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The aims of this study were to define, by cluster analysis, a pattern of clinical variables that differentiate desaturator (D) from nondesaturator (ND) patients affected by COPD, and to identify daytime variables that are predictive of nocturnal desaturation.

To evaluate the effects of early exercise training in patients recovering from acute respiratory failure needing mechanical ventilation (MV).

There is a lack of information on respiratory function and mechanics after COPD exacerbations.

To compare patient-ventilator interaction and comfort in patients with chronic ventilatory failure (CVF) who are undergoing noninvasive positive-pressure ventilation with five different commercial bilevel pressure home ventilators. Also, we wanted to evaluate the short-term effects of the five ventilators on physiologic variables, namely, breathing patterns and inspiratory muscles.

To compare the short-term physiologic effects of mask pressure support ventilation (PSV) and proportional assist ventilation (PAV) in patients in clinically stable condition with chronic ventilatory failure (CVF).

To answer the following questions: in patients with chronic airway obstruction (CAO), (1) can pulmonary rehabilitation lead to similar short-term gains at successive, yearly interventions, and (2) is there any real clinical or physiologic long-term benefit by yearly repetition of pulmonary rehabilitation programs (PRPs)?

To evaluate the short-term physiologiceffects of two settings of nasal pressure-support ventilation(NPSV) in stable COPD patients with chronic hypercapnia.

To compare the effectiveness of two modalities of external ventilation during rigid bronchoscopy: intermittent negative pressure ventilation (INPV) and external high-frequency oscillation (EHFO).

Changes in cardiopulmonary function were retrospectively evaluated back to two years before acute exacerbations requiring ICU admission in 16 COLD patients with chronic hypercapnic respiratory insufficiency (age: 61±6 years, group A). Fifteen hypercapnic COLD patients matched for age, sex, lung function, and blood gas values not requiring an ICU admission in a period of two years, served as control subjects (age: 66±7, group B). Periodic assessments of spirometry, arterial blood gas values, echocardiography, body weight, and red blood cell count performed in stable state were compared for differences between groups and changes over a period of two years. The results indicated that basal body weight, rate of deterioration over time in FEV1, VC, blood gas values, bicarbonates, and RVD may be related to the necessity of ICU admission in COLD patients with hypercapnic respiratory insufficiency.

We retrospectively evaluated the clinical effectiveness of a treatment schedule with intermittent positive pressure ventilation via nasal mask in 49 patients with acute exacerbations of COLD. According to the ability to successfully tolerate a preliminary trial with NIPPV, patients were submitted either to standard treatment plus NIPPV (25 patients) or to ST alone (24 patients). The ST consisted of medical, oxygen and physical therapy. The NIPPV was delivered by a volume cycled ventilator in control mode at least 4 h a day for five consecutive days a week, for three weeks. Comparison of baseline with measurements performed after 10 and 21 days of treatment respectively showed a significant improvement in PaO2and in PaCO2in both groups. After 21 days of treatment, VC, FEV1, inspiratory muscle strength, and dyspnea significantly improved in both groups. No significant difference was found between groups at any time of treatment. We conclude that the treatment schedule of NIPPV used is not more effective than ST alone in acute exacerbations of COLD.

To evaluate the efficacy of negative pressure ventilation (NPV) in avoiding or reducing apneas and related hypoxemia and respiratory acidosis during laser therapy (LT) of endobronchial lesions.

To evaluate the frequency of the causes of exercise limitation in patients with chronic pulmonary disease and to assess the relationship between the resting pulmonary functional parameters and the degree of exercise dyspnea, we reviewed the data from 88consecutive stable patients with chronic lung disease (62COPD, 16interstitial lung disease [ILD]). In each patient, the intensity of dyspnea was measured by a Borg scale (BS) during an incremental symptom-limited exercise test. COPD patients stopped exercise due to fatigue (46%),dyspnea (36%),cardiac limitation (12%),and peripheral circulatory limitation (6%). ILDpatients stopped exercise due to dyspnea (62%),fatigue (25%),and cardiac limitation (12%).In all patients, dyspnea severity increased linearly with exercise intensity as measured as VO2, VE, and VE/MW. The severity of dyspnea expressed as the slope of the relationship between BS and VE/MW (DBS/D[VE/MVV]) showed in COPD a significant inverse correlation with VC, FEV1, MIP, and a positive correlation with PaCO2and VE/MVVat rest. In ILD, DBS/D(VE/MVV) showed a significant inverse correlation with VC, FEV1, TLC, and PaO2and a positive correlation with VE/MWat rest. The predicting power of all equations was very low.

Nasal pressure support ventilation (NPSV) has been shown to be useful in the treatment of acute and chronic pulmonary failure. However, little is known about respiratory muscle activity during NPSV in stable patients with COPD. The aim of this study was to test the effect of two levels (10 and 20 cm H2O) of NPSV on diaphragmatic activity, in a group of seven stable, severe COPD patients (FEV120 percent ± 7 of pred, FEV1/FVC 35 percent) with hypercapnic respiratory insufficiency. Since these patients had an intrinsic PEEP (PEEPi) of 2.6 ± 1.3 cm H2O, we also investigated the effect of adding 5 cm H2O external PEEP (PEEPe) during NPSV. Blood gases, ventilatory pattern by inductive plethysmography, integrated electromyogram of the diaphragm (Edi), transdiaphragmatic pressure (Pdi), and the diaphragmatic pressure time product (PTPdi) were recorded during randomized 15-min runs of both levels of NPSV with and without the addition of PEEPe. Minute ventilation did not change with the application of NPSV, but a significant decrease in breathing frequency with a parallel increase in tidal volume was observed, so that blood gas determinations improved at the higher levels of support. A marked statistically significant reduction in diaphragmatic activity, as assessed by a decrease in Pdi swings, PTPdi, and Edi, was detected at the levels of 10 and 20 cm H2O; a further significant decrease in these values was observed when PEEPe was added. PEEPi decreased significantly only with the application of PEEPe, resulting in a small increase in end-expiratory lung volume. We conclude that NPSV improves diaphragmatic function in patients with severe stable COPD; this effect may be enhanced by the applications of external PEEP.

We evaluated the physiologic effects of pressure support ventilation by nasal route (NPSV) in eight patients with severe stable COPD and chronic hypercapnia who were randomly submitted to 2-h sessions of NPSV both with a portable ventilator (Respironics BIPAP device) and with a standard ventilator (Bird 6400ST device) at an inspiratory airway pressure of 22 cm H2O. Two sessions with each ventilator were performed using an FIo2of 0.21 in each patient on two consecutive days. One patient did not tolerate either form of ventilation. Comparison of spontaneous with BIPAP ventilation showed a significant improvement in pH, PaCO2, and PaO2. Ventilatory pattern assessed by a respiratory inductive plethysmograph showed a significant increase in minute ventilation (VE), VT, and Ttot. Integrated surface diaphragmatic EMG activity measured only during BIPAP device ventilation decreased from that measured during spontaneous breathing. Similar changes in blood gases and ventilatory pattern were observed during ventilation by the Bird 6400ST except for VT/Ti ratio, which significantly increased. Comparison of baseline with measurements performed 12 h after the whole cycle of treatment showed a significant increase in pH and VE and a decrease in PaCO2. We conclude that short-term NPSV may be useful in improving respiratory pattern and blood gases in stable COPD patients with chronic hypercapnia.

In the present study, we assessed the occurrence of respiratory muscle rest during long lasting INPV runs using a pneumowrap ventilator at different pressure levels. We measured two indices of diaphragmatic activity: transdiaphragmatic pressure and the electrical activity of the diaphragm. Five healthy volunteers and six COPD patients were studied during spontaneous breathing and during 30-minute runs of INPV at a pressure of –2, –15 and –30 cmH2O. Ventilation, rib cage and abdomen motion were measured by inductive plethysmography; Pdi was obtained as the difference between gastric and esophageal pressures; Edi was recorded with surface electrodes. About 10 minutes of INPV (adaptation phase) were needed to obtain stable values in all the variables recorded. Ventilation increased in both groups up to threefold by increasing the negative pressure applied, this being due to changes in tidal volume. Changes in Pga swings mainly accounted for the reduction in Pdi that became negative during the run at –30 cmH2O. In both groups, Edi, after adaptation, showed no change during INPV at –2 cmH2O but a progressive reduction from control, during INPV at –15 and –30 cmH2O. We conclude that INPV by a pneumowrap ventilator can induce partial respiratory muscle rest in normal subjects and COPD patients.