Diagnosis Of Acute Respiratory Failure Research Articles

Role of biomarkers in the differential diagnosis of acute respiratory failure in the immediate postoperative period of lung transplantation

Abstract Lung transplant recipients are at high risk of suffering many complications during the immediate postoperative period, such as primary graft dysfunction, acute graft rejection or infection. The most common symptom is the presence of acute respiratory failure, and the use of biomarkers could be useful for establishing an early diagnosis of these conditions. Different biomarkers have been studied, but none have proven to be the gold standard in the differential diagnosis of acute respiratory failure. This paper offers a review of the different biomarkers that have been studied in this field.

Aetiological diagnosis of acute respiratory failure in critical care oncology

Acute complications are frequent in cancer patients and their adequate management, including in critical care units, may be crucial [1]. The prognosis of such complications in terms of intensive care unit (ICU) and hospital mortality is mainly determined by the acute physiological perturbations they induce, as reflected by gravity scores in critically ill cancer patients [2, 3], but also by the degree of life-supporting therapy that is required, such as mechanical ventilation [3, 4, 5] or extra renal epuration [6]. This has been confirmed by many other studies summarised in a systematic review of the literature [7]. After recovery from the acute complication, the further prognosis is determined by the characteristics of the underlying cancer and no longer related to the perturbations induced by the complication [1]. The most frequent cause of ICU admission in cancer patients is acute respiratory failure (ARF). It can be due to a direct manifestation of the malignant disease (for example by airway obstruction or pleural effusion), treatment toxicity (for example by radiation or drug pneumonitis) or indirect complications, such as infections …

Les hospitalisations pour asthme chez l’enfant en France, 2002–2010

Most hospital admissions for asthma exacerbation are avoidable with adequate disease management. The objective of this study was to describe admissions for asthma in children in France using data from the French nationwide hospital database. We selected admissions having either a main diagnosis of asthma or a main diagnosis of acute respiratory failure (ARF) with asthma as an associated diagnosis, occurring in children (age<15years) between 2002 and 2010 in France (excluding French Guyana). In 2010, 35,004asthma admissions and 1381cases of asthma-related ARF were recorded (crude admission rate, 30.1/10,000 children); the mean length of stay was 2days. The in-hospital lethality rate ranged from 0.01% to 0.03% depending on the year. The annual age-standardized admission rate increased between 2002 and 2010 (+2.5% per year on average in metropolitan France). In 2010, 11.8% of children admitted for asthma or asthma-related ARF were readmitted for asthma or asthma-related ARF at least once within the same calendar year, and 1.3% were readmitted within the week following admission. The proportion of children aged less than 5 years who were readmitted within the same calendar year increased between 2002 and 2010. The increase in admission and readmission rates indicates non-optimal management of asthma in children in France.

High Resource Utilization Does Not Affect Mortality in Acute Respiratory Failure Patients Managed With Tracheostomy

Tracheostomy practice in patients with acute respiratory failure (ARF) varies greatly among institutions. This variability has the potential to be reflected in the resources expended providing care. In various healthcare environments, increased resource expenditure has been associated with a favorable effect on outcome. To examine the association between institutional resource expenditure and mortality in ARF patients managed with tracheostomy. We developed analytic models employing the University Health Systems Consortium (Oakbrook, Illinois) database. Administrative coding data were used to identify patients with the principal diagnosis of ARF, procedures, complications, post-discharge destination, and survival. Mean resource intensity of participating academic medical centers was determined using risk-adjusted estimates of costs. Mortality risk was determined using a multivariable approach that incorporated patient-level demographic and clinical variables and institution-level resource intensity. We analyzed data from 44,124 ARF subjects, 4,776 (10.8%) of whom underwent tracheostomy. Compared to low-resource-intensity settings, treatment in high-resource-intensity academic medical centers was associated with increased risk of mortality (odds ratio 1.11, 95% CI 1.05-1.76), including those managed with tracheostomy (odds ratio high-resource-intensity academic medical center with tracheostomy 1.10, 95% CI 1.04-1.17). We examined the relationship between complication development and outcome. While neither the profile nor number of complications accumulated differed comparing treatment environments (P > .05 for both), mortality for tracheostomy patients experiencing complications was greater in high-resource-intensity (95/313, 30.3%) versus low-resource-intensity (552/2,587, 21.3%) academic medical centers (P < .001). We were unable to demonstrate a positive relationship between resource expenditure and outcome in ARF patients managed with tracheostomy.

Epidemiology and outcomes of acute respiratory failure in the United States, 2001 to 2009: A national survey

The objective of this study was to evaluate trends in hospitalization, cost, and short-term outcomes in acute respiratory failure (ARF) between 2001 and 2009 in the United States. Using the Nationwide Inpatient Sample we identified cases of ARF based on International Classification for Diseases, Ninth Revision, Clinical Modification codes. We calculated weighted frequencies of ARF hospitalizations by year and estimated population-adjusted incidence and mortality rates. We used logistic regression to examine hospital mortality rates over time while adjusting for changes in demographic characteristics and comorbidities of patients. The number of hospitalizations with a diagnosis of ARF rose from 1,007,549 in 2001 to 1,917,910 in 2009, with an associated increase in total hospital costs from $30.1 billion to $54.3 billion. During the same period we observed a decrease in hospital mortality from 27.6% in 2001 to 20.6% in 2009, a slight decline in average length of stay from 7.8 days to 7.1 days, and no significant change in the mean cost per case ($15,900). Rates of mechanical ventilation (noninvasive [NIV] or invasive mechanical ventilation [IMV]) remained stable over the 9-year period, and the use of NIV increased from 4% in 2001 to 10% in 2009. Over the period of 2001 to 2009, there was a steady increase in the number of hospitalizations with a discharge diagnosis of ARF, with a decrease in inpatient mortality. There was a significant shift during this time toward the use of NIV, with a decrease in the rates of IMVuse.

Clinical surrogate markers of hypoxemia: Correlation of clinical variables with PaO2/FiO2 ratio

Background: Acute respiratory failure is the most common type of organ failure encountered in intensive care unit. PaO2/FiO2 Materials and Methods: This cross sectional study was conducted in intensive care unit of a 1000 bedded hospital. All patients with clinical diagnosis of acute respiratory failure were included in the study. For each patient PaO2 was recorded by obtaining arterial blood gas. Each time P/F ratio was correlated with corresponding clinical signs like single breath count, heart rate, systolic blood pressure, cyanosis, use of accessory muscle etc. Results: Correlation was found between single breath count, heart rate and P/F ratio.

423 Acute Respiratory Failure in Children - A 3 Years Epidemiological Study

Background and AimsAcute respiratory failure is the most frequent reason for admission in a pediatric emergency department. This study aimed to investigate the epidemiological characteristics of patients admitted with acute...

Lung Ultrasound in the Critically Ill Neonate

Critical ultrasound is a new tool for first-line physicians, including neonate intensivists. The consideration of the lung as one major target allows to redefine the priorities. Simple machines work better than up-to-date ones. We use a microconvex probe. Ten standardized signs allow a majority of uses: the bat sign (pleural line), lung sliding and the A-line (normal lung surface), the quad sign and sinusoid sign indicating pleural effusion regardless its echogenicity, the tissue-like sign and fractal sign indicating lung consolidation, the B-line artifact and lung rockets (indicating interstitial syndrome), abolished lung sliding with the stratosphere sign, suggesting pneumothorax, and the lung point, indicating pneumothorax. Other signs are used for more sophisticated applications (distinguishing atelectasis from pneumonia for instance...). All these disorders were assessed in the adult using CT as gold standard with sensitivity and specificity ranging from 90 to 100%, allowing to consider ultrasound as a reasonable bedside gold standard in the critically ill. The same signs are found, with no difference in the critically ill neonate. Fast protocols such as the BLUE-protocol are available, allowing immediate diagnosis of acute respiratory failure using seven standardized profiles. Pulmonary edema e.g. yields anterior lung rockets associated with lung sliding, making the B-profile. The FALLS-protocol, inserted in a Limited Investigation including a simple model of heart and vessels, assesses acute circulatory failure using lung artifacts. Interventional ultrasound (mainly, thoracocenthesis) provides maximal safety. Referrals to CT can be postponed. CEURF proposes personnalized bedside trainings since 1990. Lung ultrasound opens physicians to a visual medicine.

The BLUE-points: three standardized points used in the BLUE-protocol for ultrasound assessment of the lung in acute respiratory failure

Sir,The BLUE-protocol is designed for immediate diagnosis ofacute respiratory failure, one of the most distressing set-tings for patients [1]. Physicians would appreciate stan-dardized areas of investigation. The BLUE-points respondto this quest. Of the seven principles of lung ultrasound [2],principle 2, indicating that the disorders are distributedalong an Earth–Sky axis, and principle 3, which recalls thatthe lung is the most voluminous organ, are used.Bedside use and absence of irradiation favor the use ofultrasound [3]. Studies have shown that most acute lungdisorders benefit from standardized locations. Clinicallyrelevant interstitial syndrome locates anteriorly [4]. Freepneumothoraces always locate anteriorly [5]. As free fluidsfollow gravity rules [6], all cases of free pleural fluideffusion, regardless its abundance locate at least posteriorlyabove the diaphragm [7]. Lung consolidation can locateeverywhere depending on the cause and extension, yieldingsensitivity lower than other disorders, 90% [8], yet itsposterior location above the diaphragm in critically illpatients with pneumonia is usual [4].We consider the hands of the patient (called BLUE-hands, roughly standard doctor’s hands size in standardadults; physicians with large or small hands would makethe adaptation once for all). The hands, applied as shown inFig. 1, define the anterior chest wall. This is of great helpin patients with major obesity, nipple ptosis, etc. Thisworks with patients of any size, neonate included. TheBLUE-hands allows to define five regions of interest. Theupper and lower BLUE-points, the phrenic line, defined inFig. 1, are anterior. The phrenic point is lateral, defined inFig. 2. The PLAPS-point, defined in Fig. 2 from the lowerBLUE-point, is posterior. The Carmen maneuver extendsthe location of the BLUE-points: by a slight back-and-forthmovement of the probe held longitudinally to the left andthe right, remaining at the same skin point and gently

Detection of Postoperative Respiratory Failure: How Predictive Is the Agency for Healthcare Research and Quality's Patient Safety Indicator?

Patient Safety Indicator (PSI) 11, or postoperative respiratory failure, was developed by the US Agency for Healthcare Research and Quality to detect incident cases of respiratory failure after elective operations through use of ICD-9-CM diagnosis and procedure codes. We sought to determine the positive predictive value (PPV) of this indicator. We conducted a retrospective cross-sectional study, sampling consecutive cases that met PSI 11 criteria from 18 geographically diverse academic medical centers on or before June 30, 2007. Trained abstractors from each center reviewed medical records using a standard instrument. We assessed the PPV of the indicator (with 95% CI adjusted for clustering within centers) and conducted descriptive analyses of the cases. Of 609 cases that met PSI 11 criteria, 551 (90.5%; 95% CI, 86.5-94.4%) satisfied the technical criteria of the indicator and 507 (83.2%; 95% CI, 77.2-89.3%) represented true cases of postoperative respiratory failure from a clinical standpoint. The most frequent reasons for being falsely positive were nonelective hospitalization, prolonged intubation for airway protection, and insufficient evidence to support a diagnosis of acute respiratory failure. Fifty percent of true-positive cases involved substantial baseline comorbidities, and 23% resulted in death. Although PSI 11 predicts true postoperative respiratory failure with relatively high frequency, the indicator does not limit detection to preventable cases. The PPV of PSI 11 might be increased by excluding cases with a principal diagnosis suggestive of a nonelective hospitalization and those with head or neck procedures. Removing the diagnosis code criterion from the indicator might also increase PPV, but would decrease the number of true positive cases detected by 20%.

Utilidad de la ecografía pulmonar en la unidad de medicina intensiva

The radiological diagnostic approach of the thorax in the critically ill patient has traditionally been based on the anteroposterior chest X-ray. However, it is generally accepted that it has important limitations regarding its diagnostic accuracy of pleuro-pulmonary disease. The introduction of computed tomography largely solved this problem, but with the dual disadvantage of a larger radiation dose and the unavoidable transportation outside of the ICU. In this context, the lung ultrasound has become an alternative technique, with the advantage that due to its portability, it is done at the patient's bedside. In the lung ultrasound, the ribs, spine and air in the thorax act as barriers to the ultrasounds, causing artifacts that must be recognized and interpreted for a correct diagnosis. However, intrathoracic diseases, existence of fluid in the pleural space and consolidation, or atelectasis in the lung provide a sufficient ultrasound window for the correct evaluation. In this review, we explain the lung and pleural ultrasound technique, define the normal pattern and the artifacts that serve to detect the abnormalities and we explain the criteria for the main diseases (consolidation, pleural effusion, pulmonary edema and pneumothorax). We also discuss the possible utility and limitations of the lung ultrasound in our daily practice, such as diagnosis of acute respiratory failure, detection, quantification and drainage of a pleural effusion, chest trauma, management and complications of acute respiratory distress syndrome and tracheal intubation success or failure.

Utility of Lung Sonography in Acute Respiratory Failure

To the Editor: I read with interest the article written by Drs. Lichtenstein and Mezière1Lichtenstein DA Mezièere GA Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol.Chest. 2008; 134: 117-125Abstract Full Text Full Text PDF PubMed Scopus (1143) Google Scholar in a recent issue of CHEST (July 2008) on the use of ultrasound to make a rapid diagnosis in patients with acute respiratory failure with the BLUE protocol. In the “Materials and Methods” section of the article, it is says that the ultrasound examination took no longer than 3 min. If the test was limited to just the evaluation of the lungs, one can believe that in experienced hands 3 min would be sufficient. But going by the protocol, a patient with an A profile (ie, anterior predominant bilateral A lines with lung sliding) would require venous analysis. In my opinion, it is not possible to do venous analysis for deep vein thrombosis within 3 min, even if one is limiting the study to compression sonography.2Kheir DE One time comprehensive ultrasonography to diagnose deep vein thrombosis: is that the solution.Ann Intern Med. 2004; 140: 1052-1053Crossref PubMed Scopus (17) Google Scholar In a patient with underlying chronic interstitial syndrome, it would be very difficult to differentiate acute exacerbation of the underlying disease from pulmonary edema; hence, the knowledge of a patient's medical history is crucial in such a situation.3Lichtenstein D Mezièere G Biderman P et al.The comet-tail artifact: an ultrasound sign of alveolar-interstitial syndrome.Am J Respir Crit Care Med. 1997; 156: 1640-1646Crossref PubMed Scopus (762) Google Scholar Pneumonia can present with different profiles (A, anterior predominant bilateral A lines with lung sliding; A/B, anterior predominant B+ lines on one side and predominant A lines on the other side; C, anterior alveolar consolidations; and B', anterior predominant B+ lines with abolished lung sliding), which can make it confusing for clinicians especially while they are learning the use of lung sonography. I find lung sonography to be very useful in patients with conditions such as pulmonary edema and pleural effusions, and in ruling out pneumothorax.4Beaulieu Y Marik PE Bedside ultrasonography in the ICU: part 1.Chest. 2005; 128: 881-895Abstract Full Text Full Text PDF PubMed Scopus (156) Google Scholar, 5Beaulieu Y Marik PE Bedside ultrasonography in the ICU: part 2.Chest. 2005; 128: 1766-1781Abstract Full Text Full Text PDF PubMed Scopus (119) Google Scholar For other clinical presentations such as COPD, pneumonia, asthma, and pulmonary embolism, one may have to acquire extensive experience before becoming comfortable in interpreting the results. The authors excluded 41 patients from analysis (16 patients with an unknown diagnosis, 16 with several final diagnoses, and 9 with a rare diagnosis). In clinical practice, these are the very patients who cause a diagnostic dilemma, in whom, besides a clinical examination and basic laboratory tests, clinicians would want to perform a diagnostic test with high accuracy. The yield of ultrasonography would decline if these patients were considered for statistical analysis.

Relevance of Lung Ultrasound in the Diagnosis of Acute Respiratory Failure: The BLUE Protocol

Relevance of Lung Ultrasound in the Diagnosis of Acute Respiratory Failure: The BLUE Protocol

Relevance of Lung Ultrasound in the Diagnosis of Acute Respiratory Failure*: The BLUE Protocol

This study assesses the potential of lung ultrasonography to diagnose acute respiratory failure. This observational study was conducted in university-affiliated teaching-hospital ICUs. We performed ultrasonography on consecutive patients admitted to the ICU with acute respiratory failure, comparing lung ultrasonography results on initial presentation with the final diagnosis by the ICU team. Uncertain diagnoses and rare causes (frequency<2%) were excluded. We included 260 dyspneic patients with a definite diagnosis. Three items were assessed: artifacts (horizontal A lines or vertical B lines indicating interstitial syndrome), lung sliding, and alveolar consolidation and/or pleural effusion. Combined with venous analysis, these items were grouped to assess ultrasound profiles. Predominant A lines plus lung sliding indicated asthma (n=34) or COPD (n=49) with 89% sensitivity and 97% specificity. Multiple anterior diffuse B lines with lung sliding indicated pulmonary edema (n=64) with 97% sensitivity and 95% specificity. A normal anterior profile plus deep venous thrombosis indicated pulmonary embolism (n=21) with 81% sensitivity and 99% specificity. Anterior absent lung sliding plus A lines plus lung point indicated pneumothorax (n=9) with 81% sensitivity and 100% specificity. Anterior alveolar consolidations, anterior diffuse B lines with abolished lung sliding, anterior asymmetric interstitial patterns, posterior consolidations or effusions without anterior diffuse B lines indicated pneumonia (n=83) with 89% sensitivity and 94% specificity. The use of these profiles would have provided correct diagnoses in 90.5% of cases. Lung ultrasound can help the clinician make a rapid diagnosis in patients with acute respiratory failure, thus meeting the priority objective of saving time.

Use of blockers and the risk of death in hospitalised patients with acute exacerbations of COPD

Cardiovascular disease is a major cause of death in patients with chronic obstructive pulmonary disease (COPD) and predicts hospitalisation for acute exacerbation, in-hospital death and post-discharge mortality. Although beta blockers improve cardiovascular outcomes, patients with COPD often do not receive them owing to concerns about possible adverse pulmonary effects. There are no published data about beta blocker use among inpatients with COPD exacerbations. A study was undertaken to identify factors associated with beta blocker use in this setting and to determine whether their use is associated with decreased in-hospital mortality. Administrative data from the University of Alabama Hospital were reviewed and patients admitted between October 1999 and September 2006 with an acute exacerbation of COPD as a primary diagnosis or as a secondary diagnosis with a primary diagnosis of acute respiratory failure were identified. Demographic data, co-morbidities and medication use were recorded and subjects receiving beta blockers were compared with those who did not. Multivariate regression analysis was performed to determine predictors of in-hospital death after controlling for known covariates and the propensity to receive beta blockers. 825 patients met the inclusion criteria. In-hospital mortality was 5.2%. Those receiving beta blockers (n = 142) were older and more frequently had cardiovascular disease than those who did not. In multivariate analysis adjusting for potential confounders including the propensity score, beta blocker use was associated with reduced mortality (OR = 0.39; 95% CI 0.14 to 0.99). Age, length of stay, number of prior exacerbations, the presence of respiratory failure, congestive heart failure, cerebrovascular disease or liver disease also predicted in-hospital mortality (p<0.05). The use of beta blockers by inpatients with exacerbations of COPD is well tolerated and may be associated with reduced mortality. The potential protective effect of beta blockers in this population warrants further study.

Variations in rates of tracheostomy in the critically ill trauma patient*

The utility of tracheostomy to expedite weaning and prevent complications in patients with acute respiratory failure is actively debated, with many physicians holding strong opinions regarding the value and timing of this intervention. We postulated that these opinions would be reflected in significant variation in tracheostomy rates across centers. Thus, we set out explore the extent and potential sources of this variation among injured patients cared for in trauma centers in the United States. This is a retrospective cohort study. We used stratification and hierarchical multivariate analysis to evaluate the effect of patient and institutional characteristics on tracheostomy rates and variance decomposition to determine the proportion of variance across institutions explained by patient characteristics. Intensive care units within trauma centers participating in the National Trauma Databank. Injured patients admitted over the years 2001-2003, age >/=16 yrs, with an Injury Severity Score >/=9 and a diagnosis of acute respiratory failure, excluding patients with burn injuries and those with a severe injury to the face or neck who might require tracheostomy for maintenance of an airway. None. There were 17,523 patients meeting inclusion criteria: 4,146 (24%) underwent tracheostomy. The mean tracheostomy rate across centers was 19.6 per 100 hospital admissions with a range of 0-59. This variation persisted after stratification by age, injury mechanism, and severity. Although several patient and injury characteristics were predictive of tracheostomy, there were no identifiable institutional characteristics associated with tracheostomy. Patient characteristics accounted for only 14% of the variance across centers. There is significant unexplained variation in the rates of tracheostomy in critically injured patients with acute respiratory failure. This variation might reflect preconceived notions of efficacy among physicians practicing in the absence of evidence to guide care. The variation provides evidence of equipoise and emphasizes the need for a well-conducted randomized controlled trial to evaluate the utility of this procedure.

Plastic bronchitis in a child with thalassemia alpha

Plastic bronchitis is an unusual condition in children, associated with formation of mucofibrinous casts and mucous plugging of the tracheobronchial tree. Given that this illness is part of the differential diagnosis of acute respiratory failure, early treatment is important for improved prognosis. The aim of this report is to describe a case of plastic bronchitis in a child with alpha-thalassemia that was treated successfully with endoscopy. A three year old, black, male child, previously healthy, presented with acute respiratory failure and a chest x-ray showing pulmonary atelectasis. There was no evidence of respiratory symptoms or previous allergy state. The diagnosis of plastic bronchitis was made using flexible and rigid bronchoscopy, and confirmed by histopathologic findings. The child progressed well, treatment was based on supportive care and antibiotics were not used. Ten days after discharge, radiographic appearance was normal. Alpha thalassemia was diagnosed through hemoglobin electrophoresis. Plastic bronchitis is clinically important because has similar presentation to other prevalent diseases, such as foreign body aspiration and asthma. When plastic bronchitis is suspected, endoscopy is indicated in order to confirm diagnosis and define treatment. Plastic bronchitis has been previously described in patients with cystic fibrosis, cardiac surgery and sickle cell disease. In this case, an association with alpha-thalassemia was observed.

Bronquite plástica em criança com talassemia alfa

OBJETIVO: A bronquite plástica é uma doença infreqüente na criança, sendo caracterizada por moldes ou cilindros mucofibrinosos na árvore traqueobrônquica. Faz parte do diagnóstico diferencial de crianças com insuficiência respiratória de início agudo, e o tratamento precoce é importante para a resolução do quadro. O objetivo deste relato é descrever um caso de bronquite plástica tratado com sucesso por endoscopia, em paciente portador de talassemia alfa. DESCRIÇÃO: Criança do sexo masculino, 3 anos de idade, sem antecedentes mórbidos significativos, apresentou quadro de insuficiência respiratória aguda, com achados radiológicos de atelectasia pulmonar sugestivos de aspiração de corpo estranho. Não havia sintomas respiratórios ou antecedentes de alergia ou infecções respiratórias de repetição. A realização de broncoscopia flexível, complementada por endoscopia rígida e exame anatomopatológico, evidenciou a presença de bronquite plástica. Após a realização da endoscopia, a criança evoluiu satisfatoriamente, com curva térmica afebril e extubação em 72 horas. Foram utilizadas medicações sintomáticas, sem necessidade de antimicrobianos. Dez dias após a alta, a radiografia de tórax encontrava-se normal. A talassemia alfa foi diagnosticada através da eletroforese de hemoglobina. COMENTÁRIOS: A importância clínica da bronquite plástica reside no fato de apresentar um quadro semelhante ao de outras doenças mais prevalentes, como a aspiração de corpo estranho e a asma brônquica. A suspeita do quadro recomenda a realização de endoscopia para diagnóstico e tratamento. É reconhecida a ocorrência de bronquite plástica em crianças com fibrose cística, pós-operatório de cirurgia cardíaca e anemia falciforme. No presente artigo, foi observada uma associação com talassemia alfa.

Insuffisance respiratoire aiguë. Démarches diagnostique et thérapeutique

In acute respiratory failure, like in all vital emergency conditions, it is necessary to identify the aetiology and initiate treatment at the same time. Symptomatic treatment is usually required, even before knowing the exact reason of respiratory failure. In the vast majority of cases, the diagnosis of acute respiratory failure is easy. Determining its aetiology is more difficult but is required to define a specific treatment able to prevent relapse. Some causes are obvious (thoracic injury, drowning, haemoptysis…), others are easy to recognize on the basis of clinical data (asthma, left cardiac failure, airway obstruction, pleural effusion, acute failure of known chronic respiratory insufficiency). In other cases, chest radiography is the key point for aetiological diagnosis: normal or almost normal results indicate neuro-muscular causes, ENT pathologies, asthma and pulmonary embolism. In other situations, chest radiography allows distinguishing parietal aetiologies (pleural effusion, diaphragmatic pathology), atelectasis, alveolar lesions (pulmonary oedema, infectious disease, allergic alveolitis, haemorrhages), and interstitial lesions (lymphangitis, pulmonary fibrosis, infectious diseases, bronchiolitis…). When aetiology remains doubtful, some pathologies more difficult to recognise must be quickly rewarded: atypical cardiac insufficiency, pulmonary embolism, chronic respiratory failure unknown before… Symptomatic treatment begins with oxygen on the basis of arterial blood gases analysis. In case of failure, mechanical ventilation may be required, non-invasive if possible, or using an intra-tracheal device.

Insuficiência respiratória aguda como primeira manifestação de esclerose lateral amiotrófica: dois casos clínicos

Amyotrophic Lateral Sclerosis (ALS) is a fast progressing neuromuscular disease that affects all but the extrinsic muscles of the eye and sphincters. The main cause of morbidity and mortality are the respiratory complications that usually start in a late stage of the diseases natural history. In a small number of cases acute respiratory failure is the initial manifestation of the disease. The authors present 2 case studies admitted to a pulmonary department, without previously known neuromuscular disease, with the diagnosis of acute respiratory failure of unknown etiology and that were later shown to be cases of ALS. Analysis of the cases presented here, and those already published in the literature, suggests that the occurrence of acute respiratory failure in patients without a previous history of pulmonary and/or heart disease, especially in the 5th and 6th decade of life, should alert to ALS as a possible diagnosis.