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Biomedical subjects

P Ramon

Publications and source records attributed to P Ramon.

At least 37 records · Page 2Linked to original sources
PubMed1996

Obstructive lesions of the central airways: evaluation by using spiral CT with multiplanar and three-dimensional reformations.

The purpose of this study was to assess the accuracy of transverse CT scans as well as multiplanar (MPR) and three-dimensional (3D) reconstructions in the evaluation of obstructive lesions of the central airways. A total of 64 patients were evaluated for the presence of obstructive lesions of the central tracheobronchial tree with transverse spiral CT scans, multiplanar reformations (MPRs), 3D shaded surface displays (3D SSDs) and minimum intensity projections (MIPs). The findings of these modalities were then compared with those obtained at bronchoscopy. The severity, length, and shape of airway narrowing were analyzed comparatively on the four sets of images. Transverse CT scans and MPRs had a similar accuracy (99%) in detecting obstructive airway lesions. The accuracy of both was significantly higher than that of 3DSSDs (90%, p < 0.05) and MIPs (81%; p < 0.01). There was no statistically significant difference between the four imaging modalities in the analysis of the morphology of airway stenoses. Symmetric stenoses were similarly analyzed on the four sets of images, whereas MPRs and MIPs failed to depict accurately simple and complex asymmetric stenoses. Transverse CT scans are accurate in the depiction of obstructive lesions of the central airways and may be complemented by MPRs and/or 3DSSDs in their morphologic evaluation.

Adolescent↗
PubMed1996

Relationship between microbiologic and histologic features in bacterial pneumonia.

To investigate the relationship between the lung damage resulting from pneumonia and the local bacterial burden, we conducted a study comparing histologic and bacteriologic findings in pigs infected with bacterial pneumonia while free of antibiotic therapy and previous or concomitant lung disease. Seventy-eight lung specimens were obtained from 17 animals. The main findings are the following: (1) histologic lesions of pneumonia as well as parenchymal bacterial burden were unevenly distributed within the lungs and even within the lung segments; (2) specimens showing histologic evidence of pneumonia had significantly higher bacterial counts than specimens with bronchial infection and specimens with neither bronchial nor lung infection; (3) there was no significant difference in bacterial counts between lesions defined as pneumonia, confluent pneumonia and abscessed pneumonia; (4) we could not define a clearcut threshold for quantitative cultures to discriminate the presence or absence of pneumonia. This study providing experimental insights into the relationship between microbiologic and histologic features in bacterial pneumonia confirms previous findings in humans. Although, for investigational purpose, lung cultures can be helpful in determining the bacterial etiology of pneumonia, these data do not support the use of quantitative cultures for establishing a definite diagnosis of pneumonia.

Animals↗
PubMed1995

Experimental models of tracheobronchial stenoses: a useful tool for evaluating airway stents.

BACKGROUND: Stent implantation is a conservative alternative to open operation for treating benign tracheobronchial strictures. Most of the presently available stents were primarily designed for endovascular use. Their respiratory use entails a risk of iatrogenic complications. From a scientific and from an ethical point of view these risks justify preclinical evaluation of new respiratory stents in experimental models of central airway stenoses. Therefore, an attempt was made to develop such models in piglets and adult minipigs. METHODS: Tracheal stenoses were obtained by creating first a segmental tracheomalacia through extramucosal resection of cartilaginous arches. The fibrous component of the stenoses was then obtained through bronchoscopic application of a caustic agent causing progressive deep mucosal and submucosal injury. Stenoses of the main bronchi were created by topical application of the caustic agent only. RESULTS: These models demonstrated the typical features of benign fibromalacic tracheobronchial stenoses with constant recurrence after mechanical dilation. Preliminary experiments showed that short-term problems of tolerance of stent prototypes are easily demonstrable in these models. CONCLUSIONS: These experimental models, which simulate quite realistically human diseases, offer the opportunity to perfect new tracheobronchial stents specifically designed for respiratory use and to evaluate their long-term tolerance before their use in humans.

Animals↗
PubMed1995

[Vascular tracheal compression presenting as bronchiolitis in infants].

BACKGROUND: Anomalies of the aortic arch and pulmonary arteries may produce compression of the trachea with chronic stridor or wheezing aggravated by crying, feeding and flexion of the neck. CASE REPORTS: Three infants, 3, 5 and 2 months-old, respectively, were admitted suffering from acute bronchiolitis. The first patient had intermittent wheezing for one month; lateral chest X-rays showed an opaque area inserted between the trachea and oesophagus and computed tomography showed pulmonary artery sling with tracheal stenosis which was successfully operated. The second patient displayed pulmonary atelectasia which required bronchoscopy; this technique showed tracheal stenosis which was due to pulmonary artery sling. The third patient had a history of congenital stridor: he required endotracheal intubation; a bronchoscopy performed because persistent pulmonary atelectasia showed tracheal stenosis which was secondary to a double aortic arch. The condition was improved after surgical correction. CONCLUSIONS: A history of stridor and/or wheezing in patients admitted for bronchiolitis must lead to consider the possibility of vascular compression of the trachea and to perform specific investigations.

Aorta, Thoracic↗
PubMed1995

Diagnostic tests for pneumonia in ventilated patients: prospective evaluation of diagnostic accuracy using histology as a diagnostic gold standard.

The diagnostic accuracy of protected-specimen brush (PSB), bronchoalveolar lavage (BAL), and endotracheal aspirates (EA) was prospectively evaluated in a series of 28 mechanically ventilated patients (MV patients) who died within 3 d of the bronchoscopic procedure, using postmortem lung examination as the gold standard for establishing the diagnosis of pneumonia. The entire fixed lungs were carefully dissected along the bronchovascular axes and each segment was cut into 5- to 10-mm thick sections, enabling gross examination of the lung parenchyma. Two tissue blocks were taken from each segment, including grossly abnormal areas whenever present. In several cases, two peripheral (subpleural) lung-tissue blocks were also taken from each lobe prior to systematic dissection of the lungs. Quantitative cultures (QC) and direct cytologic and microbiologic examination (DE) was performed on respiratory samples obtained within 72 h before death. Values of 10(3) cfu/ml of Ringer's solution, 10(4) cfu/ml of retrieved fluid, and 10(6) cfu/ml of respiratory secretions were used as cutoff points for quantitative PSB, BAL, and EA cultures, respectively. The main findings in this study were that: (1) Pneumonia was present in 67% of the patients. (2) Histologic lesions of pneumonia were mainly bilateral and predominated in the dependent lung segments. (3) Coexistence of a variety of noninfectious processes was a common finding in patients with pneumonia. (4) In several cases pneumonia was absent from peripheral lung samples while more central areas of the same segment displayed typical foci of pneumonia. (5) The sensitivity of quantitative cultures was 55%, 57%, and 47% for EA, PSB, and BAL, respectively, and the specificity was 85%, 88%, and 100%, respectively. Reducing the diagnostic threshold of EA to 10(5) cfu/ml of respiratory secretions instead of 10(6) cfu/ml resulted in a sensitivity of 63.1% and a specificity of 75% for EA. The sensitivity of direct examination (DE) was 50%, 47%, and 47%, respectively, and the specificity was 75%, 88%, and 87%. (6) The presence of intracellular organisms (ICO) in BAL had a 36.8% sensitivity and 100% specificity in establishing the diagnosis of pneumonia regardless of their percentage. (7) Although 15 patients (53%) were not on antibiotics or were off antibiotics for more than 48 h before testing, no relationship could be established between the patients' antibiotic status and the result of any diagnostic test. By using a recommended methodology for respiratory sampling techniques together with complete postmortem lung examination as a diagnostic "gold standard," this study provides a realistic insight into the diagnostic values of EA, PSB, and BAL in MV patients with suspected pneumonia.

Biopsy↗
PubMed1995

Pleural amyloidosis: thoracoscopic aspects.

We describe the case of a 60 year old man with primary amyloidosis, who suffered from peripheral neuropathy and cardiomyopathy and who presented with recurrent right pleural effusion. For this reason, he was admitted to hospital for thoracoscopic examination with pleurodesis. Macroscopic examination of the parietal pleura revealed a diffuse inflammation and light brown deposits that where covered with nodules. Biopsy specimens confirmed the amyloid deposition. This macroscopic appearance is described for the first time, and suggests that a local pleural synthesis of amyloid substance may occur during the course of systemic amyloidosis.

Amyloidosis↗
PubMed1995

[Endoscopic treatment of post-intubation tracheal stenosis. Apropos of 58 cases].

Over a period of 6 years, 58 patients aged between 55 +/- 16 years have been treated for post-intubation tracheal stenosis (STPI). These patients were characterised by their frequency of an underlying respiratory or cardiac failure, a duration of intubation which was sometimes short and a delay between the extubation and the detection of stenosis which was les than one month in about one half of the cases. Thirty of the 58 patients presented with respiratory distress on admission. All the stenoses were treated initially by mechanical dilatation using a rigid bronchoscope. Radial incisions using an Nd-Yag laser were performed when necessary to facilitate the dilatation. The great majority of stenoses which were not fitted up with a tracheal endoprosthesis (EPT) at the first attempt recurred, leading to repeated therapeutic bronchoscopies (221 sessions in all). Fitting an EPT (Dumon prosthesis) was necessary in 35 cases on 12 occasions at the first attempt with the first bronchoscopy, and 23 times following a recurrence. Amongst the recurring stenoses a stabilisation was obtained at the price of repeated dilatations (4.3 sessions on average in only nine patients). Seven patients finally had a surgical resection and anastamosis of the trachea, of whom four had a transitory instillation of an EPT for the stenosis. The removal of the EPT was later attempted in 11 patients. Four did not present with any symptomatic recurrence. The secondary migration of the EPT is in practice one of the main inconveniences of the silicon prosthesis (8 cases now experienced). Our approach, which used to favour the mechanical dilatation has lead to a relatively high number of failures and thus to repeated bronchoscopies. This has lead us to re-define our therapeutic approach. The current schema which we propose is in the course of being validated in which we use EPT and surgical repair of the trachea more often. Only short stenoses (less than 1 cm) with a diaphragm are treated by dilatation and laser. The others are fitted initially with an EPT. The final management is guided by the progress in the stenosis, the tolerance of the endoprosthesis and the operability of the patients.

Adolescent↗
PubMed1994

Diagnostic value of direct examination of the protected specimen brush in ventilator-associated pneumonia.

Interpretation of the protected specimen brush (PSB) technique is based on quantitative bacterial cultures (QC), which unfortunately requires at least 24 h. We prospectively compared the diagnostic value of direct examination (DE) and QC of PSB specimens in 75 patients with suspected pneumonia. We also determined the optimal technique for DE. QC was performed using the serial dilution technique. From the original suspension, two cytospin slides were obtained and stained by the May-Grünwald Giemsa (MGG) and the Gram method for DE. If the prescreening on the MGG-stained slide was positive, the morphology and the Gram staining of the organisms were assessed on the Gram-stained slide. Using the 10(3) colony forming units (cfu.ml-1) threshold for defining PSB as positive or negative, DE had a sensitivity of 85% and a specificity of 94%. In a parallel in vitro study, 18 pairs of PSB specimens were collected from respiratory secretions inoculated with S. aureus. From each pair, one brush was processed as described above and the other was smeared on a glass slide prior to performance of QC. Using direct smear instead of cytocentrifuged preparation, slightly but significantly affected QC. Direct examination of cytospin slides is highly predictive of quantitative bacterial culture results, and provides rapid information regarding the Gram-stain morphology of the causative organisms. It may therefore guide initial therapy.

Adolescent↗
PubMed1994

[Treatment with intermittent high dosage corticotherapy in chronic interstitial pneumonia in an infant. A case report].

Chronic interstitial pneumonia (PIC) are rare in infants. We report a case of an infant who presented with a chronic interstitial pneumonia following an infection with a respiratory syncytial virus. The diagnosis was confirmed histologically (open lung biopsy). The failure of oral steroid therapy (Prednisolone 2 mg/kg/day) led to the use of boluses of methylprednisone (30 mg/kg/day, daily for three days in three series one month apart). The treatment led to a progressive improvement and thirty months after the last bolus the respiratory examination was normal as was the radiology. The efficacy of bolus steroid therapy observed by other authors should be confirmed in multicentre trials using surgical biopsy to precise the pulmonary lesions.

Administration, Oral↗
PubMed1994

Determinants of response to immunosuppressive therapy in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) response to corticosteroids and cytotoxic medications appears to be the most important determinant of survival. The purpose of this retrospective study was to analyse the determinants of response to immunosuppressive therapy with prednisone alone, or prednisone and cyclophosphamide, in IPF. Twenty five consecutive patients were studied. Initial evaluation in untreated patients included clinical, biological and functional parameters. Sequential evaluation by pulmonary function tests (forced vital capacity (FVC) and transfer factor of the lungs for carbon monoxide (TLCO)) was performed at a 3 month interval. Response to therapy was defined as an improvement in FVC and/or TLCO of more than 10% after 12 months, with maintenance of this improvement for at least another 12 months. Twelve of the 25 patients were classified as responders. A symptomatic disease of less than 12 months duration before onset of therapy related to response. FVC was more impaired in the group of responders when the comparison was limited to patients with an FVC of less than 90%. Bronchoalveolar lavage cell counts were not significantly different between responders and non-responders. Assessment of pulmonary function after 3 months of treatment was predictive of maintenance of the response or of even further improvement. Patients with improved FVC after 3 months of therapy had a significantly shorter symptomatic disease before onset of treatment (7.6 +/- 7.1 vs 20.2 +/- 18.6 months). A beneficial effect of addition of cyclophosphamide was observed only in patients who demonstrated an early but short-lived improvement to steroids. Adverse reactions of immunosuppressive therapy were noticed in 10 patients, and required discontinuation of treatment in six of them.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchoalveolar Lavage Fluid↗
PubMed1994

[BCG vaccination].

Given especially to children, BCG vaccine has a protective effect against severe forms of tuberculosis in 70 to 80% of the subjects. It has a modest epidemiological effect since socioeconomic and sanitary conditions as well as human immunodeficiency virus infection influence disease spread. The precise mechanisms and the duration of BCG protection remains poorly defined. Vaccine complications in HIV positive subjects appear minimal compared with expectations. The tuberculosis irradication policy is defined in each country depending on the annual risk of infection. The threshold of 0.01% (0.03% in France) would justify BCG vaccination of exposed persons alone. Today there is renewed interest in research concerning BCG, 70 years after its first introduction for clinical use.

AIDS-Related Opportunistic Infections↗
PubMed1993

Diagnosis of pneumonia in mechanically ventilated patients. Repeatability of the protected specimen brush.

The repeatability (i.e., the variation in repeated measurements of the same quantity) of the protected specimen brush (PSB) with quantitative cultures was assessed in 22 consecutive mechanically ventilated (MV) patients with suspected nosocomial pneumonia. Five PSB samples were collected in the same lung area during the same bronchoscopic procedure and processed for bacteriologic identification and quantitative culture. A laboratory control was also performed in order to assess the in vitro repeatability of the quantitative culture technique. The five PSB always recovered the same microorganisms, indicating a 100% qualitative repeatability for the PSB. Conversely, the quantitative repeatability was somewhat lower since in 59% of the patients the quantitative results varied by more than one log10, which is the minimal precision affordable with quantitative cultures. The distinction between presence or absence of infection based on the 10(3) cfu/ml recommended diagnostic threshold was, however, only moderately affected by the variability of the quantitative results since only three of 22 patients (13.6%) displayed results spread out on each side of the 10(3) cfu/ml break point. Intrasubject variability of quantitative results was not explained by problems with the quantitative culture technique, which proved excellent repeatability in the laboratory. This study indicated that, although the PSB technique with quantitative cultures displays an acceptable level of repeatability, caution is advisable when interpreting PSB results in critically ill patients with suspected pneumonia, especially if one refers to the 10(3) cfu/ml recommended diagnostic threshold and if a decision to treat or to abstain from treating is to be made.

Bacteria↗
PubMed1993

Diagnostic efficiency of endotracheal aspirates with quantitative bacterial cultures in intubated patients with suspected pneumonia. Comparison with the protected specimen brush.

The objectives of the study were to determine the agreement between the protected specimen brush technique (PSB) with quantitative cultures and endotracheal aspirates (EA) with quantitative cultures when using increasing interpretative cutoff points and to investigate the respective operating characteristics for the diagnosis of pneumonia of PSB and EA when using quantitative cultures. Consecutive sampling of respiratory secretions using these two techniques was conducted in the respiratory intensive care units in 52 mechanically ventilated patients with clinical and radiologic suspicion of pneumonia. Quantitative bacterial cultures of PSB and EA samples were obtained. The 10(6) cfu/ml cutoff point was the most accurate diagnostic threshold for the EA technique. When using this threshold, there was a high level of agreement (84.6%) between PSB and EA results. Among the few discrepancies, the EA result was always indicative of pneumonia, whereas the PSB result was nonindicative, thus permitting us to classify correctly five patients in whom pneumonia would have been erroneously excluded on the basis of the sole result of PSB. Conversely, there was no case where the PSB result was indicative of pneumonia when the EA result (at the 10(6) cfu/ml level) was not. The operating characteristics of the PSB technique for the diagnosis of pneumonia were in accordance with previously published studies. The operating characteristics of the EA technique (when taking the 10(6) cfu/ml of respiratory secretions as the interpretative cutoff point) compared favorably with those of the PSB technique. Diagnostic accuracy rates were similar. The specificity of EA was somewhat lower (83 versus 96%), but the sensitivity was higher (82 versus 64%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Protected specimen brush in the assessment of ventilator-associated pneumonia. Selection of a certain lung segment for bronchoscopic sampling is unnecessary.

The protected specimen brush (PSB) with quantitative cultures is one of the most reliable techniques for assessing pneumonia in mechanically ventilated (MV) patients. The need to select a certain lung segment for bronchoscopic sampling is still debated. We investigated whether the results of PSB specimens collected within an area radiographically involved with pneumonia (inv-PSB) differed from the results of PSB specimens collected within a lung area without radiographic abnormalities (non-inv-PSB) in 39 MV patients with suspected pneumonia. The comparison of bacterial titers of inv-PSB and non-inv-PSB cultures did not disclose significant differences. Agreement regarding the diagnosis of pneumonia according to recommended diagnostic threshold was observed in 34 of 39 patients (87.1 percent). These results which are in accordance with the pathophysiology of ventilator-associated pneumonia and histologic studies do not support the need to select a certain lung segment for bronchoscopic sampling in most MV patients with suspected pneumonia.

Acinetobacter Infections↗
PubMed1992

[Bronchial endoscopy. Technical aspects in adults].

The author analyses all the practical aspects of bronchial endoscopy: the choice of equipment amongst equipment available from the makers for flexible and rigid endoscopes; the place of the most recent developments such as video-endoscopy; the upkeep of the equipment and specific problems linked to disinfection. Then the examination techniques of endoscopy are described from the admission of the patient and the anaesthesia to the completion of the report. Finally side effects and possible complications are reviewed. A protocol is specified.

Adult↗
PubMed1991

[Auricular chondritis, malignant glomerulonephritis and pulmonary hemorrhage].

Relapsing polychondritis is a rare connective tissue disorder characterized by inflammation of cartilagenous structures such as ears, nose, joints, trachea and larynx. Renal disease is unusual. A 41 years old man presented with auricular chondritis, subacute renal failure and lung hemorrhage. A renal biopsy disclosed a diffuse proliferative glomerulonephritis with extensive crescents. Immunofluorescent studies suggested a GNRP type III so called "non immunologic disease". He was treated by prednisone and plasmapheresis with rapid disappearance of pulmonary hemorrhages and good renal functional improvement.

Adult↗