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Correct Position (correct + position)

Distribution by Scientific Domains

Medical Sciences	66%

Selected Abstracts

Bronchial blocker compared to double-lumen tube for one-lung ventilation during thoracoscopy

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2001
C. Bauer
Background: Video-assisted thoracoscopic surgery (VATS) requires one-lung ventilation with a properly collapsed lung. This study compared the Broncho-Cath double-lumen endotracheal tube with the Wiruthan bronchial blocker to determine the advantages of one device over the other during anaesthesia with one-lung ventilation for thoracoscopy. Methods: Thirty-five patients undergoing VATS were randomly assigned to one of two groups. Sixteen patients received a left-sided double-lumen tube (DLT) and nineteen a Wiruthan bronchial blocker (BB). The BB group was subdivided in two: BB in the right mainstem bronchus (BBR) for right-sided VATS (9 patients), BB in the left mainstem bronchus (BBL) for left-sided VATS (10 patients). The position of the devices was checked using a fibreoptic bronchoscope. The following variables were measured: 1) number of unsuccessful placement attempts; 2) number of malpositions of the devices; 3) time required to place the device in the correct position; 4) number of secondary dislodgements of the devices after turning the patient into the lateral decubitus position. The quality of lung deflation was evaluated by the surgeons who were blinded to the type of tube being used. Results: The number of unsuccessful placement attempts was one in the DLT group (1/16), three in the BBL group (3/10) and none in the BBR group (0/9). The number of malpositions was significantly greater in the BBL group (10/10) compared to the DLT group (2/16) and to the BBR group (1/9) (P<0.001). The time (mean±SD) required to place a BBL was 4.21 min±1.28, significantly longer than the time required to place a DLT (2.26 min±0.55, P<0.0006) or a BBR (2.41 min±0.53, P<0.008). The difference in placement time between DLT and BBR was not significant. The number of secondary dislodgements was one in the DLT group, one in the BBR group and none in the BBL group (NS). The quality of lung deflation was judged excellent or fair in all patients in the DLT and the BBL groups and poor in 44% of the patients in the BBR group. Conclusion: It took significantly longer to place a left BB than a DLT (P<0.0006) or a right BB (P<0.008). The number of initial malpositionings of the left BB was significantly greater than in the other groups (P<0.001). The quality of lung deflation was better in the BBL and in the DLT groups than in the BBR group. We conclude that for routine use during left-sided VATS, the use of a DLT is preferable to a left BB because of its greater ease of placement. For right-sided VATS, DLT and right BB showed the same facility of placement but the DLT provided a better quality of lung deflation. [source]

Stereotactic-Guided Excisional Biopsy: A New Technique for Very Thin Breasts

THE BREAST JOURNAL, Issue 6 2006
Maria L. Diaz MD
Abstract:, Stereotactic biopsies are widely used for the diagnosis of breast lesions. Most biopsy devices require breast thickness of at least 25,30 mm with compression. We describe an alternative technique in order to perform excisional stereotactic-guided biopsies for very thin breasts using the prone stereotactic table. In the outpatient setting and with local anesthesia, this procedure can be performed by a radiologist, a surgeon, and a nurse. After conventional stereotactic localization, a fine needle is placed at the site of the lesion. Once the point is marked with a skin marker, a 25G × 16 mm needle is introduced. Then, a couple of stereotactic views are taken to confirm the correct position of the needle. Later, the surgeon excises the lesion guided by the needle. Additional radiographs of the specimen and the remaining breast tissue are obtained to ensure the accuracy of the procedure. [source]

Conformational features of crystal-surface cellulose from higher plants

THE PLANT JOURNAL, Issue 6 2002
Remco J. Viëtor
Summary Native cellulose in higher plants forms crystalline fibrils a few nm across, with a substantial fraction of their glucan chains at the surface. The accepted crystal structures feature a flat-ribbon 21 helical chain conformation with every glucose residue locked to the next by hydrogen bonds from O-3, to O-5 and from O-2 to O-6,. Using solid-state NMR spectroscopy we show that the surface chains have a different C-6 conformation so that O-6 is not in the correct position for the hydrogen bond from O-2. We also present evidence consistent with a model in which alternate glucosyl residues are transiently or permanently twisted away from the flat-ribbon conformation of the chain, weakening the O-3, , 0-5 hydrogen bond. Previous molecular modelling and the modelling studies reported here indicate that this ,translational' chain conformation is energetically feasible and does not preclude binding of the surface chains to the interior chains, because the surface chains share the axial repeat distance of the 21 helix. Reduced intramolecular hydrogen bonding allows the surface chains to form more hydrogen bonds to external molecules in textiles, wood, paper and the living plant. [source]

Visualisation of needle position using ultrasonography

ANAESTHESIA, Issue 2 2006
G. A. Chapman
Summary Anaesthetists and intensivists spend a considerable proportion of their working time inserting needles and catheters into patients. In order to access deeper structures like central veins and nerves, they have traditionally relied on surface markings to guide the needle into the correct position. However, patients may present challenges due to anatomical abnormalities and size. Irrespective of the skill of the operator, there is the ever-present risk of needle misplacement with the potential of damage to structures like arteries, nerve bundles and pleura. Repeated attempts, even if ultimately successful, cause patient suffering and probably increase the risk of infection and other long term complications. Portable and affordable, high-resolution ultrasound scanners, has accelerated the interest in the use of ultrasound guidance for interventional procedures. Ultrasound guidance offers several advantages including a greater likelihood of success, fewer complications and less time spent on the procedure. Even if the target structure is identified correctly there is still the challenge to place the needle or other devices in the optimum site. The smaller and deeper the target, the greater the challenge and potential usefulness of ultrasound guidance. As a result of limited training in the use of ultrasound we believe that many clinicians fail to use it to its full potential. A lack of understanding, with regard to imaging the location of the needle tip remains a major obstacle. Needle visualisation and related topics form the basis for this review. [source]

Percutaneous dilational tracheostomy: a safer technique of airway management using a microlaryngeal tube

ANAESTHESIA, Issue 3 2002
L. Fisher
Summary Management of the airway in an intubated patient during formation of a tracheostomy can be hazardous. The usual method involves withdrawal of the tracheal tube, which has been providing a secure airway, prior to inserting the tracheostomy tube. A method of airway management, using a microlaryngeal tube, has been devised with the aim of maintaining full tracheal intubation and ventilation until the correct position of the tracheostomy tube can be verified. An audit of 250 successive cases of percutaneous tracheostomy demonstrated this method to be safe and effective. [source]

Correcting electron-density resolution bias in reciprocal space

ACTA CRYSTALLOGRAPHICA SECTION A, Issue 3 2009
Angela Altomare
Fourier syntheses are always affected by series-termination errors, which generate sets of positive and negative ripples around each main peak in the map. The interaction among the ripples distorts the profile of the map and moves peaks away from their correct positions. In a previous paper [Altomare et al. (2008). Acta Cryst. A64, 326,336] an algorithm was described which reduces the resolution bias by removing the effects of the ripples in direct space. In this paper the correction is performed in reciprocal space: the effect of the ripples on the atomic scattering factors is calculated and subtracted from the usual atomic scattering factors. The modified scattering factors are used to calculate new structure factors, from which more accurate electron-density maps may be obtained. The experimental tests show that the procedure minimizes the effects of the resolution bias and provides atomic positions that are more accurate than those provided by traditional approaches. [source]