[Evolution of Spanish scientific production in international respiratory system journals from 1987 to 1998]

BACKGROUND

A relevant increase in the clinical relevance of respiratory system area has occurred in the last few years. The aims of this study were: to analyze the evolution of production and impact of Spanish scientific activity in the respiratory system area between 1987 to 1998; and to assess the participation of the different Spanish autonomic communities in this activity.

METHODS

Papers published in 38 international journals of respiratory system during this period of time were selected by the MedLine system, delimiting Spanish production. Geographical and institutional distribution of the production, specialist of authors, main publication journals and type of publication were recorded. Production and impact bibliometric indicators were estimated.

RESULTS

The number of Spanish documents from 1987 to 1998 multiplied by eight, reaching the 1.49% of the total published documents in 1998. However, the growth model of scientific production during this period was lineal. The increase in the scientific production was associated with a increase over time in the expected impact factor. In 1998, expected impact factor was 2. 206. Forty-two percent of the papers were signed by pneumologists. The highest contributor were hospitals. The most productive autonomous communities were Catalonia, Cantabria and Madrid. The communities with the highest expected impact factor were Balears and Catalonia.

CONCLUSIONS

A relevant increase has occurred in the scientific production and impact of Spanish biomedical activity in respiratory system area.

An evaluation of tissue polypeptide antigen (TPA) in the two bronchoalveolar lavage fractions of lung cancer patients

BACKGROUND

It has been proven that cytokeratins (CKs) are useful tumor markers for the follow-up, treatment monitoring and prognosis evaluation of lung cancer and among these, tissue polypeptide antigen (TPA) plays an important role. Nevertheless, only a small number of studies have been reported about their diagnostic capacity. Bronchoalveolar lavage (BAL) can be divided into two fractions: bronchiolar (BF) and alveolar (AF). For the above reasons, our aims were (1) to analyze the diagnostic usefulness of TPA in the BAL of lung cancer patients and (2) to observe if, in lung cancer patients, TPA levels in the two BAL fractions are different. This should mean that the study of tumor markers in the BAL should be carried out in both fractions to increase their diagnostic capacity.

METHODS

We studied 289 BALs divided into two phases. In phase I, TPA was analyzed in the BAL of six groups of subjects (healthy persons, chronic bronchitis, asthma, respiratory infections, diffuse interstitial pulmonary diseases and lung cancer). In phase II, TPA was studied in both BAL fractions of a group of patients with lung cancer.

RESULTS

We observed that TPA levels were significantly higher in the BAL of patients with bronchogenic neoplasias. In these patients, TPA was increased in the BF of the lavage in relation to the AF. In smoker patients with pulmonary carcinomas, TPA was higher in the AF of the BAL than in the lavage of non-smokers. This did not occur in the BF. We found no relation between the TPA concentrations and cancer histology.

CONCLUSIONS

We believe that TPA is a useful tumor marker with diagnostic capacity and this capacity is increased when it is studied in the two BAL fractions. Smoking habit may play a role in the secretion of tumor markers by the tumor cells.

Acute eosinophilic pneumonia associated with antidepressant agents

Acute eosinophilic pneumonia is a severe syndrome characterized by fever, lung infiltrates, blood eosinophilia and respiratory failure. We describe a case of acute eosinophilic pneumonia associated with clomipramine and sertraline. A 40-year-old woman was admitted to the emergency department with 37.9 degrees C and respiratory rate of 35 respirations per minute. Blood analysis showed PaO2 = 57.6 mm Hg and HCO3- = 21.7 mmol/l and 12.2% eosinophils. Chest X-ray showed infiltrates in both lower lobes. She was taking clomipramine 25 mg bid for the last 4 weeks and sertraline 50 mg/day for the last week. Other causes of acute eosinophilic pneumonia such as parasitic and fungal infections or collagen diseases were discarded. Both antidepressant were stopped and the patient became afebrile and asymptomatic. A week later the patient was discharged from hospital. Physicians should be aware of this adverse antidepresant reaction which may result in severe pulmonary symptoms.

[What is the cost of inappropriate admission of pneumonia patients?]

BACKGROUND

The number of patients admitted with community-acquired pneumonia (CAP) varies greatly from one hospital to another. Prognostic models for CAP can help physicians decide which cases to treat on an outpatient basis. Our aims were: a) to validate a model for predicting low-risk CAP, and b) to estimate savings that would have resulted if the low-risk patients identified by the model had been treated at home rather than in hospital.

PATIENTS AND METHODS

All CAP cases diagnosed by the emergency room physicians of a hospital in northwestern Spain (Ferrol) were enrolled prospectively over a period of 19 months. The prediction rule of Fine et al was used to classify all patients. Mortality in each category was compared with the mortality predicted by Fine's system. Patients in the lowest risk categories (I and II) were considered to have been inappropriately admitted unless they were hypoxemic or had significant comorbidity. Costs were figured based on data provided by our accounting department.

RESULTS

Of 192 CAP patients enrolled, 131 were admitted and 61 were treated as outpatients. Ten patients died, none of whom was in classes I or II. The costs of the apparently unnecessary hospital stays of the 34 patients in these classes was 6,979,756 pesetas. The estimated savings that would have derived from treating these patients out-of-hospital was 6,133,292 pesetas (36,862 euros; 322,804 pesetas/month).

CONCLUSIONS

a) The predictive model used has been found useful for identifying patients at very low risk of dying from CAP; b) Using this model can improve CAP admission criteria, and c) Application of the model can lead to savings.

[Estimate of bibliometric indicators of the impact of +Archivos de Bronconeumología]

The main bibliographic impact factors of ARCHIVOS DE BRONCONEUMOLOGIA for the past two years are estimated. Citations of ARCHIVOS DE BRONCONEUMOLOGIA in 1996 and 1997 by Medicina Clínica and all citing journals grouped under the heading "Respiratory System" in the Science Citation Index were counted. The year the citation appeared and the year of publication of the article in ARCHIVOS DE BRONCONEUMOLOGIA were recorded. The total number of articles published by ARCHIVOS DE BRONCONEUMOLOGIA between 1994 and 1996 were also counted. Based on these data we calculated our journal's impact factor for each year studied. Relative impact factor was also figured. In 1996 the exposure factor achieved was 1.602, the half-life of articles was 2.00 years, the impact factor was 0.069 and the relative impact factor was 1.371. In 1997 the exposure index was 1.477, the citation half-life was 3.00 years and the impact factor was 0.030. In conclusion, the international impact of ARCHIVOS DE BRONCONEUMOLOGIA is modest, although our relative impact factor is greater than that of some other internal medicine publications or specialized journals listed in Journal Citation Reports.

[Lymphangioleiomyomatosis and tuberous sclerosis: a casual association or a causative one?]

Lymphangioleiomyomatosis (LAM) is a rare lung disease that mainly affects women of childbearing age. Pulmonary disease that is indistinguishable from LAM appears in 1% of patients with tuberous sclerosis (TS). At present we can not say whether we are looking at an association of two rare diseases or at a single disease with different clinical profiles. To date, open lung biopsy has been required for definitive diagnosis. We report the case of a women with TS and LAM in whom a diagnosis of pulmonary involvement was based on clinical signs and high resolution computerized tomography of the chest.

CT in the evaluation of the upper airway in healthy subjects and in patients with obstructive sleep apnea syndrome

AIM

To study if the caliber of the upper airway, measured by CT, allows us to distinguish patients with obstructive sleep apnea syndrome (OSAS) from healthy people.

PATIENTS AND METHODS

Sixteen OSAS patients (with an apnea-hypopnea index > 10) and 39 healthy volunteers were studied. Polysomnography and CT of the upper airways during awake periods were performed in both groups. We used third-generation equipment (Toshiba model TCT 600QT). The area of the nasopharynx, oropharynx, and hypopharynx (in inspiration and expiration), the uvula diameter, and retropharyngeal tissue were evaluated. The simultaneous identification of the variables that differentiate between control and OSAS groups was determined by a multivariate discriminant model.

RESULTS

The retropharyngeal tissue in OSAS men was greater than those of the control men (10.3+/-3.6 mm vs 6.4+/-2.7 mm; p < 0.01). The multivariate analysis was performed on the 29 men (14 OSAS and 15 non-OSAS) who had information compiled in the selected parameters. The retropharyngeal tissue, expiratory hypopharynx, and uvular diameter are used to create a discriminant model (Wilks' lambda=0.556; p < 0.01). Two non-OSAS and five OSAS patients were incorrectly classified by this model as members of the other group (total rate of error, 24.14%). Therefore, the point estimates of specificity and sensitivity are 86.67% and 64.29%, respectively, for this model. The Pearson correlation coefficient between body mass index and retropharyngeal tissue is 0.63 (p < 0.001).

CONCLUSIONS

CT could play an important role in studying the upper airway in patients with OSAS. The determination of the retropharyngeal tissue by CT could be a useful procedure to evaluate OSAS.

[Definitive diagnosis of pulmonary sequestration using magnetic resonance. Description of 3 cases]

Pulmonary sequestration is a congenital malformation in which the pulmonary parenchyma is isolated from the rest of the lung and receives irrigation. Traditionally this malformation has been diagnosed by arteriography, but in recent years the usefulness of magnetic resonance, a technique that can probably substitute for arteriography on many occasions, has been emphasized. We report 3 cases of intralobar pulmonary sequestration diagnosed by magnetic resonance, a procedure that provided adequate presurgical assessment. The magnetic resonance images were later shown to be consistent with anatomical findings.

[Evolution of the bibliometric indicators of production and consumption of Archivos de Bronchopneumología in the last 20 years]

The aim of this study was to evaluate the evolution of bibliometric indicators for authorship and citation of ARCHIVOS DE BRONCONEUMOLOGIA over the past 20 years. At least 16 articles reporting new research or case reports were analyzed for every other year from 1976 to 1996. The following data were collected for each article: type of document, number of authors and their place of work and specialty, time interval between acceptance and publication, and references (including number, types, language, journal name and year of publication). The number of authors per article (collaboration index) averaged around five and has not varied significantly over the 20 years studied. Pulmonologists predominated among the authors, accounting for about 60% of the total, and most contributions came from a few provinces, mainly Barcelona and Madrid. The interval between reception and publication has gradually increased over the 20 years under review, coming to stand around 9.9 +/- 1.6 months in 1996. Most references (over 80%) cite journals and the proportion of references to books has decreased in recent years (from 12.3% in 1976 to 3.5% in 1996). The journal's index of isolation has increased (from 6.2 to 12.1%), as has the index of self-citation (from 0.4 to 6.2%). Although most cited works are in English (over 80%), the proportion of Spanish-language references increased (from 6.2 to 12.1%). In conclusion, maintenance of the number of collaborating authors, the predominance of journals and English-language sources among references are the main traits that characterize the bibliometric indicators for authorship and citation in ARCHIVOS DE BRONCONEUMOLOGIA.

[Bibliometric indicators of production and usage of Archivos de Bronchoneumologia]

We studied the bibliometric indexes referring to production and scientific output published in ARCHIVOS de BRONCONEUMOLOGIA. All issues published between 1993 and 1994 were studied with the exception of monógraphic or supplementary numbers. For each article we recorded article type, number of authors, authors' place of work, specialty, time until acceptance, time until publication, type of references, language of references, journal and year of references. For each year we calculated the productivity index and the cooperation index, or index of signers per work. We also determined the citation period for references, the Price index, and the insularity index. Productivity index was 1.97 in 1993 and 2.05 in 1994. The cooperation index for the two years reached 4.5 +/- 1.9 (1-10). Authors were widely distributed by provinces and by specialties, although "nuclei" of production could be identified. The citation half-life period was 5.67 years for references in 1993 and 5.94 years in 1994, and the Price index surpassed 40%. The insularity index was very low at 7.76%. In conclusion, the bibliometric indicators for production, readership and obsolescence for the two years analyzed indicate that ARCHIVOS de BRONCONEUMOLOGIA occupies an intermediate position in the ranking of Spanish medical journals.

[The diagnosis of sleep apnea syndrome with a portable device. Our experience with 100 cases]

Portable devices might be an alternative method to diagnose patients suspected for obstructive sleep apnea syndrome (OSAS). We have analized one hundred patients consecutively referred to our especialized out-patient clinic for sleep breathing disorders. We have used a previously validated portable device-Polygraphics CNS-which records thoracoabdominal movement, nasobuccal airflow, ECG, oxymetry, body position, and continuous positive airway pressure (CPAP). Sixty patients showed an apnea/hypopnea index (AHI) > 15. Seven patients showed an AHI > 10f plus symptoms suggestive of OSAS. Two patients had an AHI between 5-10 and very high suspicion for OSAS; a subsequent CPAP treatment showed the disappearance of respiratory events and an evident improvement in oxymetric records. Twenty two patients showed an AHI < 5. Nine patients could not be classified and other diagnostic method were deemed necessary.

CONCLUSION

A previously validated cardiorrespiratory portable polygraphic device was useful in most cases for taking diagnostic decisions in OSAS.