Anesthesiology
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Preclinical studies demonstrate increased neuroapoptosis after general anesthesia in early life. Neuraxial techniques may minimize potential risks, but there has been no systematic evaluation of spinal analgesic safety in developmental models. We aimed to validate a preclinical model for evaluating dose-dependent efficacy, spinal cord toxicity, and long-term function after intrathecal morphine in the neonatal rat. ⋯ The therapeutic ratio for intrathecal morphine (toxic dose/antinociceptive dose) was at least 300 at P3 and at least 20 at P21 (latter doses limited by side effects). These data provide relative efficacy and safety for comparison with other analgesic preparations and contribute supporting evidence for the validity of this preclinical neonatal safety model.
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Animal studies suggest that regional anesthesia and optimal postoperative analgesia independently reduce cancer metastasis. Retrospective clinical studies suggest reductions in recurrence of several cancer types in patients receiving perioperative neuraxial analgesia. Thus, the authors determined the association between perioperative epidural analgesia and cancer recurrence in patients undergoing colorectal cancer surgery. ⋯ In contrast to previous retrospective studies in the colon, breast, and prostate cancer surgery, the authors found that the use of epidural analgesia for perioperative pain control during colorectal cancer surgery was not associated with a decreased cancer recurrence; however, a potential benefit was observed in older patients. The benefit of regional anesthesia on cancer recurrence may thus depend on the specific tumor type.
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Ca is the dominant second messenger in primary sensory neurons. In addition, disrupted Ca signaling is a prominent feature in pain models involving peripheral nerve injury. Standard cytoplasmic Ca recording techniques use high K or field stimulation and dissociated neurons. To compare findings in intact dorsal root ganglia, we used a method of simultaneous electrophysiologic and microfluorimetric recording. ⋯ Refined observation of Ca signaling is possible through natural activation by conducted APs in undissociated sensory neurons and reveals features distinct to neuronal types and injury state.
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Clinical observation suggests that the number of serious epidural catheter-associated infections have increased recently in children. This increase is likely attributed to an increase in reporting and in frequency of epidural analgesia usage. Estimates of infection rates are difficult to determine primarily because of insufficient study of large pediatric populations. ⋯ Although rare, epidural catheter-associated infections remain a serious concern in high-risk children who may benefit the most from epidural analgesia. The findings of the authors support the low rate of epidural infection previously reported despite growing concerns of serious infections in children. These findings highlight the importance of vigilance to early diagnostic indicators of infection and provide practitioners and families with incidence data to guide informed medical decision-making.
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Hypercapnic acidosis frequently occurs when patients with acute lung injury are initially ventilated with low tidal volume "protective" strategies. Hypercapnic acidosis per se, in the absence of any change in tidal volume or airway pressure, is protective when instituted before the onset of injury. However, the mechanisms by which hypercapnic acidosis confers this protection are incompletely understood, in particular, the effects on pulmonary oxidative reactions, which are potent mediators of tissue damage, have not been previously examined in vivo. ⋯ Hypercapnic acidosis reduced oxidative reactions in the acutely injured lung in vivo, within minutes of onset and was not reliant on nitric oxide-dependent peroxynitrite production. This rapid onset antioxidant action is a previously undescribed mechanism by which hypercapnic acidosis could act, even when acute lung injury is well established.