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Biomedical subjects

M Crawford

Publications and source records attributed to M Crawford.

At least 163 records · Page 9Linked to original sources

Design of a multicenter, double-blind study to assess the effects of prophylactic diltiazem on early reinfarction after non-Q-wave acute myocardial infarction: diltiazem reinfarction study.

This protocol describes the design of an international study to examine the potential prophylactic effect of 14 days of diltiazem therapy to prevent early reinfarction in patients initially presenting with non-Q-wave acute myocardial infarction. Reinfarction was defined by the detection of a secondary elevation of plasma MB-creatine kinase. The results of clinical trials, instrumental in this protocol design, that established the increased propensity for early reinfarction after initial non-Q-wave infarction are described and the implications of the present study are discussed.

Clinical Trials as Topic↗

Placental essential fatty acid transport and prostaglandin synthesis.

The studies reported here demonstrate two important aspects of placenta EFA transport and metabolism. (1) A mechanism exists within the placenta for the selective incorporation of 20:4 omega 6 into phosphoglycerides and the export of those phosphoglycerides to the fetal circulation. This mechanism allows the selective sequestering of 20:4 omega 6 in the fetoplacental unit and may provide the fetus with important performed structural membrane components. (2) Placental PG synthesis is directed mostly to the maternal circulation and stimulated placental PG synthesis is directed totally to the maternal circulation. This mechanism may protect the fetus from fluctuations in maternal and placental PG synthesis and may direct stimulated placental PG synthesis to a target organ, the myometrium. The perfused human placental model provides a valuable method for the study of a variety of biochemical phenomena in a whole human organ and its use may further elucidate the role of this tissue in the maintenance of pregnancy, the transport of EFA to the developing fetus and the involvement of placental PG synthesis in fetal development and parturition.

Biological Transport↗

High-frequency, small-volume ventilation during thoracic surgery.

Surgical conditions during conventional mechanical ventilation (CMV) and pulmonary gas exchange were compared with those during high-frequency ventilation (HFV) in 24 patients undergoing anesthesia for intrathoracic surgery. HFV at an oscillatory frequency of 3 Hz and a delivered gas volume of 1.3-1.9 ml/kg provided excellent surgical conditions for peripheral lung procedures. However, surgical conditions for procedures on the major airways or mediastinal structures were unsatisfactory during HFV. Adequate pulmonary gas exchange was achieved with HFV when the chest was open. Further evidence is presented for expiratory flow limitation during HFV. Expiratory flow limitation seems to occur particularly in patients with chronic obstructive airway disease, leading to increased lung volume. Currently, the authors do not recommend HFV for routine use during anesthesia for thoracic surgery.

Adult↗

Resonant amplification of delivered volume during high-frequency ventilation.

The volume of gas delivered from a high-frequency ventilation (HFV) circuit was measured with an ultrasonic flowmeter. The measurements were done in vitro (20-liter air-filled glass bottle) and in vivo (9 anesthetized dogs lying supine) at oscillation frequencies ranging from 4 to 23 Hz and stroke volumes of the pump ranging from 36 to 150 ml. We varied the length and diameter of the tube connecting the pump with the endotracheal tube, the length and diameter of the bias outflow tube, the diameter of the endotracheal tube, and the stroke volume of the pump. Both in vitro and in vivo, there was resonant amplification of the delivered gas volume; i.e., the delivered gas volume exceeded the stroke volume at certain frequencies. Altering the dimensions of connecting tube, endotracheal tube, bias outflow tube, or stroke volume, i.e., changing the resistance to gas flow, gas compliance, and/or gas inertance in these elements, altered the ratio of gas delivered to stroke volume that could be predicted by an electric analog. These data indicate that the delivered gas volume during HFV depends critically on the configuration of the HFV circuit, the size of the endotracheal tube, the oscillation frequency, and the pump stroke volume. Knowledge of the delivered gas volume during HFV and appreciation of the phenomenon of resonant amplification of the delivered gas volume will permit a more accurate description of factors contributing to gas transport during HFV.

Animals↗

Marketing: the creative advantage.

Success is celebrated best by sharing the process that led to its achievement. The marketing of nursing products at the 507-bed Akron General Medical Center is a success worth sharing with other nurse executives. The authors describe the marketing process that generated new sources of revenue to support staff education and clinical specialist services.

Hospital Bed Capacity, 500 and over↗