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Biomedical subjects

O Sanchez

Publications and source records attributed to O Sanchez.

At least 19 recordsLinked to original sources
PubMed2006

Clinical probability and alveolar dead space measurement for suspected pulmonary embolism in patients with an abnormal D-dimer test result.

BACKGROUND: Most patients with suspected pulmonary embolism (PE) have a positive D-dimer test and undergo diagnostic imaging. Additional non-invasive bedside tests are required to reduce the need for further diagnostic tests. OBJECTIVES: We aimed to determine whether a combination of clinical probability assessment and alveolar dead space fraction measurement can confirm or exclude PE in patients with an abnormal D-dimer test. METHODS: We assessed clinical probability of PE and alveolar dead space fraction in 270 consecutive in- and outpatients with suspected PE and positive D-dimer. An alveolar dead space fraction < 0.15 was considered normal. PE was subsequently excluded or confirmed by venous compression ultrasonography, spiral computed tomography and a 3-month follow-up. Radiologists were unaware of the results of clinical probability and capnography. RESULTS: PE was confirmed in 108 patients (40%). Capnography had a sensitivity of 68.5% (95% confidence interval [CI]: 58.9-77.1%) and a specificity of 81.5% (95% CI: 74.6-87.1%) for PE. Forty-five patients (16.6%) had both a low clinical probability and normal capnography (sensitivity: 99.1%, 95% CI: 94.9-100%) and 34 patients (12.6%) had both a high clinical probability and abnormal capnography (specificity: 100%, 95% CI: 97.7-100%). CONCLUSION: Capnography alone does not exclude PE accurately. The combination of clinical probability and capnography accurately excludes or confirms PE and avoids further testing in up to 30% of patients.

Capnography↗
PubMed2005

[Treatment of venous thromboembolic disease].

Adequate initial anticoagulant treatment is required to prevent thrombus growth and recurrence. Intravenous unfractionated heparin is being replaced by low-molecular-weight heparin as the anticoagulant of choice for initial treatment of venous thromboembolism. Vitamin K antagonists remain the only oral anticoagulant available (target international normalized ratio: 2.5). The duration of therapy should be individualized according to the risk of recurrence and the risk of bleeding. Three months of treatment is usually adequate if thrombosis was provoked by a reversible risk factor such as surgery. For patients with unprovoked ("idiopathic") thrombosis, anticoagulant treatment for at least 6 months is indicated. For patients with a recurrence of venous thromboembolism or with an irreversible risk factor such as cancer, indefinite anticoagulant therapy is recommended. Long-term treatment with low-molecular-weight heparin is usually preferable for patients with active cancer. Systemic thrombolysis is indicated for patients with massive pulmonary embolism but controversy persists for those with isolated right ventricular dysfunction.

Anticoagulants↗
PubMed2004

Effect of solid hold-up on nitrite accumulation in a biofilm reactor--molecular characterization of nitrifying communities.

Biological ammonium oxidation was carried out in two inverse turbulent bed reactors fed with synthetic mineral wastewater containing a high ammonium concentration (100 mg N-NH4+/L). Both reactors were started-up and operated in the same conditions except for the solid carrier concentration: the solid hold-up ratios applied, defined as the ratios of static to expanded bed height, were 0.1 and 0.3 in reactors R10 and R30 respectively. These two solid hold-up ratios generate different particle-to-particle collision frequencies and, therefore, detachment forces. The influence of solid hold-up on biofilm growth and nitrifying performance was studied from a macroscopic (i.e. nitrate and/or nitrite production) and microbiological point of view. After 60 days of operation, both reactors contained the same amount of biomass. However, R10 produced only nitrate while nitrite accumulated in R30. A comparison of microbial populations in the reactors showed that R10 contained both ammonium and nitrite oxidizing populations such as Nitrosomonas and Nitrospira, whereas in R30, ammonium oxidizing populations were much greater than those of nitrite oxidizers. The major ammonium-oxidizing organism was not the same in both reactors.

Biofilms↗
PubMed2003

[Pulmonary artery hypertension associated with connective tissue diseases].

MOST IMPORTANT: Pulmonary hypertension (PH) is a severe, potentially life-threatening complication of connective tissue diseases, among which scleroderma is first line. The aim of this paper was to review the literature and report our experience with this particular complication of connective tissue diseases. In our centre of pulmonary vascular diseases, connective tissue diseases represent the third cause of PH. RESULTS: Scleroderma and particularly its limited cutaneous variant, the CREST syndrome, is the most common connective tissue disease affected by pulmonary hypertension. It can be related to a specific lung parenchymal involvement (hypoxic PH), to an isolated pulmonary vascular involvement or to a cardiac dysfunction secondary to specific myocardial lesions. DIAGNOSIS: Echocardiography is an excellent examination to detect pulmonary hypertension. However, right heart catheterisation is necessary to confirm the diagnosis of pulmonary hypertension and to test vasoreactivity with a potent vasodilator such as nitric oxide (NO). REGARDING TREATMENTS: Oral calcium channel blockers are indicated in patients who are responders to acute NO tests. Treatment with continuous intravenous prostacylin is obviously an improvement, at least functionally, although it appears less effective than in primary PH. With the new subcutaneous, oral and inhaled vasodilatators (prostaglandin and endothelin receptor antagonists), a few cases of improvement of PH with intensive immunosuppressive therapy were observed, essentially during systemic lupus erythematosus and Sharp syndrome. IN PRACTICE: PH is a severe complication of connective tissue diseases. Early detection of this complication should allow an earlier and more aggressive therapeutic approach in these patients, before irreversible vascular lesions occur.

Adult↗
PubMed2003

[Pulmonary hypertension complicating systemic diseases other than connective tissue diseases].

A COMPLICATION OF CERTAIN SYSTEMIC DISEASES: Pulmonary hypertension (PH) can complicate the progression of certain systemic diseases such as sarcoidosis, histiocytosis X and some vasculites. The mechanisms at the origin of PH are varied and always require rigorous analysis in order to optimise treatment. DEPENDING ON THE DISEASE: PH associated with sarcoidosis is essentially related to specific lung parenchymal fibrosis and is poorly responder to corticosteroids. Other mechanisms may be more rarely incriminated (compressive andenopathies, mediastinal fibrosis, florid sarcoidosis concomitant to a pulmonary occlusive vascular disease...). During histiocytosis X, the ventilatory limitation of these patients does not always correlate with the severity of the respiratory failure, suggesting the existence of a pulmonary vascular disease progressing independently of the pulmonary parenchymal lesions. The pulmonary artery damage during Takayasu's arteritis and other auto-immune pulmonary arteritis may lead to potentially life-threatening complications, notably through stenosis and/or obstruction of the pulmonary arteries. Pulmonary hypertension is exceptional during Wegener's disease or periateritis nodosa. CONCLUSION: PH can complicate the progression of certain systemic diseases. The physiopathological mechanisms responsible are unclear (specific parenchymal fibrosis, isolated vascular involvement...). Globally, available treatments are disappointing.

Cardiac Catheterization↗
PubMed2002

[Pulmonary hypertension associated with connective tissue diseases].

PURPOSE: Pulmonary hypertension is a rare but well-known life-threatening complication of connective tissue diseases. The aim of this article is to analyse the available literature and to report the experience of a pulmonary vascular diseases centre about this complication. CURRENT KNOWLEDGE AND KEY POINTS: Scleroderma and its limited variant, the CREST syndrome (calcification, Raynaud phenomenon, esophageal dysmotility, sclerodactily, telangiectasia), is the most common connective tissue disease affected by pulmonary hypertension. Dyspnea is the main symptom and is frequently severe. Echocardiography is an excellent exam to detect pulmonary hypertension. However, right heart catheterization is necessary to confirm the diagnosis of pulmonary hypertension and to test vasoreactivity with a potent vasodilator such as nitric oxide. Pulmonary hypertension is less severe in patients with connective tissue diseases perhaps because of an earlier diagnosis. A significantly lower proportion of patients presents an acute vasodilator response, suggesting an early constitution of irreversible pulmonary vascular lesions. Continuous intravenous epoprostenol therapy seems to be less effective as compared with patients with primitive pulmonary hypertension and does not improve survival. So, we observed dramatic improvement in rare cases after immunosuppressive therapy. FUTURE PROSPECTS AND PROJECTS: New treatments with oral, subcutaneous or inhaled stable prostacyclin analogs or with an endothelin receptor antagonist are currently being evaluated. The role of immunosuppressive therapy has to be defined.

Antihypertensive Agents↗
PubMed2001

[Infection of a pneumonectomy site 16 years after intervention].

BACKGROUND: Infection of the residual cavity after pneumonectomy generally occurs early after surgery. CASE REPORT: A 67-year old patient was hospitalized with fever 16 years after pneumonectomy for lung cancer. Investigations led to the diagnosis of infection of the pneumonectomy cavity. DISCUSSION: Late infection several years after pneumonectomy is exceptional and usually occurs in a setting of bacteriemia. Diagnosis is difficult due to modifications of the thoracic signs but should be entertained whenever unexplained fever or an inflammatory syndrome occurs in a pneumonectomized patient. The thoracic CT scan shows an abnormally enlarged cavity. Bacteriological examination of evacuated fluid provides the key to diagnosis. Drainage-lavage is indicated. Surgery may be needed exceptionally.

Aged↗
PubMed2001

Subacute diencephalic angioencephalopathy: biopsy diagnosis and radiological features of a rare entity.

Subacute diencephalic angioencephalopathy (SDAE) is a rare and fatal disease of unknown etiology that involves the thalami bilaterally. To date, there have been four cases reported, in which the diagnosis was established only after post mortem examination of the brain. We report two male patients, ages 69 and 41 years, who presented with progressive dementia and somnolence. Radiological evaluation revealed enhancing lesions involving both thalami. The differential diagnosis included a number of neoplastic, inflammatory and vascular processes. In both cases, pathological evaluation of biopsy specimens suggested the diagnosis of SDAE. Despite supportive care, the disease progressed rapidly and both patients died within weeks after initial presentation. The diagnosis was confirmed at autopsy in both cases. SDAE is a rare cause of bithalamic disease that can be mistaken for a neoplasm as well as a number of conditions that necessitate different treatment choices. The histopathological findings can establish the diagnosis when combined with radiological and clinical information. This report emphasizes the utility of stereotactic biopsy in early diagnosis of SDAE.

Adult↗
PubMed2000

[Acute circulatory failure caused by primary pulmonary hypertension or pulmonary embolism].

Patients with acute massive pulmonary embolism or primary pulmonary hypertension may develop acute circulatory failure and are therefore admitted in the intensive care. The mortality rate of patients with pulmonary embolism and shock varies between 25 and 35% whereas the corresponding figure in patients with submassive embolism is less than 10%. Spiral computed tomography may be the most convenient test for diagnosing pulmonary embolism in the setting of acute circulatory failure. In the few patients who remain unstable despite adequate symptomatic treatment, transthoracic echocardiography combined with clinical judgement is appropriate. Inotropic support and thrombolytic therapy are clearly indicated for patients with massive embolism and shock. The role of the latter is more controversial in patients with right ventricular distension and normal blood pressure. The optimal duration of anticoagulant therapy for pulmonary embolism remains to be defined. Most patients are adequately treated with a six-month course of oral anticoagulants. A shorter duration may be sufficient when a transient risk factor is the cause of the initial event whereas patients with cancer or antithrombin deficiency may require a life long treatment. Primary pulmonary hypertension is a much more uncommon disease which can also lead to right ventricular failure. Symptomatic treatment combines oxygen, inotropic drugs, as well as the optimisation of right ventricular filling pressure. Specific treatment includes inhaled nitric oxide or intravenous epoprostenol followed by anticoagulants with either calcium channel blockers in patients responding acutely to vasodilators or a continuous infusion of epoprostenol in those who do not respond to acute challenge or who are not improving with calcium channel blockers. Although the long term survival has markedly improved as a result of epoprostenol treatment, some patients with refractory primary pulmonary hypertension remain candidates for lung transplantation.

Acute Disease↗
PubMed1999

Localization of a gene for familial patella aplasia-hypoplasia (PTLAH) to chromosome 17q21-22.

Patella aplasia-hypoplasia (PTLAH) is a rare genetic defect characterized by congenital absence or marked reduction of the patella. PTLAH can occur either as an isolated defect or in association with other malformations, and it characteristically occurs in the nail-patella syndrome and in some chromosome imbalances. We report the first evidence of linkage for isolated PTLAH in an extended Venezuelan family. After exclusion of the candidate chromosome regions where disorders associated with PTLAH have been mapped, a genomewide scan was performed that supported mapping of the disease locus within a region of 12 cM on chromosome 17q22. Two marker loci (D17S787 and D17S1604) typed from this region gave maximum LOD scores >3. Accordingly, multipoint analysis gave a maximum LOD score of 3.39, with a most likely location for the disease gene between D17S787 and D17S1604. Sequencing of the noggin gene, a candidate mapping between these markers, failed to reveal any mutation in affected subjects.

Adolescent↗
PubMed1999

Short-term and long-term epoprostenol (prostacyclin) therapy in pulmonary hypertension secondary to connective tissue diseases: results of a pilot study.

Continuous intravenous epoprostenol improves exercise capacity, haemodynamics, and survival in severe primary pulmonary hypertension. Pulmonary hypertension can also be life-threatening in patients with connective tissue diseases. In a prospective open monocentre uncontrolled study, the effects of epoprostenol were evaluated in patients with severe pulmonary hypertension secondary to connective tissue diseases who were unresponsive to oral vasodilators (including calcium channel blockers) and continued to be in the New York Heart Association (NYHA) functional class III or IV despite conventional medical therapy. Seventeen patients received epoprostenol administered by a portable infusion pump associated with conventional therapy (oral anticoagulants, diuretics, supplemental oxygen). During the first six weeks of therapy, two (12%) patients died, of pulmonary oedema (n = 1) and severe sepsis (n = 1). In the fifteen remaining subjects, clinical and haemodynamic parameters improved significantly at six weeks. These patients were subsequently monitored for 80+/-48 (range 14-154) weeks after initiation of epoprostenol. Five (33%) patients died, of right heart failure (n = 2), severe sepsis (n = 2) or syncope (n = 1) and two patients were successfully transplanted 24 and 52 weeks after initiation of epoprostenol. Seven of the remaining eight patients had a persistent clinical improvement. Short-term epoprostenol therapy is effective in some patients with connective tissue diseases as demonstrated by better clinical status and haemodynamics at six weeks. However, this study reports several cases of early and late major complications including severe sepsis and pulmonary oedema. Additional information is needed to evaluate the benefit: risk ratio of long-term epoprostenol therapy in pulmonary hypertension secondary to connective tissue diseases.

Adult↗
PubMed1998

Endocardial and epicardial ablation guided by nonsurgical transthoracic epicardial mapping to treat recurrent ventricular tachycardia.

INTRODUCTION: An epicardial site of origin of ventricular tachycardia (VT) may explain unsuccessful endocardial radiofrequency (RF) catheter ablation. A new technique to map the epicardial surface of the heart through pericardial puncture was presented recently and opened the possibility of using epicardial mapping to guide endocardial ablation or epicardial catheter ablation. We report the efficacy and safety of these two approaches to treat 10 consecutive patients with VT and Chagas' disease. METHODS AND RESULTS: Epicardial mapping was carried out with a regular steerable catheter introduced into the pericardial space. An epicardial circuit was found in 14 of 18 mapable VTs induced in 10 patients. Epicardial mapping was used to guide endocardial ablation in 4 patients and epicardial ablation in 6. The epicardial earliest activation site occurred 107+/-60 msec earlier than the onset of the QRS complex. At the epicardial site used to guide endocardial ablation, earliest activation occurred 75+/-55 msec before the QRS complex. Epicardial mid-diastolic potentials and/or continuous electrical activity were seen in 7 patients. After 4.8+/-2.9 seconds of epicardial RF applications, VT was rendered noninducible. Hemopericardium requiring drainage occurred in 1 patient; 3 others developed pericardial friction without hemopericardium. Patients remain asymptomatic 5 to 9 months after the procedure. Interruption during endocardial pulses occurred after 20.2+/-14 seconds (P = 0.004), but VT was always reinducible and the patients experienced a poor outcome. CONCLUSION: Epicardial mapping does not enhance the effectiveness of endocardial pulses of RF. Epicardial applications of RF energy can safely and effectively treat patients with VT and Chagas' disease.

Adult↗