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PubMed2006

IPPB-assisted coughing in neuromuscular disorders.

In neuromuscular disorders, reduced peak cough flows (PCFs) are considered to increase the risk of respiratory complications such as pneumonia or chronic atelectasis. Different methods were described to improve PCF. However, these studies were primarily carried out in adults, and there is limited information regarding the use and efficacy of these methods in children with respiratory muscle weakness. The aim of this study was to investigate whether hyperinsufflation with an intermittent positive-pressure breathing (IPPB) device is effective in cough augmentation in pediatric patients. Spirometry (forced inspiratory vital capacity, FIVC; forced expiratory volume in 1 sec, FEV1), respiratory muscle pressures (peak inspiratory pressure, PIP; peak expiratory pressure, PEP), and PCF were measured in 29 schoolchildren with various neuromuscular disorders. IPPB-assisted hyperinsufflation was taught individually to increase lung volumes (maximum insufflation capacity, MIC) above FIVC. The impact of hyperinsufflation on peak cough flow was documented. In 28/29 patients, IPPB-assisted hyperinsufflation enhanced FIVC from 0.68 +/- 0.40 l to an MIC of 1.05 +/- 0.47 l (P < 0.001). Unassisted PCF was 119.0 +/- 57.7 l/min, and increased to 194.5 +/- 74.9 l/min (P < 0.001) in 27/29 patients. This effect was similar in young patients (ages 6-10 years) and older patients (aged >10 years). Augmentation of lung volumes from FIVC to MIC correlated with an increase of PCF (R = 0.42, P < 0.05). IPPB-assisted hyperinsufflation improves PCF in pediatric neuromuscular disorders. The results suggest that this technique can be used to improve clearance of airway secretions and therefore reduce respiratory morbidity in children with NMD.

Adolescent↗
PubMed1989

Alveolar pressure and airway resistance during maximal and submaximal respiratory efforts.

A digital computing technique was used to extract continuous calculations of average alveolar pressure and airway resistance from body plethysmographic measurements during forced inspiratory and expiratory vital capacity maneuvers and tidal breathing in human subjects. Derived alveolar pressures were similar to those obtained using an interrupter technique (linear regression slope, 0.99 +/- 0.02; r = 0.98) and by comparison with esophageal pressure measurements. Studies in normal subjects revealed a characteristic pattern of increasing airway resistance throughout the expiratory phases of maximal and submaximal respiratory maneuvers, with maximal resistance of 33 to 110 cm H2O/L/s at low lung volumes during forced vital capacities. In contrast, inspiratory resistance remained low and constant throughout maximal and submaximal inspiratory maneuvers. Patients with COPD showed substantially higher inspiratory and expiratory resistances. In three patients with flow-volume loops suggestive of variable extrathoracic upper airway obstruction, measurements of alveolar pressure and airway resistance made it clear that two of the patients had upper airway obstruction, whereas the other was exerting an inadequate effort. We conclude that this noninvasive technique provides valid estimates of alveolar pressure and airway resistance continuously throughout both phases of the respiratory cycle over a wide range of volumes and flow rates. It may prove to be useful in the assessment of effort and airway obstruction in patients with a variety of pulmonary conditions.

Adult↗
PubMed1994

Total lung capacity in young highlanders of Aymara ancestry.

Total lung capacity (TLC) and its components, including residual volume (RV) and vital capacity (VC), are described in a sample of 164 male and 143 female youths of Aymara ancestry (10.0-19.9 years) who were born and raised at high altitudes (> 2,500 m) and who were residing in La Paz, Bolivia (average altitude of about 3,600 m). The hypothesis was tested that the enhanced lung volumes of adult highlanders are attained during the period of growth and development. As found in adult male highlanders, TLC in young highlanders was significantly larger than in lowlanders of the same sex and body size, primarily as a result of increases in RV and secondarily through increases in VC. In addition, estimates of the magnitude of the effect of chronic hypobaric hypoxia on all of the measures of pulmonary function, including TLC, RV, and VC, were positively related to age. This finding suggests that growth and development at high altitude is associated with a constant increase in TLC and other measures of pulmonary function relative to those of lowlanders, a finding which is consistent with the expectations of the developmental adaptation hypothesis. However, although these relationships were statistically significant in males, they were not significant in females. Thus, although the magnitude of the estimated effects of chronic hypobaric hypoxia on TLC, RV, and VC were similar in males and females, the developmental pattern by which these enhanced volumes are achieved may differ between sexes.

Adolescent↗
PubMedDate not supplied

Determinants of the first inspiratory volume and functional residual capacity at birth.

We have investigated the pattern of pressure and volume changes that occur in vaginally delivered, full-term infants during the onset of spontaneous respiration. Within a few seconds of delivery of the head, simultaneous measurements were made of stomach and esophageal pressure changes together with volume changes determined at the mouth. Values obtained for volume were very similar, but pressure changes were of a greater magnitude than previously reported. A significant correlation has been shown between first inspiratory volume and functional residual capacity (FRC) at the end of the first breath (p less than 0.004). No significant relationship was found between first inspiratory pressure and FRC. However, using a calculated index of inspiratory pressure and time ("inspiratory effort"), a significant relationship of this to FRC was observed (p less than 0.02).

Delivery, Obstetric↗
PubMed1993

Effect of aminophylline on respiratory muscle strength after upper abdominal surgery: a double blind study.

BACKGROUND: The effect of aminophylline on maximum respiratory muscle strength in patients undergoing upper abdominal surgery was investigated. METHODS: An open pilot study was performed in which aminophylline was administered continuously for 48 hours after surgery (protocol I). In a second group of subjects aminophylline was given for 24 hours after cholecystectomy in a double blind placebo controlled trial (protocol II). Twelve patients participated in the pilot study (group A) and 25 in protocol II of which 14 received aminophylline (group B) and 11 placebo (control, group C). Respiratory muscle strength was assessed by measuring mouth pressures during maximum static inspiratory and expiratory efforts. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), vital capacity (VC), inspiratory maximum pressures (PImax), expiratory maximum pressures (PEmax) were measured 24 hours preoperatively, PImax and serum theophylline 24 hours postoperatively, and FEV1, FVC, VC, PImax, PEmax, and serum theophylline 48 hours after surgery. RESULTS: FEV1, FVC, and VC decreased in all groups of patients at +48 hours. PImax fell at +24 hours and +48 hours but this decrease was significantly smaller in the two groups who received aminophylline than in the control group. PEmax showed a decrease at +48 hours but this reduction was similar in all three groups studied, independent of the treatment given. These data suggest that either aminophylline had a protective effect only on the inspiratory muscles or, most probably, that the effect of aminophylline was central, reducing the phrenic nerve inhibition induced by cholecystectomy and thus improving diaphragmatic function. CONCLUSIONS: Upper abdominal surgery decreases inspiratory and expiratory muscle strength and aminophylline has a protective effect only on inspiratory muscle function. This may have important clinical applications in minimising pulmonary complications after cholecystectomy.

Abdomen↗
PubMed1989

Pulmonary function in Parkinson's disease.

Pulmonary function was investigated in 31 consecutive patients with relatively severe Parkinson's disease. Clinical disability was assessed by Hoehn and Yahr scale, Northwestern University Disability Scale and Websterscore. All patients were on levodopa substitution therapy and used anticholinergics. Pulmonary function was investigated by spirography, determination of a maximal inspiratory and expiratory flow-volume curve and, when possible, maximal static mouth pressures were determined. Peak inspiratory and expiratory flow, maximal expiratory flow at 50% and maximal static mouth pressures were significantly below normal values. Vital capacity, forced inspiratory volume in 1 s and the ratio of forced expiratory volume in 1 s and vital capacity were relatively normal. Nine patients had upper airway obstruction (UAO) as judged by abnormal values for peak inspiratory flow, the ratio of forced expiratory volume in 1 s and peak expiratory flow and the ratio of maximal expiratory and inspiratory flow at 50%. Flow-volume curves were normal in eight patients; four patients demonstrated flow decelerations and accelerations (type A) and 16 had a rounded off flow-volume curve (type B). Type A can be explained by UAO and type B by a combination of decreased effective muscle strength and possible UAO. Overall results of pulmonary function tests in patients without any clinical signs or symptoms of pulmonary disease point to subclinical upper airway obstruction and decreased effective muscle strength in a significant proportion of patients.

Aged↗
PubMed1994

Effect of lung transplantation on diaphragmatic function in patients with chronic obstructive pulmonary disease.

BACKGROUND: To date there are no data on the effects of lung transplantation on diaphragmatic function in patients with end stage chronic obstructive pulmonary disease (COPD). It is not known whether the relation between the transdiaphragmatic pressure (PDI) and lung volume is altered in recipients after transplantation as a result of changes in diaphragmatic structure caused by chronic hyperinflation. The effect of lung transplantation on diaphragmatic strength was determined in patients with COPD and the relation between postoperative PDI and lung volume analysed. METHODS: Diaphragmatic strength was assessed in eight double lung transplant recipients, six single lung transplant recipients, and in 14 patients with COPD whose lung function was similar to those of the transplant recipients preoperatively. PDI obtained during unilateral and bilateral phrenic nerve stimulation at 1 Hz (twitch PDI) at functional residual capacity (FRC) and during maximal sniff manoeuvres (sniff PDI) at various levels of inspiratory vital capacity (VCin) served as parameters for diaphragmatic strength. Sniff PDI assessed at the various VCin levels were used to analyse the PDI/lung volume relation. RESULTS: Lung transplantation caused a reduction in lung volume, especially in the double lung transplant recipients. As a consequence sniff PDI was higher in the double lung transplant recipients than in the patients with COPD at all levels of VCin analysed. However, sniff PDI values analysed at comparable intrathoracic gas volumes were not reduced in the patients with COPD when compared with those who underwent lung transplantation. Bilateral twitch PDI values were similar in the patients with COPD and in the lung transplant recipients. In the single lung transplant recipients unilateral twitch PDI values were similar on the transplanted and the non-transplanted side. The relation between PDI and lung volume was similar in the patients with COPD and in the lung transplant recipients. CONCLUSIONS: In patients with COPD lung transplantation leads to an increase the maximal sniff induced PDI values by placing the diaphragm in a more favourable position for pressure generation. Since patients with COPD and postoperative lung transplant recipients showed similar PDI/lung volume relations, this suggests that chronic pulmonary hyperinflation does not cause major functional alterations of the diaphragm.

Adult↗
PubMed1993

[Effect of aminophylline on respiratory function in patients with chronic renal failure treated by peritoneal dialysis].

In 8 patients with chronic renal failure aminophylline influence was studied on respiratory function. No changes were seen in lung volumes after 30 minutes of intravenous aminophylline infusion. After 2 weeks of intraperitoneal infusion of aminophylline, maximal ventilation, vital capacity, forced vital capacity and inspiratory residual volume rose significantly. Residual volume and the ratio residual volume/total lung capacity, decreased. This changes may indicate an improved contractility of the respiratory muscles. A rise in the concentration of oxypurines after peritoneal dialysis and a significant improvement in the arterial oxygen tension indicate that aminophylline influences the respiratory function by bronchodilatation and by contractility improvement of the respiratory muscles.

Aminophylline↗
PubMed1998

The stress hormone adrenocorticotropin enhances sympathetic outflow to the muscle vascular bed in humans.

OBJECTIVE: To examine the role of adrenocorticotropin in the regulation of the sympathetic outflow to the muscle vascular bed in healthy female humans. DESIGN: Eight healthy, nonsmoking female subjects (aged 18-33 years) were examined before and after injection of 0.25 mg adrenocorticotropin 1-24 or placebo according to a balanced, double-blind cross-over protocol. METHODS: Muscle sympathetic nerve activity, arterial pressure, and heart rate were continuously recorded both under basal conditions and during a 50 min period after injection of each substance. Furthermore, sympathoexcitatory capacities of inspiratory apneas and cold pressure tests performed before and after injection of adrenocorticotropin were determined. RESULTS: The injection of adrenocorticotropin rapidly increased burst frequency of muscle sympathetic nerve activity (P < 0.01). The maximal effect of adrenocorticotropin, with an increase in burst frequency of 63%, occurred during the third minute after injection and waned subsequently, but muscle sympathetic nerve activity remained significantly increased during the first 10 min after injection. The stimulatory effect of adrenocorticotropin had disappeared 40 min after injection. The sympathoexcitatory capacity of a maximal inspiratory apnea and a cold pressure test, respectively, remained unchanged 10 and 45 min after the administration of adrenocorticotropin compared with control. Neither blood pressure nor heart rate was significantly affected by administration of the peptide. CONCLUSIONS: The data establish that the stress hormone adrenocorticotropin acutely increases sympathetic outflow to the muscle vascular bed in female humans. This effect is most likely mediated via central nervous system autonomic centers. The influence of adrenocorticotropin on the sympathetic nervous system might contribute to the alteration of response to stress in the course of the development of hypertension and could also add to the hypertensiogenic effects of corticosteroids and mineralocorticoids in states with excess adrenocorticotropin.

Adolescent↗
PubMed1994

Residual lung volume and ventilatory muscle strength changes following maximal and submaximal exercise.

In order to evaluate a mechanism which may be responsible for the often observed acute increase in residual lung volume (RV) following exercise, 12 non-smoking males (20-30 yrs) performed two bouts of exercise on separate days; one to maximal heart rate (HRmax) and one to 85% of HRmax for 20 min. Prior to exercise and at 5, 15, 30, 60 and 120 min post-exercise, the following parameters were measured: RV, forced vital capacity (FVC), forced expiratory volume (FEV1.0), forced expiratory flow (FEF75-85), maximal expiratory pressure (PEmax), and maximal inspiratory pressure (PImax). Significant (p < 0.05) increases occurred in RV at 5, 15 and 30 min following maximal exercise and at 5 and 30 min after submaximal exercise. Changes in RV between the two exercise bouts were generally greater (p < 0.05) for maximal exercise. Accompanying the increases in RV were significant (p < 0.05) decreases in PEmax and decreases in FVC, while FEV1.0 and FEF75-85 remained generally unchanged or were slightly elevated. The data suggest that decreases in expiratory muscle strength due to fatigue may in part be responsible for increases in RV.

Adult↗
PubMed1989

[Study of the respiratory profile in symptomatic asthma patients].

The following indexes were measured in 10 normal volunteers and 25 symptomatic asthmatic patients: --tidal volume (VT), breathing frequency (f), minute ventilation (Ve); --forced expiratory volume in 1 s. (FEV1), vital capacity (VC), residual volume (RV) and partial pressure of 02-C02 in arterial blood (Pa02-C02); --mean inspiratory flow (VT/Ti); --inspiratory duty cycle (Ti/Tt). Our data suggest a "ventilatory pattern" of the asthmatic patients may be characterized by the following features: --increasing of tidal volume (VT) and minute ventilation (Ve); --increasing of the mean inspiratory flow (Vt/Ti); --reduction of inspiratory duty cycle (Ti/Tt). This suggest that the breathing pattern may help to differentiate symptomatic asthmatic patients form patients with chronic obstructive pulmonary disease who have similar degrees of pulmonary hyperinflation, but breathe with faster rates and slightly elevated tidal volumes.

Adult↗
PubMed1988

Moderately severe chronic airflow obstruction. Can corticosteroids slow down obstruction?

In a former study in patients with severe chronic airflow obstruction (CAO), (forced expiratory volume in one second (FEV1) ranging from 350-910 ml), we concluded that daily oral corticosteroids might slow down the progression of disease. The results of the present long-term (14-20 yr) study on 139 non-allergic patients with less severe CAO (FEV1 greater than or equal to 1200 ml, FEV1 as a percentage of vital capacity (FEV1%VC) 40-55%) confirm and extend our former observations. Four patterns of the course of FEV1 and inspiratory vital capacity (VC) in time were recognized: 1) linear decrease; 2) no change; 3) initial increase, followed by decrease; 4) initial decrease, followed by increase. Groups 1 and 3 had a higher functional residual capacity as a percentage of total lung capacity (FRC%TLC) as compared to group 2 and 4; the work of breathing was lower in group 2 than in the other three groups. Otherwise the initial 82 parameters, including the degree of reversibility of airflow obstruction and smoking habits were comparable in the four groups. The four patterns of FEV1 showed a strong association with the long-term use of prednisolone. When oral prednisolone was instituted or increased to a dose of at least 10 mg/day continuously, FEV1 either remained constant, decreased more slowly or even increased over many years of follow-up. When the oral dose was diminished to below 10 mg/day, FEV1 decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Inspiratory resistive loading improves cycling capacity: a placebo controlled trial.

BACKGROUND: Respiratory muscle training has been shown to improve both its strength and endurance. The effect of these improvements on whole-body exercise performance remains controversial. OBJECTIVE: To assess the effect of a 10 week inspiratory resistive loading (IRL) intervention on respiratory muscle performance and whole-body exercise endurance. METHODS: Fifteen apparently healthy subjects (10 men, 5 women) were randomly allocated to one of three groups. One group underwent IRL set at 80% of maximum inspiratory pressure with ever decreasing work/rest ratios until task failure, for three days a week for 10 weeks (IRL group). A second placebo group performed the same training procedure but with a minimal resistance (PLA group). IRL and placebo training were performed at rest. The remaining five control subjects performed no IRL during the 10 week study period (CON group). Cycling endurance capacity at 75% VO(2)peak was measured before and after the intervention. RESULTS: After the 10 week IRL intervention, respiratory muscle strength (maximum inspiratory pressure) and endurance (sum of sustained maximum inspiratory pressure) had significantly improved (by 34% and 38% respectively). An increase in diaphragm thickness was also observed. These improvements translated into a 36% increase in cycling time to exhaustion at 75% VO(2)peak. During cycling trials, heart rate, ventilation, and rating of perceived exertion were attenuated in the IRL group. No changes were observed for the PLA or CON group either in the time to exhaustion or cardiorespiratory response to the same intensity of exercise. CONCLUSION: Ten weeks of IRL attenuated the heart rate, ventilatory, and perceptual response to constant workload exercise, and improved the cycling time to exhaustion. Familiarisation was not a factor and the placebo effect was minimal.

Adult↗
PubMed2004

A short-term comparison of two methods of sputum expectoration in cystic fibrosis.

The aim of this study was to determine whether repeated maximum inspiratory vital capacity manoeuvres against a fixed resistance increased effective short-term sputum clearance in adults with cystic fibrosis (CF). Twenty adults with CF were randomised to receive, on alternate days, either standardised physiotherapy (SP) for 30 min, comprising postural drainage and the active cycle of breathing technique, or a series of resistive inspiratory manoeuvres (RIM) at 80% of their maximum sustained inspiratory pressure developed between residual volume and total lung capacity during the first 4 days of the treatment of an exacerbation of respiratory symptoms. Expectorated sputum was collected during and for 30 min after each treatment and weighed. Total protein, immunoreactive interleukin (IL)-8 and human neutrophil elastase (HNE) concentrations, and the amount of each component expectorated, were determined. Compared with SP, RIM increased sputum weight two-fold, independent of treatment order or day. The concentrations of protein, IL-8 and HNE in sputum were similar for both treatments, while the quantity expectorated was greater with RIM treatment. In conclusion, short-term resistive inspiratory manoeuvres treatment was more effective at clearing sputum and inflammatory mediators than standardised physiotherapy.

Adult↗
PubMed1997

Quality of life in patients with cystic fibrosis.

The majority of patients with cystic fibrosis (CF) will grow into adulthood. Despite this improvement in survival, the disease is progressive, especially with respect to the decline in pulmonary function, which in turn may have an impact on a patient's quality of life. In this study we evaluated the quality of life in CF adults and examined the relationship between quality of life and pulmonary function, exercise capacity, and dyspnea. We assessed in 15 patients in stable clinical condition their forced expired volume in the first second (FEV1) inspiratory vital capacity (IVC), cycle exercise capacity (Wmax), and subjective degrees of dyspnea during daily living (MRC dyspnea scale). Quality of life was assessed with the Sickness Impact Profile (SIP). A sample of 100 healthy individuals, ranging in age from 18 to 30 years, served as the control group. Mean (SD) age of the patients was 25.9 (7.3) years, FEV1 was 38 (16)% predicted, IVC was 65 (17)% predicted, FEV1 IVC ratio was 46 (10)%, and Wmax was 90 (54) W. The overall SIP and physical SIP scores in CF patients were significantly higher than in the controls, indicating more impairment in overall and physical functioning in the patients than in the control group (P < 0.001). The psychosocial SIP score did not differ significantly between the two groups. Overall SIP score correlated poorly with FEV1 % predicted (r = -0.33; n.s) and IVC % predicted (r = -0.36; n.s.) but showed a better and significant relationship to the maximal exercise capacity (r = -0.57; P < 0.05). MRC dyspnea scores showed a strong correlation with overall SIP scores (r = 0.75; P < 0.001). These results show that CF affects quality of life in adults primarily due to a limitation in physical functioning. Psychosocial functioning did not differ from that of healthy controls. Exercise capacity and dyspnea scores were related to the impairment in the quality of life. Therefore, the effects of programs aimed to improve exercise capacity and reduce dyspnea on CF patients' quality of life need to be evaluated.

Adolescent↗