Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2004
Clinical TrialNocturnal arterial oxygen desaturation and episodic airway obstruction after ambulatory surgery.
Some patients experience disordered breathing during sleep and arterial oxygen desaturation after major inpatient surgery. We performed this study to determine whether similar events occur after ambulatory surgery. Forty-five ambulatory surgery patients received an unrestricted anesthetic. ⋯ Nine patients had a respiratory disturbance index >10 and/or >1% of recording time with oxygen saturation <90% on at least one study night. These nine patients had a significantly older median age and a significantly larger median body mass index. Their median respiratory disturbance index and median percentage of time with oxygen saturation <90% were significantly higher on the first postoperative night than on the preoperative night.
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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
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
Case ReportsLate presentation of esophageal injury after transesophageal echocardiography.
Esophageal injury is a rare complication of intraoperative transesophageal echocardiography (TEE) associated with cardiac surgery. We report two cases of delayed presentation (2 and 6 days after surgery) of esophageal injury that were likely due to TEE. The differential diagnosis of postoperative pleural effusion or anemia must include esophageal injury from TEE, even 6 days after the procedure.