Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2004
Comparative StudyLung recruitment improves the efficiency of ventilation and gas exchange during one-lung ventilation anesthesia.
Atelectasis in the dependent lung during one-lung ventilation (OLV) impairs arterial oxygenation and increases dead space. We studied the effect of an alveolar recruitment strategy (ARS) on gas exchange and lung efficiency during OLV by using the single-breath test of CO(2) (SBT-CO(2)). Twelve patients undergoing thoracic surgery were studied at three points in time: (a) during two-lung ventilation and (b) during OLV before and (c) after an ARS. The ARS was applied selectively to the dependent lung and consisted of an increase in peak inspiratory pressure up to 40 cm H(2)O combined with a peak end-expiratory pressure level of 20 cm H(2)O for 10 consecutive breaths. The ARS took approximately 3 min. Arterial blood gases, SBT-CO(2), and metabolic and hemodynamic variables were recorded at the end of each study period. Arterial oxygenation and dead space were better during two-lung ventilation compared with OLV. PaO(2) increased during OLV after lung recruitment (244 +/- 89 mm Hg) when compared with OLV without recruitment (144 +/- 73 mm Hg; P < 0.001). The SBT-CO(2) analysis showed a significant decrease in dead-space variables and an increase in the variables related to the efficiency of ventilation during OLV after an ARS when compared with OLV alone. In conclusion, ARS improves gas exchange and ventilation efficiency during OLV. ⋯ In this article, we showed how a pulmonary ventilatory maneuver performed in the dependent lung during one-lung ventilation anesthesia improved arterial oxygenation and dead space.
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Anesthesia and analgesia · Jun 2004
Comparative StudyA specific alteration in the electroretinogram of Drosophila melanogaster is induced by halothane and other volatile general anesthetics.
In higher organisms, physiological investigations have provided a valuable complement to assays of anesthetic effects on whole-animal behavior. However, although complex motor programs of Drosophila melanogaster have been used to identify genes that influence anesthesia, electrophysiological studies of anesthetic effects in this invertebrate have been limited. Here we show that the electroretinogram (ERG), the extracellular recording of light-evoked mass potentials from the surface of the eye, reveals a distinct effect of halothane, enflurane, isoflurane, and desflurane. Behaviorally relevant concentrations of these volatile anesthetics severely reduced the transient component of the ERG at lights-off. Other prominent ERG components, such as the photoreceptor potential and the lights-on transient, were not consistently affected by these drugs. Surprisingly, for most anesthetics, a diminished off-transient was obtained only with short light pulses. An identical effect was observed in the absence of anesthetic by depressing the function of Shaker potassium channels. The possibility that halothane acts in the visual circuit by closing potassium channels was examined with a simple genetic test; the results were consistent with the hypothesis but fell short of providing definitive support. Nevertheless, our studies establish the ERG as a useful tool both for examining the influence of volatile anesthetics on a simple circuit and for identifying genes that contribute to anesthetic sensitivity. ⋯ Electroretinography (ERG) provides a useful monitor of anesthetic effects on the fruit fly. The effects of volatile anesthetics on the ERG are recapitulated by inactivation of potassium channels.
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Anesthesia and analgesia · Jun 2004
Case ReportsA severe complication after laser-induced damage to a transtracheal catheter during endoscopic laryngeal microsurgery.
Subcutaneous emphysema and pneumothorax is a rare and severe complication of percutaneous transtracheal jet ventilation, usually caused by obstruction of the upper airway or displacement of the tracheal catheter. Nevertheless, it is our preferred technique for endoscopic laryngeal laser surgery. We report a patient with acute subcutaneous emphysema and pneumothorax during laser surgery, caused by unobserved laser damage and discuss the associated risk factors. ⋯ The percutaneous transtracheal jet ventilation for elective laryngeal laser surgery reduces the risk of airway fires and gives a free endoscopic operative field. This case report suggests that, even when using a teflon catheter, laser-induced damage with severe complications might occur.
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Anesthesia and analgesia · Jun 2004
Case ReportsChange in bispectral index during epileptiform electrical activity under sevoflurane anesthesia in a patient with epilepsy.
We observed abnormal fluctuation in Bispectral Index (BIS) caused by repeated alternations between two electroencephalographic (EEG) waveform patterns in a patient with a recent history of epileptic seizure under sevoflurane anesthesia. The repetitive development of the abnormal EEG changes (slow delta with or without spike) and the fluctuation in BIS disappeared almost immediately after administration of anticonvulsants. BIS may give useful information not only on the sedative-hypnotic state, but also on the development of and recovery from abnormal epileptiform EEG activity. ⋯ During epileptiform electroencephalographic activity (EEG), the Bispectral Index shows an abnormal fluctuation caused by repeated abrupt alterations between normal EEG and abnormal epileptiform EEG patterns.
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Anesthesia and analgesia · Jun 2004
Case ReportsThe use of dexmedetomidine to facilitate opioid and benzodiazepine detoxification in an infant.
Prolonged use of opioids and benzodiazepines for the care of critically ill infants and children can generate physical dependence. We present a case of an 8-mo-old infant with Hunter's syndrome who was maintained on very large doses of fentanyl and midazolam and who could not be weaned from these drugs by conventional taper. We used dexmedetomidine, an alpha(2)-adrenergic agonist, to facilitate opioid and benzodiazepine withdrawal. A processed electroencephalogram (Bispectral Index) was used to guide the titration of dexmedetomidine in this neurologically impaired infant. This is the first report of this drug being used in an infant to manage chemical dependence withdrawal. ⋯ Dexmedetomidine was used to facilitate opioid and benzodiazepine withdrawal in an 8-mo-old infant. A processed electroencephalogram (Bispectral Index) was used to guide the titration of dexmedetomidine in this neurologically impaired infant. This is the first report of dexmedetomidine use in an infant to manage chemical dependence withdrawal.