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As part of the multicenter National Heart, Lung, and Blood Institute registry of patients with severe deficiency of [[Alpha].sub.1]-antitrypsin with 1,129 enrollees, this report describes measures undertaken to achieve high-quality [FEV.sub.1] measurements, the rates of satisfying reproducibility and acceptability criteria, and clinical features of participants unable to achieve reproducible [FEV.sub.1] values at baseline. Spirograms were performed both before and after an inhaled bronchodilator in enrollees followed up at 37 participating clinical centers. Using a reproducibility criterion of [is less than] 100 mL or 5% (whichever greater), high reproducibility rates for [FEV.sub.1] measurements at baseline were observed for both prebronchodilator (95.0% of 1,090 sessions) and postbronchodilator measurements (95.7% of 1,077 sessions). Using the more recently published reproducibility criterion of [is less than or equal to] 200 mL, reproducibility rates were even higher. Eighty-four percent of clinical centers submitted [FEV.sub.1] values that satisfied reproducibility criteria for at least 90% of spirograms. Also, the mean coefficient of variation for prebronchodilator [FEV.sub.1] values measured over serial visits separated by up to 9 months was 5.6% for participants with baseline [FEV.sub.1] 55 to 90% predicted. This degree of reproducibility is similar to that observed in the Lung Health Study. Rates of satisfying acceptability criteria for prebronchodilator spirograms were lower, almost universally (98% of tests) due to failure to achieve end-of-test criteria (which usually required 15 s of expiration in this population with mean [FEV.sub.1]=42.6 ± 29.6% [SD] predicted). Multivariate logistic regression models show that clinical correlates of failure to achieve reproducible prebronchodilator [FEV.sub.1] efforts include symptoms of chronic wheeze, chronic cough, and chronic phlegm, and the degree of airflow obstruction. We conclude that highly reproducible [FEV.sub.1] measurements are achievable in a population with severe airflow obstruction despite the additional challenges posed by testing in multiple centers on a variety of spirometers. Furthermore, the difficulty of satisfying end-of-test criteria in a large cohort with severe airflow obstruction did not preclude achieving high rates of reproducibility for [FEV.sub.1] measurements. Finally, our study confirms prior observations that failure to achieve reproducible efforts is associated with the presence of pulmonary symptoms and the degree of airflow obstruction. Thus, excluding patients with nonreproducible [FEV.sub.1] efforts from epidemiologic studies would bias results by including only healthier participants. (CHEST 1997; 111:899-909) Key words: acceptability; [α.sub.1]-antitrypsin deficiency; emphysema; quality control; spirometry Abbreviations: A1AT=[[Alpha].sub.1]-antitrypsin; ATS=American Thoracic Society; CI=confidence interval; OR=odds ratio, Despite study in several longitudinal series to date, the natural history of severe deficiency of [[Alpha].sub.1]-antitrypsin (A1AT) remains poorly understood.[1-9] Shortcomings of available studies[1-9] include the small number of individuals [...]

Nine medical centers collaborated in a prospective randomized study to evaluate prolonged extracorporeal membrane oxygenation (ECMO) as a therapy for severe acute respiratory failure (ARF). Ninety adult patients were selected by common criteria of arterial hypoxemia and treated with either conventional mechanical ventilation (48 patients) or mechanical ventilation supplemented with partial venoarterial bypass (42 patients). Four patients in each group survived. The majority of patients suffered acute bacterial or viral pneumonia (57%). All nine patients with pulmonary embolism and six patients with posttraumatic acute respiratory failure died. The majority of patients died of progressive reduction of transpulmonary gas exchange and decreased compliance due to diffuse pulmonary inflammation, necrosis, and fibrosis. We conclude that ECMO can support respiratory gas exchange but did not increase the probability of long-term survival in patients with severe ARF.(JAMA 242:2193-2196, 1979)

Forty-two patients underwent open-lung biopsy during the early phase of acute respiratory insufficiency. Correlation between the gross appearance of the lung at operation and the microscopic findings was good. Although only fair correlation was found between lung and tracheal cultures, the findings of two positive cultures in the lung only was of utmost importance. Biopsying multiple areas from the same operation showed identical pathology in 86 per cent of cases. The mortality rate of open-lung biopsy was zero; the morbidity rate was 4 per cent. The over-all survival rate of acute respiratory insufficiency (ARI) due to trauma was 39 per cent; that of pneumonia, 11 per cent. In 17 (33 per cent) patients specific diagnoses and/or specific therapies were employed as a direct result of the biopsy or the thoracotomy. The incidence and prognostic implications of fibrosis and microthromboembolism are presented and discussed. Open-lung biopsy has been extremely safe and valuable in characterizing and managing ARI.

• Clinical evaluation and pulmonary function tests were performed in 218 patients with motor neuron disease, mainly amyotrophic lateral sclerosis (ALS). Serial studies were obtained in 103 patients, in 31 until death from ALS. Most patients, regardless of the pattern of motor neuron involvement, had characteristic abnormalities in pulmonary function, including reduced forced vital capacity (FVC) and maximum voluntary ventilation (MVV). Reductions in the FVC and MVV to as low as 50% were commonly missed by clinical evaluators. Spirometry is therefore of value in detecting early involvement of respiratory neurons. Progressively greater reductions in the FVC and MVV in all the fatal cases indicate that serial spirometry has prognostic value in ALS.

Twenty-five patients suffering from acute respiratory insufficiency were treated with extracorporeal membrane oxygenation (ECMO) when all other forms of conventional management had failed. Since not all forms of acute respiratory insufficiency are reversible, an effort has been made to identify the patients and conditions in which this therapy will be most beneficial. The results are reviewed and the etiologic, clinical, pathological, and physiological factors most affecting the outcome are identified. Unfavorable signs are a long initial illness, a persistent “severe fixed shunt,” pulmonary fibrosis, increasing hypercapnia, and uncontrollable disseminated intravascular coagulation (DIC). With early recognition of favorable signs, ECMO offers the possibility of altering the course of acute respiratory insufficiency. In these patients, the reversal of pulmonary pathology was dramatic and beneficial.

IN REPLY.— We agree with Dr Bensam that the vast majority of reduced flow rates in amyotrophic lateral sclerosis (ALS) are caused by the neuromuscular disease. Airway obstruction was only diagnosed when there were other objective findings to indicate airway obstruction, eg, curvature of the flow volume loop or a delayed helium mixing time. Thus, 19% of our patients were considered to suffer from airway obstruction in addition to neuromuscular impairment. This is not surprising since more than 50% of those studied were cigarette smokers.We disagree that tracheostomy would always be needed when the vital capacity falls below 1,200 cc. Some patients maintain adequate gas exchange with vital capacities much less than 1 L or less than 20% predicted. Conversely, some patients with larger vital capacities have frequent respiratory difficulties due to bulbar involvement, causing recurrent aspiration, pneumonia, or atelectasis. When such clinical problems arise, we generally try to avoid tracheostomy