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Biomedical subjects

D Wermert

Publications and source records attributed to D Wermert.

8 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↗
PubMed2002

[Bilateral pleurisy and cardiac tamponade. A rare etiology: pancreatico-pleural fistula].

Pancreatico-pleural fistula is a rare complication of chronic pancreatitis. It commonly presents with small, but recurrent, pleural effusions. Pericarditis rarely occurs in this context. We report a case presenting with bilateral large pleural effusions associated with cardiac tamponade. The diagnosis was suspected on detection of high concentration of pancreatic enzyme in the pleural fluid and was confirmed by both endoscopic retrograde pancreatography and magnetic resonance pancreatography. Both examinations demonstrated a fistula and a calculus of the Wirsung duct. In addition, they identified a pancreas divisum, a congenital abnormality which can rarely lead to complications. The usual medical and endoscopic management of this condition failed and a surgical solution for the fistula was needed. This case is unique due to the dramatic presentation of this complication of pancreas divisum and to the complexity of treatment required.

Cardiac Tamponade↗
PubMed1999

Characterization of an animal model of ventilator-acquired pneumonia.

To develop an experimental model of ventilator-acquired pneumonia (VAP), we investigated whether healthy piglets could develop endogenously acquired pulmonary infection as a result of prolonged mechanical ventilation (MV). Thirty-three piglets underwent MV with anesthesia, analgesia, and paralysis produced by continuous infusion of midazolam, fentanyl, and pancuronium bromide. Ten animals received antibioprophylaxis with ceftriaxone (ATB group) and 23 received no antibiotics (control group). Eighteen control animals and 9 ceftriaxone-treated animals completed the 4-day study protocol. The presence of pneumonia on day 4 was ascertained by multiple pulmonary biopsy specimens, processed for microscopic examination and quantitative cultures. The anesthetic regimen provided satisfactory electrolyte balance and cardiovascular stability. Under these circumstances, 17 of 18 animals and 4 of 9 animals developed VAP in the control and the ATB groups, respectively. Lesions of different grades of severity were unevenly distributed through both lungs with a predominance and a higher severity in dependent lung segments. Noninfectious lesions frequently associated with VAP in humans were not observed. Pneumonia was usually polymicrobial with a predominance of Gram-negative organisms. Most of the causative organisms originated from the oropharynx. Histologic lesions and lung bacterial concentrations were less in the ATB group than in control animals. We then investigated the effects of intrabronchial challenge with bacterial pathogens in the absence of MV. Intrabronchial bacterial inoculation resulted in the development of pneumonia that spontaneously resolved even when using very highly titrated inocula. Therefore, MV seems to be the main predisposing factor in the development of pneumonia in this model. This model that resembles human VAP in its histologic, bacteriologic, and pathogenic aspects may be useful to further study pathogenesis, diagnosis, prevention, and therapy of VAP.

Animals↗
PubMed1998

Influence of pulmonary bacteriology and histology on the yield of diagnostic procedures in ventilator-acquired pneumonia.

We investigated the influence of pulmonary bacteriology and histology on the yield of diagnostic procedures in a clinically relevant model of ventilator-acquired pneumonia (VAP). Twenty-seven piglets entered a 4-d protocol of ventilatory support under general anesthesia. Endotracheal aspirates (EA), protected specimen brush (PSB), and bronchoalveolar lavage (BAL) were obtained on Day 4. PSB and BAL were performed under bronchoscopic guidance in dependent and nondependent lung segments. Immediately thereafter sternotomy allowed bilateral lung biopsies including the segments studied by bronchoscopic techniques. All respiratory specimens were then processed for microscopic examination and quantitative cultures (QC). In this model where many of the confounding factors often present in human studies were absent, we found that (1) although the local bacterial burden tended to correlate with the presence and the severity of histologic lesions, no definite bacteriologic cutoff could differentiate the histologic presence or absence of pneumonia; (2) histologic lesions of pneumonia and parenchymal bacterial burden were unevenly distributed through the lungs; (3) this heterogeneity in bacterial distribution also held true for single bacterial species; (4) using discriminative values of >= 10(3) cfu/ml, >= 10(4) cfu/ml, and >= 10(5) cfu/ml to define positive PSB, BAL, and EA cultures, respectively, these techniques identified the histologic presence of pneumonia with a sensitivity of 69%, 78%, and 100%, respectively; (5) the specificity of these techniques in recognizing VAP was less than 50%; (6) with these discriminative values, less than 50% of PSB and BAL specimens correctly identified the causative organisms, whereas 94% of EA specimens correctly established the microbiologic diagnosis of pneumonia. We believe that the peculiar histologic and bacteriologic features of VAP may account for the difficulties of PSB and BAL, which combine QC with the use of discriminative thresholds, to reliably recognize pneumonia and to identify the causative organisms. For clinical practice, no technique confidently helps in recognizing pneumonia in mechanically ventilated patients. With regard to bacterial diagnosis, use of quantitative cultures of EA seems to be the best technique to identify the causative organisms in patients suffering VAP.

Animals↗
PubMed1997

[Fibroscopic bronchoscopy in intensive care].

The field of application for fibreoptic bronchoscopy (FB) in the intensive care unit has been extended since the generalised introduction of fibroscopes of 4.9 mm in diameter (previously called paediatric fibroscopes). Paediatric and neonatal intensive care units have benefited from the availability in the market of these small endoscopes for 3.5 and 2.2 mm. The protected brush and alveolar lavage (LBA) enables a specific diagnosis to be made in bacterial pneumonia acquired during ventilation. The sensitivity of these techniques however is insufficient to be able to recommend their use as routine. Inversely, the FB with LBA remains a fundamental feature in the diagnosis of opportunistic infections in pneumonia. For the treatment of atelectasis, FB is overall not superior to physiotherapy. Aspiration with a fibroscope can however be recommended straight away in cases of alteration in blood gasses if cough is ineffective or if the atelectasis complicates endobronchial bleeding. The FB enables problems with difficult intubation to be resolved or for the positioning of probes. The conditions under which this is performed are more delicate than in routine anaesthesia (in cases of urgency, hypoxia). In the case of respiratory burns, tracheobronchial fracture and post intubation stenosis, FB enables both the diagnosis to be established and the level at which the lesion occurs. In paediatric intensive care, a fibroscope of 3.5 mm is used for performing LBA (opportunistic pneumonias), difficult intubation (facial dysmorphia), endoscopic diagnoses, in particular where there is a suspicion of an endobronchial foreign body, the assessment of unexplained dyspnoea (tracheal stenosis by vascular ring) and obstructive lesions. In neonatal intensive care, a fibroscope of 2.2 mm is used for difficult intubation and the localisation of lesions induced by ventilation.

Adult↗
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↗