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Biomedical subjects

A J Roncoroni

Publications and source records attributed to A J Roncoroni.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Non-invasive mechanical ventilation in intensive care].

Non-invasive mechanical ventilation is useful in order to delay or avoid endotracheal intubation. Continuous positive airway pressure (CPAP) is helpful for patients with decreased lung compliance, airways obstruction due to vocal cord paralysis or tracheobronchomalacia, presence of auto-PEEP (positive end-expiratory pressure) and as a weaning method. Non-invasive intermittent positive pressure ventilation (IPPV) is not very different from conventional mechanical ventilation except for the absence of an endotracheal tube. It is specially useful in patients with neuromuscular diseases or central hypoventilation. It has been also helpful for patients with decrease of lung compliance or COPD and as a weaning procedure. It may be applied with or without PEEP and by means of a bi-level IPPV system. All of these methods require cooperative patients and by means of a bi-level IPPV system. All of these methods require cooperative patients and they do not allow an adequate management of increased respiratory secretions. Non-invasive mechanical ventilation has the advantages of not showing complications associated to endotraqueal intubation and may be performed by means of less expensive equipment.

Critical Care↗
PubMed1994

[Functional obstruction of the upper airway].

Laryngeal wheezing caused by emotional stress is usually confused with that caused by bronchospasm and diagnosed as asthma, a well known emotionally influenced entity. Therefore, it is treated with bronchodilators, including corticosteroids, frequently resulting in a iatrogenic Cushing's syndrome. This case report concerns a patient initially considered to have bronchial asthma. Physiological and endoscopic studies allowed us to exclude this disease, as well as any organic obstruction of the upper and lower airway. Flow-volume curve showed that the tidal volume (VT) loop was displaced towards RV during the crisis and the expiratory flow of the VT reached the envelope of the maximal expiratory flow (Fig. 1). Direct larynx observation during fiberoptic bronchoscopy showed not only expiratory but also inspiratory vocal cords adduction. A diagnosis of emotional laryngeal wheezing was made. Excluding asthma, bronchodilators were progressively discontinued. She started to receive alprazolam and psychotherapy and during one year of follow-up she remained symptomless. Two mechanisms may be present in our patient: partial inspiratory adduction of vocal cords and breathing at low lung volume. Despite reported dissimilarities between these two mechanisms both seem to have a similar emotional origin.

Airway Obstruction↗
PubMed1994

[Hodgkin's disease of mediastino-pulmonary onset associated with tuberculosis of unusual presentation].

A 36 year-old non-smoker woman was admitted because of a rapidly growing mass at the left hilum. Fiberoptic bronchoscopy did not show any abnormality. A percutaneous Rotex needle biopsy and a cutting needle biopsy showed atypical cells suggestive of an anaplastic tumor, possibly a sarcoma. A thoracotomy biopsy demonstrated nodal and pulmonary involvement by Hodgkin lymphoma (nodular-sclerosis form) and pulmonary TBC (granulomas with caseum and acid fast bacilli (AFB)). The patient started treatment with isoniazid, rifampin and pirazynamide and then she received chemotherapy and radiotherapy. One year later her chest and abdominal CT were normal. Twelve months after that she developed severe dyspnea with a chest x-ray film with interstitial infiltrates and a mass at the left-hilum. She worsened quickly and died. At autopsy no evidence of active TBC was found and extensive involvement by lymphoma was demonstrated. The diagnosis in this patient was not obtained by clinical-radiological signs or by non-invasive tests but only by surgical biopsy. The association between neoplasm and TBC is well known, but now is very rare. In Argentina TBC prevalence in lymphomas is 1.2% (higher than control population). TBC diagnosis can occasionally be difficult. In most of undiagnosed patients TBC is the main contributor to death. In this patient the mediastinopulmonary mass was adequately diagnosed only after an open biopsy which showed it to be caused by two coexistent diseases, previously unsuspected and both amenable of effective treatment. This case shows the heterogeneity of TBC presentation and stresses the need to consider it in each non-defined mediastino-pulmonary lesion in countries where TBC is highly prevalent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Chronic obstructive pulmonary disease].

Several meetings of chest specialists were held in order to update basic knowledge on Chronic Obstructive Pulmonary Disease (COPD) and to establish guidelines regarding its prevention and treatment. This Consensus was prompted by the important morbidity and mortality due to COPD. Pulmonary emphysema, chronic bronchitis and asthma may evolve into COPD when developing chronic, persistent, non reversible airflow obstruction. Its pathologic features, physiopathology, pulmonary function derangements and clinico-radiological picture are summarized. Early detection and prevention accomplished through smoking cessation are essential to stop health damage due to this condition. Strategies directed to smoking cessation are described. Once COPD is established, inhaled bronchodilators (IB)--anticholinergics, beta-2 agonists or both--might be useful. Teophylline is indicated additionally when no improvement is obtained with IB. Inhaled steroids (IE) may stop progression of airways obstruction; they are recommended in patients who remain symttomatic and/or with severe airflow obstruction (FEV1 less than 50% predicted) despite treatment with beta-2 adrenergics and teophylline. Vaccination against influenza and pneumococcal pneumonia is suggested. Other medications (antibiotics, psychoactive drugs, alpha-1 antitrypsine, respiratory stimulants) or surgical interventions, including lung transplantation, might be of help in certain circumstances. In patients with physiotherapy, supplementary nutrition, muscle retraining, prolonged oxygen therapy and, eventually, noninvasive mechanical ventilation might improve survival and quality of life. Acute decompensations leading to respiratory failure should be promptly detected and treated with oxygen, IB, teophylline, corticosteroids, antibiotics and, eventually, mechanical ventilation. The main role of public education in disease prevention is emphasized. Moreover, patient and family education is essential for adequate treatment of COPD.

Humans↗
PubMed1994

[Response to bronchodilators among patients with bronchial asthma].

The response to bronchodilators was evaluated in 295 spirometric studies performed in 82 patients with asthma (defined according to ATS criteria, with at least one previous basal test with 20% of change in FEV1 compared with the present test). The response to bronchodilators (Bd) was measured fifteen minutes after the inhalation of salbutamol 200 mcg by metered dose inhaler and in the absence of Bd inhalation in the previous six hours. Sixty-eight spirometries (23%) were classified as with no response to Bd (NR) (absolute delta FEVI[delta abs] < 200 ml, delta FEV1 in percentage of initial FEVI[delta%] < 15%, delta FVC in percentage of the initial [delta FVC] < 15% and delta FEF 25-75% in percentage of the initial [delta FEF] < 25%). Only 23% (n = 16) of them showed an initial FEVI greater than 80% of predicted. In this group 4 tests (5% of NR, 1.3% of the whole) showed delta abs > 150 ml and 1 (1.5% of NR, 0.3% of whole) delta% > 12%. Thirty six percent of the whole population (n = 109) would have been classified as NR taking as unique criterion delta VEF1% < 15%, 24 of which (8% of whole population) showed delta VEF1 abs > 200 ml (initial FEVI 2.48 +/- 0.60 l) (Table 3). On the other hand, 94 spirometries (31% of the whole) would have been classified as NR taking as unique criterion delta abs < 200 ml. twelve of which (4% of the whole) showed delta% > 15% (initial FEVI 0.81 +/- 0.171) (Table 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Albuterol↗
PubMed1994

[Central alveolar hypoventilation with cor pulmonale: successful treatment by non-invasive intermittent positive pressure ventilation].

A 62 year-old woman with a bilateral carotid body paraganglioma presented, 2 years after the removal of the right one, with signs of right-heart failure. Hypoxemia, hypercapnia, polycythemia and pulmonary hypertension with normal ventilatory capacity were found. Central alveolar hypoventilation was diagnosed on the basis of absence of ventilatory response and sensation of provoked hypercapnia, prolonged breath-holding time and correction of hypercapnia by voluntary ventilation. Progesterone (200 mg/d during 3 weeks) or naloxone did not improve either arterial blood gases (ABG) or the P 0.1/PCO2 curve. Hypoxemia and hypercapnia were not corrected during metabolic acidosis provoked by acetazolamide (250 mg/d). Nasal CPAP did not control hypoventilation periods. Mechanical ventilation was initiated with negative pressure (NPV) through a poncho. The patient presented severe discomfort with NPV and obstructive apneas were verified during it. She refused to continue NPV. Mechanical ventilation was initiated with positive intermittent pressure (IPPV) through a nasal mask. The patient had excellent tolerance to the procedure. SpO2 during IPPV was always higher than 95%. During sleep induction (under IPPV), respiration in phase with the ventilator 1: 1 was observed; instead, during consolidated sleep there was a complete dependence of the ventilator with apnea for over 2 min when IPPV was interrupted (Fig. 1). After 2 months of treatment, a relief of right ventricular failure occurred and hematocrit fell to 39%. There was an improvement of day-time ABG (Table I). The P. 0.1/PaCO2 curve 3 months after IPPV was the same as the previous one (Fig. 2). The patient has been for 18 months on home ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1994

[Treatment of respiratory insufficiency secondary to vocal cord bilateral paralysis with continuous positive pressure].

Vocal cord paralysis can produce extrathoracic airway obstruction with severe respiratory failure, post-surgical traumatism being the most frequent. Definitive treatment can require aritenoidectomy. For emergency treatment tracheal intubation of tracheotomy are frequently needed. We report a patient with acute post-surgical upper airway obstruction successfully treated with CPAP application through nasal mask. A 29 year-old female showed stridor and retraction of the supraclavicular, intercostal and epigastric region following an uncomplicated tracheal extubation immediately after surgery (radical thyroidectomy with nodal dissection). Pulsosaturometry showed O2 desaturation despite high flow O2 administration. She received intravenous steroids and O2 through intermittent positive pressure by nasal mask (manual resuscitator) increasing SpO2 to 90%. Laringoscopy showed both vocal cords fixed at medium line. CPAP through a nasal mask was initiated with a 5 cm H2O pressure and high FIO2. Immediately afterwards, dyspnea, stridor, supraclavicular retraction and respiratory accessory muscles use disappeared. Heart rate decreased (120 to 92 x min.) and SpO2 increased to 99%. Arterial blood gases did not show hypercapnia. Dyspnea and physical signs of upper airway obstruction appeared immediately after interrupting CPAP application, with a marked decrease in SpO2. So the mask was reinstalled keeping the same pressure level during 18 hs. The procedure was well tolerated. There were no local or hemodynamic complications. CPAP was progressively discontinued.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Error factors in spirometry].

Spirometry is the more frequently used method to estimate pulmonary function in the clinical laboratory. It is important to comply with technical requisites to approximate the real values sought as well as adequate interpretation of results. Recommendations are made to establish: 1--quality control 2--define abnormality 3--classify the change from normal and its degree 4--define reversibility. In relation to quality control several criteria are pointed out such as end of the test, back-extrapolation and extrapolated volume in order to delineate most common errors. Daily calibration is advised. Inspection of graphical records of the test is mandatory. The limitations to the common use of 80% of predicted values to establish abnormality is stressed. The reasons for employing 95% confidence limits are detailed. It is important to select the reference values equation (in view of the differences in predicted values). It is advisable to validate the selection with local population normal values. In relation to the definition of the defect as restrictive or obstructive, the limitations of vital capacity (VC) to establish restriction, when obstruction is also present, are defined. Also the limitations of maximal mid-expiratory flow 25-75 (FMF 25-75) as an isolated marker of obstruction. Finally the qualities of forced expiratory volume in 1 sec (VEF1) and the difficulties with other indicators (CVF, FMF 25-75, VEF1/CVF) to estimate reversibility after bronchodilators are evaluated. The value of different methods used to define reversibility (% of change in initial value, absolute change or % of predicted), is commented. Clinical spirometric studies in order to be valuable should be performed with the same technical rigour as any other more complex studies.

Adolescent↗
PubMed1993

Central and peripheral diaphragmatic fatigue in loaded normal and vagotomized dogs.

Severe inspiratory elastic load terminated by respiratory arrest (RA) was studied in 24 anesthetized dogs (group 1, normal: n = 14; group 2, vagotomized: n = 10). The peripheral and central components of the decrease in diaphragmatic force generation and the events preceding RA were studied. We measured stimulated tetanic transdiaphragmatic pressure (Pdi), single twitch compound action potentials, integrated diaphragmatic electromyographic activity (iEMGdi), respiratory frequency (f), inspiratory time, inspiratory drive, overall diaphragmatic activation, and Pdi single twitch superimposed over peak Pdi. Imposed target pressure was -68.8 +/- 4.37 cmH2O for group 1 and -70.9 +/- 4.19 cmH2O for group 2, and the tension-time index of the diaphragm was the same for both groups (0.22 +/- 0.010). During load, 1) f increased in group 1 from 25.4 +/- 1.33 to 41.3 +/- 4.66 cycles/min, and tachypnea was prevented by vagotomy; 2) twitch occlusion persisted until RA and compound action potentials did not change; 3) iEMGdi and inspiratory drive increased and remained high until RA; 4) overall diaphragmatic activation increased 514 (group 1) and 260% (group 2) and then decreased to 228% of the basal value 10 s before RA in group 1 because of a fall in f; and 5) after RA, Pdi stimulated at 60 Hz fell to 39 (group 1; P < 0.0025) and 51% (group 2; NS with group 1) of the basal value. In summary, 1) peripheral fatigue developed without transmission failure; 2) diaphragmatic activation remained maximal until RA; 3) the fall in f appeared as a preterminal event only in group 1; and 4) vagus nerves are necessary for load-induced tachypnea.

Action Potentials↗