Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2003
Clinical TrialA prospective cohort study of emergence agitation in the pediatric postanesthesia care unit.
Emergence agitation (EA) is a postanesthetic problem that interferes with a child's recovery and presents a challenge in terms of assessment and management. In this prospective cohort study, we sought to determine the incidence of EA, evaluate factors associated with and predictive of EA, and describe associated outcomes in healthy children. Children aged 3-7 yr who were undergoing general anesthesia for elective outpatient procedures were included. All perioperative care was documented, and postoperative behaviors in the postanesthesia care unit were recorded. Parents completed the Behavioral Style Questionnaire for 3- to 7-yr-olds. Five-hundred-twenty-one children were studied, of whom 96 (18%) had EA. Agitation lasted up to 45 min in some cases (range, 3-45 min; mean, 14 +/- 11 min), required pharmacologic intervention in 52% of children, and was associated with a prolonged postanesthesia care unit stay (117 +/- 66 min versus 101 +/- 61 min for nonagitated children; P = 0.02). Ten factors were found to be associated with EA, including age, previous surgery, adaptability, ophthalmology and otorhinolaryngology procedures, sevoflurane, isoflurane, sevoflurane/isoflurane, analgesics, and time to awakening. Of these, otorhinolaryngology procedures, time to awakening, and isoflurane were shown to be independent risk factors. ⋯ Children may become agitated after general anesthesia. This study describes several factors that may increase the risk for agitation. These data are important in planning anesthesia care for young children.
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Anesthesia and analgesia · Jun 2003
Clinical TrialSmall risk of serious neurologic complications related to lumbar epidural catheter placement in anesthetized patients.
Previous studies have identified pain during needle/catheter placement or during the injection of local anesthetic as a risk factor for the development of persistent paresthesias after regional anesthetic techniques. The performance of regional blockade on anesthetized patients theoretically increases the risk of postoperative neurologic complications, because these patients are unable to respond to painful stimuli. In this study, we evaluated the frequency of neurologic complications in 4298 thoracic surgical patients undergoing lumbar epidural catheter placement while under general anesthesia. Catheters were placed immediately after the induction and tracheal intubation or on completion of the surgical procedure, before emergence. Most epidural catheters (4220, or 98.2%) were used solely for postoperative analgesia; only 78 (1.8%) epidural catheters were used for intraoperative anesthesia. In 4239 (98.6%) patients, an opioid alone was administered. The remaining 56 (1.3%) patients received a local anesthetic or local anesthetic/opioid mixture epidurally. Analgesia was graded as excellent or good in 92.2% of patients. Side effects included sedation in 455 (10.6%), nausea or emesis in 328 (7.6%), pruritus in 116 (2.7%), and respiratory depression (pH
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Anesthesia and analgesia · Jun 2003
Clinical TrialAn evaluation of the Laryngeal Tube during general anesthesia using mechanical ventilation.
The Laryngeal Tube is a new supraglottic ventilatory device for airway management. It has been developed to secure a patent airway during either spontaneous or mechanical ventilation. In this study, we sought to determine the effectiveness of the Laryngeal Tube for primary airway management during routine surgery with mechanical ventilation. One-hundred-seventy-five subjects classified as ASA physical status I and II, scheduled for elective surgery, were included in the study. After the induction of general anesthesia and insertion of a Size 4 Laryngeal Tube, measurements of oxygen saturation, end-tidal CO(2) and isoflurane concentration, and breath-by-breath spirometry data were obtained every 5 min throughout surgery. The lungs were ventilated with volume-controlled mechanical ventilation. The number of attempts taken to insert the Laryngeal Tube and the insertion time were recorded. In 96.6% of patients, it was possible to maintain oxygenation, ventilation, and respiratory mechanics by using mechanical ventilation throughout the surgical procedure. The results of this study suggest that the Laryngeal Tube is an effective and safe airway device for airway management in mechanically ventilated patients during elective surgery. ⋯ In 96.6% of patients intubated with the Laryngeal Tube, it was possible to maintain oxygenation, ventilation, and respiratory mechanics during mechanical ventilation.
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Anesthesia and analgesia · Jun 2003
Knowledge and practice regarding prophylactic perioperative beta blockade in patients undergoing noncardiac surgery: a survey of Canadian anesthesiologists.
A lack of awareness of the "best" current practice is frequently cited as a major barrier to the practice of evidence-based medicine. The purpose of this study was to survey Canadian anesthesiologists to determine their knowledge and practices associated with prophylactic perioperative beta blockade, a therapy that has been widely discussed in the literature and has the potential for a significant positive impact on patient outcomes. We sent questionnaires to 1234 members of the Canadian Anesthesiologists' Society. The overall response rate was 54%. Ninety-five percent of respondents were aware of the perioperative beta blocker literature, and of these, 93% agreed that beta blockers were beneficial in patients with known coronary artery disease (CAD). Fifty-seven percent reported always or usually administering prophylactic beta blockers in patients with known CAD, and 34% of these regular users continued therapy beyond the early postoperative period. Only 9% of respondents reported that a formal protocol existed at their facility. This study suggests that barriers to the translation of research to practice were not related to a lack of awareness of the current best evidence. With respect to perioperative beta blockers, controversies within the literature as well as practical considerations may be greater barriers to implementation of best evidence. ⋯ This survey found that anesthesiologists were aware of and supported the use of prophylactic perioperative beta blockers in patients with risk factors or known coronary artery disease; however, only 57% frequently prescribed perioperative beta blockers. A lack of awareness of the current "best" evidence was not a barrier to use.
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Anesthesia and analgesia · Jun 2003
Comparative StudyThe effects of enflurane, isoflurane, and intravenous anesthetics on rat diaphragmatic function and fatigability.
We examined the effect of isoflurane, enflurane, midazolam, ketamine, propofol, and thiopental on diaphragmatic functions under unfatigued and fatigued conditions in 228 rat isolated muscle strips. Diaphragmatic twitch characteristics and tetanic contractions were measured before and after muscle fatigue, which was induced by repetitive tetanic contraction with or without exposure to one of the anesthetics at clinically relevant plasma concentrations, and at 10 and 100 times this concentration, or at 1, 2, and 3 minimum alveolar anesthetic concentration (MAC). Isoflurane, midazolam, ketamine, propofol, and thiopental did not induce a direct inotropic or lusitropic effect under unfatigued and fatigued conditions. Enflurane did not change contraction or relaxation in fresh isolated diaphragm, but enflurane at 2-3 MAC enhanced diaphragmatic fatigability itself and fatigue-induced impairment of twitch characteristics and tetanic tensions. These effects were greater at 3 MAC than at 2 MAC. Our findings suggest that the reduction of diaphragm function previously reported in in vivo experiments using propofol, midazolam, and isoflurane is not related to a direct effect on intrinsic diaphragmatic contractility. Our results also indicate that large concentrations of enflurane may impair the diaphragmatic function at sites other than excitation-contraction coupling. ⋯ Enflurane did not change contraction or relaxation in fresh isolated rat diaphragm, but enhanced diaphragmatic fatigability itself and fatigue-induced impairment of twitch characteristics and tetanic tensions. Isoflurane, midazolam, ketamine, propofol, and thiopental had no direct effects on diaphragmatic functions under unfatigued and fatigued conditions. Isoflurane and these i.v. anesthetics may be advantageous over enflurane to anesthetize and/or sedate patients who are predisposed to diaphragmatic fatigue.