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Biomedical subjects

P Desfonds

Publications and source records attributed to P Desfonds.

8 recordsLinked to original sources
PubMed1987

Nitroglycerin-induced decrease of carbon monoxide diffusion capacity in acute myocardial infarction reversed by elevating legs.

Hemodynamic and respiratory variables were measured in 18 supine patients with acute myocardial infarction uncomplicated by left ventricular failure. Measurements were done during a control period and then when pulmonary capillary bed filling was decreased by iv injection of 3 mg nitroglycerin (NTG) and finally when pulmonary capillary bed filling was increased by raising the patients' legs. Heart rate increased significantly (p less than .05) ventricular filling, and mean aortic pressures dropped significantly (p less than .001) after NTG injection. Heart rate and mean aortic pressure returned to control level and ventricular filling pressures increased significantly (p less than .001) after elevating patients' legs. Mean carbon monoxide diffusion capacity decreased significantly (p less than .01) from 9.8 +/- 3.4 to 8.5 +/- 2.9 ml/min X mm Hg after NTG injection and increased significantly (p less than .02) to 9.3 +/- 3.5 ml/min X mm Hg after elevating patients' legs. Pulmonary wedge pressure decreased significantly (p less than .001) from 15 +/- 5 to 8 +/- 4 mm Hg after NTG injection and increased significantly (p less than .001) to 10 +/- 4 mm Hg after elevating patients' legs. We conclude that NTG reduces pulmonary capillary filling and pulmonary diffusion by reducing the available pulmonary gas exchange surface.

Adult↗
PubMed1987

Effects of a low dose of pancuronium on oxygen consumption during sustained muscular exercise.

The effects of a low dose of pancuronium on muscular performance were studied in six healthy volunteers. Three dynamic exercise tests at increasing levels of power were performed by each subject on two consecutive days using an ergometric bicycle. To assess muscular function, oxygen consumption was measured in a steady state at each level of power output. Pancuronium 6-8 micrograms kg-1 or placebo was administered i.v. in a double-blind fashion before the second test each day. Plasma pancuronium levels were measured 8 min after administration but even with pancuronium clearly detectable in the plasma no significant differences were found either in oxygen consumption or in the haemodynamic measurements made. The authors conclude that such doses of non-depolarizing neuromuscular blocking agents do not disturb oxygen consumption during dynamic muscular exercise and are therefore unlikely to have a significant effect on muscular function.

Adult↗
PubMed1979

Effect of dopamine on intrapulmonary shunt fraction and oxygen transport in severe sepsis with circulatory and respiratory failure.

The hemodynamic response to a dopamine HCl infusion (10 microgram/kg per min) was measured in 25 adult patients with severe sepsis: there were 6 patients with circulatory hyperdynamic states, 9 patients with myocardial failure, and 10 with hypovolemia. Each patient also had acute respiratory failure. Changes of intrapulmonary shunt fraction (Qs/Qt), arterial and mixed venous oxygen tension (PaO2 and PvO2), oxygen transport, and oxygen consumption (VO2) were evaluated before and after dopamine infusion. Dopamine infusion produced clinical improvement and increased cardiac output. The hemodynamic response seemed to differ slightly according to the pattern of circulatory failure: chronotropic effect appeared to be predominant in hyperdynamic states, whereas inotropic effect appeared to be predominant in myocardial failure or hypovolemia. Moreover, in hypovolemic patients we noted a rise in pulmonary capillary wedge pressure suggesting an additional increase in venous return. During this treatment, we also noted a worsening of the Qs/Qt despite the increase in pulmonary blood flow; this worsening did not prevent significant improvements in VO2, but the improvement in PVO2 was offset by increased Qs/Qt and PaO2 remained unchanged.

Adult↗
PubMed1979

Hemodynamic factors influencing arterial hypoxemia in massive pulmonary embolism with circulatory failure.

Arterial hypoxemia is a common finding in acute pulmonary embolism, and its severity is generally assumed to be proportional to the extent of pulmonary artery obstruction. We studied blood gases (during room air breathing and 100% oxygen breathing) and hemodynamic data is seven patients with massive pulmonary embolism and circulatory failure. All measurements were made before and 30 minutes after medical therapy of shock. We observed that a low cardiac output state can result in a misleading improvement in arterial oxygenation during massive pulmonary embolism, and that an improved circulatory status resulting from medical therapy (including inotropic drug infusion with or without blood volume expansion) can paradoxically increase arterial hypoxemia. We conclude that severity of arterial hypoxemia may not reflect the severity of pulmonary artery obstruction in acute pulmonary embolism if shock is present.

Adult↗