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PubMedDate not supplied

Evaluation of diaphragm electromyogram contamination during progressive inspiratory maneuvers in humans.

The diaphragm electromyogram (EMGdi) is susceptible to contamination by non-diaphragm related electrical signals such as the ECG, electrode motion artifacts, and other sources of noise. It is difficult to distinguish between these contaminating signals and those that are representative of the non-contaminated EMGdi, especially during periods when the EMGdi amplitude is relatively small, as during mild contractions of the diaphragm. The aim of the present study was to evaluate how contaminating signals influence the EMGdi power spectrum center frequency (CF) during progressive inspiratory maneuvers. EMGdi and transdiaphragmatic pressure (Pdi) were measured via an esophageal electrode in eight patients with cervical cord injury performing inspiratory capacity (IC) maneuvers. The influence of the contaminating sources on CF was evaluated by two spectral deformation indices, one which is sensitive to both high and low frequency spectral deformation (omega index), and the other which is sensitive to high frequency deformation only (CF1000/CF500 index). The results indicated that EMGdi CF values scattered over a wide frequency range, particularly when the signals were obtained at Pdi levels less than 15% of Pdimax, or at lung volumes less than 30% of IC. When the spectral deformation indices were applied, the scattering in CF values was drastically reduced. This was expressed by a factor of 4 reduction in the coefficient of variation of the CF values. The majority of the excluded EMGdi signals (i.e. not satisfying the spectral deformation index inclusion levels), had low CF values mainly due to the presence of electrode motion artifacts. It was concluded that: 1) The majority of EMGdi power spectrums are deformed early on during unloaded inspirations, and their CF values should be carefully interpreted as being representative of diaphragm function. 2) The relative contribution of contaminating signals in the EMGdi decreases proportionally throughout the first two thirds of an inspiration to IC. 3) The use of visual inspection of the signal in the time domain is questionable as a method to discriminate non-contaminated signals. 4) Analysis of the signal in the frequency domain makes it possible to detect the influence of signal contamination.

Adult↗
PubMed1998

[Effects of bathing on lung mechanics in patients with severe COPD].

Although it is well known that the majority of patients with severe COPD complain of exacerbated dyspnea while taking a Japanese-style bath, the mechanism has not been elucidated. We therefore investigated changes in lung volume (LV) and SaO2 in 16 seated patients with severe COPD, receiving treated with home oxygen therapy (HOT), and in 10 healthy subjects (C) immersed to the navel (N) and to the shoulder (S). We then subdivided the COPD patients into 2 groups, A and B. Group A was composed of patients taking less than 2 L oxygen/min, while group B was taking equal to or greater than 2 L oxygen/min. Expiratory reserve volume (ERV) decreased with statistical significance (p < 0.05) while inspiratory capacity (IC) substantially increased as immersion progressed. However, changes in LV were smaller, as obstructive ventilatory changes progressed. It also appeared that a significant O2 desaturation occurred in patients with COPD when movement was associated with taking a bath. The drop in SaO2 during bathing was significantly improved after patients received instructions concerning posture, slow movements, and pursed-lip breathing. These findings suggest that immersion, such as when taking a Japanese-style bath, 1) may change various LV to a lesser degree than in healthy subjects because of previously existent airway obstruction in COPD, 2) may aggravate arterial desaturation through further impairment of the VA/Q imbalance, 3) instructions for COPD patients could improve, their condition while bathing and, 4) the 6 minute walking distance (6 MD) might be important in predicting the severity of arterial desaturation while COPD patients are immersed.

Aged↗
PubMed1976

[Synoptical X-ray diagnostics of pulmonary emphysema (author's transl)].

In marked chronic obstructive pulmonary emphysema, especially in the classical emphysematous type of abnormal thorax, a good correlation can be found between the anteroposterior expansion of the thorax, the reduced inspiratory capacity, the clinical state, disturbed mechanics of breathing and the x-ray-state. On the contrary, in clinical emphysema of a lower degree, especially in subclinical, i. e. in predominantly asymptomatic pulmonary emphysema of the elderly, the effectiveness of the roentgenological examination is very small.

Aged↗
PubMed2001

Expiratory and inspiratory forced vital capacity and one-second forced volume in asymptomatic never-smokers in Norway.

The objectives of this study were to examine within and between individual variation detected during forced expiratory (FE) and forced inspiratory (FI) manoeuvers in a general population and to investigate the dependence of these variables on age, body size, and gender. A random sample of asymptomatic never smokers who had never been exposed occupationally to quartz or asbestos and who were living on the south-western coast of Norway were examined by spirometry; 81% of the individuals invited to attend did so. Of the 488 subjects between 18 and 73 years of age, 98% contributed three acceptable recordings for forced expiratory vital capacity (FVC) and one-second forced expiratory volume (FEV1), 94% contributed three acceptable recordings for forced inspiratory vital capacity (FIVC) and 85% contributed three acceptable recordings for one-second forced inspiratory volume (FIV(1)). The within-subject variation increased with body height and was considerably larger for FIV(1) than for FVC, FEV(1) or FIVC. A four-parameter model of pulmonary function measurement divided by height squared, including a gender term and a linear and quadratic term of age, fit the median of the observed values well. The residuals had a close-to-normal distribution, and the fifth-percentile values were estimated as the lower limit of normal. The peak value of dynamic lung volumes was observed into the middle of the fourth decade of life, and the decline thereafter did not differ greatly between the genders or among the different indices. The forced inspiratory volumes are the first reported in any reference population.

Adolescent↗
PubMed2006

Chest wall motion after thixotropy conditioning of inspiratory muscles in healthy humans.

Inspiratory muscle conditioning at a lower or higher lung volume based on the principles of muscle thixotropy causes acute changes in end-expiratory chest wall and lung volumes. The present study aimed to demonstrate the time course of effects of this conditioning on both end-expiratory chest wall volume and thoracoabdominal synchrony. We measured chest wall motion with respiratory induction plethysmography at 0.5, 1, 2, 3, and 6 min after conditioning at three different lung volumes in 15 healthy men. After conditioning at total lung capacity - 20% inspiratory capacity, increases in end-expiratory chest wall volume were significant at 0.5, 1, and 2 min (P < 0.05), being most obvious at 0.5 min (Delta 0.24 +/- 0.20 liter). After conditioning at residual volume, reductions in end-expiratory chest wall volume were significant at any time point (P < 0.05), being most obvious at 0.5 min (Delta 0.16 +/- 0.08 liter). Conditioning at functional residual capacity had little effect on the volume. Spirometric inspiratory capacity at 6 min after conditioning at residual volume (2.68 +/- 0.35 liter) was higher than the baseline value (2.53 +/- 0.31 liter, P < 0.05). Reductions in the phase angle, quantified by the Konno-Mead diagram, occurred after conditioning at residual volume at any time point (P < 0.05), being most obvious at 2 min (Delta 3.47 +/- 3.02 degrees). In conclusion, there is a 6-min time course of changes in end-expiratory chest wall volume after conditioning. More synchronous motion between the rib cage and abdomen occurs after conditioning at residual volume.

Adult↗
PubMed2004

Inspiratory muscle load and capacity in chronic heart failure.

BACKGROUND: Although breathlessness is common in chronic heart failure (CHF), the role of inspiratory muscle dysfunction remains unclear. We hypothesised that inspiratory muscle endurance, expressed as a function of endurance time (Tlim) adjusted for inspiratory muscle load and inspiratory muscle capacity, would be reduced in CHF. METHODS: Endurance was measured in 10 healthy controls and 10 patients with CHF using threshold loading at 40% maximal oesophageal pressure (Poes(max)). Oesophageal pressure-time product (PTPoes per cycle) and Poes(max) were used as indices of inspiratory muscle load and capacity, respectively. RESULTS: Although Poes(max) was slightly less in the CHF group (-117.7 (23.6) v -100.0 (18.3) cm H(2)O; 95% CI -37.5 to 2.2 cm H(2)O, p = 0.1), Tlim was greatly reduced (1800 v 306 (190) s; 95% CI 1368 to 1620 s, p<0.0001) and the observed PTPoes per cycle/Poes(max) was increased (0.13 (0.05) v 0.21 (0.04); 95% CI -0.11 to -0.03, p = 0.001). Most of this increased inspiratory muscle load was due to a maladaptive breathing pattern, with a reduction in expiratory time (3.0 (5.8) v 1.1 (0.3) s; 95% CI 0.3 to 3.5 s, p = 0.03) accompanied by an increased inspiratory time relative to total respiratory cycle (Ti/Ttot) (0.43 (0.14) v 0.62 (0.07); 95% CI -0.3 to -0.1, p = 0.001). However, log Tlim, which incorporates the higher inspiratory muscle load to capacity ratio caused by this altered breathing pattern, was >/=85% predicted in seven of 10 patients. CONCLUSIONS: Although a marked reduction in endurance time was observed in CHF, much of this reduction was explained by the increased inspiratory muscle load to capacity ratio, suggesting that the major contributor to task failure was a maladaptive breathing pattern rather than impaired inspiratory muscle endurance.

Aged↗
PubMed1992

Perceived effect on shortness of breath of an acute inhalation of saline or terbutaline: variability and sensitivity of a visual analogue scale in patients with asthma or COPD.

The purpose of the study was to validate a bipolar visual analogue scale (VAS) to assess the perceived effect on shortness of breath of an acute inhalation and to search for differences in perception between asthmatics and subjects with chronic obstructive pulmonary disease (COPD). Thirty two subjects with airway obstruction and a diagnosis of either asthma (n = 16) or COPD (n = 16) received three consecutive inhalations of isotonic saline, followed by two inhalations of 400 micrograms terbutaline. Saline was perceived by asthmatics as a slight improvement: VAS (median, 95% confidence interval) 9%, 0-18% of line length. COPD subjects could be separated into two subgroups: "high perceivers" (n = 8, VAS 43%, 33-53%) and "low perceivers" (n = 8, VAS 5%, 3-7%). The median intrasubject coefficient of variation of the three post-saline VAS ratings was 19.4% (asthma), 12.5% (COPD high perceivers), and 14.5% (COPD low perceivers). After terbutaline, asthmatics had, by selection, a larger increase in forced expiratory volume in one second (FEV1) than COPD subjects. However, for other indices (expiratory specific resistance, inspiratory vital capacity and maximal inspiratory flow at 50% forced vital capacity) the changes were smaller in COPD low perceivers than in both asthmatics and COPD high perceivers. The parallel improvement in VAS was 24%, 20-39% (asthma), 15%, 6-25% (COPD high perceivers) and 1%, -1-8% (COPD low perceivers). The most sensitive index was FEV1 in asthmatics, vital capacity in COPD subjects, VAS being among the most sensitive indices in the former, but among the least sensitive in the latter. We conclude that the sensitivity of this VAS to bronchodilation is better in asthmatics than in COPD subjects. The latter can however be separated into subgroups with high and low level of perception.

Asthma↗
PubMed1995

[Patients with chronic airflow limitation: effects of the inspiratory muscle training with threshold load valve, built with appropriate technology, associated to nutritional support].

AIM: To assess prospectively the effects of a controlled program of inspiratory muscle training program and nutritional support in patients with chronic obstructive lung disease (COPD). PATIENTS AND METHODS: Twenty-three patients with COPD were randomly assigned into four groups. Group I received a 1000 kcal/day nutritional supplement, given as a casein based enteral nutritional formula; group III was subjected to inspiratory muscle training, using an inexpensive pressure threshold load valve constructed according to the Appropriate Technology principles of the WHO, adjusted at 30% of Maximal Inspiratory Mouth Pressure and received also the nutritional supplement; group IV was trained but did not receive the nutritional supplement and group II was not trained nor supplemented. Patients were studied during three months and monthly, inspiratory muscle function, exercise capacity and anthropometry were measured. RESULTS: A significant improvement in exercise capacity, maximal inspiratory pressure and inspiratory muscle endurance was observed in the four groups throughout the study. Trained subjects had greater improvement in their inspiratory muscle endurance, compared to untrained subjects. Nutritional support had no effect in inspiratory muscle function or exercise capacity. No changes in anthropometric measures were observed. CONCLUSIONS: The pressure threshold load valve used in this study, improved inspiratory muscle endurance and nutritional support had no effect in patients with COPD.

Aged↗
PubMed2004

Inspiratory-to-total lung capacity ratio predicts mortality in patients with chronic obstructive pulmonary disease.

Static lung hyperinflation has important clinical consequences in patients with chronic obstructive pulmonary disease. We analyzed the power of lung hyperinflation as measured by the inspiratory capacity-to-total lung capacity ratio (IC/TLC) to predict mortality in a cohort of 689 patients with chronic obstructive pulmonary disease (95% males; FEV(1), 1.17 L) with a mean follow-up of 34 months. We also compared the predictive value of IC/TLC with that of the BODE (body mass index, airflow obstruction, dyspnea, exercise performance) Index. Subjects who died (183; 27%) were older; had lower body mass index, FEV(1), and IC/TLC ratio; walked less in the 6-minute walking distance; and had more dyspnea, a higher BODE Index, and comorbidity (p < 0.001). On the basis of logistic regression analysis, IC/TLC was found to be a good and independent predictor of all-cause and respiratory mortality. On the basis of receiver operating characteristic Type II curves, IC/TLC compared favorably with FEV(1) and predicted mortality independently of the BODE Index. We conclude that IC/TLC is an independent risk factor for mortality in subjects with chronic obstructive pulmonary disease. We propose that this ratio be considered in the assessment of patients with chronic obstructive pulmonary disease.

Aged↗
PubMed1992

Postoperative pulmonary function abnormalities after coronary artery bypass surgery.

In 18 patients, postoperative effects of coronary bypass surgery were evaluated. Pulmonary function studies were conducted preoperatively, and 1 and 6 weeks postoperatively, by means of spirometry, respiratory pressures, body plethysmography and impedance measurement of the respiratory system using the forced oscillation technique. One week postoperatively, total lung capacity (P less than 0.0001), inspiratory vital capacity (P less than 0.0001) forced expiratory volume (P less than 0.0001) and functional residual capacity (P less than 0.01) decreased significantly, while residual volume remained unchanged. This restrictive respiratory impairment was accompanied by significant decreases in inspiratory (P less than 0.0001) and expiratory (P less than 0.01) mouth pressures and significant decreases in respiratory resistance values (P less than 0.01). Six weeks postoperatively, significant differences in total lung capacity (P less than 0.0001), inspiratory vital capacity (P less than 0.0001) and forced expiratory volume (P less than 0.0001) persisted, while respiratory pressures returned to the preoperative values. It is concluded that respiratory muscle weakness contributes to the immediate postoperative restrictive lung function loss. Furthermore, structural alterations of chest wall mechanics have to be supposed for the persisting late restrictive pulmonary impairment.

Adult↗
PubMed2003

Physical training during intrahepatic chemotherapy.

OBJECTIVE: To evaluate the role of strength and endurance training for the muscular, cardiac, respiratory, and immune systems and the quality of life (QOL) during intrahepatic chemotherapy (folinic acid, 5-fluorouracil). DESIGN: Single case. SETTING: Teaching hospital in Germany. PARTICIPANT: An elderly athlete with liver metastasis after resection of a carcinoma of the rectum (pT3, N0, M-liver, G2). INTERVENTION: Strength and endurance training during chemotherapy. MAIN OUTCOME MEASURES: During the intervals between training cycles (14d), beginning in postoperative week 6, a strength and endurance training regimen was performed twice weekly for 13 weeks, with an intensity of 40% to 60% of the maximum postoperative individual power and endurance. Before and after chemotherapy, we checked echocardiograms, resting and exercise electrocardiograms, lung function, natural killer (NK) cells, and the Gastrointestinal Quality of Life Index (GIQLI) scores. RESULTS: The increase in strength was between 0% and 144%. The improvement in endurance expressed by reduction of heart rate and lactate concentration was 10% and 21.5%, respectively. Lung function also improved with regard to forced expiratory volume in 1 second (12.9%), forced vital capacity (11.3%), and inspiratory vital capacity (11.4%). The relative count of the NK cells increased to 27.2%. An improvement in the GIQLI was observed from 109 points (pathologic) to 129 points. CONCLUSION: Strength and endurance training was associated with an increase of physical strength and endurance with positive influence on illness-related QOL. Postoperative physical exercise during regional chemotherapy is beneficial.

Adenocarcinoma↗
PubMedDate not supplied

Postoperative acute respiratory failure following thoracotomy in a patient with Charcot-Marie-Tooth disease.

We present the case of a patient with Charcot-Marie-Tooth (CMT) disease who required prolonged ventilatory support following a thoracotomy due to respiratory muscle weakness. Although CMT was traditionally believed to affect only skeletal muscles, recent evidence suggests that respiratory involvement is relatively common, even in the absence of pulmonary symptoms. Assessment of respiratory muscle strength using measurements of vital capacity and negative inspiratory force is helpful in evaluating pulmonary reserve in patients with CMT.

Adult↗
PubMed2005

[Diaphragmatic weakness and its impact on respiratory function in primary myopathies].

BACKGROUND: Diaphragmatic weakness (DW) is a potential manifestation of primary myopathies. Prevalence and impact on respiratory function have not been defined. METHODS: Respiratory function (inspiratory vital capacity, IVC; maximal inspiratory muscle pressure, PImax; respiratory muscle effort, P (0.1)/PImax) and polysomnography/nocturnal capnometry (PtcCO(2)) was analysed in 49 patients with primary myopathies. DW was defined as > 25 % drop of IVC upon shift from upright to supine position. RESULTS: 19/54 (35 %) of patients, mostly AMD (68 %) and DMD (42 %) had DW. Restrictive ventilatory defect was moderate (IVC 37.2 +/- 26.2 %) in patients with and without DW (IVC 46 +/- 26 %, p = n. s.). DW caused a -33 %, respective - 25 %, supine drop of IVC and PImax, resulting in severe restriction in supine position (IVC (supine) 24.9 +/- 19.1 %, PImax (supine) 2.0 +/- 1.0 kPa, P (0.1)/PImax (supine) 19.9 +/- 12,8 %). All patients with DW and 75 % without had sleep-disordered breathing. This was significantly more severe in DW: 90 % (vs 17 % without DW) had continuous nocturnal hypoventilation (PtcCO(2) 62 +/- 2 mm Hg), 70 % (vs 18 % without DW) had combined nocturnal and diurnal hypercapnic respiratory failure (PaCO(2) 54,7 +/- 11.8 mm Hg). DW was an independent risk factor for sleep disordered breathing, for nocturnal and diurnal respiratory failure (r = 0.95, p < 0,05). Predictive thresholds thereof were accurate and identical to previously determined only for supine function data. CONCLUSION: DW is common in primary myopathies and predictive of nocturnal and diurnal respiratory failure. Supine respiratory function tests are necessary for clinical diagnosis and respiratory risk stratification.

Adolescent↗
PubMed2001

The impact of nutritional supplementation and resistance training on the health functioning of free-living Chilean elders: results of 18 months of follow-up.

Body composition changes and loss of functionality in the elderly are related to substandard diets and progressive sedentariness. The aim of this study was to assess the impact of an 18-mo nutritional supplementation and resistance training program on health functioning of elders. Healthy elders aged > or = 70 y were studied. Half of the subjects received a nutritional supplement. Half of the supplemented and nonsupplemented subjects were randomly assigned to a resistance exercise training program. Every 6 mo, a full assessment was performed. A total of 149 subjects were considered eligible for the study and 98 (31 supplemented and trained, 26 supplemented, 16 trained and 25 without supplementation or training) completed 18 mo of follow-up. Compliance with the supplement was 48%, and trained subjects attended 56% of programmed sessions. Activities of daily living remained constant in the supplemented subjects and decreased in the other groups. Body weight and fat-free mass did not change. Fat mass increased from 22.2 +/- 7.6 to 24.1 +/- 7.7 kg in all groups. Bone mineral density decreased less in both supplemented groups than in the nonsupplemented groups (ANOVA, P < 0.01). Serum cholesterol remained constant in both supplemented groups and in the trained groups, but it increased in the control group (ANOVA, P < 0.05). Upper and lower limb strength, walking capacity and maximal inspiratory pressure increased in trained subjects. In conclusion, patients who were receiving nutritional supplementation and resistance training maintained functionality, bone mineral density and serum cholesterol levels and improved their muscle strength.

Aged↗
PubMed1994

Pulmonary function before surgery for pectus excavatum and at long-term follow-up.

Pulmonary function tests were performed before surgery on 152 patients who were operated on for pectus excavatum between 1970 and 1987 and at long-term follow-up to assess the degree of impairment and to investigate any changes caused by surgical correction. The mean age at surgery was 15.3 +/- 5.5 years. Pulmonary function was found to be restricted preoperatively. Multivariate analysis showed that preoperative pulmonary function was not related to age, the severity of the deformity at physical examination, or to pulmonary complaints. Only the patients with obstructive disease showed significantly more pulmonary complaints (p = 0.042). The total lung capacity (TLC) and inspiratory vital capacity (IVC) were significantly related to the age-corrected (delta) anteroposterior diameter of the chest (lower vertebral index [LVI]) (p = 0.0001). At follow-up (mean, 8.1 +/- 3.6 years), the restriction of pulmonary function was increased despite improvement in the symptoms of most patients and despite a significant increase in the anteroposterior diameter of the chest (p = 0.0001): the TLC was decreased from 83.7 percent predicted (pred) preoperatively to 73.8 percent pred (p = 0.0001) and the IVC from 78.3 percent pred to 70.7 percent pred (p = 0.0001). The surgical results were satisfactory in 83.6 percent. No relation was found between the changes in pulmonary function measured at follow-up and the surgical results. Only the age at surgery and the changes in the TLC and IVC at follow-up were significantly related (p = 0.0036, 0.0043, respectively), although the correlation coefficients were low (r = 27 percent and 28 percent, respectively). The reduction in lung function at follow-up was most pronounced in the patients who had the least functional impairment (TLC > 75 percent pred) preoperatively. No correlation was found between the changes in the pulmonary function test results at follow-up and follow-up interval, preoperative delta LVI, and the change in delta LVI at follow-up.

Adolescent↗
PubMed1994

Analysis of the inspiratory flow-volume curve. Should it always precede the forced expiratory maneuver?

The inspiratory flow-volume (FV) curve can be used to identify patients with upper airway obstruction, air trapping, and restriction. Current computed pulmonary function testing equipment often mandates a forced expiratory maneuver (FEM) immediately prior to the forced inspiratory maneuver (standard method). We evaluated the inspiratory FV curve with and without an antecedent FEM in 119 subjects referred for pulmonary function testing. The subjects were divided into four groups by grading the degree of airway obstruction using confidence intervals of the FEV1/FVC percent predicted minus the actual FEV1/FVC percent measured from the best FEM according to Intermountain Thoracic Society recommendations. The forced inspiratory vital capacity (FIVC), forced inspiratory flow 50 (FIF50), and peak inspiratory flow (PIF) from the inspiratory FV curve with an antecedent FEM was compared with the FIVC, FIF50, and PIF without an antecedent FEM in each category of obstructive lung disease. The FIVC without the antecedent FEM was significantly larger than that with an antecedent FEM by 170 ml (p < 0.002) in subjects with severe airway obstruction, but was not significantly different in the other groups. The FIF50 was not significantly different in any group, but approached significance in both normal subjects and subjects with severe obstruction. The PIF was not significantly different in any group, but approached significance in the normal subjects, order for patients with severe obstructive airway disease to generate a valid forced inspiratory FV curve, it should be obtained without an antecedent FEM. When a plateau of the inspiratory FV curve is encountered, we suggest that is useful to generate the inspiratory FV curve prior to the FEM and to analyze its flow and volume characteristics independent of the FEM. The "best" inspiratory FV curve should then be displayed with the "best" FEM for proper evaluation of the FV loop.

Adult↗