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Biomedical subjects

P Aubas

Publications and source records attributed to P Aubas.

At least 19 recordsLinked to original sources
PubMed2006

Measuring agreement for ordered ratings in 3 x 3 tables.

OBJECTIVES: When two raters consider a qualitative variable ordered according to three categories, the qualitative agreement is commonly assessed with a symmetrically weighted kappa statistic. However, these statistics can present paradoxes, since they may be insensitive to variations of either complete agreements or disagreements. METHODS: Agreement may be summarized by the relative amounts of complete agreements, partial and maximal disagreements beyond chance. Fixing the marginal totals and the trace, we computed symmetrically weighted kappa statistics and we developed a new statistic for qualitative agreements. Data sets from the literature were used to illustrate the methods. RESULTS: We show that agreement may be better assessed with the unweighted kappa index, kappa(c), and a new statistic zeta, which assesses the excess of maximal disagreements with respect to the partial ones, and does not depend on a particular weighting system. When zeta is equal to zero, maximal and partial disagreements beyond chance are equal. With its estimated large sample variance, we compared the values of two contingency tables. CONCLUSIONS: The (kappa(c), zeta) pair is sensitive to variations in agreements and/or disagreements and enables locating the difference between two qualitative agreements. The qualitative agreement is better with increasing values of kappa(c) and zeta.

Data Interpretation, Statistical↗
PubMed2004

Can endobronchial biopsy analysis be recommended to discriminate between asthma and COPD in routine practice?

BACKGROUND: International guidelines stress the importance of accurately discriminating between asthma and chronic obstructive pulmonary disease (COPD). Although characteristic pathological features have been described for both conditions, their discriminatory power has never been systematically assessed. METHODS: Endobronchial biopsy (EBB) specimens from patients with a clear clinical diagnosis of asthma and COPD (50 per group) were examined by three pathologists in a double blind manner. They were asked to propose a pathological diagnosis of either asthma or COPD and to analyse qualitatively the most frequent abnormalities reported in the literature. RESULTS: The sensitivity and specificity of EBB ranged from 36% to 48% and from 56% to 79%, respectively. Eosinophils strongly biased the pathological diagnoses in favour of asthma, whereas their estimated prevalence was similar (11-37% in asthma and 13-41% in COPD). Metaplasia (11-39% in COPD, 1-18% in asthma) and epithelial inflammation (28-61% in COPD, 11-38% in asthma) tended to be specific to COPD, whereas epithelial desquamation (80-98% in asthma, 61-88% in COPD) and basement membrane thickening (71-94% in asthma, 53-88% in COPD) tended to be associated with asthma. There was acceptable intra- and inter-observer agreement only for metaplasia and epithelial eosinophils. CONCLUSIONS: Specific histopathological features of asthma and COPD probably exist, but current routine analysis procedures to assess EBB specimens are not sufficiently discriminatory. This might be rectified by improving pathological definitions.

Adult↗
PubMed2001

Fatal and non fatal cardiac arrests related to anesthesia.

PURPOSE: The aim of this study was to assess the incidence and causes of cardiac arrests related to anesthesia. METHODS: All patients undergoing anesthesia over a six year period were included in a prospective study. The cardiac arrests encountered during anesthesia and the first twelve postoperative hours in the PACU or ICU were analysed. For each arrest, partially or totally related to anesthesia, the sequence of events leading to the accident was evaluated. RESULTS: Eleven cardiac arrests related to anesthesia were identified among the 101,769 anesthetic procedures (frequency: 1.1/10,000 [0.44-1.72]). Mortality related to anesthesia was 0.6/10,000 [0.12-1.06]. Age over 84 yr and an ASA physical status > 2 were found to be risk factors of cardiac arrest related to anesthesia. The main causes of anesthesia related cardiac arrest were anesthetic overdose (four cases), hypovolemia (two cases) and hypoxemia due to difficult tracheal intubation (two cases). No cardiac arrests due to alveolar hypoventilation were noted during the postoperative periods in either PACU or ICU. At least one human error was noted in ten of the eleven cardiac arrests cases, due to poor preoperative evaluation in seven. All cardiac arrests totally related to anesthesia were classified as avoidable. CONCLUSION: Efforts must be directed towards improving preoperative patient evaluation. Anesthetic induction doses should be titrated in all ASA 3 and 4 patients. The prediction of difficult tracheal intubation, and if required, the use of awake tracheal intubation techniques, should remain a priority when performing general anesthesia.

Adolescent↗
PubMed2000

Static and dynamic MRI of a urinary control intra-vaginal device.

The aim of this study was to describe by MRI, in dynamic conditions at rest and straining, the anatomical modifications induced by a commercially available intravaginal device (IVD) aimed at relieving female stress urinary incontinence. Ten female patients complaining of stress urinary incontinence (SUI) had pelvic MRI with static and dynamic sequences, without and with a self-inserted IVD. We studied positions and angulations of the IVD in the pelvis. Paired t-test allowed comparisons of: position of the bladder neck; urethral angulation with the pubis axis; position of the urethra; and posterior urethro-vesical angle (PUVA) without and with IVD. At rest, in ten of ten cases IVD laid cranial to the pubo-rectal muscle; with an average angulation of 95 +/- 10 degrees with the pubis axis, laterally tilted in three of ten cases. In maximum straining with IVD bladder neck descent was lower by an average of 5.2 +/- 3.1 mm (p = 0.001), pubo-urethral angle opening was smaller by an average of 22 +/- 20 degrees (p = 0.015), and bladder neck to pubis distance was shorter by an average of 5.7 +/- 4 mm. Posterior urethro-vesical angle was not significantly modified. Dynamic MRI allowed a non-invasive assessment of the mode of action of an IVD. The main modifications were a support of the bladder base and bladder neck, with a superior displacement of the urethra toward the pubis.

Adult↗
PubMed1999

[Abdominal and pelvic segmented T1-weighted echo-planar imaging and MRI. Comparison with T1-TSE and T2-UTSE sequences].

PURPOSE: To assess, quantitatively and qualitatively, the diagnostic value of a segmented EPI T1W sequence compared to T1W and T2W TSE sequences. MATERIAL AND METHODS: A prospective analysis of abdominal and pelvic MRI examinations of 70 patients (44 women, 26 men, mean age of 61 years), was performed on a 0.5 T supraconductive magnet with 15 mT/m gradients. The sequences were randomized and compared in a blinded fashion by 3 independent reviewers: TSE T1W (TR/TE = 500/12 ms, NSA = 6, turbo factor 5, 3:49 min), EPI T1W (TR/TE = 500/30 ms, NSA = 6, EPI factor = 7, 2:13 min) and UTSE T2W (TR/TE = 1600-2500/100, NSA = 6, turbo factor = 31, 2:20 min). RESULTS: Quantitatively, no significant difference was found between T1W sequences for signal to noise ratio. The EPI T1W sequence had lower signal but stronger enhancement after gadolinium injection. Qualitatively, EPI T1W had significantly less flow artefacts (p < 0.001, wilcoxon test), and more chemical shift artifact (p < 0.01). For lesion detection, differences were not statistically significant between T1W sequences or between paired T1W and T2W sequences (sensitivity and specificity 84 and 86% for TSE T1W 76 and 86% for EPI T1W, 78 and 79% for UTSE T2W, 90 and 65% for TSE T1W-UTSE T2W, 88 and 65% for EPI T1W-UTSE T2W). Kappa concordance test (0.686) and Mac Nemar symmetry test (3.55) were high between T1W sequences. CONCLUSION: The segmented EPI T1W sequence used had equivalent results compared to the TSE T1W sequence, it allows a 40% reduction in acquisition time and this without difference in the diagnostic performances of the reviewers.

Abdomen↗
PubMed1998

Causes and prediction of maldistribution during continuous spinal anesthesia with isobaric or hyperbaric bupivacaine.

BACKGROUND: Many cases of cauda equina syndrome after maldistribution of local anesthetics during continuous spinal anesthesia have been reported. In experiments, a caudad route of catheter travel and the use of hyperbaric agents have been shown to induce these limited blocks. The aim of this clinical study was to verify this hypothesis and seek a predictive factor for the maldistribution of bupivacaine. METHOD: Continuous spinal anesthesia via a 19-gauge end port spinal catheter was performed in 80 elderly patients randomly assigned to receive either isobaric or hyperbaric solutions. Successive injections of 2.5 mg bupivacaine were performed at 5-min intervals until a sensory level at or cranial to T8 was obtained. Maldistribution was defined by a sensory level caudal to T12 despite a total dose of 17.5 mg of either isobaric or hyperbaric bupivacaine. After surgery, all catheters were injected with contrast media and examined radiographically. RESULTS: The frequency of maldistribution was not significantly different in the isobaric and hyperbaric groups. A caudally oriented catheter tip was found to be a major cause of maldistribution (P < 10(-5)). A thoracic sensory level could be reached in all patients presenting a limited block by simply changing the baricity of the bupivacaine, the position of the patient, or both. The sensory level obtained 10 min after the first injection of 2.5 mg isobaric or hyperbaric bupivacaine was found to be a predictive factor of maldistribution. CONCLUSIONS: Hyperbaric solutions do not appear to be a clinical factor in the development of limited block. The principle factor causing the maldistribution of bupivacaine is the caudal orientation of the tip of the end-hole catheter rather than its level or the route of catheter travel.

Aged↗
PubMed1996

Haemodynamic effects of moderate normovolaemic haemodilution in conscious and anaesthetized patients.

We have assessed the haemodynamic effects of moderate normovolaemic haemodilution in ASA I patients, either conscious or during enflurane-fentanyl anaesthesia (10 patients in each group). Cardiac index (CI), stroke index (SI) and ejection fraction (EF) were measured by transthoracic electrical bioimpedance and, in the anaesthesia group, arterial and central venous blood samples were obtained to assess oxygen delivery (DO2), oxygen consumption (VO2) and oxygen extraction ratio (O2ER). In conscious patients, heart rate (HR) remained unchanged as SI, EF and CI increased. When haemodilution was performed during anaesthesia, CI remained stable in spite of a slight increase in SI, as HR decreased. This produced a reduction in DO2 which was compensated for by an increase in O2ER, allowing maintenance of VO2 without alteration in blood lactate concentration.

Adolescent↗
PubMed1995

[Pulmonary embolism: contribution of spiral x-ray computed tomography].

PURPOSE: Spiral computed tomography was compared retrospectively with digital subtraction pulmonary angiography (PA) in 45 patients suspected of having acute or chronic pulmonary embolism. MATERIALS AND METHODS: 45 patients in whom the presence of acute or chronic pulmonary embolism was suspected underwent examination by spiral CT and PA. Diagnosis of pulmonary embolism was based on the direct visualization of intraluminal clots. The study of the agreement between the two methods was based on the Kappa test. In 35 cases, pulmonary emboli were proved. Acute pulmonary emboli were present in 28 cases and chronic in 7 cases. RESULTS: Spiral computed tomography represents an excellent way to detect acute pulmonary embolism. In the chronic form, spiral CT is better than PA to detect intraluminal clots. However, Spiral CT can fail to detect small embole in the peripheral arterial bed. In the 10 patients without pulmonary embolism, the spiral CT proved diagnosis pulmonary oedema (n = 3), lymphangitic carcinoma (n = 4), pleural effusion (n = 3). CONCLUSION: This study suggest that the spiral CT examination is accurate for diagnosis of pulmonary embolism specifically in case of suspected important embolism. The advantages of spiral CT are multiple (non invasive, wide diagnosis spectrum). However, may be a limitation to is use is insufficient distal thrombi detection. This eventuality (5 to 10% in the Pioped study) justify the practice of pulmonary angiography. Spiral CT improvements should reduce this insufficiency in the next future.

Acute Disease↗
PubMed1994

Bronchoalveolar lavage for diagnosing bacterial pneumonia in mechanically ventilated patients.

To assess the usefulness of BAL in diagnosing bacterial pneumonia in mechanically ventilated patients, 80 BAL fluid samples obtained from 72 patients with lung infiltrates were studied using the following parameters: infected cell count (polymorphonuclear leukocytes or macrophages with intracellular organisms), microscopic examination of stained smears, and quantitative culture with the determination of the simplified bacterial index (SBI) and the predominant species index (PSI). Of the 80 BAL samples studied, 56 were performed under antibiotic therapy. Bacterial pneumonia was the final diagnosis in 28 cases. The SBI is the sum of the whole numbers of each bacterial concentration expressed as a common logarithm. The PSI is the whole number of the predominant microorganism's concentration expressed as a common logarithm. The discriminative value of each test was assessed using a receiver operating characteristic (ROC) curve, whereby the possibility of establishing a cutoff value used to discriminate between the presence or absence of pneumonia is evaluated. The percentage of infected cells was higher in the pneumonia group (8.8 +/- 18.1 versus 0.4 +/- 1.1%, p < 10(-3), but no cutoff value could be proposed. Under microscopic examination, the presence of bacteria was noted with a significantly greater frequency in the pneumonia group (sensitivity 67.8% and specificity 82.7%). A total of 58 BAL samples were positive when cultured. The SBI was significantly higher in the pneumonia group (6.5 +/- 2.9 versus 1.6 +/- 1.7, p < 10(-4).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[The Relative Complexity Index beta: value of each parameter].

The French health policy PMSI project (Program for a Medical Information System) is mainly aimed at development of cost analysis based on diagnosis related groups. An indicator of the relative costs of anaesthetics, the relative complexity index (ICR beta), was defined as the result of a computation of different indexes of surgical and anaesthetic procedures such as duration, patients ASA status, degree of emergency, stay in the recovery room. The aims of this study were 1) to analyze relative part of each index in ICR beta value and in ICR beta variance and 2) to assess the value of ICR beta as a cost or a complexity index. The study included 14,435 anaesthetics analyzed with the Dunn and Clarks multiple linear regression. Mean ICR beta was 267.28. The duration of the procedure accounted for 46% of the ICR beta value and surgery for 25%. The anaesthesia and the recovery accounted for 15% of the ICR beta value, but only for 0.0341 and 0.0347 respectively of the ICR beta variance. The product of the surgical procedure index by the ASA status index accounted for 0.259 of the ICR beta variance and the duration index for 0.650. The comparison of homogeneous groups with regard to the surgical procedure shows that intravenous anaesthesia accounts for 12.4% of the ICR beta value, inhalational anaesthesia for 13.84%, but exceeds 15% for regional anaesthesia (44.5% for caudal anaesthesia). For appendectomies (n = 114) duration index is still an important parameter in ICR beta variance (delta R2 = 0.354) but equivalent to the emergency index (delta R2 = 0.363).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗
PubMed1992

Comparison of hydrophobic heat and moisture exchangers with heated humidifier during prolonged mechanical ventilation.

Inspired gases must be warmed and humidified during mechanical ventilation. In a prospective randomized study we compared the performance of a heated humidifier (HH) (Draegger Aquaport) and a heat and moisture exchanger (HME) (Pall Filter BB 2215). A total of 116 patients requiring mechanical ventilation (Servo 900 C Siemens) were enrolled into the study and were randomly assigned to 2 groups. Patients in group I were ventilated with a traditional breathing circuit with HH and patients in group II using a simplified circuit with HME. Pre-existing and hospital acquired atelectasis and pneumonia, occurrence of endotracheal tube (ET) occlusion and ventilatory parameters (respiratory rate, tidal volume) were studied. No statistical difference was found between groups for each parameter except the greater frequency of ET occlusions in the II group (0/61 vs 9/55) (p = 0.0008). Pall Filter (PF), a hydrophobic filter, humidifies the dry gases from the condensed water which is put down on the HME surfaces during cooling of saturated expired gases. This purely physical property is linked to the magnitude of the thermic gradient between the expired gases and the ambiant temperature. Performance impairment of PF in our study might be due to high ambiant temperature in the intensive care unit (usually around 28 degrees C) which reduces thermic gradient and water exchanges. We conclude that efficiency of PF may be weak in some conditions of ambiant temperature.

Adult↗
PubMed1991

Morpho-semantic analysis and translation of medical compound terms.

This paper describes an automatic procedure for morphosemantic analysis and translation of compound medical terms. This analysis is of interest for the automatic indexation of medical discharge reports and summaries. Since words with the suffix -osis may have many different semantic interpretations, such -osis forms are taken as examples for a general method that avoids the difficulties in interpreting medical terms as reported in other studies.

Algorithms↗
PubMed1989

[Pulmonary opacities in the shape of ribbon streamers. Apropos of a case].

The authors report a case of chronic interstitial pneumonia with a very unusual appearance (on plain films and CT); in fact such ribbon-like linear opacities with concentric and pseudo-cavitary disposition have not been previously described. They are comparable but different from the linear opacities described by Carrington in some cases of chronic eosinophilic interstitial pneumonia, which are vertical and peripheral. They are also different from the curvilinear sub-pleural opacities reported in some cases of asbestosis. On the basis of the anatomic findings they discuss the specificity of such radiologic patterns or their sole value as an evolutive state.

Female↗
PubMed1988

Kaposi's sarcoma of the bronchial tree in a renal transplant recipient.

An unusual case of disseminated Kaposi's sarcoma with endobronchial lesions is presented; these localizations are quite uncommon in the course of the disease, particularly in kidney transplant recipients. Some of the multifactorial etiologies of Kaposi's sarcoma are present: immunosuppression, ethnic origin and CMV infection. We emphasize that the diagnosis of bronchial involvement can be made during fiberoptic bronchoscopy and confirmed by biopsy without excessive complications.

Bronchial Neoplasms↗
PubMed1988

Approaches to the diagnosis of viral pneumonias in the immunocompromised host: the importance of assaying cytopathogenic viral effects in bronchoalveolar lavage cells.

Pneumonopathic conditions in the immunocompromised host (IH) are frequent and often serious. Rapid diagnosis is essential and is made possible by bronchoalveolar lavage (BAL). Sixty-two pneumonopathic episodes in 53 immunocompromised patients were examined by BAL, for viral cytopathogenic effects (CPE) in isolated cells, with appropriate viral culture techniques. Viral culture was positive in seventeen of the eighteen episodes in renal allograft recipients and AIDS patients as against eight of the fourty-four episodes in other causes of IH (p less than 0.001). CPE was found thirteen times; in seven cases it was characteristic of cytomegalovirus. Positive viral culture and CPE were shown simultaneously during thirteen episodes in eleven patients. Ten patients died (autopsies performed in three cases confirmed viral presence). Positive viral culture with absence of CPE was observed in twelve cases. There were only four fatalities in this group (the autopsies performed in three cases did not establish the presence of a virus in the pulmonary parenchyma). The percentage of lymphocytes was high in both groups of patients (18.6 +/- 2.8%). CPE is a simple and rapid examination for the diagnosis of viral pneumonopathology in the IH. Prognosis at present is gloomy; more complex examinations such as viral cultures and/or identification of the virus by immunofluorescence will be indicated only when effective antiviral agents become available.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[Pregnancy and asthma].

One in a hundred pregnant females has asthma. Pregnancy may change the course of the asthma and inversely foetal and obstetric prognosis may be affected by the illness and by the potentially deleterious effect of treatment. The maternal physiological changes which occur during pregnancy throw little light on the variations in asthma during pregnancy. Clinical studies in the literature suggest that the quality of follow-up and treatment in patients allows for a satisfactory outcome in pregnancy and that it is an important prognostic factor. Overall, taking account of the pregnancy and confinement the therapeutic approach of the thoracic physician differs little from that in management outside pregnancy. The first objective is to relieve the bronchial obstruction. Broncho-dilator therapy with beta-agonist and by theophylline remains usable in most cases. The side effects of steroid therapy ought to be balanced against the advantages, in order to maintain a normal physiological state. Immunotherapy, and antibiotics should be adapted appropriately for the pregnancy and for their respective contra-indications. Finally, the prevention of atopy should be envisaged.

Adrenergic beta-Antagonists↗