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Biomedical subjects

S Gentry

Publications and source records attributed to S Gentry.

At least 19 recordsLinked to original sources
PubMed1998

Advancing from flexible sigmoidoscopy to colonoscopy in rural family practice.

This paper describes the background, experience, training, and preceptorship of a rural family physician that culminated in provision of diagnostic and therapeutic colonoscopy to his patients. Initial training took place in a two-day continuing medical education course. Subsequent training consisted of one-on-one training in 11 colonoscopies and five polypectomies, correspondence, recommended readings, a one-on-one preceptorship, and telephone consultation. Training was provided by University of Tennessee faculty who were experts in the area of colonoscopy and polypectomy procedures. The outcomes of 250 consecutive colonoscopies performed by the rural family physician are documented here. Training requirements vary widely by professional organization and subspecialty. Some subspecialists have recommended as many as 100 supervised colonoscopies and 25 polypectomies as a minimum training requirement for hospital privileges. It is our contention that unnecessarily high training requirements add to educational costs and may restrict qualified rural physicians from providing these services.

Adolescent↗
PubMed1992

Enhancement of a critical care transport service.

The MICU has provided a much needed mode of transportation for the critically ill or injured patient in the Metro LIFE FLIGHT service area. Even though our primary focus is helicopter transport, the MICU has proved to be a valuable "backup" to our helicopter service. The MICU has paved the way to provide a more comprehensive service to the critically ill or injured patient in Northeastern Ohio, regardless of weather or lack of landing zones.

Ambulances↗
PubMed1990

Ventilatory responses to inspiratory threshold loading in humans.

Normal alveolar ventilation tends to be maintained during external mechanical loading. The precise manner by which this occurs is unclear but may involve intrinsic mechanisms related to the muscular pump, neural influences, and chemoreceptor control. Recent observations suggest that submaximal threshold loads may result in hyperventilation. In this study we explicitly examined the respiratory effects of sustained threshold loading in normal subjects. We found that sustained threshold loading resulted in hyperventilation associated with high P100's (mouth pressure 100 ms after the start of an occluded breath) and increased tidal volumes but with little effect on duty cycle or respiratory rate. In addition, this increased respiratory motor output was sustained for 30-60 s after the load was removed. At very high threshold loads, hyperventilation failed to occur, despite increased P100's. We conclude that threshold loading results in increased respiratory motor output and hyperventilation, a response that is different from that observed with either resistive or elastic loads, and that the failure to hyperventilate at the higher loads may be the result of mechanical limitation.

Carbon Dioxide↗
PubMed1980

Topical antimicrobial cream sensitivity testing.

These gratifying results have made topical antimicrobial sensitivity testing an integral part of bacteriologic monitoring of the burn wound. Presently, we use the needle extrusion test routinely on all burn patients at our center. Its selection over the other antimicrobial tests is based on technical considerations. The needle extrusion test can be completed by an experienced technician within five minutes, but the disk diffusion test and agar-well diffusion test take two and five times longer, respectively. This time saving is an important consideration when the microflora of ten or more burn patient at our center are being monitored by this test every other day. This test system may prove useful for the topical antibiotic selection for the treatment of other wounds beside the burn wound. Its potential value in these other conditions must await the results of carefully controlled clinical studies.

Anti-Bacterial Agents↗
PubMed1978

Comparison of cardiovascular responses and left ventricular work during exercise before and after artificial heart implantation.

Cardiovascular dynamics and left ventricular work were evaluated in 15 resting, standing, and treadmill-exercised calves before and at periodic intervals after their natural hearts (NH) were replaced with an artificial heart (AH). Standing produced increases in heart rate, cardiac output, oxygen uptake, and left ventricular work and decreases in mean aortic pressure and systemic vascular resistance in NH calves which were more marked with exercise. AH calves had higher aortic pressures, cardiac output, systemic vascular resistance, oxygen uptake, and left ventricular work during resting conditions in the first 2 postoperative weeks than did NH calves, which gradually returned to values similar to the latter by the fifth week after operation. Exercise was not tolerated early after AH implantation, but was after 5 to 6 weeks. Our results indicate that AH calves increase cardiac output with exercise by reducing systemic vascular resistance, whereas NH animals respond similarly, but also increase heart rate. The data suggest that a marked elevation in systemic vascular resistance early after AH implantation increases left ventricular work and prevents adequate rises in cardiac output to all but minor increases in metabolic requirements.

Animals↗
PubMed1977

Peripheral vascular and cardiac effects of nitrous oxide in the bovine.

Peripheral vascular and myocardial effects of increasing concentrations of nitrous oxide (0 to 70 per cent) in oxygen were determined in 15 unanaesthetized calves before and after replacement in their natural heart (NH) with a pneumatically driven artificial heart (AH). Nitrous oxide produced concentration-related decreases in arterial and mixed venous pH and increases in minute ventilation and arterial and mixed venous carbon dioxide tensions in both NH and AH calves. Nitrous oxide resulted in significant increases in cardiac output, stroke volume and mean aortic, pulmonary artery and right atrial pressures in NH and AH calves, but did not significantly change systemic vascular resistance in either group of animals. Heart rate was increased in NH calves but was fixed in AH calves. Elevations in heart rate and cardiac output at nitrous oxide concentrations greater than 30 per cent and aortic pressure at 70 per cent nitrous oxide were significantly greater in NH than AH animals (P less than 0.05). These data demonstrate that nitrous oxide stimulates the cardiovascular system in spontaneously breathing mammals and that the changes result from improved venous return and an increase in myocardial chronotropy. Our findings also suggest that cardiovascular stimulation during nitrous oxide breathing may be related to increased concentrations of arterial and/or venous carbon dioxide.

Animals↗
PubMed1977

Effects of ventilatory techniques during cardiopulmonary bypass on post-bypass and postoperative pulmonary compliance and shunt.

Pulmonary compliance and shunt were evaluated preoperatively, 30 minutes after cardiopulmonary bypass, and two hours postoperatively in 132 calves undergoing open-heart surgery with halothane and oxygen anesthesia. The calves were divided into 11 groups with respect to maintenance of the lungs during bypass. In Group 1 the lungs were collapsed during bypass. In all other groups the lungs were mechanically ventilated, statically inflated, or both, with either pure oxygen or nitrous oxide, 50 per cent, in oxygen. All groups had similar compliance and shunt values before operation and sustained significant decreases in compliance and increases in shunt 30 minutes after bypass. Calves exposed to positive-pressure breathing during bypass had higher shunt and lower compliance values after bypass and postoperatively than those not exposed to mechanical ventilation, irrespective of the inflating gas or presence or absence of any amount of static airway pressure. Animals not ventilated during bypass had compliance and shunt values that were not significantly different from preoperative values, while calves that were ventilated had compliance and shunt values that were still significantly altered two hours postoperatively. These data demonstrate that positive-pressure breathing during bypass decreases pulmonary compliance after bypass and postoperatively and increases intrapulmonary shunt, but that the gas inflating the lungs during bypass does not influence either of these variables. The findings also suggest that static pulmonary inflation during bypass offers no advantage over allowing the lungs to remain collapsed.

Animals↗
PubMed1976

Peripheral vascular versus direct cardiac effects of calcium.

Peripheral vascular and direct cardiac effects of calcium chloride were determined in a new animal model, the unanesthetized calf, before and after replacement of its natural heart (NH) with a pneumatically driven artificial heart (AH). Calcium (5 and 10 mg/kg) significantly increased cardiac output (Qt) and reduced systemic vascular resistance (SVR) before and after AH implantation. Increases in Qt in AH calves and reductions in SVR in both NH and AH calves were, however, transient, being present 5 minutes but not 15 minutes after both doses of calcium. Increases in Qt and reductions in SVR were significantly (P less than .05) greater after 10 mg/kg than after 5 mg/kg calcium in NH and AH calves. Both doses of calcium produced greater (P less than .05) increases of Qt in NH than in AH animals but similar reductions in SVR. Pulmonary vascular resitance, heart rate and pulmonary arterial and right atrial pressures were not significantly altered by either dose of calcium in NH or AH calves. Mean aortic pressure was influenced by 10 mg/kg calcium only, being transiently reduced in AH calves and increased in NH animals. Pulmonary shunt (QS/Qt) was increased by both doses of calcium in NH calves but only by 10 mg/kg in AH animals. Correlations of mean change in QS/Qt with mean change in Qt were high both before (r=.99) and after (r=.97) AH implantation. These data demonstrate that calcium significantly reduces SVR in a dose-related manner as well as exerting a positive inotropic effect on the myocardium.

Animals↗