Biomedical subjects
Publications and source records attributed to J Southwick.
Over the last two decades forces have been at work which have changed the ethic of many of the professions. This paper examines the nature of these forces, the evidence of the changes and possible ways of retaining our professionalism.
OBJECTIVE: To correlate cardiac index in normal late third-trimester pregnancy using the thoracic electrical bio-impedance technique with that obtained from the oxygen extraction technique. METHODS: Eight carefully screened normal pregnant women underwent assessment of cardiac index using both the thoracic electrical bio-impedance technique and the oxygen extraction technique. Measurements were obtained in various positions. RESULTS: The correlation was good between the thoracic electrical bio-impedance and oxygen extraction techniques in the left lateral (r = 0.915) and right lateral (r = 0.863) positions, and the intercepts at the midpoints of the oxygen extraction data in these positions suggested good absolute correlation as well. Correlation between thoracic electrical bio-impedance and the Fick cardiac index was poor in all other positions. CONCLUSIONS: Thoracic electrical bio-impedance cardiac index assessment is influenced by maternal position and must be used with caution in clinical research protocols. This technique appears to be inappropriate for general clinical use during pregnancy.
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Ten carefully screened primiparous patients between 36 and 38 weeks' gestation underwent pulmonary artery catheterization, arterial line placement, and central hemodynamic assessment in the left lateral recumbent position. Studies were repeated in the same patients between 11 and 13 weeks post partum. Compared with the nonpregnant state, there was a significant fall in systemic vascular resistance, pulmonary vascular resistance, colloid oncotic pressure, and colloid oncotic pressure-pulmonary capillary wedge pressure gradient by the late phase of the third trimester (p less than 0.05). Pregnancy was associated with a significant rise in cardiac output and pulse in all patients (p less than 0.05). There was no significant change in pulmonary capillary wedge pressure, central venous pressure, left ventricular stroke work index, or mean arterial pressure. Normally the late phase of the third trimester is not associated with hyperdynamic left ventricular function as assessed by the left ventricular stroke work index/pulmonary capillary wedge pressure ratio.