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Biomedical subjects

F Lemaire

Publications and source records attributed to F Lemaire.

At least 145 records · Page 8Linked to original sources
PubMed1985

[Acute adult respiratory distress syndrome after lymphography].

Pulmonary complications of lymphography are usually described as radiological infiltrates without clinical symptoms. However, a case is here reported of an adult respiratory distress syndrome occurring after lymphography in a 60 year old female lymphoma patient. Pulmonary oedema developed within 48 h; haemodynamic study showed a normal capillary wedge pressure. The patient died from intractable low cardiac output within 24 h. Post-mortem examination showed pulmonary lymphocytic infiltration and multiple fat emboli. The lack of lymphatic drainage was probably responsible for the intravascular passage of lipid-soluble contrast medium, this giving endothelial lesions. In such patients with preexisting lung disease or pulmonary involvement in haematological disease, lymphography has to be considered carefully.

Embolism, Fat↗
PubMed1985

Recurrent high-permeability pulmonary edema associated with diabetic ketoacidosis.

Delayed-onset pulmonary edema complicating severe diabetic ketoacidosis was observed twice in one patient. Hemodynamic measurements during the second episode showed normal transmural pulmonary capillary wedge pressure, suggesting an alteration in alveolocapillary permeability. Hyperventilation and acidosis may underlie this alteration. Vigorous fluid therapy, while decreasing oncotic pressure, may also contribute to the pulmonary edema. The two episodes in one patient suggest that pulmonary microvascular diabetic angiopathy may predispose some diabetics with severe ketoacidosis to increased-permeability pulmonary edema.

Adult↗
PubMed1985

Mechanical ventilation with 100% oxygen does not increase intrapulmonary shunt in patients with severe bacterial pneumonia.

Pure oxygen ventilation has been shown to increase the right to left shunt QS/QT in both normal and diseased lungs. Nitrogen absorption atelectasis, an explanation of the phenomenon, is likely to occur in lung units with low ventilation/perfusion ratio. In 11 patients with severe unilateral or bilateral bacterial pneumonia, we assessed the effects of increasing FlO2 from maintenance level (m = 0.44 +/- 0.11) to 1.0. Venous admixture (QVA/QT) was calculated using the O2 method, and the distribution of the VA/Q ratios were assessed with the 6 inert gas (IG) technique providing the distribution between the true shunt (QS/QT IG) and the low VA/Q units. Although a large part of perfusion was distributed preferentially to low VA/Q units, ranging from 2 to 43% of cardiac output, thus placing large zones of lung parenchyma at risk of absorption atelectasis, QVA/QT decreased from 31 +/- 13% to 25 +/- 10% and IG shunt did not increase after 30 min of O2 ventilation. In addition, QS/QT IG remained unaltered despite PVO2 increased from 32 to 43 mmHg, suggesting a poor level of hypoxic vasoconstriction in human bacterial pneumonia.

Bacterial Infections↗
PubMed1985

Influence of caloric intake on the respiratory mode during mandatory minute volume ventilation.

Mandatory minute volume ventilation has been proposed as a method for weaning patients from ventilators. The purpose of this study was to delineate the influence of caloric intake on spontaneous ventilation in patients receiving mandatory minute volume ventilation. While the value of such ventilation remained unchanged, eight patients were studied at the following three different levels of daily caloric intake: (1) level A, mean of 223 kcal/sq m; (2) level B, mean of 1,380 kcal/sq m; and (3) level C, mean of 2,100 kcal/sq m. We performed gas exchange measurements and a 24-hour recording of ventilation with a monitoring system providing distinction between spontaneous and mechanical cycles. We found that the ventilatory mode was markedly dependent upon the nutritional intake; the percentage of spontaneous ventilation over 24 hours increased from 11 +/- 7 percent (+/- SE) during diet A to 50 +/- 9 percent during diet B and 79 +/- 8 percent during diet C. This increment paralleled the increase in production of carbon dioxide with caloric intake. We suggest therefore that the patient's ability to breathe spontaneously when receiving mandatory minute volume ventilation should be interpreted according to caloric intake.

Aged↗
PubMed1985

Hypoxemia in acute pulmonary embolism.

Most patients with severe, acute pulmonary embolism (PE) have arterial hypoxemia. To further define the respective roles of ventilation to perfusion (VA/Q) mismatch and intrapulmonary shunt in the mechanism of hypoxemia, we used both right heart catheterization and the six inert gas elimination technique in seven patients with severe, acute PE (mean vascular obstruction, 55 percent) and hypoxemia (mean PaO2, 67 +/- 11 mm Hg). None had previous cardiopulmonary disease, and all were studied within the first ten days of initial symptoms. Increased calculated venous admixture (mean QVA/QT 16.6 +/- 5.1 percent) was present in all patients. The relative contributions of VA/Q mismatching and shunt to this venous admixture varied, however, according to pulmonary radiographic abnormalities and the time elapsed from initial symptoms to the gas exchange study. Although all patients had some degree of VA/Q mismatch, the two patients studied early (ie, less than 48 hours following acute PE) had normal chest x-ray film findings and no significant shunt; VA/Q mismatching accounted for most of the hypoxemia. In the others a shunt (3 to 17 percent of cardiac output) was recorded along with radiographic evidence of atelectasis or infiltrates and accounted for most of the venous admixture in one. In all patients, a low mixed venous oxygen tension (27 +/- 5 mm Hg) additionally contributed to the hypoxemia. Our findings suggest that the initial hypoxemia of acute PE is caused by an altered distribution of ventilation to perfusion. Intrapulmonary shunting contributes significantly to hypoxemia only when atelectasis or another cause of lung volume loss develops.

Acute Disease↗
PubMed1985

Right atrial septal aneurysm: an unusual cause of recurrent pulmonary embolism.

Angiography was used to diagnose atrial septal aneurysm in a 46-yr-old man suffering from recurrent pulmonary emboli, who had normal venograms of his lower extremities. This case demonstrates the usefulness of searching for sources of emboli other than deep venous thrombosis, but illustrates the limits of two-dimensional echocardiography in diagnosing atrial septal aneurysm.

Heart↗
PubMed1984

[Acute respiratory distress syndrome in the adult. Distribution of the ventilation-perfusion ratio].

Hypoxemia in the acute respiratory distress syndrome may be due to a variety of causes: trùe pulmonary shunt, decreased ventilation/perfusion ratios, impaired diffusion and/or fall of mixed venous oxygen. In order to sort out these different tension mechanisms, 18 patients with acute respiratory distress syndrome were explored by the inert gas method. In 6 of them hypoxemia was due to a true shunt (35 +/- 10%). The remaining 12 patients also had a true shunt (26.5 +/- 9.5%), but 4.5% of the cardiac output was distributed to areas with a ventilation/perfusion ratio between 0.1 and 0.005. Thus, in these 18 patients with acute respiratory distress, hypoxemia could be explained essentially by a true shunt.

Adult↗
PubMed1984

[Increase in functional residual capacity induced by positive end-expiratory pressure. Prediction using the thoracopulmonary pressure curve].

Prediction of FRC using a respiratory P-V curve (2 1 syringe method) has been tested in eight patients with normal lungs and in 12 ARDS patients. FRC was measured using nitrogen dilution technique with a closed circuit. Correlation between measured and predicted FRC was excellent, especially when the expiratory limb of the P-V curve was used (r = 0.92, in patients with pulmonary edema, and r = 0,97 when patients were evaluated after a few weeks). PEEP induced increase in FRC was larger between 10 and 20 cmH2O than between 0 and 10 cmH2O. As expected, Qs/Qt decrease was correlated with the FRC augmentation.

Adolescent↗
PubMed1984

Redistribution of pulmonary blood flow induced by positive end-expiratory pressure and dopamine infusion in acute respiratory failure.

The mechanism by which mechanical ventilation (MV) with positive end-expiratory pressure (PEEP) improves hypoxemia in patients with acute respiratory failure (ARF) is unclear, and may be attributed in part to a decrease in cardiac output inducing by itself a reduction of the shunt. Using the multiple inert gas elimination technique we evaluated the effects of PEEP on ventilation-perfusion (VA/Q) distribution in 8 patients while cardiac output was maintained at control value by means of a dopamine infusion. In each patient, evaluation was performed during MV without PEEP (control) then with PEEP (17 +/- 2 cm H2O) and dopamine. After application of PEEP, PaO2, PvO2, and oxygen transport (TO2) increased significantly, whereas venous admixture decreased from 37.5 +/- 5 to 17 +/- 2% (p less than 0.01). Comparison of VA/Q distribution during PEEP and zero end-expiratory pressure documented a redistribution of pulmonary blood flow; the shunt decreased markedly from 30 +/- 4 to 13 +/- 2% (p less than 0.001), whereas the fraction of cardiac output distributed to "normal" VA/Q ratio units (0.1 to 10) increased from 62 to 78.5% (p less than 0.001). Dead space increased slightly with PEEP, from 44 to 49% (p less than 0.01) of total ventilation. The pattern of ventilation distribution was essentially unaltered; specifically, no additional high VA/Q mode was observed during PEEP. It is concluded that cardiac output maintenance with dopamine infusion during PEEP does not suppress the beneficial effects of PEEP on gas exchange, but induces a redistribution of pulmonary blood toward the main VA/Q ratio.

Acute Disease↗
PubMed1984

Total respiratory pressure-volume curves in the adult respiratory distress syndrome.

To assess the value of measuring compliance in the adult respiratory distress syndrome, sequential pressure-volume curves were obtained in 19 patients with this syndrome. Analysis of the pressure-volume curves allowed separation of the patients into the following four groups: (1) group 1 (n = 6), normal compliance measured during deflation, little hysteresis, and no inflection in the ascending limb of the pressure-volume tracing; (2) group 2 (n = 8), normal compliance during deflation, increased hysteresis, and presence of an inflection; (3) group 3 (n = 10), decreased compliance during deflation, marked hysteresis, and presence of an inflection; and (4) group 4 (n = 10), reduced compliance during deflation, no increased hysteresis, and no inflection. These patterns were correlated with the stage of the adult respiratory distress syndrome and to the pattern of the chest x-ray film. Group 2 corresponds to the initial stage of the syndrome and to pure alveolar opacities on the chest x-ray film. Group 3 is seen later in the course of the syndrome and corresponds to mixed alveolar and interstitial opacities. Group 4 corresponds to patients with end-stage adult respiratory distress syndrome (two weeks) and a predominant interstitial pattern on the chest x-ray film. Group 1 corresponds to a nearly normal chest x-ray film and to recovery.

Adolescent↗
PubMed1983

[Acute Actinobacillus actinomycetem comitans aortic endocarditis].

A 55 year old man presented an acute massive primary aortic endocarditis, with blood cultures showing the presence of Actinobacillus actinomycetem comitans. The rapidly worsening character of this endocarditis, which required an emergency valve replacement, was the hallmark of this case. The clinical and haemodynamic signs of the often missed massive acute aortic incompetence are recalled.

Actinobacillus Infections↗
PubMed1983

[Contamination of an oxygen delivery circuit by compressed air].

Routine checking of the FIO2 of a mixture delivered by a ventilator revealed large discrepancies between the FIO2 assigned and that effectively delivered, the latter being low. Measurements of FIO2 at the wall outlets showed the O2 delivery pipeline to be contaminated by compressed air. By disconnecting all the ventilators supplied by this pipeline one after the other, one ventilator, or rather its blender, was found responsible.

Air↗
PubMed1983

A new device for measurement of pulmonary pressure-volume curves in patients on mechanical ventilation.

Measurement of total (lung plus chest wall) pulmonary compliance is routinely obtained in mechanically ventilated patients by dividing the tidal volume (VT) by the airway pressure (Paw) gradient from end-inspiration to end-expiration. In order to obtain the pressure-volume (P-V) tracing during inspiration, we developed a method using a continuous and slow (1.7 L/min) oxygen inflow. When gas flow is kept constant, changes in lung volume are proportional to time and do not require direct measurement. In 22 patients, P-V curves traced using the continuous-flow method were identical to those obtained from the syringe method. The advantages of the inflow method are simplicity, reproducibility, and better visualization of the initial part of P-V curve.

Humans↗
PubMed1982

A comparative study of the cardiorespiratory effects of continuous positive airway pressure breathing and continuous positive pressure ventilation in acute respiratory failure.

Positive end expiratory pressure (PEEP) produces cardiopulmonary effects whether administered by controlled positive pressure ventilation (CPPV) or continuous positive airway pressure (CPAP). In eight patients with acute respiratory failure, the effects of 20 cm PEEP administered via CPPV and CPAP were compared. An esophageal balloon was used to calculate the transmural vascular pressures. The control values under mechanical ventilation with no PEEP (IPPV) for PaO2 and QS/QT (FiO2 being 1.0) were respectively 132 +/- 15 mmHg and 31 +/- 3%; CPPV gave a PaO2 of 369 +/- 27 mmHg and QS/QT fo 14 +/- 1.6%, CPAP 365 +/- 18 mmHg and 18 +/- 1.3% respectively. The two different modes of ventilation (CPPV and CPAP) gave identical blood gas improvement through the same level of end expiratory transpulmonary pressure despite marked differences between absolute mean airway and esophageal pressures. Conversely, hemodynamic tolerance was very different from one technique to the other: CPPV depressed cardiac index from 3.4 +/- 0.3 to 2.4 +/- 0.2 1/min/m2 as well as decreasing transmural filling pressures, suggesting a reduction in venous return. Conversely, filling pressures maintained at control values during CPAP and cardiac indexes were unchanged.

Acute Disease↗
PubMed1982

[Assessment of acute respiratory failure: shunt versus alveolar arterial oxygen difference].

Information provided by computation of shunt and alveolar arterial oxygen differences have been compared in 58 episodes of acute respiratory failure. In order to demonstrate the role of hemodynamic factors on pulmonary gas exchange, we compared blood gas measurements made in 29 patients with a high cardiac output and a reduced arteriovenous oxygen difference [C(a--v-)O2 less than 3.5 ml], with 33 measurements corresponding to a low cardiac output and a widened C(a--v-)O2 (greater than 6.5 ml). When the data was pooled together, the same P(A--a)O2 corresponded to many different shunt values, depending on the level of mixed venous oxygenation (PV-O2). QS/Qtot and P(A--a)O2 were quasi linearly correlated only when they corresponded to patients with the same C(a--v-)O2. For the same value of shunt, the PaO2 was always raised when the PV-O2 was raised. As far as pulmonary gas exchange is concerned, shunt calculation in acute respiratory failure is preferable to P(A--a)O2, especially when some hemodynamic disturbance is present.

Acute Disease↗