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Biomedical subjects

G Susini

Publications and source records attributed to G Susini.

At least 37 records · Page 2Linked to original sources
PubMed1991

Systemic to pulmonary bronchial blood flow in mitral stenosis.

We measured systemic to pulmonary bronchial blood flow [Qbr(s-p)] during total cardiopulmonary bypass in 15 patients with mitral stenosis and elevated pulmonary venous pressure (group A, mean pulmonary wedge pressure = 22.2 +/- 5.4 mm Hg, mean +/- SD) and in 15 patients with coronary artery diseases and normal pulmonary venous pressure (group B). Qbr(s-p) is the volume of blood accumulating in the left side of the heart in the absence of pulmonary and coronary flows. This blood was vented through a cannula introduced into the left atrium and measured. Qbr(s-p) was 76.3 +/- 13.9 ml/min (2.18 +/- 0.37 percent of extracorporeal circulation pump flow) and 22.3 +/- 2.1 (0.63 +/- 0.15) in group A and B, respectively (p less than 0.01). During total cardiopulmonary bypass, pulmonary venous pressure is approximately atmospheric pressure, and no differences in systemic blood pressure, extracorporeal circulation pump flow, and airways pressure were observed between group A and B. Therefore, vascular resistance through the bronchial vessels draining into the pulmonary circulation is reduced in patients with mitral stenosis and elevated pulmonary venous pressure.

Adult↗
PubMed1991

[The surgical treatment of pre-excitation syndromes].

In the recent years the approach to the patients with tachycardias due to the Wolff-Parkinson-White (WPW) syndrome has changed in relation to the favourable results obtained by the surgical treatment. In this review the significance of the pre-operative electrophysiologic study is analyzed, as to a guide to localize the accessory pathway and, in particular, to disclose the presence of complicated substrates, such as multiple accessory pathways, AV nodal reentry; these latter situations if not correctly diagnosed, are a cause of surgical failure. We report the use of the epicardial surgical approach (Guiraudon technique). With the recent modifications, this technique avoids in the most cases the use of extracorporeal circulation. This simplified and safe surgical technique is a suitable alternative to other therapeutic strategies.

Electrocardiography↗
PubMed1990

Changes in circulating norepinephrine with hemofiltration in advanced congestive heart failure.

In congestive heart failure (CHF), hemofiltration is associated with an obvious decrease in circulating norepinephrine. This method was used for investigating the mechanisms whereby plasma norepinephrine is increased in chronic CHF. In 23 cases of advanced CHF, hemofiltration (2,983 +/- 1,228 ml) lowered plasma norepinephrine by 515 +/- 444 pg/ml. This effect was prompt, persisted or became greater in the next 24 hours. It was not associated with significant changes in cardiac output, aortic pressure or systemic vascular resistance. It did not appear to depend on variations in parameters related to the sympathetic activity, such as plasma renin, right atrial, wedge pulmonary artery and renal perfusion pressures, and was independent of duration and amount of hemofiltration. These observations did not support the concept that the norepinephrine decrease was the main consequence of a neural sympathetic inhibition. Hemofiltration increased diuresis by 606 +/- 415 ml; changes were prompt and correlated inversely (r = -0.7; p less than 0.01) with those in plasma norepinephrine. The same unknown mechanism of the increased urinary output might potentiate the norepinephrine removal from the blood by the kidney, or hemofiltration and the augmented diuresis might result in a regression of congestion of lungs and kidneys, leading to an improved extraction of norepinephrine. In CHF, a relation may exist between fluid retention and norepinephrine and in advanced stages, circulating norepinephrine, although strikingly increased, is devoid of important cardiovascular effects. At these stages, plasma norepinephrine is probably unreliable as an index of the sympathetic neural activity.

Adult↗
PubMed1990

Isolated ultrafiltration in cardiogenic pulmonary edema.

Twenty patients (ten with mitral and/or aortic valve disease and ten with ischemic heart disease, all in the New York Heart Association class IV, aged between 18 and 74 yr, with cardiogenic pulmonary edema unresponsive to drug treatment) were treated with polysulphone membrane ultrafiltration (UF) in a veno-venous circuit. All patients had dyspnea, pulmonary rales, hypoxemia, tachycardia, hypotension, overhydration, radiologic evidence of engorged pulmonary vasculature, and Kerley-B lines. Systemic and pulmonary arterial pressures, cardiac output (by thermodilution), and intrapulmonary shunt fraction (Qsp/Qt) were determined and chest x-ray was obtained at the beginning and the end of UF. Average duration of the treatment was 150 +/- 28 min; UF volume averaged 3000 +/- 170 ml. UF reduced the Qsp/Qt by 58% from control condition, and did not significantly affect hemodynamic variables. Chest x-rays documented clearing of alveolar edema and venous congestion. These changes were associated with unequivocal clinical improvement and no mechanical ventilation was necessary to improve gas exchange. Short-term fluid subtraction did not result in undesired circulatory alternations. Because the ultrafiltrate composition is similar to plasmatic fluid, no modification in the plasma osmolarity was detected. In conclusion, UF may be considered an effective tool for the treatment of acute pulmonary edema refractory to drug therapy, as an alternative to mechanical ventilation, and as a remedy for excessive extravascular lung water.

Adult↗
PubMed1990

Inspired gas relative humidity affects systemic to pulmonary bronchial blood flow in humans.

To our knowledge, the effects of humidity of inspired air on bronchial blood flow in humans are unknown. During total cardiopulmonary bypass, we measured systemic to pulmonary bronchial blood flow (Qbr[s-p]) which is the volume of blood accumulating into the left side of the heart in the absence of pulmonary and coronary flow. A cannula was introduced into the right upper pulmonary vein and advanced into the lowermost portion of the left side of the heart. From this cannula Qbr(s-p) was vented by gravity and measured. Inspired gas (10 L/min, endotracheal tube, 50 percent O2 + 50 percent N2O) relative humidity was less than 20 percent and greater than 85 percent in group A (n = 25) and in group B (n = 25), respectively. Mean (+/- SE) Qbr(s-p) was 40.7 +/- 0.06 ml/min or 1.32 +/- 0.12 ml/min (percent cardiac output) in group A and 21.7 +/- 1.8 ml/min or 0.68 +/- 0.06 ml/min in group B. These data indicate that under these conditions Qbr(s-p) is increased by dry gas lung inflation in humans.

Cardiopulmonary Bypass↗
PubMed1990

[Neurohumoral changes induced by hemofiltration in congestive heart failure: physiopathological inferences].

Hemofiltration is a method suitable for rapid substraction of plasma water that generally allows reduction of circulating levels of norepinephrine. Using that non-pharmacological approach we investigated the mechanisms involved in the metabolism of the hormone as well as the hemodynamic correlates of a prompt and great fall of the sympathetic neurotransmitter in patients with chronic refractory congestive heart failure (CHF). In 23 patients with CHF, hemofiltration of 2983 +/- 1228 ml of plasma water (in 5 +/- 2 hours of treatment) increased urinary output by 606 +/- 415 ml in the day of the procedure as well as sodium excretion by 53 +/- 38 mEq/24 h; simultaneously, a mean fall in plasma norepinephrine concentration by 515 +/- 444 pg/ml was observed. These effects were prompt and persisted or even rose in the next 24 and 48 hours, not being related to changes in plasma renin activity, right atrial, wedge pulmonary artery and renal perfusion pressures and to the amount and duration of hemofiltration. Our data did not clarify the mechanism involved in the increase of the diuresis and for its coupling with the fall in plasma norepinephrine. Nevertheless, we found a strong and statistically significant correlation (r = 0.7; p less than 0.01) between percent changes from baseline values of norepinephrine and diuresis. It is therefore suggested that the same, still unknown, mechanism which increased urinary output also potentiated norepinephrine removal by the kidney: or that water reabsorption from extravascular spaces (triggered by hemofiltration and continued by increased diuresis) resulted in regression of organ congestion leading to an improved clearance of norepinephrine by different organs.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Increase of alveolar pressure reduces systemic-to-pulmonary bronchial blood flow in humans.

We studied the effect of positive alveolar pressure (PA) on systemic to pulmonary bronchial blood flow, Q?? in humans. The Q?? was measured during total cardiopulmonary bypass as the volume of blood accumulating in the left heart. This blood was vented by gravity from the left heart via a cannula introduced in the right upper pulmonary vein and advanced to the lowest portion of the left heart. In group A (n = 10) the Qbr(s-p) was measured for 25 to 95 min with constant PA (4.0 +/- 0.2 cm H2O, mean +/- SE). In group B (n = 10) Qbr(s-p) was measured for 20 min with PA = 4.1 +/- 0.2 cm H2O and for a further 20 min with PA = 14.1 +/- 0.4 cm H2O. The Qbr(s-p) ranged between 0.32 and 2.76 percent of cardiac output (pump flow) and remained constant with time (group A). The increase of PA from 4.1 +/- 0.2 to 14.1 +/- 0.4 cm H2O reduced Qbr(s-p) by approximately 40 percent (p less than 0.01, group B). We conclude that positive PA reduces Qbr(s-p) during total cardiopulmonary bypass. Therefore, we advise using low PA during assisted ventilation to preserve bronchial blood flow.

Bronchi↗
PubMed1987

Hemofiltration as short-term treatment for refractory congestive heart failure.

Hemofiltration has been suggested as a new therapeutic tool in refractory heart failure. In this study, 11 patients with primary or ischemic heart disease in New York Heart Association class IV, in whom there was no response to medical treatment, were subjected to hemofiltration. The pathophysiologic adjustments promoted by subtraction of plasma water were investigated, and guidelines for an appropriate use of this procedure in heart failure are provided. Fluid was removed from plasma at a rate of 500 ml/hour until either normalization of the right atrial pressure (which was increased in all cases) was achieved or the hematocrit exceeded 50 percent. According to these criteria, the duration of treatment ranged from four to six hours and the total amount of fluid removed was 2,000 to 3,000 ml. In each case, hemofiltration promoted relief of dyspnea and of clinical and radiographic evidence of lung congestion and pleural effusion, and substantially reduced the dependent edema and abdominal girth. These effects were paralleled by progressive decrease of the right (-70 percent) and left (-45 percent) ventricular filling pressures and of the pulmonary arterial pressure and arteriolar resistance, without significant variations in heart rate, aortic pressure, cardiac index, and systemic vascular resistance. Changes in the right atrial and wedge pulmonary pressures are interpreted as reflecting a combined effect of a decrease in pressure on the outside of the heart due to fluid reabsorption (from lung interstitial spaces and pericardial, pleural and abdominal cavities) and of intravascular volume subtraction. The arterial partial pressure of oxygen was raised, the partial pressure of carbon dioxide and pH were unchanged, and urinary output was substantially enhanced by the procedure. The study indicates that: hemofiltration may be a short-term treatment for refractory cardiac insufficiency with overhydration; a filtration rate of 500 ml/hour is effective and safe; and the central venous pressure may be a reliable guide to volume subtraction.

Aged↗