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Biomedical subjects

Y Domart

Publications and source records attributed to Y Domart.

At least 37 records · Page 2Linked to original sources

Pharmacokinetics of cefodizime in elderly patients with moderate or severe renal impairment.

In young adults, the elimination half-life of cefodizime is 3.5-4 h. A pharmacokinetic study was performed in eight patients, aged 63 to 85 years, divided into two groups with the following creatinine clearances (group I: greater than or equal to 50 ml/min and group II: less than 30 ml/min). Cefodizime was administered as a 1.0-g iv bolus. In group I, pharmacokinetic parameters did not differ from those observed in young healthy volunteers in a previous study. In group II, the half-life was increased (3.42-7.41 h). There is a linear correlation between the creatinine clearance and total clearance. The daily dose given needs to be based not on the age of the patient but on the degree of renal impairment. In elderly patients with severe renal impairment, the daily dose should be reduced if the creatinine clearance falls below 30 ml/min.

Adult↗

Characterization of distal bronchial microflora during acute exacerbation of chronic bronchitis. Use of the protected specimen brush technique in 54 mechanically ventilated patients.

To obtain accurate information on distal bronchial microflora during acute exacerbation in patients with chronic bronchitis, we prospectively studied 54 such patients who had been receiving mechanical ventilation because of hypercapnic respiratory failure. Fiberoptic bronchoscopy using a protected specimen brush (PSB) was performed on each patient within the first 24 h after admission. Cultures of protected brush specimens demonstrated no growth in 27 patients (50%). With the exception of fever (38.2 +/- 0.8 versus 37.7 +/- 0.6 degrees C; p less than 0.05), the initial severity of the episode of exacerbation was similar in patients with and without infection. A total of 44 organisms were isolated in the 27 patients with positive cultures; the predominant pathogens were Hemophilus spp. and Streptococcus spp. (involved in 74% of cases), but other organisms were isolated in 12 of 27 patients. Mortality rates, duration of mechanical ventilation, and duration of hospitalization were not significantly different between patients with bronchial microflora treated with appropriate antimicrobial therapy (n = 27) and patients without bronchial microflora either receiving empirical antibiotic therapy (n = 18) or not (n = 9). These data suggest that distal bronchial infection due to the usual pathogens, as far as shown by protected specimen brush cultures, may not be the sole or even the predominant cause of acute exacerbation of chronic bronchitis in patients requiring mechanical ventilation.

Acute Disease↗

Incidence and morbidity of cytomegaloviral infection in patients with mediastinitis following cardiac surgery.

To determine the incidence and morbidity of infections with CMV associated with mediastinitis after conventional cardiac surgery, 115 consecutive adult patients with mediastinitis were evaluated with viral cultures of blood and urine. Shedding of CMV was seen in 29 patients (25 percent) within a mean period of 37 +/- 22 days after cardiopulmonary bypass. Viremia was documented in 79 percent (23) of these 29 patients. Acute renal failure and enzymatic abnormalities (AST and LDH) were significantly more common in patients with virologically proven infection with CMV (p less than 0.05). In patients who survived the initial period of bacterial infection, major differences in their clinical course were observed according to their virologic status. After the 15th day of hospitalization following the débridement, the persistence of local infection was more frequent (p less than 0.05) and the mortality was higher (p less than 0.01) in CMV-infected patients. Moreover, the mean duration of hospitalization in the ICU for survivors was 69 +/- 36 days in viral shedders, compared with 48 +/- 27 days in nonshedders (p less than 0.05). Infection with CMV in mediastinitis occurs frequently and is associated with persistence of local infection, prolonged hospitalization, and increased late mortality.

Antibodies, Viral↗

Diagnosis of nosocomial pneumonia in intensive care unit patients.

The optimal technique for diagnosing nosocomial bacterial pneumonia in critically ill patients cared for in the intensive care unit remains unclear, especially in the subgroup of patients requiring mechanical ventilation. An important advance has been the development of the protected specimen brush technique. We and others have demonstrated that secretions obtained using this technique and evaluated by quantitative cultures are useful in distinguishing patients with and without pneumonia. However, this procedure has important limitations in that results are not available immediately and in that a few false negative or false positive results may be observed. Recently, the use of bronchoalveolar lavage has been suggested to be of value in establishing the diagnosis of pneumonia, since the cells and liquid recovered can be examined microscopically immediately after the procedure and are also suitable for quantitative culture. We believe that microscopic identification of bacteria within cells recovered by lavage may provide a sensitive and specific means for early and rapid diagnosis of pneumonia in this setting and that the lavage technique can be conveniently incorporated into a protocol along with the quantitative culture of samples obtained using the protected specimen brush. This combination will probably improve the overall accuracy of diagnosis while allowing the administration of prompt empiric antimicrobial therapy in the majority of patients with pneumonia.

Cross Infection↗

Study of the effects of liposomal amphotericin B on Candida albicans, Cryptococcus neoformans, and erythrocytes by using small unilamellar vesicles prepared from saturated phospholipids.

We compared the anticellular effects of liposomal amphotericin B (AmB) formed from AmB and small unilamellar vesicles. The small unilamellar vesicles with or without cholesterol were prepared from three L-alpha-phosphatidylcholines with saturated acyl chains of different lengths: distearoyl (C18), dipalmitoyl (C16), and dimyristoyl (C14). We found that the anticellular potency of liposomal AmB, compared with that of free AmB, decreased with decreasing length of the acyl chain of the phospholipid and increased with the addition of cholesterol. In a parallel study (S. Jullien, A. Vertut-Croquin, J. Brajtburg, and J. Bolard, Anal. Biochem. 172:197-202, 1988), we found that binding of AmB to vesicles decreased with increasing length of the acyl chain of the phospholipid and decreased with the addition of cholesterol. We conclude that the anticellular effects of liposomal AmB preparations are due to the levels of AmB remaining free (unbound to the lipids) in these preparations.

Amphotericin B↗

Nosocomial pneumonia in patients receiving continuous mechanical ventilation. Prospective analysis of 52 episodes with use of a protected specimen brush and quantitative culture techniques.

Epidemiologic studies of nosocomial bacterial pneumonia in patients requiring mechanical ventilation have been limited because of the poor reliability of diagnosis procedures in this setting. To determine prognostic and descriptive factors of ventilator-associated (V-A) pneumonia, we prospectively studied 567 patients who had been receiving mechanical ventilation for more than 3 days in our unit. Fiberoptic bronchoscopy using a protected specimen brush (PSB) was performed on each patient suspected of having pneumonia because of the presence of a new pulmonary infiltrate and purulent tracheal secretions. The diagnosis of V-A pneumonia was retained only if PSB specimens yielded greater than 10(3) cfu/ml of at least one microorganism, unless this result was established to be a false positive result on follow-up. V-A pneumonia developed in 49 patients for a total of 52 episodes (9%). The actuarial risk of V-A pneumonia was 6.5% at 10 days, 19% at 20 days, and 28% at 30 days of ventilation. Patients with pneumonia were significantly older (65 versus 57 yr of age, p less than 0.01) and more frequently had severe underlying illnesses (24 versus 10%, p less than 0.01) than did patients without pneumonia. A total of 84 microorganisms (51 gram-negative and 33 gram-positive) were isolated in significant concentrations from PSB specimens. Pseudomonas aeruginosa and Staphylococcus aureus were involved in 31 and 33% of these pneumonias, respectively. Forty percent of all specimens yielded a polymicrobial flora with more than one potential pathogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Diagnosis of nosocomial bacterial pneumonia in intubated patients undergoing ventilation: comparison of the usefulness of bronchoalveolar lavage and the protected specimen brush.

PURPOSE: To compare the usefulness of specimens recovered using a protected specimen brush and those recovered by bronchoalveolar lavage in the diagnosis of nosocomial pneumonia occurring in intubated patients undergoing ventilation, we performed both procedures in patients suspected of having pneumonia because of the presence of a new pulmonary infiltrate and purulent tracheal secretions. PATIENTS AND METHODS: Twenty-one patients (16 men and five women) with an average age of 57 +/- 12 years were studied. They had been receiving mechanical ventilation for 8 +/- 6 days before inclusion in the trial. The clinical suspicion for nosocomial bacterial pneumonia was high in these patients. Fiberoptic bronchoscopy was performed in each patient. Bronchoscopy specimens were obtained by a protected specimen brush and by bronchoalveolar lavage, and were then processed for quantitative bacterial and fungal culture using standard methods. Total cell counts were performed on an aliquot of resuspended original lavage fluid. Differential cell counts were made on at least 500 cells. In addition, 300 cells were examined at high-power magnification and the percentage of cells containing intracellular microorganisms and the average number of extracellular organisms per oil-immersion field were determined. RESULTS: Quantitative culture of specimens recovered using the protected specimen brush were positive (more than 10(3) colony-forming units [cfu]/ml) in five of five patients with subsequently confirmed pneumonia, and negative (less than 10(3) cfu/ml) in 13 of 13 patients without bacterial pneumonia, but results were not available until 24 to 48 hours after the procedure. Quantification of intracellular organisms in cells recovered by lavage was also useful in distinguishing patients with pneumonia (more than 25 percent of cells with intracellular organisms in five of five patients) from those without pneumonia (less than 15 percent of cells with intracellular organisms in all cases), and results were available immediately. In contrast, quantitative culture of lavage fluid and differential cell counts were of little value in identifying infected patients. CONCLUSION: The protected specimen brush and microscopic identification of intracellular organisms in cells recovered by lavage yield useful and complementary information, and together permit rapid and specific treatment of most patients with nosocomial pneumonia.

Bacteria↗

Detection of nosocomial lung infection in ventilated patients. Use of a protected specimen brush and quantitative culture techniques in 147 patients.

To determine the usefulness of samples obtained by bronchoscopy using a protected specimen brush and evaluated by quantitative culture techniques in establishing the diagnosis of nosocomial pneumonia in patients requiring mechanical ventilation, we prospectively studied 147 ventilated patients suspected of having nosocomial pneumonia because of the presence of a new pulmonary infiltrate and purulent tracheal secretions. Positive cultures of protected brush specimens (greater than 10(3) cfu/ml) were found in only 45 patients (31%). Subsequent follow-up confirmed the diagnosis of pneumonia in 34 of 45 patients, and in only 4 of 45 patients was a positive culture firmly established to be a false positive result. No patient with less than 10(3) cfu/ml was subsequently shown to have had pneumonia, and the diagnosis was definitely excluded in 72 of 102 patients by the absence of pneumonia at autopsy or recovery without antibiotic therapy. In contrast, when 16 clinical variables were evaluated by stepwise logistic regression analysis, no combination could be identified that was useful in distinguishing patients with bacterial pneumonia. Furthermore, when the actual costs of evaluation and therapy of our patients were compared with the projected costs entailed in treating all patients suspected of having pneumonia with antibiotics, evaluation using the protected specimen brush and quantitative cultures was less expensive after only 6 days of treatment. These results suggest that the appearance of pulmonary infiltrates and purulent tracheal secretions does not result from bacterial pneumonia in a majority of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Pharmacokinetics of teicoplanin in critically ill patients with various degrees of renal impairment.

The pharmacokinetics of teicoplanin were studied in 15 adult patients in the acute phase of severe infections caused by gram-positive cocci. All the subjects were given a daily intravenous bolus dose of 6 mg of teicoplanin kg-1 (body weight). The pharmacokinetic study was performed over a 48-h period after injection 4. The subjects were categorized according to their mean creatinine clearances (ml.min-1.kg-1) during the study period: group 1 (n = 3), greater than 1.6; group 2 (n = 6), 0.8 to 1.6; and group 3 (n = 6), 0.15 to 0.8. Mean concentrations of teicoplanin in serum at 1, 24, and 48 h were 33 +/- 8, 9 +/- 3, and 6 +/- 2.5 micrograms.ml-1, respectively. The mean half-lives of the concentration-time curve from 12 to 48 h were 28 +/- 4, 44 +/- 24, and 48 +/- 14 h in groups 1, 2, and 3, respectively (group 3 versus group 1: P less than 0.05). The mean area under the serum concentration-time curve from time zero to 24 h was 344 +/- 92 mg.h.liter-1, and the mean hybrid volume of distribution was 1.09 +/- 0.46 liter.kg-1. These values were similar for the three groups, with a trend for larger areas under the curve in group 3. Creatinine clearance correlated directly with the total body clearance of teicoplanin (r = 0.70) and with the renal clearance of teicoplanin (r = 0.82). However, in critically ill patients, the wide interindividual variations in pharmacokinetic parameters are more relevant than those related to the variations in renal function when creatinine clearance is above 0.30 ml.min-1.kg-1. We concluded that, in such conditions, monitoring of concentrations of teicoplanin in serum is mandatory.

Adolescent↗

[Urinary tract obstruction by Candida bezoars, or fungus balls].

Two patients admitted to an intensive care unit for severe bacterial infection develops Candida albicans superinfection with obstruction of the urinary canals by "fungus balls". The development of medico-surgical techniques using antibiotics and immunosuppressive drugs accounts for the increasing incidence of disseminated candidiasis. The kidneys are particularly sensitive to Candida infections. Fungus balls are conglomerates of mycelium which may result in obstruction of the urinary tract. Their clinical, radiological and ultrasonic features, as well as the microbiological and serological diagnostic problems they raise are described. Ultrasonically guided percutaneous nephrostomy is a very interesting technique for the diagnosis of the condition and its local treatment by drainage and lavage with amphotericin B. This antifungal, combined with flucytosine is still used for the systemic treatment of candidiasis.

Aged↗

Pharmacokinetic and pharmacodynamic interactions between nifedipine and propranolol or betaxolol.

Pharmacokinetic and pharmacodynamic interactions between nifedipine and two beta-blocking agents were investigated. Eighty mg propranolol twice daily, and 20 mg betaxolol once daily, were randomly administered orally to six young healthy male volunteers, either singly for four days, or combined with nifedipine for the two subsequent days. Nifedipine had similar effects on the pharmacodynamics of both drugs. Nifedipine significantly enhanced propranolol bioavailability and Cmax, but reduced its tmax, in three out of six subjects who were also good absorbers of beta-blockers when taken alone. These effects might be due to enhanced intestinal absorption and/or enhanced first-pass effect, induced by nifedipine.

Adrenergic beta-Antagonists↗