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Biomedical subjects

D Dreyfuss

Publications and source records attributed to D Dreyfuss.

At least 73 records · Page 4Linked to original sources
PubMed1992

Evaluation of risk factors for laryngeal edema after tracheal extubation in adults and its prevention by dexamethasone. A placebo-controlled, double-blind, multicenter study.

Because laryngeal edema (LE) after tracheal extubation is likely to result from an exudative response, corticosteroids often are given routinely as a preventive treatment. No adequate controlled study supports this strategy, however. A prospective, randomized, placebo-controlled, double-blind, multicenter trial that included 700 consecutive patients requiring tracheal intubation and mechanical ventilation was conducted to determine risk factors for LE occurrence after tracheal extubation in adults and to evaluate the efficacy of corticosteroids in its prevention. One hour before extubation, patients were given either an intravenous bolus of 8 mg dexamethasone or a placebo. Patients were divided into two groups: 1) those in whom short-duration intubation (SDI, less than 36 h) was administered; and 2) those in whom long-duration intubation (LDI, more than 36 h) was administered. Minor LE was diagnosed when either stridor or laryngeal dyspnea, or both, occurred; major LE was diagnosed when reintubation due to LE was required, with LE evidenced during direct laryngoscopy. The overall incidence of LE was 4.2% and varied among the six participating centers from 2.3 to 6.9% (not significant). In only seven patients (1%), all with LDI, was tracheal reintubation required for LE. Laryngeal edema occurred more frequently after LDI than after SDI (7.2 vs. 0.9%; P less than 0.001). It also was more frequent in female than in male patients (20/284 vs. 8/379; P less than 0.05), irrespective of intubation duration and treatment. There was no association between LE and either difficulty/route of intubation or admission diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Spontaneous resolution of pulmonary edema caused by short periods of cyclic overinflation.

Mechanical ventilation with high or even moderate peak inspiratory pressure produces pulmonary permeability edema. Besides the level of overinflation, duration may affect both severity and type of edema. We studied the effect of 2 min of 35-mmHg peak pressure mechanical ventilation (HV) on microvascular permeability and deep lung fluid balance in rats. It resulted in increased extravascular lung water (+50%), bloodless dry lung weight (+25%), and albumin uptake in lungs (+450%). The increase in dry lung weight and albumin uptake compared with that of lung water suggested major permeability alterations. Ultrastructural examination showed the presence of numerous endothelial blebs. Epithelial lining fluid (ELF) volume, its potassium and protein concentrations, and cellular composition were assessed by bronchoalveolar lavage. There was an increase in ELF volume (+180%), a decrease in ELF potassium concentration (-50%), and an increase in ELF protein content (+76%). A few blood cells were recovered, suggesting the presence of a few large epithelial breaks. Some animals were allowed to recover for periods less than or equal to 180 min after HV. Extravascular lung water, dry lung weight, and albumin distribution space returned to control levels within 45 min. ELF volume diminished but remained larger than in controls, and ELF protein concentration increased probably because of alveolar fluid resorption. No further hemorrhage was observed. These results indicate that periods of HV as short as 2 min transiently alter microvascular permeability in rats.

Animals↗
PubMed1992

A comparative study of the effects of almitrine bismesylate and lateral position during unilateral bacterial pneumonia with severe hypoxemia.

The management of patients with unilateral pneumonia and severe hypoxemia often represents a therapeutic challenge. Mechanical ventilation with the diseased lung uppermost may improve gas exchange, but it is not devoid of adverse effects. No hemodynamic measurements have been reported in patients ventilated in this manner; therefore, whether or not the improvement in PaO2 is counterbalanced by hemodynamic deterioration remains unknown. Almitrine bismesylate is a drug that seems able to improve gas exchange in patients with chronic obstructive pulmonary disease or the adult respiratory distress syndrome. The increase in PaO2 after its administration has been attributed to an improvement in ventilation-perfusion relationships. Its use has never been reported during unilateral pneumonia with severe hypoxemia. We therefore compared its effects with those of lateral position in eight consecutive mechanically ventilated patients with unilateral pneumonia. Blood gas and hemodynamic measurements were performed both at maintenance FIO2 and at an FIO2 of 1.0. Almitrine (1 mg/kg over 1 h) had no effect on PaO2 under either FIO2 condition. Cardiac output remained unchanged, but mean pulmonary artery pressure increased from 22.5 +/- 1.2 to 26.5 +/- 1.3 mm Hg (p < 0.02). By contrast, lateral position had striking effects on PaO2, which increased from 100 +/- 14 mm Hg in supine position to 156 +/- 23 mm Hg (p < 0.01) when the abnormal lung was placed uppermost at maintenance FIO2 and from 207 +/- 21 (supine) to 300 +/- 28 mm Hg (lateral) (p < 0.01) at FIO2 1.0.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Nontraumatic acute anterior mediastinitis in two HIV-positive heroin addicts.

We present the cases of two young heroin addicts seropositive for HIV who had life-threatening spontaneous acute anterior mediastinitis due to Staphylococcus aureus. This was the consequence of the spreading to the mediastinum of an infection of the chest wall. Complete cure was achieved with antibiotics and surgical drainage. Spontaneous mediastinitis should arouse suspicion of the possibility of HIV infection.

Acute Disease↗
PubMed1991

Luminal glucose enhances transepithelial Na+ and fluid transports in rat lungs.

The effects of luminal glucose on transepithelial Na+ and fluid transports were investigated in rat lungs. Two preparations were used: isolated, perfused lungs and lungs in situ perfused with blood (cross-circulations), a situation more comparable to that existing in vivo. Unidirectional (efflux from air spaces, J(out)) and net (Jnet) Na+ fluxes and fluid absorption from air spaces were estimated in lungs filled with bicarbonate-buffered solutions containing 10 mmol/l of either mannitol, glucose or alpha-methyl-D-glucopyranoside, or 0.1 mmol/l phlorizin in the presence of glucose. In the presence of mannitol J(out) was estimated to be 7.8 +/- 1.02 pmol cm-2 s-1 in isolated lungs and 9.2 +/- 0.97 pmol cm-2 s-1 in lungs in situ, and Jnet 1.0 +/- 0.33 and 2.5 +/- 0.35 pmol cm-2 s-1, respectively. When glucose replaced mannitol J(out) (+ 30% + 40%), Jnet (+200% + 300%) and fluid absorption (+ 100% + 400%) were enhanced in both preparations. Substituting methyl glucoside for mannitol increased Na+ and fluid absorption rates to the same extent as glucose. Phlorizin, in the presence of glucose, reduced Na+ and fluid transports to values similar to those observed in the presence of mannitol. These changes did not result from modifications of the paracellular permeabilities (assessed with [3H]mannitol).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Hemodialysis for acute renal failure in patients with hematologic malignancies.

OBJECTIVE: To assess the prognosis of patients with hematologic malignancies in acute renal failure who require hemodialysis. DESIGN: Retrospective study. SETTING: ICU. PATIENTS: Forty-three consecutive patients. METHODS: Prognostic analysis using both univariate and multivariate (stepwise regression) methods. RESULTS: Fifteen (35%) patients recovered from acute renal failure and 12 (28%) were discharged from the ICU. The prognosis of patients with acute renal failure linked to sepsis is poorer than the prognosis of the patients with acute renal failure from other etiologies. Only one patient survived in the former group (n = 26) and 11 in the latter group (n = 17); p less than .0001 in multivariate analysis. When accompanied by associated respiratory failure, mortality rate was higher (93% vs. 33%; p less than .0001). The Simplified Acute Physiology Score (SAPS) calculated within the first 24 hr of admission was significantly (p less than .001) related to mortality when the SAPS was greater than or equal to 13. The presence of neutropenia and the type of hematologic malignancy were not related to a worse prognosis. Tolerance to hemodialysis appeared good, and complications were rare.

Acute Kidney Injury↗
PubMed1991

Prospective study of nosocomial pneumonia and of patient and circuit colonization during mechanical ventilation with circuit changes every 48 hours versus no change.

Circuits on mechanical ventilators with cascade humidifiers are routinely changed every day or every other day, although humidifying cascades have been considered unlikely to increase the risk of respiratory infection because they do not generate aerosols. Moreover, changing ventilator tubings every 24 rather than every 48 h increases the risk of ventilator-associated pneumonia. To study the effects of ventilator circuit changes on the rate of nosocomial pneumonia and on patient and circuit colonization, 73 consecutive patients requiring continuous mechanical ventilation for more than 48 h were randomly assigned to either ventilator circuit changes every 48 h (Group 1, n = 38) or no change (Group 2, n = 35). Patients dying or being weaned before 96 h were not analyzed (Group 1 n = 3; Group 2 n = 7; leaving Group 1 n = 35 and Group 2 n = 28; p = 0.13). Ventilator-associated pneumonia was defined as the occurrence during mechanical ventilation or within 48 h after weaning of a new and persistent infiltrate on chest X-ray, purulent tracheal secretions, and a positive culture of a protected brush specimen (greater than or equal to 10(3) cfu/ml). Bacterial colonization was assessed every 48 h by quantitative cultures of pharyngeal swab, tracheal aspirate, humidifying cascade, and expiratory tubing trap. The two groups were similar in terms of age, indication for and duration of ventilation, and severity of illness.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Hyponatremia of acute pulmonary infections].

The mechanism of hyponatremia associated with pneumonia has been debated. In particular, the responsibility of inappropriate antidiuretic hormone secretion has been questioned. We have shown that inappropriate antidiuretic hormone secretion is a nearly constant finding during pneumonia and is roughly proportional to the extent of pneumonia. Nevertheless, it must be emphasized that extracellular fluid volume may be increased, diminished or normal during pneumonia, depending on the underlying condition (congestive heart failure, cirrhosis) or on the importance of extrarenal losses (sweats, fever). Careful clinical and laboratory assessment of extracellular fluid volume should enable adequate therapy.

Acute Disease↗
PubMed1990

Does the stress of admission to an intensive care unit influence arginine vasopressin secretion and renal diluting ability?

The pathogenesis of excessive arginine vasopressin (AVP) release and hyponatraemia in euvolaemic intensive care unit (ICU) patients is poorly understood. Stress has frequently been proposed as a possible determinant, but its actual responsibility has not been adequately assessed. Therefore, water-load tests were prospectively performed in 11 patients admitted to the ICU for severe or potentially severe diseases, but who had no other condition which could result in excessive AVP release or impairment of renal diluting ability. Renal diluting ability was normal in 9 patients. Two patients exhibited very slight defects, which might be the consequence of subclinical haemodynamic alterations, since one had a pulmonary embolism and the other manifested a gastrointestinal haemorrhage just after the completion of the water load. Nevertheless, plasma AVP levels decreased in response to the water load in all the patients, resulting in a significant decrease in mean values. Plasma norepinephrine values were found to be elevated both before and after water loading. A highly significant correlation existed between the levels of norepinephrine and those of AVP measured before the load, but was lost after it. In addition, norepinephrine values were markedly elevated in two patients who exhibited strictly normal renal diluting abilities, and no correlation was found between plasma norepinephrine values and any parameter of renal water excretion. Our study shows that the stress of a serious illness and of admission to an ICU does not seem to interfere, by itself, with osmotic regulation of AVP secretion and renal diluting ability, and that sympathetic activation is not, under such circumstances, a predominant stimulus for AVP release.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Fiberoptic bronchoscopy in ventilated patients. Evaluation of cardiopulmonary risk under midazolam sedation.

One hundred seven acutely ill ventilated patients were prospectively studied to ascertain the severity and frequency of alterations in gas exchange and hemodynamic parameters during brief bronchoscopy. Sedation was performed using midazolam (0.1 mg/kg IV) without topical anesthesia. An average decline in PaO2 of 26 percent was observed at the end of the procedure, compared to the baseline value, and this was associated with a mild increase in PaCO2 in spite of the use of a special adapter. Alterations in mean systolic blood pressure appeared to be modest, consisting of a 10 percent decrease from the control level, related to sedation, and a 10 percent rise from baseline during the procedure, associated with a concomitant mild tachycardia. At that time, central hemodynamic measurements performed in a subset of 31 patients showed a significant increase in cardiac output associated with higher pulmonary wedge pressure. Fourteen patients developed hypoxemia of less than 60 mm Hg on FIO2 adjusted to 0.8. Of the ten risk factors univariately associated with hypoxemia, only the presence of ARDS (p less than 0.001) and "fighting" the ventilator during the procedure (p less than 0.05) remained significant after stepwise logistic regression. Attempts to prevent hypoxemia in critically ill patients should focus on inducing complete sedation, with careful attention to hemodynamic status, or providing maximal levels of oxygen to the ventilator (or both).

Adult↗
PubMed1989

Tall T waves during metabolic acidosis without hyperkalemia: a prospective study.

The specific ECG characteristics of metabolic acidosis have not been satisfactorily defined in man. We addressed this question by prospectively studying 14 consecutive patients admitted with metabolic acidosis and without hyperkalemia. Arterial blood gas analysis and serum potassium determinations were performed during acidosis and after its correction. ECGs were recorded at the same times. Mean pHa increased from 7.11 +/- 0.05 to 7.40 +/- 0.01 (p less than .001) in response to an increase in total CO2 content from 6.8 +/- 1.4 to 21.2 +/- 0.7 mmol/L (p less than .001). Serum potassium concentration decreased only slightly after correction of the acidosis from 4.2 +/- 0.1 to 3.9 +/- 0.14 mmol/L (p less than .05). T waves were taller during acidosis than after correction (0.68 +/- 0.1 vs. 0.28 +/- 0.04 mV, p less than .001 and 0.64 +/- 0.08 vs. 0.38 +/- 0.04, p less than .005, in precordial leads V2 and V3, respectively). Moreover, the amplitude of T waves in V2 was correlated positively with the arterial concentration of H+ (r = .786, p less than .001) and negatively with the arterial total CO2 content (r = -.71, p less than .005). In addition to their augmented amplitude, T waves were peaked and symmetrical with a narrow base ("tent-shaped"). Thus, metabolic acidosis may be accompanied by an increase in the amplitude of T waves, even in the absence of hyperkalemia.

Acid-Base Equilibrium↗
PubMed1988

High inflation pressure pulmonary edema. Respective effects of high airway pressure, high tidal volume, and positive end-expiratory pressure.

The respective roles of high pressure and high tidal volume to promote high airway pressure pulmonary edema are unclear. Positive end-expiratory pressure (PEEP) was shown to reduce lung water content in this type of edema, but its possible effects on cellular lesions were not documented. We compared the consequences of normal tidal volume ventilation in mechanically ventilated rats at a high airway pressure (HiP-LoV) with those of high tidal volume ventilation at a high (HiP-HiV) or low (LoP-HiV) airway pressure and the effects of PEEP (10 cm H2O) on both edema and lung ultrastructure. Pulmonary edema was assessed by extravascular lung water content and microvascular permeability by the drug lung weight and the distribution space of 125I-labeled albumin. HiP-LoV rat lungs were not different from those of controls (7 cm H2O peak pressure ventilation). By contrast, the lungs from the groups submitted to high volume ventilation had significant permeability type edema. This edema was more pronounced in LoP-HiV rats. It was markedly reduced by PEEP, which, in addition, preserved the normal ultrastructural aspect of the alveolar epithelium. This was in striking contrast to the diffuse alveolar damage usually encountered in this type of edema. To our knowledge, this constitutes the first example of a protective effect of PEEP during permeability edema.

Animals↗
PubMed1988

Acute infectious pneumonia is accompanied by a latent vasopressin-dependent impairment of renal water excretion.

The mechanism of hyponatremia associated with pneumonia has not been definitely established. Moreover, renal water excretion was never systematically investigated in cases of pneumonia without hyponatremia. We therefore studied nine consecutive patients breathing spontaneously (nasal oxygen in five), with acute infectious pneumonia and normal plasma sodium concentration. All the patients were previously healthy. Water loads were administered during illness and after recovery. Extracellular fluid volume, arterial blood pressure, PaO2, and PaCO2 were identical during and after pneumonia. By contrast, renal water excretion was markedly impaired during pneumonia and returned to normal values after recovery. This was attested to by a significant decrease in minimum urine osmolality together with significant increases in the percentage of the excreted water load and the maximum free water clearance, after resolution of the pneumonia. Plasma arginine vasopressin values were significantly higher during pneumonia than after recovery despite similar plasma sodium concentrations, both before and after water load. A positive correlation between plasma arginine vasopressin and minimum urine osmolality was found during pneumonia. Thus, impairment in renal water excretion appeared to be due to resetting of the vasopressin osmostat and could not be attributed to any recognized nonosmotic stimulus for vasopressin secretion. On the other hand, these defects varied in severity depending on the extent of the pneumonia and persisted until clearing of alveolar opacities, accounting for their protracted course in some patients. We conclude that water excretion is impaired in most if not in all patients with acute infectious pneumonia (especially if extended), and that the administration of hypotonic solutions should be avoided in these patients.

Acute Disease↗