Anesthesia and analgesia
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Nitrous oxide can cause hematologic abnormalities, including death, if it is administered for several days. However, the adverse hematologic effects of its use for surgical anesthesia are unclear. Accordingly, we have studied the hematologic responses of patients undergoing procedures involving hematologic stress or prolonged anesthesia with and without nitrous oxide. ⋯ Nitrous oxide did not affect the production of red blood cells or platelets. Nitrous oxide treatment was associated with an increase in postoperative leukocyte levels that was modestly but significantly smaller than that found in patients not given nitrous oxide. There was no evidence that this small decrease in maximal leukocytosis adversely affected clinical outcome.
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Anesthesia and analgesia · Dec 1990
Comparative StudyTransesophageal Doppler ultrasonography: evidence for improved cardiac output monitoring.
Cardiac output monitoring by transesophageal Doppler ultrasound has not gained wide clinical acceptance. A recently developed transesophageal Doppler device, Accucom 2, features technological advances aimed to reduce the error of this approach to the monitoring of cardiac output. ⋯ Results using Accucom 2 were highly correlated with the results obtained with thermodilution (R = 0.91) and provided significantly greater accuracy in comparison with a previously developed Doppler cardiac output monitor, Accucom 1. Technological advances in transesophageal Doppler ultrasound hold promise for clinically useful noninvasive monitoring of cardiac output.
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Anesthesia and analgesia · Dec 1990
Comparative StudyElimination kinetics of sevoflurane and halothane from blood, brain, and adipose tissue in the rat.
Using the rat as an animal model, the elimination kinetics of sevoflurane and halothane from brain, blood, and adipose tissue were compared. Elimination of sevoflurane and halothane from blood and brain was biexponential. ⋯ However, the slower beta-elimination rates from brain and blood, as well as the elimination rates from adipose tissue, were similar for both volatile anesthetics. Thus, the potential for residual postoperative impairment from subanesthetic tissue concentrations of halothane and sevoflurane may be similar even though sevoflurane is initially eliminated more rapidly from blood and brain.
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Anesthesia and analgesia · Dec 1990
Emergency tracheal intubation in the postanesthesia care unit: physician error or patient disease?
Inadequate airway maintenance has been a major factor in perioperative morbidity. To determine the incidence and etiology of emergency tracheal intubations in the postanesthesia care unit (PACU), we retrospectively reviewed 13,593 consecutive admissions to our PACU from October 1986 through October 1988. Twenty-six patients (26/13,593 = 0.19%) required the insertion of an endotracheal tube while in the PACU. ⋯ There was no association between intubation and gender (P = 0.74), anesthetic technique (P = 0.41), or anesthetic agent (P = 0.49). Of the 26 intubations, 18 (69%) were considered to be directly related to anesthetic management. Despite the extremely low incidence of emergency tracheal intubation in a heterogeneous group of patients admitted to our PACU, preventable anesthesia-related etiologic factors including excessive sedative or anesthetic effect, inappropriate fluid management, persistent muscle relaxant effect, and upper airway obstruction contributed to the majority of these intubations.
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Anesthesia and analgesia · Dec 1990
Tracheal insufflation of oxygen at low flow: capabilities and limitations.
Tracheal insufflation of oxygen (TRIO) may provide temporary oxygenation for patients or sustain life in apneic mass casualties when conventional ventilatory techniques are not available or feasible. Logistically, minimum flows of TRIO (Vmin) are desirable for field use and to reduce barotrauma should airway obstruction occur. We carried out a feasibility study to determine the efficacy of Vmin of TRIO delivered within 1 cm of the carina, in nine anesthetized and paralyzed dogs. ⋯ The oscillations (60 mL at 16.3 Hz) increased carbon dioxide excretion but significantly impaired oxygenation. In completely apneic animals, TRIO at low flow delivered by cricothyroidotomy may be useful as an emergency procedure when upper airway obstruction limits the use of other airway management techniques. However, enhancement of gas mixing during low-flow TRIO impairs oxygenation, so that higher flows would be required when respiratory efforts occur.