Biomedical subjects

Brian J Robinson

Publications and source records attributed to Brian J Robinson.

4 recordsLinked to original sources

PubMed2003

Phenotypic library-based microbial source tracking methods: efficacy in the California collaborative study.

As part of a larger microbial source tracking (MST) study, several laboratories used library-based, phenotypic subtyping techniques to analyse fecal samples from known sources (human, sewage, cattle, dogs and gulls) and blinded water samples that were contaminated with the fecal sources. The methods used included antibiotic resistance analysis (ARA) of fecal streptococci, enterococci, fecal coliforms and E. coli; multiple antibiotic resistance (MAR) and Kirby-Bauer antibiotic susceptibility testing of E. coli; and carbon source utilization for fecal streptococci and E. coli. Libraries comprising phenotypic patterns of indicator bacteria isolated from known fecal sources were used to predict the sources of isolates from water samples that had been seeded with fecal material from the same sources as those used to create the libraries. The accuracy of fecal source identification in the water samples was assessed both with and without a cut-off termed the minimum detectable percentage (MDP). The libraries (approximately 300 isolates) were not large enough to avoid the artefact of source-independent grouping, but some important conclusions could still be drawn. Use of a MDP decreased the percentage of false-positive source identifications, and had little effect on the high percentage of true-positives in the most accurate libraries. In general, the methods were more prone to false-positive than to false-negative errors. The most accurate method, with a true-positive rate of 100% and a false-positive rate of 39% when analysed with a MDP, was ARA of fecal streptococci. The internal accuracy of the libraries did not correlate with the accuracy of source prediction in water samples, showing that one should not rely solely on parameters such as the average rate of correct classification of a library to indicate its predictive capabilities.

Animals↗

PubMed2002

Acquisition and maintenance of endoscopic skills: developing an endoscopic dexterity training system for anesthesiologists.

The acquisition and maintenance of essential psychomotor skills that are only required sporadically is a significant problem in medical training and practice. It is of particular relevance to anesthesiologists with regard to fiberoptic intubation, a technique that may be under-utilized despite its central role in the management of the difficult airway. Dexterity deficit due to current training models, dexterity decay due to lack of practice, and situational stress related to the clinical environment may combine to impede effective training and confident use of endoscopes in airway management. We describe an educational resource (Dexter), which has been developed to overcome these problems. Dexter is a nonanatomical, endoscopic dexterity training system designed to encourage practice and help establish and maintain a state of procedural readiness, even if clinical exposure to difficult airway situations is sporadic.

Anesthesiology↗

PubMed2002

The role of strain gauge plethysmography in the assessment of patients with suspected deep vein thrombosis.

Suspicion of deep vein thrombosis (DVT) is a common reason for medical referral to hospital. Clinical signs and symptoms are notoriously unreliable, hence there is the need for objective testing. Strain gauge plethysmography (SGP) has been marketed as a technique for excluding lower limb DVT. We therefore set out to evaluate this screening tool. Over a 2 year period, 437 consecutive patients referred with suspected DVT were assessed using both plethysmography and Doppler ultrasound. When the two techniques were compared, plethysmography was found to have a negative predictive value of 90%. We conclude that strain gauge plethysmography has a role in the screening of patients with suspected DVT but should not be used as the sole method in patient assessment.

False Negative Reactions↗

PubMed2002

Vascular responsiveness to brachial artery infusions of phenylephrine during isoflurane and desflurane anesthesia.

UNLABELLED: Compared with equi-minimum alveolar anesthetic concentration (MAC) isoflurane, desflurane is associated with greater levels of sympathetic nerve activity in humans but similar reductions in blood pressure. To explore these divergent effects, we evaluated vascular alpha(1)-adrenoceptor responses in the human forearm during isoflurane and desflurane anesthesia to determine if alpha(1)-adrenoceptor responses were more substantially attenuated during desflurane administration. Bilateral forearm venous occlusion plethysmography was used to examine arterial blood flow and to determine changes in forearm vascular resistance during brachial artery infusions of saline and phenylephrine (0.2, 0.4, 0.8, and 1.6 microg/min) in 22 conscious subjects and during anesthesia with 0.65 and 1.3 MAC isoflurane or desflurane. Infusion of phenylephrine into the brachial artery increased the forearm vascular resistance in a dose-dependent manner. The arterial response to phenylephrine was significantly attenuated by 0.65 and 1.3 MAC desflurane and similarly attenuated during 1.3 MAC isoflurane (P < 0.05). Impaired arterial alpha(1)-adrenoceptor responsiveness occurred during desflurane. However, this effect was statistically similar (P > 0.05) to the impaired responses during isoflurane. Blood pressure decreases during volatile anesthesia may be, in part, caused by decreased alpha(1)-adrenoceptor responsiveness. IMPLICATIONS: alpha-receptors on blood vessels regulate constriction and dilation and therefore modulate blood pressure. This research indicates that vasoconstriction via the alpha(1)-receptor vascular response is impaired during isoflurane and desflurane anesthesia.

Adrenergic alpha-Agonists↗