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Biomedical subjects

M J Roberts

Publications and source records attributed to M J Roberts.

At least 73 records · Page 4Linked to original sources
PubMed1984

Computer simulation to predict patient responses to alterations in the ventilation regime.

We have developed a technique for simulating artificially ventilated patients using a computer model of the respiratory system and have investigated its ability to predict the patient's response to alterations in the ventilation regime. The majority of those studied were in a stable condition following cardiac surgery. Predictions for PaO2 showed a reasonable correlation with measured values (r = 0.94), although individual predictions could differ appreciably (SEE = +/- 17.3 mmHg). Predictions for PaCO2 correlated less well (r = 0.89, SEE = +/- 2.0 mmHg) and there was a consistent tendency to overestimate this variable. The least accurate predictions were those for PvO2 (r = 0.61, SEE = +/- 3.8 mmHg). Errors in prediction were attributable to deficiencies in the model (most importantly the three-compartment lung and the modelling of CO2 production, storage and excretion), compounded by unpredictable alterations in the patient's physiology (mainly Vo2, Vco2 and Qt). However, allowing for accepted clinical variability and routine measurement accuracy, the predictions are generally reasonable. This suggests that, with some further modifications, computer modelling of this, and other, systems may prove to be a clinically and educationally useful technique.

Adult↗
PubMed1983

A multipatient mass spectrometer based system for the measurement of metabolic gas exchange in artificially ventilated intensive care patients.

A commercially available multi-patient mass spectrometer based system [MPMS] has been evaluated for the measurement of metabolic gas exchange in artificially ventilated patients. The system automatically measures and displays oxygen uptake, (VO2) carbon dioxide output, (VCO2) respiratory quotient (RQ) expired minute volume, (Ve) and the percentage concentration of inspired gases. Measurements of VO2, VCO2, RQ and Ve, obtained using this system were compared with those determined by simultaneous Douglas bag collections. The measurement of carbon dioxide and oxygen concentrations was assessed separately by direct comparison with infra-red and paramagnetic analysis respectively. The MPMS measurements of metabolic gas exchange were found to have insignificant systematic errors with precisions of +/- 12 ml/min VO2, +/- 7 ml/min VCO2, +/- 0.03 RQ and +/- 0.1 l/min Ve; (2SD).

Carbon Dioxide↗
PubMed1983

Genetic analysis of multiple sclerosis in Shetland.

In a family study of all patients with multiple sclerosis in Shetland the number of inbred patients, although high for Britain and higher than in Orkney, is not higher than the number among controls, and the inbreeding coefficients suggest that there is no recessive involvement of rare genes in the aetiology. The kinship coefficients show close interweaving of ancestries of patients and controls and eliminate from the aetiology any involvement of recently introduced single genes dominant or codominant in effect. Family histories show that single locus inheritance is unlikely. Any genetic involvement is likely to be polygenic, but on a multifactorial hypothesis the estimates of heritability are very low. The findings suggest that the genetic contribution to the aetiology of the disease in Shetland is slight.

Consanguinity↗
PubMed1983

Procedures for handling antineoplastic injections in comprehensive cancer centers.

The procedures for handling injectable antineoplastic drugs in comprehensive cancer centers in the U.S. are summarized. In May 1982, a survey was sent to directors of pharmacy at 27 institutions designated as comprehensive cancer centers. Some questions duplicated a 1979 survey, while others addressed points in recently published guidelines on handling antineoplastic medications. Representatives of 21 institutions responded. These institutions represented 13,638 beds, 1,848 of which were oncology beds. Seventeen institutions had written policies for the preparation of antineoplastics, but only nine had a training program. The pharmacist or pharmacy technician prepared these medications in 12 institutions. Ten institutions prepared antineoplastics in a vertical laminar-flow hood. Gloves and masks were worn by employees in 20 and 13 of the institutions, respectively. Six institutions in some way assessed the health of employees handling antineoplastics. Eleven institutions had written policies on disposal of antineoplastics; 13 institutions disposed of this waste separately. Ten institutions had a training program for administration of antineoplastics. Compared with 1979, the trend is toward increased protection of persons handling injectable antineoplastic agents, but the procedures used at comprehensive cancer centers are not uniform.

Antineoplastic Agents↗
PubMed1982

Simple and rapid method for the assessment of the oxygen affinity of haemoglobin.

The affinity of haemoglobin for oxygen may be expressed as the oxygen tension at 50% saturation under standard conditions (P50). A rapid technique for the determination of P50 using a micro-tonometer with pH electrode and oximeter was evaluated. Equilibration time was found to be 15 minutes with no change in PCV, although plasma haemoglobin levels were slightly elevated. Estimation of P50 in blood from 32 non-smokers gave a mean of 26.4 +/- 0.9 (SD) mm Hg (3.51 +/- 0.12 kPa) with a precision of 0.3 (SD) mm Hg (0.04 kPa). The system was found to be accurate, precise, and simple in operation, allowing up to 16 P50 determinations an hour to be performed with 85 microliters blood samples.

Hematocrit↗
PubMed1982

Pharmacist activities under alternative staffing arrangements.

The proportions of time pharmacists spent in professional and nonprofessional activities is compared under alternative staffing arrangements. Daily activities were observed in three pharmacy satellites each serving approximately 100 beds of a 730-bed hospital. Ten pharmacy administrators and residents recorded more than 8000 observations over a 14-day period, 24 hours per day. In each observation, basic functions were noted; these were chosen from a list compiled to include all pharmacy activities. A specific staffing pattern was identified in each observation. The observations were then categorized as professional or nonprofessional activities as predefined by the majority of the pharmacy staff. As staffing patterns varied, significant differences occurred in the ratio of professional to nonprofessional activities. The greatest percentage of professional activity was observed when one pharmacist worked with more than one technician; where the staffing pattern contained more pharmacists than technicians, a smaller percentage of the pharmacists' time was used in professional activity. Overall, pharmacists were engaged in activities considered professional in 52% of the observations. Assuming that the most efficient use of pharmacy personnel involves a high ratio of professional to nonprofessional activity in the pharmacists' workload, the optimum staffing arrangement would include at least the same number of technicians as pharmacists. Factors other than staff mix affect efficient management of pharmacists' professional time.

Humans↗
PubMed1981

A self-help program for childhood asthma in a residential treatment center.

A structured program designed to enhance self-treatment was successfully implemented in a residential center for asthmatic children. The ultimate objective of the program was to improve compliance with therapeutic regimens, which was felt to be a factor that had necessitated placement of many of the patients. The program was designed to educate the patient and the patient's family regarding the nature of asthma, its treatment and the importance of self-help. Efforts were also made to enhance the emotional maturity of the child. Patients remembered to take their medication over 90% of the time within 1 month of implementation of the program. a similar program was instituted for outpatient use.

Asthma↗
PubMed1979

Genetic analysis of multiple sclerosis in Orkney.

In a family study of all patients with multiple sclerosis (MS) in Orkney, the number of inbred among patients, although high for Britain, is not higher than the number among controls, and the inbreeding coefficients appear to eliminate recessive involvement of rare genes from the aetiology. The kinship coefficients show that the ancestries of patients and controls are closely enmeshed, and eliminate from the aetiology involvement of recently introduced genes dominant or codominant in effect. Family histories show that single locus inheritance is unlikely unless penetrance is very low. Multifactorial genetic involvement is much more likely, and it is compatible with all recent findings; on this hypothesis heritability estimates, not altogether satisfactory because of the limited number of patients in the population, suggest that the genetic contribution to the aetiology of the disease in Orkney is only moderate.

Consanguinity↗