PubMed Health⌕ Search

Biomedical subjects

C Rampulla

Publications and source records attributed to C Rampulla.

At least 19 recordsLinked to original sources
PubMed1992

Evidence of acute diaphragmatic fatigue in a "natural" condition. The diaphragm during labor.

Acute diaphragmatic fatigue has been experimentally shown to occur in normal healthy subjects and in patients with chronic obstructive pulmonary disease by asking them to modify their pattern of breathing or to breathe against high inspiratory resistances. During the expulsive period of labor women are asked periodically to make strong expulsive efforts and to sustain them isometrically for many seconds; this is likely to produce "natural" diaphragmatic fatigue. To investigate whether this was the case, six women were studied in the delivery room from the moment of the rupture of the amnion until delivery of the infant occurred. The development of diaphragmatic fatigue was assessed both by measuring the static maximal inspiratory pressure (MIP) and by analyzing the electromyographic power spectrum of the diaphragm (H/L ratio). The majority of contractions were concentrated in the expulsive period of labor. MIP, recorded in the supine position, significantly decreased from 103.2 +/- 17.2 cm H2O (at the beginning of the expulsive period) to 73.8 +/- 10.1 cm H2O (after the delivery). The H/L ratio fell progressively during the expulsive period; after the delivery, it was 59.2 +/- 15.7% of the value recorded at the beginning of the expulsive period. This study demonstrates that (1) the diaphragm is active in the expulsive efforts during labor and (2) the tension developed and the time each contraction is maintained may lead to the development of diaphragmatic fatigue. Therefore, we provide evidence of acute diaphragmatic fatigue in a natural condition.

Acute Disease↗
PubMed1992

Effect of a beta 2-agonist (broxaterol) on respiratory muscle strength and endurance in patients with COPD with irreversible airway obstruction.

The effect of broxaterol, a new beta 2-agonist, on respiratory muscle endurance and strength was studied in a double-blind, placebo-controlled, randomized crossover clinical trial in 16 patients with chronic obstructive pulmonary disease (COPD) with irreversible airway obstruction (FEV1 = 57.1 percent of predicted). One patient withdrew from the study because of acute respiratory exacerbation. Inspiratory muscle strength was assessed by maximal inspiratory pressure (MIP) and endurance time was determined as the length of time a subject could breathe against inspiratory resistance (target mouth pressure = 70 percent of MIP, Ti/Ttot = 0.4). Broxaterol (B) or placebo (P) was given orally for seven days at the dose of 0.5 mg three times a day with a washout period of 72 h between study treatments. Measurements were performed before administration of B or P and 2 h (six patients) or 8 h (nine patients) after the end of each treatment. No significant changes in FEV1 or FRC were observed after B or P suggesting that diaphragmatic length was maintained constant with each treatment. The MIP did not significantly change, while endurance time increased after B in the patients tested at 2 h (from 234.8 +/- 48.1 s to 284.0 +/- 48.0 s, p less than 0.05) and at 8 h (from 187.2 +/- 31.1 s to 258.2 +/- 40.4 s, p less than 0.005). No changes were observed after P. Minute ventilation, airway occlusion pressure (P0.1), integrated electromyographic activities of the diaphragm (Edi), and intercostal parasternals (Eic) (normalized to the value obtained during MIP) showed no change during the endurance run with different treatments. We conclude that in a group of COPD patients with irreversible airway obstruction, B significantly improves respiratory muscle endurance, and that this does not arise as a result of an effect on neuromuscular drive or pulmonary mechanics, but may be mediated by peripheral factors.

Adrenergic beta-Agonists↗
PubMed1992

Physiologic evaluation of pressure support ventilation by nasal mask in patients with stable COPD.

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 FIO2 of 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.

Humans↗
PubMed1992

Respiratory muscle fatigue does not limit exercise performance during moderate endurance run.

The role of respiratory muscle fatigue in limiting exercise performance in well-trained subjects is still controversial, especially as far as relatively short runs are concerned. To determine the occurrence of respiratory muscle impairment, we studied six well-trained athletes before, during (middle of the run) and after a 17 km run. They were all asked to produce the maximum effort they could during the race. Strength was assessed by measuring maximal inspiratory mouth pressure against close airways (MIP), dynamic lung volumes were monitored using a spirometer. No changes in forced vital capacity (FVC), maximal expiratory flow (PEF) and forced expiratory volume in 1 sec (FEV1) were observed throughout the experiment. This suggested that functional residual capacity and subsequently the initial length of respiratory muscle were unchanged. Respiratory muscle strength did not significantly vary at the different time of measurements (154.8 +/- 20.9 cm H2O at the beginning, 157.5 +/- 23.7 cm H2O after 7.5 km, 155.8 +/- 22.5 cm H2O at the end and 152.3 +/- 17.6 cm H2O after 30 min of recovery). We therefore conclude that respiratory muscle fatigue does not impair the exercise performance of well-trained athletes in a relatively short race. The difference between these results and others reported in literature, could be explained by the different degree of training of the subjects performing the race.

Adult↗
PubMed1992

Dyspnea on exercise. Pathophysiologic mechanisms.

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 88 consecutive stable patients with chronic lung disease (62 COPD, 16 interstitial 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%). ILD patients 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/MVV. The severity of dyspnea expressed as the slope of the relationship between BS and VE/MVV (DBS/D[VE/MVV]) showed in COPD a significant inverse correlation with VC, FEV1, MIP, and a positive correlation with PaCO2 and VE/MVV at rest. In ILD, DBS/D(VE/MVV) showed a significant inverse correlation with VC, FEV1, TLC, and PaO2 and a positive correlation with VE/MVV at rest. The predicting power of all equations was very low.

Aged↗
PubMed1991

Inhaled furosemide prevents both the bronchoconstriction and the increase in neutrophil chemotactic activity induced by ultrasonic "fog" of distilled water in asthmatics.

Inhaled furosemide has been shown to prevent bronchoconstriction induced by inhalation of ultrasonic nebulization of distilled water (UNDW) in bronchial asthma. To evaluate whether inhaled furosemide also prevents the increase in serum neutrophil chemotactic activity (NCA) observed during UNDW bronchoconstriction, we measured NCA during UNDW challenge without (control) and immediately after inhalation of furosemide (40 mg) or placebo (saline) in 10 asthmatics responsive to UNDW, in a randomized, double-blind study. NCA was assessed by measuring the maximal distance reached by neutrophils in a filter when challenged with the subject serum in a Boyden chamber ("leading front"). UNDW inhalation produced a significant increase in NCA in each subject. Gel filtration chromatography on S400 column indicated that the NCA released were 600 to 700 kD. Saline had no effect on bronchoconstriction nor on NCA increase induced by UNDW in nine patients. Furosemide did not change baseline FEV1, but it prevented bronchoconstriction and NCA increase in nine patients. In the whole group the maximal decrease in FEV1 after UNDW was -31.1%, SEM 4.7 after saline and -7.5%, SEM 5.2 after furosemide, p less than 0.001, the maximal increase in NCA after UNDW was +52.9%, SEM 9.2 after saline and +3.8%, SEM 3.1 after furosemide, p = 0.001. These results indicate that inhaled furosemide prevents both the bronchoconstriction and the NCA increase induced by UNDW inhalation in most asthmatic patients. This finding adds support to the suggestion that furosemide acts on mast cells.

Administration, Inhalation↗
PubMed1990

Hemodynamic effects of negative-pressure ventilation in patients with COPD.

In order to evaluate the hemodynamic effects of INPV, eight patients with COPD (FEV1/FVC, 54 +/- 6 percent; mean +/- SD), respiratory failure (PaO2, 52 +/- 6 mm Hg; PaCO2, 56 +/- 4 mm Hg), and clinical signs of inspiratory muscle fatigue underwent right cardiac catheterization while performing 20 minutes of INPV by a cuirass ventilator at a pressure (-20 to -40 cm H2O) able to reduce the diaphragmatic electromyographic activity. Patients showed a mild basal pulmonary artery hypertension. During INPV, no changes in the mean values of HR (from 79 +/- 20 to 80 +/- 18 beats per minute), systolic BP (141 +/- 19 to 139 +/- 16 mm Hg), CO (5.2 +/- 0.8 to 5.1 +/- 1.3 L/min), mean PAP (23.8 +/- 3.8 to 23.9 +/- 4.4 mm Hg), RAP (4.3 +/- 2.6 to 5.5 +/- 2.5 mm Hg), PWP (10.3 +/- 4.5 to 9.4 +/- 2.9 mm Hg), TPR (369 +/- 76 to 392 +/- 124 dynes.s.cm-5), and PVR (199 +/- 51 to 233 +/- 94 dynes.s.cm-5) were observed. Direct systemic BP monitoring could be performed in six patients. During INPV, three patients showed "pulsus paradoxus," as assessed by an inspiratory fall in systolic BP of 11, 13, and 20 mm Hg, respectively. We conclude that INPV by cuirass ventilator does not induce adverse hemodynamic effects in patients with COPD who have pulmonary artery hypertension.

Adult↗
PubMed1990

Hypophosphatemia in course of chronic obstructive pulmonary disease. Prevalence, mechanisms, and relationships with skeletal muscle phosphorus content.

Serum phosphorus levels (Ps), dietary intake of phosphorus, and renal phosphate handling indexes were evaluated in 158 patients with chronic obstructive pulmonary disease (COPD) of varying degrees of severity; moreover, skeletal muscle phosphorus content (Pm) was measured in muscle samples obtained by quadriceps femoris needle biopsy in 14 of the same patients. Hypophosphatemia (Ps less than or equal to 2.5 mg/dl) was found in 34 (21.5 percent) of 158 patients without differences between groups of COPD patients presenting increasing severity of respiratory illness. No relationship was found between serum levels and dietary intake of phosphorus; hypophosphatemia was associated with low renal phosphate threshold (TmPO4/GFR) values in 31 (91 percent) of 34 patients. The prevalence of hypophosphatemia was significantly higher among COPD patients taking one or more drugs commonly used in COPD and known as negatively influencing renal phosphate handling: xanthine derivatives, corticosteroids, loop diuretics, and beta 2-adrenergic bronchodilators. Short-term administration of therapeutic doses of these drugs in COPD patients previously not taking any drug reduced TmPO4/GFR values; phosphaturic effect of short-term theophylline administration on renal phosphate handling was additive to that of long-term assumption of the drug. Muscle phosphorus content was both reduced in COPD patients as compared with control subjects and significantly correlated to serum phosphorus levels and to TmPO4/GFR values. The present investigation revealed a high prevalence of hypophosphatemia among COPD patients as well as a defect in renal phosphate reabsorption secondary, at least in part, to pharmacologic therapy. Moreover, it also suggests that in COPD patients muscle phosphorus content is likely to be reduced in presence of hypophosphatemia.

Adult↗
PubMed1990

Diaphragmatic rest during negative pressure ventilation by pneumowrap. Assessment in normal and COPD patients.

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.

Adult↗
PubMed1990

Simultaneous Doppler and thermodilution assessment of pulmonary artery flow during acute interventions in patients with chronic obstructive pulmonary disease.

Subcostal pulsed wave Doppler echocardiography of the right ventricular outflow tract was used to assess pulmonary arterial flow at basal conditions and during interventions in 20 patients with chronic obstructive pulmonary disease. The changes in the pulmonary flow induced by interventions ranged from -1.5 l/min to +4.18 l/min (73% to 183% of the basal value). When considered alone, heart rate changes induced by the interventions could explain 53% of the changes in pulmonary flow measured with thermodilution. When Doppler-assessed right ventricular stroke volume changes were also considered the coefficient of determination (R) increased to 77% (r = 0.88, p less than 0.001, SEE = 12%). Doppler echocardiography was less precise in predicting absolute basal values of pulmonary artery flow (r = 0.70, p less than 0.001, SEE = 1.00 l/min), probably indicating inaccurate assessment of the diameter of the right ventricular outflow tract.

Administration, Sublingual↗
PubMed1990

Short term effect of intermittent negative pressure ventilation in COPD patients with respiratory failure.

Ten patients with stable chronic obstructive pulmonary disease (COPD) and hypercapnic respiratory failure were randomly submitted to intermittent negative pressure ventilation (INPV) 6 h per day for 5 consecutive days by either a cuirass or pneumo wrap ventilator. The effects were assessed by measurements of spirometry, blood gases, maximal inspiratory (MIP) and expiratory (MEP) pressures, 12 minutes walking distance test (12 mwd), sensation of dyspnoea by a visual analogue scale (VAS) and diaphragmatic electromyographic activity (Edi). Edi was recorded during INPV sessions in only 7 patients. The same measurements apart from Edi were also performed in 8 matched control patients randomly submitted to conventional physiotherapy. During INPV, Edi activity was reduced, at least temporarily down to 50% of baseline values. Comparison of baseline with post INPV values showed no changes in thoracic gas volume (TGV), forced expiratory volume in one second (FEV1), FEV1/forced vital capacity (FVC), arterial oxygen partial pressure (Pao2) and MEP; significant improvements were seen in MIP, vital capacity (VC), VAS, and 12 mwd only in patients submitted to INPV. A significant improvement in PaCO2 was observed in both groups of patients. We conclude that INPV may be effective in improving the functional reserve of the inspiratory muscles in selected COPD patients with hypercapnic respiratory failure and signs of inspiratory muscle dysfunction.

Breathing Exercises↗
PubMed1989

Smoking habit and bronchial reactivity in normal subjects. A population-based study.

The relationship between smoking habits and airway responsiveness has been studied in a cross-sectional sample of subjects in a small Lombardy (Italy) town. The subjects were between 15 and 64 yr of age; they were representative of the general population. There were 295 normal nonsmokers, 70 normal smokers, and 50 past smokers. All clinically asymptomatic and functionally normal subjects underwent methacholine challenge. The distribution of responsiveness to methacholine (as expressed by LnPD15FEV1) was found to be significantly different between these normal smokers and nonsmokers. A multinomial logistic regression model showed a statistically significant difference in the response to the challenge on the basis of pack-years. When the number of years of smoking and the daily number of cigarettes were separately considered, the current amount had the significant correlation with LnPD15FEV1. Bronchial reactivity for past smokers was found not to be different from that for normal nonsmokers. We conclude that smoking habits, especially current habits, affect bronchial reactivity even in the absence of airway obstruction.

Adolescent↗
PubMed1989

Bronchial responsiveness to inhaled methacholine in epidemiological studies: comparison of different indices.

We evaluated the sensitivity and specificity of different indices drawn from the forced expiratory curve in order to detect the best one for evaluating bronchial reactivity in the general population, and particularly, for distinguishing between normal and asthmatic subjects. 654 subjects, between 15 and 64 years of age, who were representative for age and sex of the general population of a small Lombardy town (Italy), were studied. Of the total sample, 448 subjects were clinically normal and asymptomatic, 87 were symptomatic or with acute upper respiratory disease within 30 days before the challenge with methacholine, 43 with allergic rhinitis, 26 asthmatics and 50 chronic bronchitics. All the subjects who had a baseline FEV1 greater than 85% predicted underwent methacholine challenge. Provocative LnDoses of a 6, 10, 15% fall in FEV1 (LnPD6, LnPD10, LnPD15) and provocative LnDose causing FEV1 to fall more than 2 SD below the mean of 5 FEV1 measurements following buffer inhalation (LnTD) were evaluated. Furthermore we calculated the "Dose-Response slope" (SL) proposed by O'Connor. The cut-off value of each index to define a responder was calculated by discriminant analysis of the response to the challenge in normal and in the asthmatic group. Sensitivity, specificity and predictive value of LnPD6, LnTD and SL were 79, 74, 14%; 71, 74, 13% and 46, 97, 48% respectively. LnPD10 had the best sensitivity (83%) with a high specificity (83%), but, as compared to LnPD15, whose sensitivity was 79% and specificity 89%, a lower predictive value (21% vs 27%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗