Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2015
Randomized Controlled TrialA pilot study on the effect of nasal continuous positive airway pressure on arterial partial pressure of carbon dioxide during spinal anesthesia with intravenous sedation for total knee arthroplasty.
Deep sedation of surgical patients may be associated with hypoventilation, airway collapse, and hypercarbia, although the extent of hypercarbia is rarely quantified. In this prospective, randomized, controlled clinical pilot study, we assessed the efficacy of nasal continuous positive airway pressure (nCPAP) for reducing arterial partial pressure of carbon dioxide (PaCO2) among deeply sedated, spontaneously ventilated patients undergoing total knee arthroplasty (TKA) under subarachnoid block (SAB), versus standard airway management in a control group. ⋯ Deep sedation of TKA patients during SAB resulted in moderate hypercarbia (mean and median PaCO2 = 55). There was a trend showing that nCPAP treatment reduced PaCO2 versus treatment for control group patients receiving standard airway management; however, estimated treatment difference varied widely, from 1.4 to 12.6 mm Hg. Among control group patients, the initial PaCO2 during deep sedation was similar to the PaCO2 when measured after a 30-minute period of continued deep sedation. Finally, baseline PaCO2 among deeply sedated patients who received an airway was not different from that of patients who did not receive an airway.
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Anesthesia and analgesia · Feb 2015
The Antihyperalgesic Effects of Intrathecal Bupropion, a Dopamine and Noradrenaline Reuptake Inhibitor, in a Rat Model of Neuropathic Pain.
Antidepressants are often used for the treatment of neuropathic pain, and their analgesic effects rely on increased noradrenaline and serotonin levels in the spinal cord. Clinical studies have also shown that bupropion, a dopamine and noradrenaline reuptake inhibitor, has strong efficacy in neuropathic pain; however, the role of spinal cord dopamine in neuropathic pain is unknown. We hypothesized that bupropion inhibits neuropathic pain by increasing noradrenaline and dopamine in the spinal cord. In the present study, we determined the efficacy and underlying mechanisms of intrathecal administration of bupropion in a rat model of neuropathic pain. ⋯ These findings suggest that plasticity of descending inhibitory pathways such as the noradrenaline and dopamine systems contributes to the maintenance of neuropathic pain and that spinal cord noradrenaline and dopamine both play an inhibitory role in neuropathic pain.
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Anesthesia and analgesia · Feb 2015
Gas analysis using Raman spectroscopy demonstrates the presence of intraperitoneal air (nitrogen and oxygen) in a cohort of children undergoing pediatric laparoscopic surgery.
Clinically significant gas embolism during laparoscopy is a rare but potentially catastrophic event. Case reports suggest that air, in addition to the insufflation gas, may be present. We studied the effects of equipment design and flushing techniques on the composition of gas present under experimental and routine pediatric surgical conditions. ⋯ Thus, when vascular injury occurs, embolized gases will contain variable quantities of N2, O2, and CO2. As the initial insufflation volume diminishes and approaches the volume of the insufflation tubing, which occurs in infants and young pediatric patients, the concentration of N2 will approximate that of room air in an unflushed system. Small insufflation volumes containing high N2 concentrations can contribute to catastrophic air emboli in neonates and small pediatric patients.
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Anesthesia and analgesia · Feb 2015
Spontaneous Pain-Like Behaviors Are More Sensitive to Morphine and Buprenorphine Than Mechanically Evoked Behaviors in a Rat Model of Acute Postoperative Pain.
Nonevoked spontaneous pain is most problematic for postoperative patients. Physicians assess this form of pain using the human visual analog scale or verbal numeric rating scale. Recent studies have proposed that spontaneous foot-lifting (SFL) behaviors are an expression of spontaneous pain in animals after spinal nerve injury or adjuvant-induced inflammation. In the current study, we characterize SFL behaviors in a rat model of acute postoperative pain, which includes comparisons with evoked behaviors to analgesic treatments. ⋯ The present study demonstrates that a hindpaw plantar incision induces SFL behaviors in rats and that these behaviors have higher bioassay sensitivity to analgesic interventions with morphine and buprenorphine compared with mechanically evoked behaviors.
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Anesthesia and analgesia · Feb 2015
Irritant Volatile Anesthetics Induce Neurogenic Inflammation Through TRPA1 and TRPV1 Channels in the Isolated Mouse Trachea.
Irritating effects of volatile general anesthetics on tracheal nerve endings and resulting spastic reflexes in the airways are not completely understood with respect to molecular mechanisms. Neuropeptide release and neurogenic inflammation play an established role. ⋯ Our results confirm the clinical experience that desflurane is more irritating than isoflurane at equal anesthetic gas concentration, whereas sevoflurane does not activate tracheobronchial sensory nerves to release neuropeptides and induce neurogenic inflammation. Both irritant receptor channels, TRPA1 more than TRPV1, are involved in mediating the adverse effects that may even extend to systemic proinflammatory sequelae.