Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2005
The predictive value of the height ratio and thyromental distance: four predictive tests for difficult laryngoscopy.
Preoperative evaluation of anatomical landmarks and clinical factors help identify potentially difficult laryngoscopies; however, predictive reliability is unclear. Because the ratio of height to thyromental distance (RHTMD) has a demonstrably better predictive value than the thyromental distance (TMD), we evaluated the predictive value and odds ratios of RHTMD versus mouth opening, TMD, neck movement, and oropharyngeal view (modified Mallampati). We collected data on 550 consecutive patients scheduled for elective-surgery general anesthesia requiring endotracheal intubation and then assessed all five factors before surgery. ⋯ In the multivariate analysis, three criteria were found independent for difficult laryngoscopy (neck movement < or =80 degrees; Mallampati Class 3 or 4, and RHTMD > or =23.5). The odds ratio (95% confidence interval) of the RHTMD, Mallampati class, and neck movement were 6.72 (3.29-13.72), 2.96 (1.63-5.35), and 2.73 (1.14-6.51), respectively. The odds ratio for RHTMD was the largest and thus may prove a useful screening test for difficult laryngoscopy.
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Anesthesia and analgesia · Nov 2005
An evaluation of bilateral monitoring of cerebral oxygen saturation during pediatric cardiac surgery.
Cerebral oximetry is a technique that enables monitoring of regional cerebral oxygenation during cardiac surgery. In this study, we evaluated differences in bi-hemispheric measurement of cerebral oxygen saturation using near-infrared spectroscopy in 62 infants undergoing biventricular repair without aortic arch reconstruction. ⋯ Mean left and right rSO2i measurements were similar (< or =2 percentage points/absolute scale units) before, during, and after cardiopulmonary bypass, irrespective of the use of deep hypothermic circulatory arrest. Further longitudinal neurological outcome studies are required to determine whether uni- or bi-hemispheric monitoring is required in this patient population.
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Anesthesia and analgesia · Nov 2005
Spatial memory performance 2 weeks after general anesthesia in adult rats.
We have previously demonstrated that general anesthesia with 1.2% isoflurane-70% nitrous oxide impairs acquisition of a radial arm maze task in both young and aged rats when testing begins 2 days after anesthesia and in aged rats when testing begins 2 wk later. We designed this study to examine whether postanesthesia learning impairment is persistent in young rats. Six-month-old rats were randomized to anesthesia for 2 h with 1.2% isoflurane-70% nitrous oxide, 1.8% isoflurane, or a control group that received 30% oxygen (n = 10 per group). ⋯ There was no main effect of group in terms of total number of errors (P > 0.05) but the group by day interaction was significant (P < 0.05), reflecting improved performance in the 1.2% isoflurane-70% nitrous oxide group relative to controls during the later days of testing (P < 0.005). Hence, in adult rats, previous general anesthesia is not associated with impaired learning 2 wk later. In fact, previous 1.2% isoflurane-70% nitrous oxide improves maze performance 2 wk later.
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Anesthesia and analgesia · Nov 2005
The optimal depth of central venous catheter for infants less than 5 kg.
To avoid fatal complications of central venous catheterization such as cardiac tamponade, the tip of the central venous catheter (CVC) should be placed outside of the cardiac chamber. To suggest a guideline for a proper depth of CVC in infants, we measured the distance from the skin puncture site to the junction between superior vena cava and right atrium (SVC-RA junction) by using transesophageal echocardiography (TEE). Fifty infants less than 5 kg undergoing surgery for congenital heart disease were enrolled in this prospective study. ⋯ After the tip of the CVC was placed at the SVC-RA junction using TEE guidance, the length of the CVC inserted beneath the skin was measured. The measured distance had a high correlation with the patient's height, weight, and age (r = 0.88, 0.76, and 0.64, respectively). In infants smaller than 5 kg, the following guideline can avoid intraatrial placement of the CVC: a depth between 40 and 45 mm for infants 2.0-3.0 kg in weight, 45-50 mm for those 3.0-3.9 kg, and 50-55 mm for those more than 4.0 kg.
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Anesthesia and analgesia · Nov 2005
Comparative StudyThe feasibility of laryngoscope-guided tracheal intubation in microgravity during parabolic flight: a comparison of two techniques.
We determined the feasibility of laryngoscope-guided tracheal intubation (LG-TI) in microgravity obtained during parabolic flight and tested the hypothesis that LG-TI is similarly successful in the free-floating condition, with the patient's head gripped between the anesthesiologist's knees, as in the restrained condition, with the torso strapped to the surface. Three personnel with no experience in airway management or microgravity participated in the study. LG-TI of a sophisticated full-size manikin was attempted on seven occasions in each condition by each investigator after ground-based training. ⋯ There were no differences in performance among investigators. We conclude that LG-TI is feasible in microgravity obtained during parabolic flight, but the success rate is infrequent because of severe time restrictions. There were no differences in success rate between the free-floating condition, with the head gripped between the knees, and the restrained condition, with the torso strapped to the surface.