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Biomedical subjects

J F Muir

Publications and source records attributed to J F Muir.

At least 37 records · Page 2Linked to original sources
PubMed2001

Noninvasive ventilation and obstructive lung diseases.

The key role of noninvasive positive pressure ventilation (NPPV) is well documented in chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure (ARF) since it may avoid endotrachal intubation in >50% of cases when used as the initial treatment. However, currently only minimal data is available to assess usefulness of NPPV in COPD patients on a long-term basis. Even if such studies are difficult to manage, there is clearly a need for prospective studies comparing long-term oxygen therapy (LTOT) and NPPV in the most severe COPD in a large amount of patients and on a real long-term basis of several years. Two randomized prospective studies are being completed in Europe and the first preliminary results show that NPPV is associated with a reduction of hospitalization for chronic respiratory failure decompensation. The main beneficial effect of long-term mechanical ventilation in COPD patients with chronic respiratory failure implies a correction of nocturnal hypoventilation that could persist beyond the ventilation period because of a temporary improvement in carbon dioxide sensitivity that is often blunted in these patients. A synthesis from the literature suggest to consider NPPV for severe COPD patients who present with chronic hypoxia and hypercapnia and develop an unstable respiratory condition. Instability may be appreciated on a clinical basis and confirmed by a progressive worsening of arterial blood gas tensions, leading to frequent cardiorespiratory decompensations with ominous ARF episodes. NPPV should also be considered after an ARF episode successfully treated by noninvasive ventilation but with the impossibility to wean the patient from the ventilator. Thus, noninvasive positive pressure ventilation could be proposed as a preventive treatment in severe chronic obstructive pulmonary disease patients with unstable respiratory condition associated with fluctuating hypercapnia before, during and after an acute respiratory failure episode, avoiding the need for a tracheotomy. Adjunction of noninvasive ventilation to exercise rehabilitation is under evaluation.

Home Care Services↗
PubMed2001

[Prevention of infections transmitted by CPAP and noninvasive ventilation].

Nosocomial infections are recognized as a major problem in patients with endotracheal ventilation, but the risk of nosocomial pneumonia is less well known and considered to be lower for patients on noninvasive ventilation. The risk factors for endotrachial ventilation involve the presence of the endoracheal canula and the direct consequences of the reclining position, use of a respirator, sedation, presence of a nosgastric tube, antiulcer treatment, etc. Most of these risk factors are not present in noninvasive ventilation while others, for example the use of a respirator and a ventilation circuit, persist. Several recent studies have demonstrated lower rates of infection in noninvasive compared with endotracheal ventilation. The notion of a specific risk of noninvasive ventilation-related nosocomial infection is less certain although current data do show a risk level no higher than in non-ventilated patients. Noninvasive ventilation should therefore be considered as a preventive measure against nosocomial infection whenever it can replace invasive ventilation. More or less specific preventive measures should however be employed. The principal actions involve taking advantage of the noninvasive nature of the ventilation to reduce the risk factors and other invasive procedures indirectly related with the use of artificial ventilation. Patients should be mobilized as rapidly as possible and oral food intake instituted early. Certain measures concerning humidification of the ventilation circuit remain important as well as other nonspecific measures including hand washing, for the prevention of cross contamination.

Procedural Sedation↗
PubMed2000

[Noninvasive ventilation for decompensation of chronic respiratory failure].

MASK DELIVERY: Noninvasive ventilation designates ventilation methods which do not use the endotracheal route. Noninvasive ventilation is generally delivered via a facial mask (generally for patients with acute respiratory failure) or a nasal mask (widely used for home-delivery systems). INDICATIONS: Following work conducted by Rideau in the eighties who made the first ventilation trials in patients with myopathy, Meduri then Brochard focused interest on noninvasive ventilation for the management of acute episodes in patients with chronic respiratory failure. Following a simple algorithm, first intention noninvasive ventilation can be used in case of acute decompensation of chronic respiratory failure when the degree of urgency and the patient's status do not require immediate endotracheal ventilation. A WEANING TOOL: In addition to this well recognized indication, recent trials have demonstrated the usefulness of noninvasive ventilation as a weaning tool for patients on conventional endotracheal ventilation.

Chronic Disease↗
PubMed2000

Evaluation of home versus laboratory polysomnography in the diagnosis of sleep apnea syndrome.

The aim of this study was to compare home polysomnography (HoPSG) with laboratory polysomnography (LabPSG) in the diagnosis of sleep apnea syndrome (SAS). A total of 103 patients referred for investigation of SAS underwent two full polysomnographies, using the portable Minisomno device at home and the Respisomnographe in the laboratory (both devices manufactured by the same company). Twenty percent of home-studied device polysomnography (HoSD-PSG) recordings and 5% of LabPSG recordings were excluded from analysis either because of lost data or poor quality data. Sleep stage distribution and subjective quality of sleep were similar by both methods. Using LabPSG, the mean (+/- SD) RDI was 25.7 (+/- 30.6) versus 22.8 (+/- 31.5) using HoSD-PSG (p > 0.05). Absolute differences between the home and laboratory respiratory disturbance index (RDI) were less than 10 for 65% of patients. Discordant RDIs (i.e., differences greater than 10) were observed for 63% of individuals with severe SAS (RDI > 30) versus 22% of those with normal or moderate SAS (RDI </= 30) (p < 0.05). Higher RDI differences were associated with poor airflow signal at home. Forty-seven percent of patients preferred LabPSG. Our results suggest that HoSD-PSG was not feasible for 33% of patients; there was no evidence of a better quality of sleep and recording tolerance at home; the reliability of HoSD-PSG for SAS diagnosis depends on the quality of data obtained under unattended conditions.

Adult↗
PubMed2000

Distribution of alpha(1)-antitrypsin alleles in patients with bronchiectasis.

STUDY OBJECTIVES: Bronchiectasis has been reported in a few patients with homozygous alpha(1)-antitrypsin (AAT) deficiency, but the distribution of AAT alleles among bronchiectatic patients is not known. PATIENTS AND DESIGN: Two hundred two patients, 104 men and 98 women, with a mean age (SD) of 63.7 +/- 15.4 years, had bronchiectasis diagnosed by CT scan alone (n = 178), bronchography with or without CT scan (n = 17), or radiography alone (n = 7). AAT phenotypes (classified according to the protease inhibitor [PI] system) were determined by isoelectric focusing in blood samples obtained from all patients. Bronchiectasis was primary in 121 cases and secondary in 81 patients. Allele and phenotype frequencies were compared retrospectively between bronchiectatic patients and healthy blood donors living in the same geographic area. RESULTS: The PI phenotype frequencies among patients were the following: MM, 81.18%; MS, 11.88%; MZ, 3.46%; IZ, 0.49%; IM, 0.49%; SS, 1.48%; SZ, 0.49%; and ZZ, 0.49%. The allelic frequencies among patients were the following: M, 89.1%; S, 7.67%; Z, 2.72%; and I, 0.49%. There was no difference in the distribution of alleles or phenotypes either between patients and control subjects or between patients with secondary and primary bronchiectasis. A significant difference was found between bronchiectatic patients with and without coexisting emphysema (p = 0.028). This difference was caused by an overrepresentation of PI*Z alleles in bronchiectatic patients with coexisting emphysema. CONCLUSIONS: Our results do not support a physiopathologic implication of the AAT genes in the development of bronchiectasis. We suggest that bronchiectasis may be a consequence of emphysema in PI*Z patients rather than a primary effect.

Adolescent↗
PubMed2000

[Proteins of the inter-alpha trypsin inhibitor (ITI) family. A major role in the biology of the extracellular matrix].

A glycoprotein with a high inhibitory activity against trypsin was isolated in 1961 from human plasma and named inter-alpha trypsin inhibitor (ITI). Since then, several other proteins that share antigenic and structural similarities with ITI have been identified and classified as members of the ITI protein family. These glycoproteins built up from different combinations of four polypeptides HC1, HC2, HC3 and bikunin are encoded by four genes H1, H2, H3, L on three chromosomes. Bikunin has two proteinase inhibitor domains and belongs to the Kunitz-type protease inhibitor family; it displays an inhibitory activity against trypsin, leukocyte elastase and plasmin. The heavy chains do not have any protease inhibitory properties but have the capacity to interact in vitro and in vivo with hyaluronic acid. This binding promotes the stability of the extra-cellular matrix. Consequently, the ITI protein family is suspected of playing a key role in the extra-cellular matrix biology. Isolation of free heavy chains in bronchial secretions and the recent emphasis about the bikunin role in tumoral invasion should enhance the interest about ITI protein family in the pathophysiology of chronic bronchopulmonary diseases or lung cancer progression.

Antifibrinolytic Agents↗
PubMed2000

[Non-invasive ventilation in acute respiratory insufficiency].

Non invasive mechanical ventilation represents all the techniques of mechanical ventilation not using endotracheal connection to the respirator. Non invasive mechanical ventilation is essentially represented nowadays by facial (generally used for acute respiratory failure) and nasal ventilation (widely used for long term mechanical ventilation at home). Following in France the first studies of Rideau in the '80 in patients with chronic respiratory failure secondary to muscular dystrophy, Meduri, then Brochard demonstrated the interest of non invasive mechanical ventilation in the management of acute on chronic respiratory failure. A simple algorithm is thus able to recommend in first attempt use of non invasive mechanical ventilation in acute on chronic respiratory failure except if the patient presents in a severe respiratory status imposing in first line endotracheal ventilation. In parallel, more recent studies have demonstrated the interest of that technique in immediate ventilatory link in the spectrum of weaning of endotracheal mechanical ventilation. In hypoxic acute respiratory failure, non invasive mechanical ventilation remains controversial and seems to be better indicated in moderate to severe respiratory status.

Acute Disease↗
PubMed2000

[A misleading tumor image].

Inflammatory pseudotumors of the lung are uncommon benign lung tumors. Their tendency for local extension requires an exact histopathological diagnosis to rule out neoplastic proliferation. The case presented here highlights the clinical findings as well as the difficulties in making the diagnosis and the therapeutic uncertainties.

Diagnosis, Differential↗
PubMed2000

[After 1440].

Explore the source record for details and available documents.

Humans↗
PubMed2000

[Noninvasive ventilation: current concepts in the treatment of chronic respiratory failure in patients with chronic obstructive lung disease].

Long-term oxygen therapy remains the mainstay treatment for advanced-stage chronic obstructive pulmonary disease that has reached the state of chronic respiratory failure. Noninvasive ventilation should be discussed for some patients with a instability and frequent hospitalizations for decompensation and progressive degradation of blood gases. Although this subpopulation remains to be perfectly defined, it is reasonable to discuss the implementation of noninvasive ventilation at night in association with daytime oxygen therapy for patients who do not respond to well conducted and well-implemented oxygen therapy if the disease instability is marked by an increasing rate of hospitalizations for decompensation. This subpopulation includes COPD patients with a worsening PaCO2 above 50 mmHg.

Chronic Disease↗
PubMed1999

[Pulmonary lymphangioleiomyomatosis: an often fortuitous diagnosis. A case report].

INTRODUCTION: Lymphangioleiomyomatosis is an uncommon disorder of unknown origin, which exclusively occurs in women of reproductive age. The condition is characterized by proliferation of immature smooth muscle cells throughout the lungs, i.e., in the peribronchial, perilymphatic, and perivascular areas. This results in obliteration of the respiratory tract and in the development of cysts. Lymphangioleiomyomatosis has a poor prognosis due to both numerous lung complications and progression of the disease to respiratory failure. EXEGESIS: We report the case of a patient in whom lymphangioleiomyomatosis was fortuitously diagnosed from chest CT scan, itself performed for the diagnosis of pulmonary embolism. This case is therefore of particular interest. CONCLUSION: Our results suggest that the prevalence of lymphangioleiomyomatosis is probably underestimated due to its clinical latency and the absence of specific laboratory tests. Therefore, the development of non-invasive radiological methods should permit early diagnosis of the disease.

Adult↗
PubMed1999

Nocturnal efficiency and tolerance of a demand oxygen delivery system in COPD patients with nocturnal hypoxemia.

OBJECTIVES: We compared the efficacy of the standard nasal cannula and the demand oxygen delivery system (DODS) during sleep in patients with COPD. SUBJECTS: Twenty patients with moderate or severe COPD were included in the study. METHODS: Four consecutive polysomnographic recordings were performed under the following conditions: DODS powered by compressed air (night 1 [N1]); oxygen delivered with a nasal cannula alone (night 2 [N2]); oxygen delivered through a DODS (night 3 [N3]); and oxygen delivered with nasal cannula alone (night 4 [N4]). Oxygen flow rates with and without DODS were adjusted the day before the first night so that the resulting transcutaneous arterial oxygen saturation (SaO2) was > or = 95%. The following parameters were evaluated each night: apnea-hypopnea index, nocturnal SaO2, total oxygen saving, and several neurophysiologic parameters. RESULTS: The oxygen saving with the DODS was, on average, 60%. All parameters obtained during N2 and N4 (oxygen alone) were identical. The percentage of total recording time spent at SaO2 > or = 95% was comparable between N2 ([mean +/- SD]; 69+/-32%) and N3 (61+/-31%) (difference is not significant [NS]), as was the time spent at SaO2 between 90% and 95% (N2, 29.8+/-31%; N3, 35.9+/-27%; NS) and < 90% (N2, 0.75+/-2.6%; N3, 2.5+/-8.6%; NS). Although the mean response time was not significantly different between N2 and N3, two patients experienced a substantial increase in response time with an SaO2 < 90% on the DODS. The DODS device did not induce any difference in the percentage of time spent in rapid eye movement (REM) sleep (N2, 12.3+/-8.7%; N3, 16.4+/-7.8%; NS) or non-REM sleep (N2, 87.7+/-8.7%; N3, 83.7+/-7.9%; NS). Non-REM distribution in stage 1-2 sleep and in stage 3-4 sleep was comparable between N2 and N3. Similarly, no difference was observed for the sleep efficiency index (N2, 71+/-15%; N3, 69.6+/-14%; NS). Differences between sleep onset latency times were NS. CONCLUSIONS: In a majority of moderate to severe COPD patients, the use of a DODS device does not induce any significant alteration of nocturnal neurophysiologic and ventilatory profiles. However, the presence of nocturnal desaturation in a few patients justifies the need to systematically perform a ventilatory polygraphic recording when prescribing a DODS device.

Female↗
PubMed1999

[Mediastinal leiomyosarcoma].

Leiomyosarcomas are extremely rare tumors which develop from smooth muscle, usually in the esophagus and large vessels (inferior vena cava, pulmonary artery, and superior vena cava). In very rare cases, leiomyosarcomas develop from small vessels in the soft tissue of the mediastinum. Clinical expression of mediastinal leiomyosarcomas (dysphagia, dysphonia) is related to their large size and the subsequent compression of mediastinal structures. At pathology examination, the gross aspect is one of a single cell tumor. Microscopically, the tumor may be highly undifferentiated making it necessary to use specific immune markers (actin and desmin) or ultra-structural analysis to establish the diagnosis. Treatment of localized tumors is based on surgical excision, either alone or in combination with radiotherapy of the mediastinum. Chemotherapy, generally dexorubicin, is indicated in case of metastatic dissemination, but outcome remains uncertain. As for all soft tissue sarcomas, the prognosis of mediastinal leiomyosarcoma depends on the size of the tumor, its histological structure and its resectability.

Antineoplastic Agents↗