Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2004
Comparative StudyGamma-aminobutyric acidA receptors do not mediate the immobility produced by isoflurane.
Many inhaled anesthetics enhance the effect of the inhibitory neurotransmitter gamma aminobutyric acid (GABA), supporting the view that the GABAA receptor could mediate the capacity of inhaled anesthetics to produce immobility in the face of noxious stimulation (i.e., MAC, the minimum alveolar concentration required to suppress movement in response to a noxious stimulus in 50% of subjects). However, only limited in vivo data support the relevance of the GABAA receptor to MAC. In the present study we used two findings to test for the relevance of this receptor to immobilization for isoflurane: 1) differences among anesthetics in their capacity to enhance the response of receptor expression systems to GABA: isoflurane (considerable enhancement), xenon (minimal enhancement), and cyclopropane (minimal enhancement); and 2) studies showing that the spinal cord mediates MAC for isoflurane. ⋯ This indicates that GABA release in the spinal cord influences anesthetic requirement. However, the increase did not consistently differ among anesthetics and did not correlate with in vitro enhancement of GABAA receptors by these anesthetics. This supports the view that GABAA receptors do not mediate immobilization for isoflurane.
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Anesthesia and analgesia · Jul 2004
Supplemental oxygen and carbon dioxide each increase subcutaneous and intestinal intramural oxygenation.
Oxidative killing by neutrophils, a primary defense against surgical pathogens, is directly related to tissue oxygenation. We tested the hypothesis that supplemental inspired oxygen or mild hypercapnia (end-tidal PCO2 of 50 mm Hg) improves intestinal oxygenation. Pigs (25 +/- 2.5 kg) were used in 2 studies in random order: 1) Oxygen Study: 30% versus 100% inspired oxygen concentration at an end-tidal PCO2 of 40 mm Hg, and 2) Carbon Dioxide Study: end-tidal PCO2 of 30 mm Hg versus 50 mm Hg with 30% oxygen. ⋯ Oxygen 100% administration doubled subcutaneous oxygen partial pressure (PO2) (57 +/- 10 to 107 +/- 48 mm Hg, P = 0.006) and large intestine intramural PO2 (53 +/- 14 to 118 +/- 72 mm Hg, P = 0.014); intramural PO2 increased 40% in the small intestine (37 +/- 10 to 52 +/- 25 mm Hg, P = 0.004). An end-tidal PCO2 of 50 mm Hg increased large intestinal PO2 approximately 16% (49 +/- 10 to 57 +/- 12 mm Hg, P = 0.039), whereas intramural PO2 increased by 45% in the small intestine (31 +/- 12 to 44 +/- 16 mm Hg, P = 0.002). Supplemental oxygen and mild hypercapnia each increased subcutaneous and intramural tissue PO2, with supplemental oxygen being most effective.
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Anesthesia and analgesia · Jul 2004
Case ReportsClinical management of cardiogenic shock associated with prolonged propofol infusion.
This case report details the development of cardiogenic shock after craniotomy in a patient sedated with a propofol infusion. The patient survived with the assistance of extracorporeal membrane oxygenation. A literature review summarizes the syndrome of cardiogenic shock associated with prolonged propofol infusion. This is the first report of survival in this syndrome resuiting from mechanical circulatory support.
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Anesthesia and analgesia · Jul 2004
The impact of factor XIII on coagulation kinetics and clot strength determined by thrombelastography.
Fibrinogen has been shown to be responsible for most protein-mediated clot strength via thrombelastography. However, factor XIII (FXIII) activity also plays a prominent role in the development of clot strength. Thus, we hypothesized that changes in FXIII activity would significantly increase clot strength. ⋯ Finally, increases in FXIII activity significantly increased A and G in a sigmoidal pattern (R = 0.89; P < 0.001). We concluded that FXHI significantly affects R, alpha, A, and G. Thus, transfusion decision making with protein-mediated thrombelastographic patterns must account for the contribution of both fibrinogen and FXIII.
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Anesthesia and analgesia · Jul 2004
A new supraglottic airway, the Elisha Airway Device: a preliminary study.
We describe the Elisha Airway Device (EAD), a new reusable supraglottic ventilatory device. Its uniqueness consists of its ability to combine three functions in a single device: ventilation, blind and/or fiberoptic-aided intubation without interruption of ventilation, and gastric tube insertion. This study was performed in 70 ASA status I-II, Mallampati class I-II patients undergoing elective knee arthroscopy and receiving general anesthesia with mechanical ventilation. ⋯ Blind intubation was possible during the first and second attempts in 15 and 2 patients, respectively. Fiberoptic intubation was then successful in two of the remaining three patients. The EAD is a new alternative in the evolution of supraglottic ventilatory devices; however, further clinical studies are necessary to evaluate its efficacy.