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Biomedical subjects

R Pitt

Publications and source records attributed to R Pitt.

15 recordsLinked to original sources
PubMed1999

Depth of insertion at flexible sigmoidoscopy: implications for colorectal cancer screening and instrument design.

BACKGROUND AND STUDY AIMS: The depth of insertion at flexible sigmoidoscopy is variable, depending upon bowel preparation, patient tolerance and distal colonic anatomy. Many endoscopists routinely aim to insert the 60 cm flexible sigmoidoscope to the splenic flexure; however internal endoscopic markers are unreliable, making the true anatomical extent of the examination difficult to assess. The aim of this study was to assess the depth of insertion at flexible sigmoidoscopy. PATIENTS AND METHODS: Two separate studies were done. In the first (study 1), magnetic endoscopic imaging was used to determine the final depth of insertion at non-sedated, screening flexible sigmoidoscopy. In the second (study 2), "real-time" imaging was utilized to determine sigmoid looping and the anatomical location of the endoscope tip after 60 cm of instrument had been inserted during total or limited colonoscopy. A total of 117 consecutive average-risk patients, aged 55-65 years participated in study 1, and 136 patients underwent either limited, (33) or attempted total colonoscopy (103) in study 2. RESULTS: In study 1 the median insertion distance was 52 cm, range 20-58. In 61 % of patients the imaging system showed that the descending colon had not been visualized by the end of the procedure. Failure to reach the sigmoid/descending junction occurred in 29 (24%) patients. Reasons for failure included poor tolerance of the procedure due to pain (23 patients) inadequate preparation (3 patients) and, excessive looping (3 patients). In study 2, after 60 cm of instrument had been inserted, the splenic flexure or beyond was reached in 29% and the descending colon in 9%, whilst in 62 % the endoscope tip had not passed beyond the sigmoid/descending colon junction. A sigmoid loop formed in 70% of patients, and unusual loops such as the alpha, reverse alpha and reverse sigmoid spiral loop occurred more frequently in women compared to men (P = 0.0249). In those 104 patients where the splenic flexure was reached the mean maximum length of instrument inserted prior to reaching the flexure was 75.4 cm, (SD = 21.9). CONCLUSIONS: Examination of the entire sigmoid was not achieved in approximately one-quarter of patients undergoing screening flexible sigmoidoscopy, mainly because of discomfort. The descending colon is intubated in a minority of cases (using standard instruments), even after 60 cm has been inserted. Alternative instruments with different shaft characteristics (floppy, narrow calibre, 80-100 cm in length) may be necessary to ensure deeper routine intubation in nonsedated patients.

Aged↗
PubMed1990

The severity of pedestrian injuries in children: an analysis of the Pedestrian Injury Causation Study.

We reanalyzed data from the Pedestrian Injury Causation Study (PICS) for 1035 urban pedestrian injuries to children and youth less than 20 years of age. Analysis of variance with the Injury Severity Score (ISS) as the dependent variable was used to evaluate variables describing the characteristics of the pedestrian, the vehicle, the driver, and the circumstances under which the collision occurred. The mean injury severity score was 5.6. Nearly 80% of pedestrians had a minor injury, 13% moderate, and 7% severe; 4.5% of these pedestrian were killed. Multivariate analysis revealed that vehicle travel speed greater than 30 mph, pedestrian age less than 5 years, time of day either early morning or late afternoon, residential zone, type of road including collectors and major roads, and center travel lanes were associated with greater severity of injury. Attempts by the driver to avoid the collision by braking or other avoidance maneuvers were associated with reduced injury severity. Even on local streets and in residential zones, nearly 20% of children were struck by vehicles exceeding 30 mph, and these children were injured much more severely than children struck by more slowly moving vehicles.

Accidents, Traffic↗
PubMed1989

Common paediatric emergencies.

A medical emergency can be defined as an acute change in physiological or psychological status likely to result in death, disability, or delayed recovery without prompt and appropriate treatment. Clinical deterioration in children develops more rapidly than in adults, but with correct treatment the child has a greater capacity for quick and complete recovery.

Airway Obstruction↗
PubMed1988

Audiological management in the recovery phase of bacterial meningitis.

During a specified 12-month period, a prospective study of all children admitted to a 139-bed city children's hospital with confirmed bacterial meningitis enabled assessment audiologically at 48 h, 6 weeks and 12 weeks post-admission using a test battery approach including auditory brainstem evoked responses and tympanometry. Results suggested conductive dysfunction to be a major cause of fluctuating hearing loss within the group. The incidence of sensori-neural loss was 16.6% of ears tested at final outcome. Results are discussed with reference to their implications for audiological management.

Acoustic Impedance Tests↗
PubMed1987

Interstitial distribution of charged macromolecules in the dog lung: a kinetic model.

A mathematic model was constructed to investigate conflicting physiologic data concerning the charge effect of continuous capillaries to macromolecules in the lung. We simulated the equilibration kinetics of lactate dehydrogenase (MR 4.2 nM) isozymes LDH 1 (pI = 5.0) and LDH 5 (pI = 7.9) between plasma and lymph using previously measured permeability coefficients, lung tissue distribution volumes (VA) and plasma concentrations (CP) in lung tissue. Our hypothesis is that the fixed anionic charges in interstitium, basement membrane, and cell surfaces determine equilibration rather than charged membrane effects at the capillary barrier, so the same capillary permeability coefficients were used for both isozymes. Capillary filtration rates and protein fluxes were calculated using conventional flux equations. Initial conditions at baseline and increased left atrial pressures (PLA) were those measured in animal studies. Simulated equilibration of isozymes over 30 h in the model at baseline capillary pressures accurately predicted the observed differences in lymph/plasma concentration ratios (CL/CP) between isotopes at 4 h and equilibration of these ratios at 24 h. Quantitative prediction of isozyme CL/CP ratios was also obtained at increased PLA. However, an additional cation selective compartment representing the surface glycocalyx was required to accurately simulate the initial higher transcapillary clearances of cationic LDH 5. Thus experimental data supporting the negative barrier, positive barrier, and no charge barrier hypotheses were accurately reproduced by the model using only the observed differences in interstitial partitioning of isozymes without differences in capillary selectivity.

Animals↗