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Biomedical subjects

R M Gardner

Publications and source records attributed to R M Gardner.

At least 163 records · Page 9Linked to original sources
PubMed1983

Sensitivity to proprioceptive feedback in obese subjects.

40 subjects, 20 obese and 20 normal, were run on a weight-discrimination task requiring judgments dependent on proprioceptive feedback. A signal-detection analysis was used to separate sensory factors from non-sensory, response-bias factors in the analysis of the discriminations. Obese subjects were inferior to normals in ability to make sensory discriminations; the largest differences occurred between obese and normal males. Obese subjects also adopted a more strict criterion (beta); the largest differences again occurred for male subjects. Obese subjects showed more variability in their sensory judgments, although there was a significant difference on only one of the 5 discrimination tasks. Results are discussed in terms of the internal-external explanation of obesity.

Adult↗
PubMed1982

System for umbilical artery monitoring.

A simple, safe, and effective system for umbilical artery monitoring controls continuous fluid infusion to prevent fluid overinfusion and keep the catheter from clotting. Accurate and continuous pressure measurements can be recorded simultaneously with fluid infusion. A convenient method for checking dynamic response fidelity is provided. The system is easy to set up and maintain. Because it is a closed system, contamination of the neonate is minimized.

Catheterization↗
PubMed1982

Computerized determination of pneumotachometer characteristics using a calibrated syringe.

A computerized method has been developed to determine the conductance characteristics of pneumotachometers. Conductance values of the flowmeter, which correspond to all pressure values, can be determined by a weighted averaging technique, when multiple strokes of a precision 3-liter calibrated syringe are used. The conductance values then allow the measured differential pressures to be converted, point by point, into flows. The accuracy of measured volumes is within +/- 0.5% for a 100-stroke calibration process, and calibration with 50 strokes provides +/- 1% accuracy. The method improves the accuracy of the on-line measurements of ventilation. O2 consumption, and CO2 production during exercise.

Calibration↗
PubMed1982

Standard waveforms for spirometer testing.

Because both the recommended American Thoracic Society standards and the proposed Association for the Advancement of Medical Instrumentation standards are based on performance requirements, the most reasonable test signals are those that represent actual patients. To test and qualify spirometers for compliance with a standard, a set of 24 standard waveforms have been selected from a larger set of FVC maneuvers performed by patients who have a diversity of abnormalities and demonstrate a range of test results. Common spirometric parameters are known for each waveform; therefore, the adherence to performance requirements can be readily verified. These standard waveforms are stored on various digital mediums and can be used to drive a controlled mechanical syringe for testing actual hardware and software, or they can be put into a system in digital format to test only the software.

Forced Expiratory Volume↗
PubMed1982

A portable volume/flow calibrating syringe.

Two samples of a manual 3 L calibrating syringe which displays an electronically calculated FEF25-75% were evaluated to determine its suitability as a flow calibrator were evaluated. Room air was discharged into a manual spirometer system known to be accurate. The calibrator-determined values correlated very closely with the spirometer values over an FEF25-75% range of 0.4 to 9 L/sec. The differences between calibrator and spirometer FEF25-75% values were small (mean +/- 1 percent, greatest 3.7 percent) and of little importance clinically. This portable, simple to operate calibrating syringe provides accurate FEF25-75% and volume values. By adding flow calibrating capability to a recommended standard volume calibrating syringe, it will facilitate the routine calibration of spirometers in the laboratory and in the field. Since it uses displaced air, it can be used at altitude and with flow measuring instruments without the correction required for calibrators using CO2 cartridges.

Calibration↗
PubMed1982

Computerized decision-making in the pulmonary function laboratory.

Computers are now in widespread use in pulmonary function laboratories, where they have made an important contribution by assisting with complex and repetitive tasks. They can be used to acquire data from testing instruments, make measurements and calculations, and prepare reports. At LDS Hospital in Salt Lake City, we use the HELP (Health Evaluation through Logical Processing) Computer System for medical decision-making. As a result of our experience with this system, we have found six definable steps between data acquisition and data interpretation: (1) establish quality instrumentation, (2) establish adequate procedures for test performance, (3) standardize measurement and computational techniques, (4) determine the adequacy and reproducibility of results and apply a test selection, (5) identify the measurements to be used for interpretation, and (6) apply strategies that lead to consistent interpretation of results. Because spirometry and blood gas tests account for the major activities of our pulmonary function laboratory, we have applied these six steps necessary for computer decision-making to these two two tests; however, they are equally applicable to other tests in the pulmonary function laboratory.

Blood Gas Analysis↗
PubMed1981

Reference spirometric values using techniques and equipment that meet ATS recommendations.

Forced expiratory volumes and flows were measured in 251 healthy nonsmoking men and women using techniques and equipment that meet American Thoracic Society (ATS) recommendations. Linear regression equations using height and age alone predict spirometric parameters as well as more complex equations using additional variables. Single values for 95% confidence intervals are acceptable and should replace the commonly used method of subtracting 20% to determine the lower limit of normal for a predicted value. Our study produced predicted values for forced vital capacity and forced expiratory volume in one second that were almost identical to those predicted by Morris and associates (1) when the data from their study were modified to be compatible with the back extrapolation technique recommended by the ATS. The study of Morris and colleagues was performed at sea level in rural subjects, whereas ours was performed at an altitude of 1,400 m in urban subjects. Either the present study or the study of Morris and co-workers, modified to back extrapolation, could be recommended for predicting normal values.

Adolescent↗
PubMed1981

Hormonal control of uterine growth: the effect of hypothyroidism on estrogen-stimulated cell division.

The increase in mitotic indices of uterine luminal epithelium, stroma, and myometrium were determined as a function of time after the administration of a single dose of 17 beta-estradiol to euthyroid and hypothyroid rats. Hypothyroidism reduced the increase in the mitotic index 5-fold in the luminal epithelium, 6-fold in the stroma, and 9-fold in the myometrium. In addition to reducing mitotic indices, hypothyroidism also produced a shift of 12 h in the time course of estrogen-stimulated cell division of all uterine cell types relative to euthyroid animals. This shift in the time course of cell division was preceded by a shift in the time course of uterine DNA synthesis measured by tritiated thymidine incorporation. In contrast, hypothyroidism did not alter the magnitude or the time course of synthesis of 2-deoxyglucose-6-phosphate from 2-deoxyglucose after estrogenic stimulation. These results indicate that hypothyroidism decreases the ability of all major uterine cell types to undergo cell division in response to acute administration of estradiol, and also shifts the time course of the uterine growth response to the hormone.

Animals↗
PubMed1980

A computerized alert program for acutely ill patients.

An integrated computer system with a central data-base and decision-making capabilities is the basis of an investigation of a computerized alerting program that rapidly detects, analyzes, and generates diagnostic interpretations and treatment protocols for life-threatening laboratory abnormalities. Preliminary study data suggests that use of the alerting program to promptly notify physicians of abnormal laboratory values results in more prompt and correct treatment of patients.

Acute Disease↗
PubMed1980

Clinical comparison of pressure-pulse and indicator-dilution cardiac output determination.

Two clinical studies of cardiac output determination using the pressure-pulse technique are presented. The Warner pressure-pulse method of estimating cardiac output was compared with the dye-dilution technique in 17 patients. Both the Warner and a variation of the Bourgeosis pressure-pulse methods were compared with thermodilution in 13 patients. The Warner vs dye-dilution comparison resulted in a poor correlation coefficient (r = 0.61). Values for the Warner equation calibration constant (K) were nonstationary, varying with time from --69 to 135% of the initial value in individual patients. When thermodilution was compared with the two methods, the correlation was poor (r = 0.58 for the Warner method; r = 0.50 for the modified Bourgeois method). The Warner and a variation of the Bourgeois pressure-pulse methods for monitoring the cardiac output of critically ill patients with widely varying mean arterial pressures are not sufficiently reliable for clinical decision-making.

Blood Pressure↗
PubMed1980

Evaluating commercially available spirometers.

This study was designed to: (1) determine the performance characteristics of available spirometers; (2) assess the practically and applicability of the American Thoracic Society's (ATS) Snowbird Workshop recommendations on Standardization of Spirometry; and (3) determine whether spirometer testing could be done with room air. Nineteen spirometers were tested with 16 different forced vital capacity waveforms. Fourteen spirometers met the ATS forced vital capacity requirements. Three of these 14 spirometers had difficulties in determining the end of expiration. Fourteen of the devices tested met the requirements for forced expiratory volume in one second. Ten of 13 devices tested for maximal voluntary ventilation were satisfactory. The standards recommended by ATS were believed to be applicable and practical. The testing methods recommended by ATS need to be expanded to include more patient waveforms. Testing with room air is easier and simpler and, for most devices, just as effective as heated and humidified air. We conclude that most available spirometers can faithfully record forced spirograms and that if a spirometer meets the ATS requirements, it makes no difference on which device the spirogram is recorded.

Evaluation Studies as Topic↗