We have shown it is both feasible and cost-efficient to use this Xe delivery method in newborn pigs for up to 16 h with or without concurrent cooling after a severe HI insult.
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Anesthesia and analgesia · Aug 2009
The effects of propofol infusion on hepatic and pancreatic function and acid-base status in children undergoing craniotomy and receiving phenytoin.
In this study, we investigated the effects of propofol infusion on hepatic and pancreatic enzymes and acid-base status compared with baseline values in children undergoing craniotomy who were receiving phenytoin for antiepileptic prophylaxis. ⋯ Despite the slightly increased pancreatic and hepatic enzyme levels during the postoperative period, anesthesia maintenance with propofol in children undergoing craniotomy had no significant clinical effect on the acid-base status or pancreas or liver enzymes.