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Biomedical subjects

J F Monsallier

Publications and source records attributed to J F Monsallier.

At least 37 records · Page 2Linked to original sources
PubMed1986

Mechanisms of decreased left ventricular preload during continuous positive pressure ventilation in ARDS.

Continuous positive pressure ventilation is associated with a reduction in left ventricular preload and cardiac output, but the mechanisms responsible are controversial. The decrease in left ventricular preload may result exclusively from a decreased systemic venous return due to increased pleural pressure, or from an additional effect such as decreased left ventricular compliance. To determine the mechanisms responsible, we studied the changes in cardiac output induced by continuous positive pressure ventilation in eight patients with the adult respiratory distress syndrome. We measured cardiac output by thermodilution, and biventricular ejection fraction by equilibrium gated blood pool scintigraphy. Biventricular end-diastolic volumes were then calculated by dividing stroke volume by ejection fraction. As positive end-expiratory pressure increased from 0 to 20 cm H2O, stroke volume and biventricular end-diastolic volumes fell about 25 percent, and biventricular ejection fraction remained unchanged. At 20 cm H2O positive end-expiratory pressure, volume expansion for normalizing cardiac output restored biventricular end-diastolic volumes without markedly changing biventricular end-diastolic transmural pressures. The primary cause of the reduction in left ventricular preload with continuous positive pressure ventilation appears to be a fall in venous return and hence in right ventricular stroke volume, without evidence of change in left ventricular diastolic compliance.

Adult↗
PubMed1985

Bicarbonate hemodialysis of patients with acute renal failure and severe sepsis.

During hemodialysis (HD), septic patients with acute renal failure (ARF) often exhibit severe hemodynamic instability, with a fall in BP that requires a large-volume infusion or even cessation of dialysis. To investigate the hypothesis that acetate transfer plays a role in the BP decrease, we compared acetate (Ac) and bicarbonate (Bi) HD in ten septic ARF patients. Patients were dialyzed daily for 4 h with a single-pass system and 1.1 m2 cuprophan dialyzers, alternately using Ac and Bi as the dialysate buffer. Heart rate and systemic arterial resistance did not change significantly during use of either buffer, and changes in pulmonary wedge pressure were similar. However, decreases in cardiac output and mean arterial pressure were more pronounced during Ac-HD than during Bi-HD. Rapid correction of metabolic acidosis and a larger decrease of plasma potassium concentration occurred during Bi-HD. These results suggest that Bi-HD was better tolerated than Ac-HD because of changes in myocardial contractility that may be related to different effects on acid-base status and plasma potassium concentrations.

Acetates↗
PubMed1984

Oxygen consumption during septic shock. Effects of inotropic drugs.

Septic shock may be defined as a clinical entity wherein a patient has an inadequate peripheral metabolism in the presence of circulating bacteria. The demands for metabolic requirements of the tissues and hence for oxygen transport to these tissues are then markedly high. The average response to increased metabolism in such patients is a percentage increase in cardiac output that is comparable to the percentage increase in oxygen consumption while oxygen extraction rate does not change or even decreases in severe or/and advanced septic shock. This emphasizes the high priority placed by the body on the ability to increase blood flow from the heart in the presence of increased metabolic demands due to sepsis. Concerning the myocardium, oxygen consumption is low in hyper- and hypodynamic states of septic shock, probably and partially due to marked arterial vasodilatation. However, in hypodynamic states, the lower value of perfusion pressure may account for a decrease in myocardial oxygen supply, especially in subendocardial areas and may be responsible for myocardial ischaemia, more especially as myocardial oxygen extraction as well as systemic oxygen extraction is impaired. The goal of therapeutics is to improve oxygen availability through: (1) maintenance of haemoglobin levels and (2) increases in stroke volume using inotropic drugs since these drugs may produce a rise in myocardial oxygen supply higher than their drug-induced increase in oxygen requirements in hypodynamic states of septic shock.

Blood Pressure↗
PubMed1983

[Improvement of dialysis tolerance in patients with severe infections using a bicarbonate dialysate].

Severe septic patients, with high cardiac output (CO) and low systemic arterial resistances (SAR), often develop an uncontrolled fall in blood pressure (BP) during acetate hemodialysis (AcHD), because they are especially unable to increase appropriately their SAR with fluid removal. To investigate the possibility that Ac transfer plays a part in this fall in BP, we studied and compared hemodynamic and biochemistry status of such 10 patients with acute renal failure by alternately using Ac and bicarbonate (Bi) dialysate. CO and mean systemic arterial pressure decrease more during AcHD than during BiHD, whereas the changes in pulmonary wedge pressure were similar; heart rate and SAR remained unchanged. Thus the better hemodynamic tolerance during BiHD seems to be due to a change in myocardial contractility that may be related to differences in acid-base status and plasmatic potassium concentrations.

Bacterial Infections↗
PubMed1982

[Acute pulmonary infiltrates in hematologic malignancies in aplasia (author's transl)].

Extensive pneumonias are usually implicated as the sole cause for acute respiratory failure complicating severe neutropenia in hematologic malignancies and are often fatal. We report study of 11 patients investigated and treated in intensive care unit, using transtracheal aspiration, continuous positive airway pressure (CPAP) via face mask and granulocyte transfusions Two groups of patients emerged from this study. The first group with immediately diffuse pulmonary infiltrates, positive blood cultures, negative tracheal cultures, marked improvement in hypoxemia during CPAP, benefits from granulocyte transfusion without impairment in ventilatory status and may be considered as non-hemodynamic pulmonary oedema. The second group with localized pulmonary infiltrates, negative blood cultures and positive tracheal culture, slight improvement in hypoxemia during CPAP, gets no benefit from granulocyte transfusion, with additional impairment in ventilatory status and may be considered as acute extensive pneumonias.

Acute Disease↗
PubMed1981

[Management of unilateral or asymmetrical lung disease (author's transl)].

To determine the indications of body position, continuous positive airway pressure and independent lung ventilation in unilateral lung disease, we turned 10 patients with overwhelming unilateral lung disease from supine to lateral position. All patients were breathing spontaneously with a mask, then associated with continuous airway pressure (10 cm H2O PEEP) in five cases. During these spontaneous ventilation methods, hemodynamic parameters did not change, but arterial blood oxygen tension increased and intra-pulmonary shunting decreased significantly. Final recovery was obtained in 7 cases. In the 3 others, mechanical ventilation was needed because spontaneous breathing methods were ineffective in improving blood gases. Lateral position and conventional ventilation with positive airway pressure were also ineffective. Only independent ventilation enhanced arterial blood oxygen tension. But only one patient survived. We conclude that spontaneous breathing methods are able to provide successful treatment in most of patients with unilateral lung disease. In other patients, only independent lung ventilation is effective.

Adult↗
PubMed1981

[Consequences of continuous positive airway pressure (CPAP) on left ventricular function. Assessment by M-mode echocardiography (author's transl)].

The consequences of continuous positive airway pressure (CPAP) on left ventricular function are uncertain. Left ventricular function was assessed by M-mode echocardiography in 8 young normal subjects during CPAP via face mask. Heart rate and arterial pressure did not change. End-diastolic volume and stroke volume significantly decreased. Ejection fraction remained unchanged. The slight decrease of stroke volume induced by increasing positive airway pressure is in relation to decreased left ventricular preload.

Adult↗
PubMed1981

[Acute neutropenia in adult severe bacterial infections. Six cases (author's transl)].

A transient neutropenia (duration : less than 48 hours) occurred in 6 patients with severe bacterial infections. The bone marrow myeloïd cellularity was high or normal; a maturation arrest of the myeloïd cells - at a variable stage - was present in each case, as well as circulating granulocyte precursors. Other causes of neutropenia were excluded. A general survey of the literature is made and the mechanisms of this bacterial neutropenia are considered : bone marrow failure seems mostly improbable ; the few previously reported cases, the experimental bacterial neutropenias, the peculiar, transient, evolution we observed, all favor a peripheral mechanism ; the bacterial infection seems to act by; two ways : in septicemia (especially during septic shock) by enhancing leucocyte margination along vascular walls ; in large septic foci (mostly pulmonary) by an important destruction of polymorphonuclear neutrophils. Such bacterial infections share a bad prognosis but the neutropenia itself needs no specific treatment.

Acute Disease↗