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Biomedical subjects

F Coste

Publications and source records attributed to F Coste.

At least 19 recordsLinked to original sources
PubMed1995

Changing heat and moisture exchangers every 48 hours rather than 24 hours does not affect their efficacy and the incidence of nosocomial pneumonia.

Heat and moisture exchangers (HME) (Dar-Hygrobac II, Peters) can safely be used every 24 h for long-term mechanical ventilation and provide a cost-saving alternative to heated humidifiers. We have prospectively determined whether changing HMEs every 48 h only affects their clinical and bacteriological efficiency in a series of consecutive nonselected ICU patients requiring long-term mechanical ventilation. Two consecutive periods were compared. During period 1, HMEs were replaced every day; during period 2, they were changed every 48 h. Patients from the two periods were similar in terms of age and indication for and overall duration of MV (10 +/- 8.6 versus 10 +/- 9 d, p = 0.9). Minute ventilation and maximum values for peak airway pressure were identical during the two periods. These values were also identical after 1 and 2 d of HME use during period 2, indicating that HME resistance was not increased by prolonged use. Obstruction of the tracheal tube occurred only once in a period 1 patient. The results of quantitative cultures indicate that the maximum and mean levels of bacterial colonization during the two periods were similar for the pharynx, trachea, Y-connector, patient, and ventilator side of the HME. More importantly, the incidence of nosocomial pneumonia was similar during the two periods (6/61 versus 8/68, p = 0.7). Thus, prolonged HME use is safe and provides a substantial reduction in the cost of mechanical ventilation.

Adult↗
PubMed1995

Mechanical ventilation with heated humidifiers or heat and moisture exchangers: effects on patient colonization and incidence of nosocomial pneumonia.

The contribution of ventilator circuit bacterial contamination to the occurrence of ventilator-associated pneumonia remains controversial. In a previous study, we found that the incidence of pneumonia was identical with ventilator circuit changes every 48 h and with no ventilator circuit changes. The present study prospectively assessed whether keeping ventilator circuits clean with a heat and moisture exchanger exhibiting antimicrobial barrier properties affects patient colonization and the incidence of nosocomial pneumonia in patients receiving mechanical ventilation for more than 48 h. Consecutive patients were randomly allocated to humidification with either a heat and moisture exchanger (Group 1, n = 61) or a heated humidifier (Group 2, n = 70). In both groups, no circuit changes were performed throughout ventilatory support. Duration of mechanical ventilation was identical in both groups (10 +/- 8.6 d (range: 2 to 47) in Group 1 and 12.5 +/- 14.2 d [range: 2 to 85] in Group 2). The incidence of pneumonia (positive quantitative culture of protected brush specimen) was similar in both groups (6/61 and 8/70 in Groups 1 and 2, respectively; p = 0.8), as was duration of ventilation prior to pneumonia (9 +/- 5.9 versus 8.2 +/- 5.7 d; p = 0.8). Ventilator tubing contamination was considerably reduced with the use of a heat and moisture exchanger. In contrast, bacterial colonization of the pharynx and trachea was identical in both groups. These results suggest that circuit colonization plays little or no role in the occurrence of ventilator-associated pneumonia, provided usual maintenance precautions are applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Use of cross-reactive antigens of the microsporidian Glugea atherinae for the possible detection of Enterocytozoon bieneusi by western blot.

The microsporidia Enterocytozoon bieneusi is reported in 10-30% of those infected with the human immunodeficiency virus. The parasite appears to be a cause of gastralgia, malabsorption, and diarrhea. A Western blot technique using another microsporidian species, Glugea atherinae, has demonstrated an antigenic similarity between this parasite and E. bieneusi. Preliminary results show the variability of the antigenic profiles obtained from the sera of immunodeficient patients infected with E. bieneusi and also of the cross-reactivity to Glugea sp. antigens of some sera from patients with cryptosporidiosis. The origin of this cross-reactivity is undetermined. The possibility of coinfection with undetected microsporidia is not excluded. These results raise questions concerning the interpretation of serologic data and of the potential immunodiagnostic value of microsporidian antigens.

AIDS-Related Opportunistic Infections↗
PubMed1992

Loma camerounensis sp. nov. (Protozoa:Microsporida) a parasite of Oreochromis niloticus Linnaeus, 1757 (Teleost:Cichlidae) in fish-rearing ponds in Melen, Yaoundé, Cameroon.

A new microsporidian, Loma camerounensis, was found in the Cichlidae Oreochromis niloticus from the Melen fish-rearing station in Yaoundé, Cameroon. Xenomas were located in the gut from the oesophagus to the intestine, but preferentially in the duodenum. Dimensions of the fresh spores were 3.96 x 2.16 microns. The ultrastructural study indicated the following characteristics: parasite stages arranged in a random, unstratified manner in the xenoma; merogony by multiple fission; sporogonic stages isolated within a sporophorous vesicle containing several sporoblasts and polysporoblastic sporogony. Ultimately the spores appeared to be isolated in a single vesicle, but this was a secondary phenomenon induced by the intervention of tubules that resolved in partitions of the initial sporophorous vesicle.

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

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↗
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

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↗
PubMed1985

[Fatal massive intravascular coagulation during phlebography. Responsibility of epsilon-aminocaproic acid?].

The occurrence during phlebography of massive intravascular coagulation involving the inferior vena cava, the right cardiac cavities and the entire pulmonary arterial network suggested that epsilon-aminocaproic acid administered before phlebography was responsible for this complication. The mechanisms of reactions to contrast media are still poorly understood, but these reactions are known to include, in some cases, disseminated intravascular coagulation. This phenomenon was histologically demonstrated in our patient, and it may be suggested that its strong enhancement by the antifibrinolytic agent had resulted in the fatal accident. In view of the possibility of such lethal reactions, the advisability of administering epsilon-aminocaproic acid--a drug widely used in France for the prevention and treatment of contrast media reactions--should be reconsidered.

Adult↗
PubMed1984

[Life cycle of Leranthropus kroyeri Van Beneden 1851, hematophagous branchial copepod of the sea bass Dicentrarchus labrax (Linné, 1758) in wild and experimental populations].

The life cycle of Lernanthropus kroyeri Van Beneden, 1851, copepod (Siphonostomatoida) parasite of Dicentrarchus labrax is described. The cycle comprises two nauplii, one infective copepodid, four fixed copepodids and one preadult. All the attached stages are caracterised by the lack of the frontal filament. This is the first description of a life cycle lacking a chalimus for Siphonostomatoida Copepods parasitic on fish.

Animals↗