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Biomedical subjects

S Field

Publications and source records attributed to S Field.

At least 37 records · Page 2Linked to original sources
PubMed1996

Linear hydraulic pressure-pulse actuator (LHPA): a versatile instrument that produces a simulated blood pressure pulse wave for small sized vessels.

An instrument is presented which produces a simulated circulatory pulsatile pressure wave for small sized vessels. The linear hydraulic pressure-pulse actuator (LHPA) is designed to be extremely versatile, that is, a blood pressure wave source of any shape, amplitude, offset and frequency can be simulated. In addition, the LHPA can reproduce accurately a real pulse pressure wave by simply imputting an actual data record of a circulatory pressure pulse. The design is accomplished by incorporating the use of a linear force solenoid driven with a voltage-to-current source power amplifier. Testing of the device is presented here, as well as pressure pulse results from a recorded pulsatile pressure input to the LHPA. The device is simple to implement in that its response is linear, for volume changes upto +/- 5 mL, without the need for feedback compensation.

Biomedical Engineering↗
PubMed1996

Should accident and emergency nurses request radiographs? Results of a multicentre evaluation.

OBJECTIVE: To evaluate whether waiting time in accident and emergency (A&E) departments is shortened when experienced nurses request peripheral limb radiographs before a patient is assessed by a doctor. DESIGN: Simultaneous prospective trial in four A&E departments in the United Kingdom with doctors and nurses requesting radiographs; 2000 patients were randomly allocated to either a "Nurse First" or "Doctor First" category. SUBJECTS: Patients older than 5 years presenting with recent peripheral limb injuries. MAIN OUTCOME MEASURES: Timing of the various stages of a patient's passage through the A&E department comparing the orthodox route with a group of patients in whom an experienced A&E nurse had the option of requesting a radiograph before a medical assessment. RESULTS: There was a significant reduction in the time spent in A&E when no radiograph was requested (P << 0.001). The mean time saved in the "Doctor First" (DF) group was 51 min, and in the "Nurse First" (NF) group 36 min. For those who were sent for an x ray 14 min was saved by getting the patient to see the nurse first. However, because the overall referral rate for x rays was greater in the NF group, (78% of patients compared with 74% of the DF group, a significant 4% increase (P = 0.05) this potential benefit was largely lost. Overall the average waiting time in the DF group of 92.5 min (95% confidence interval: 89.2 to 96.1 min) was reduced to 88.5 min (95% CI:85.2 to 91.8 min) in the NF group, a non-significant saving of 4 min. There was no overall difference between the proportion of relevant abnormalities reported by the radiologists for the DF or NF groups (G2 = 0.739, 1df, P = 0.30); however, there was a significant association between the number of relevant abnormalities reported by the radiologists and the different hospitals (G2 = 9.7626, 3df, P = 0.02). Hospital C had the highest abnormality rate reported by the radiologists in both the DF (45%) and the NF (51%) groups. The most time saved in A&E was in the DF category when comparing those who did not have an x ray [58 (CI 54-63) min] with those who did [109 (CI 104-114) min], a saving of 51 min. The corresponding time saved in the NF category between those who did not have an x ray [59 (CI 53-65) min] and those who did [95 (CI 91-99) min] was 36 min. CONCLUSIONS: 14 min can be saved by getting the patient to see the nurse first; however, because nurses in three out of four hospitals requested more radiological examinations than doctors, overall only 4 min waiting time was saved when peripheral limb radiographs were requested by nurses. The findings are somewhat against expectations but do identify that specific training and constant monitoring is essential if nurses are to request peripheral limb radiographs, as reflected in hospital C results.

Appointments and Schedules↗
PubMed1996

Self-determination instructional strategies for youth with learning disabilities.

The concept of self-determination is rapidly gaining attention and acceptance within the disability fields. The focus on self-determination is particularly strong in the transition-from-school-to-adulthood movement. The recent Individuals With Disabilities Education Act of 1990 mandated that students with disabilities be involved in the development of their transition plans and that students' preferences and interests be taken into account as transition plans are developed. This article describes four self-determination models and examines several instructional programs and strategies to promote self-determination in students with learning disabilities. Emerging issues in self-determination are examined, and the research and policy implications of these issues are discussed. These issues include (a) redefinition of roles, (b) the importance of taking risks, (c) individual versus group orientation for self-determination, and (d) the importance of early experiences.

Curriculum↗
PubMed1994

Compliance with guidelines for choice of radiographic projections: a multicentre study.

A study of compliance with guidelines for choice of radiographic projections was carried out in each of six centres. The study concerned 5851 examinations undertaken by 116 radiographers under the supervision of 29 consultant radiologists. The results showed good compliance between centres for examination of the chest (range 81-93%), abdomen (range 73-100%), thoracic spine (range 82-96%), pelvis/hip (range 78-99%) but not for examination of cervical spine (range 0-85%), paranasal sinus (range 0-100%) and lumbar spine (range 52-84%). The reasons given for these wide variations are discussed and estimates are given for the potential reductions in exposure to the UK population consequent upon national implementation of guidelines such as these.

Decision Making↗
PubMed1993

Development of an anti-idiotype monoclonal antibody mimicking the structure of lipopolysaccharide (LPS) inner-core determinants.

An anti-idiotype antibody has been developed which is specific for idiotypic determinants of a BALB/c mouse IgG3 monoclonal antibody (MAbY1-4A6) directed against the inner-core Kdo region of lipopolysaccharide (LPS). Armenian hamsters were immunized with MAbY1-4A6 and splenocytes from immunized animals fused with Sp2/0 myeloma cells. Eight clones secreting antibodies that bound to MAbY1-4A6, but not control IgG3, were identified and subcloned. Culture supernatants from one hybridoma, termed MAb4G2, contain monoclonal antibody that binds to the variable region of MAbY1-4A6 and dose-dependently inhibits binding of MAbY1-4A6 to Re chemotype rough mutant LPS (Re-LPS). This antibody also inhibits binding of three additional mouse monoclonal antibodies specific for the inner-core of Re-LPS. MAb4G2 also recognizes a significant proportion of antibodies present in polyclonal R-chemotype antisera generated in mice (Re-LPS) and rabbits (J5 Rc-LPS). Mice and hamsters immunized with MAb4G2 or Re-LPS generate antibodies which cross-react with both immunogens. Cumulatively, these data suggest that MAb4G2 can function as an internal image of the Kdo-specific monoclonal antibody, MAbY1-4A6, mimicking the antigenic structure and immunogenicity of a portion of the LPS inner-core Kdo region.

Animals↗
PubMed1993

Parallel risks of automobile collisions and thefts: a potential means of separating driver and vehicle factors.

This paper examines the value of data published by the Highway Loss Data Institute (HLDI) on the collision frequency of different automobile models as a potential guide to vehicle safety. It is argued that these data fail to control for factors other than design, including vehicle usage and driving quality. An alternative measure of collision risk, controlled for some of these factors, is constructed employing the fact that theft risk is determined by many of the same usage characteristics as collision risk. This alternative measure is validated by demonstrating that it is a more effective predictor of injury risk than collision frequency. In conclusion it is argued that if HLDI collision data are to provide a more useful guide to the relative design safety of different automobile models, the data need to be controlled for a wider range of potentially confounding factors.

Accident Prevention↗
PubMed1993

Real-time left ventricular volume of the canine heart from ultrasonic dimension data.

A real-time (instantaneous) system is presented to measure the dynamic volume of the left ventricle. This system uses the invasive measurement of long axis diameter, short axis diameter, and wall thickness of the cardiac left ventricle. Three pairs of pulse-transit ultrasonic dimension transducers are used to obtain these measurements. The dynamic volume was then found by applying these measurements to an ellipsoidal shell model of the left ventricle. It is possible to obtain on-site, real-time, continuous measurements of the left ventricular volume (LVV) by employing an electronic device which implements a corrected volume equation for the ellipsoidal shell model. The device's output is a calibrated estimation for the LVV. The function of the device is shown to compare well with other accepted measurements for the LVV.

Animals↗
PubMed1992

Discomfort and pain during mammography: description, prediction, and prevention.

OBJECTIVE: To identify the nature of pain and discomfort experienced during mammography and how it can be ameliorated. DESIGN: Questionnaire survey before invitation for mammography and immediately after mammography. Responses before screening were related to experience of discomfort. SETTING: Health district in South East Thames region. SUBJECTS: 1160 women aged 50-64 invited routinely for screening; 774 completed first questionnaire, of whom 617 had mammography. 597 completed the second questionnaire. MAIN OUTCOME MEASURES: Reported discomfort and pain, comparisons of discomfort with that experienced during other medical procedures, qualitative description of pain with adjective checklist. RESULTS: 35% (206/597) of the women reported discomfort and 6% (37/595) pain. 10 minutes after mammography these figures were 4% (24/595) and 0.7% (4/595) respectively. More than two thirds of women ranked having a tooth drilled, having a smear test, and giving blood as more uncomfortable than mammography. The most important predictor of discomfort was previous expectation of pain (discomfort was reported by 21/32 (66%) women who expected pain and 186/531 (35%) who did not). Discomfort had little effect on satisfaction or intention to reattend. CONCLUSIONS: The low levels of reported pain and discomfort shortly after mammography and the favourable comparisons with other investigations suggest that current procedures are acceptable. Since two thirds of the women experienced less pain than expected health education and promotion must ensure that accurate information is made available and publicized.

Female↗