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Biomedical subjects

A B Greene

Publications and source records attributed to A B Greene.

5 recordsLinked to original sources
PubMed1999

Studies in calf venous pump function utilizing a two-valve experimental model.

OBJECTIVES: to explore the hydrodynamic mechanisms involved in the regulation of ambulatory venous pressure. DESIGN: an experimental model of calf venous pump was constructed with collapsible tubes and valves. MATERIAL: the model consisted of a conduit and a pump with an intervening competent valve. Another valve that could allow reflux into the pump was mounted above the pump. METHODS: conduit pressure and recovery times were monitored under conditions of different degrees of ejection fraction and reflux into the pump. Model variables included using poorly compliant tubes for the pump, the conduit and for both the pump and conduit. RESULTS: the latex tube exhibited a non-linear volume-pressure relationship and a bi-modal regimen of compliance. This bestowed pressure-buffering properties. Ambulatory venous hypertension resulted when reflux beyond buffering capacity occurred. Substituting less compliant PTFE for latex at the pump had a relatively minor effect on post-ejection pressure and recovery times. Using PTFE at the conduit had a profound but divergent effect on both of these parameters. Conduit capacitance reduction had a similar effect. CONCLUSION: conduit elastance plays a significant role in the regulation of ambulatory venous pressure in this experimental model. The hydrodynamic principles illustrated by the model may enhance our understanding of the human calf venous pump.

Blood Pressure Determination↗
PubMed1988

Terbutaline metered-dose inhalation vs metaproterenol by hand-held nebulization: a comparison in black inner-city COPD patients.

A greater percentage of the inner-city black population suffers from chronic obstructive pulmonary disease (COPD) than does the white population in general. Urban black patients are also more likely than urban white patients to receive primary care for their COPD symptoms in area emergency rooms, which can affect the resources available for medical care in these institutions. The present study compared the standard of therapy at Provident Medical Center, metaproterenol, administered by a hand-held nebulizer (HHN), with therapy using terbutaline, administered by a metered-dose inhaler (MDI) with a spacer, in 60 black patients with mild to moderate respiratory distress.Measurements of peak expiratory flow rates before and after therapy indicated that both methods of treatment provided similar relief. The terbutaline MDI modality, however, required less equipment and therapist time, and patients could continue the same therapy at home. All 60 patients were sent home on terbutaline MDI therapy. Follow-up by questionnaire, two to three weeks later, showed 95 percent of 36 respondents preferred the terbutaline MDI with spacer compared with their previous therapy.

Administration, Inhalation↗