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At least 973 records · Page 54Linked to original sources
PubMed1989

Constancy of individual exponents for inspired lung volume: a comment on Harver (1987).

In this paper we made two brief commentaries on Harver's (1987) experiment. The first comment is an observation on the growing area of respiratory psychophysics for which we prefer the name Behavioral Physiology. In the second comment it is suggested that the stable individual differences in the exponent of the psychophysical power law reported by Harver may be an artifact of the psychophysical method employed: category production.

Arousal↗
PubMed1988

Contribution of impedance measurement of the respiratory system to bronchial challenge tests.

The contribution of impedance measurement of the respiratory system to bronchial challenge tests was studied in 64 asthmatics and 23 control subjects. After histamine challenge, resistance values increased significantly at all frequencies but most markedly at the lower frequencies in the asthmatic group; reactance values significantly decreased at all frequencies. In the control group, resistance significantly increased at 8 and 12 Hz. However, reactance decreased significantly at all frequencies. By multiple logistic model analysis, a simple discriminant score was found with great discriminating power to differentiate asthmatics and nonasthmatics. The discriminating score equals 9 X FEV1 aft - 7 X FEV1 bef. Adding the forced oscillation technique to the equipment for measuring the bronchial response after challenging procedures can give information about the localization of the response to the challenge in the respiratory system.

Adult↗
PubMedDate not supplied

Electromyographic study of sternocleidomastoid and scalene muscles in tetraplegic subjects during respiration.

An electromyographic investigation of inspiratory respiratory muscles was carried out in six tetraplegic and two normal subjects using needle electrodes. When the normal subjects were using tidal breathing there was no activity present. In the majority of tetraplegic subjects, activity was present in the scalene muscle during tidal breathing. This activity became more marked during deep inspiration. The muscles were hypertrophied and these muscles filled an important respiratory role.

Adult↗
PubMed2001

Forced inspiratory nasal flow-volume curves: a simple test of nasal airflow.

OBJECTIVE: To observe and describe normal and abnormal inspiratory nasal flow-volume patterns. PATIENTS AND METHODS: In this observational case series, individuals with and without nasal symptoms underwent forced inspiratory nasal flow-volume (FINFV) curve measurements. The participants were volunteer adults from the staff and patients of a pulmonary subspecialty private practice office. To examine the flow patterns from the FINFV curves, definitions of normal and abnormal were established. Normal curves were defined as those from participants who had no nasal symptoms and a peak inspiratory nasal flow greater than 2.5 L/s. Abnormal curves were defined as those from participants who had 1 or more nasal symptoms, a peak inspiratory nasal flow lower than 2.5 L/s, and normal oral inspiratory flow. RESULTS: Study participants consisted of 10 staff and 58 patients. Fourteen individuals (21%) met the definition of normal and had FINFV curves that mimicked the shapes of normal oral flow-volume curves; 39 (57%) met the definition of abnormal and had FINFV curves that mimicked the patterns of abnormal oral flow-volume curves. The abnormal curves showed both fixed (33/39 [85%]) and variable (6/39 [15%]) patterns of obstruction. Fifteen participants (22%) did not meet either established definition. CONCLUSIONS: Forced inspiratory nasal flow-volume curves are a potentially useful clinical tool to measure nasal airflow. Normal and abnormal flow patterns are easily identifiable.

Adult↗
PubMed2006

[Inspiratory muscle function, hemodynamic parameters and dyspnea in patients with mitral valve stenosis].

BACKGROUND: The mechanism involved in dyspnea in patients with mitral valve stenosis (MS) is not completely understood. AIM: To evaluate in patients with MS, changes in hemodynamic parameters during the assessment of inspiratory muscle endurance (IME) and the relationship between IME, hemodynamics and dyspnea. SUBJECTS AND METHODS: We studied 13 patients (9 in NYHA class II and 4 in class III). Endurance was evaluated using a two minute incremental threshold loading test, to obtain the maximal sustainable inspiratory pressure (SIP), and maximal inspiratory load (MIL). During the test, cardiac output (CO), mean pulmonary and capillary pressures (PAP and PCP, respectively), were evaluated. RESULTS: Compared to six normal subjects, MS patients had reduced SIP and MIL (p <0.01), which correlated with baseline index of dyspnea (r= 0.57 and r=0.52, respectively, p <0.05). At the end of the test period, basal CO, cardiac index (CI), PAP and PCP increased from 3.4 to 4.0 l/min-1; 2.1 to 2.5 l/min-1/m-2; 15 to 25 and 11 to 18 mmHg, respectively (p <0.01). No relationship between IME and hemodynamic parameters was found. CONCLUSIONS: IME is reduced and is closely related to dyspnea in these patients with MS. The observed low CI, suggests that muscle underperfusion could contribute to this dysfunction during the inspiratory.

Adult↗
PubMed1999

Functional and high-resolution computed tomographic studies of divers' lungs.

OBJECTIVES: Several cross-sectional studies have described a decrease in the expiratory flow rates of divers. The objective of this study was to determine whether the combined application of high-resolution computed tomography (HRCT) and lung function testing supports the reported development of small airway obstruction in divers. METHODS: Thirty-two navy divers, 27 commercial divers, and 48 referents matched for age and smoking history underwent pulmonary function testing and HRCT of the lungs supplemented by a limited number of expiratory scans. The commercial divers were older and dived longer than the navy divers. Multivariate regression analysis was used to assess the relevant correlations of age, height, pack-years of cigarette smoking, and indices of diving exposure with lung function parameters. RESULTS: The inspiratory vital capacity and forced vital capacity (FVC) were greater, while the FEV% [(100 x FEV10)FVC] and maximum expiratory flow (MEF) at 25% (MEF25) of the FVC were lower for the navy divers than for the referents. The lung volumes and expiratory airflow pattern did not differ between the commercial divers and the corresponding referents. The forced expiratory volume in 1 second (FEV10), FEV%, MEF75, and MEF25 correlated negatively with the years of diving experience. This association was independent of age, height, and pack-years of cigarette smoking. For the majority of the divers and referents the expiratory HRCT revealed minor lobular air trapping without any difference between the groups. The HRCT did not show relevant morphologic abnormalities of small or large airways. CONCLUSIONS: The data confirm that diving may affect pulmonary function. However, there is no radiologic evidence for the development of small airway disease in these 2 subgroups of divers.

Adult↗
PubMed1976

[Respiratory function tests in epidermoid cancers of the bronchi].

The results of functional tests are analyzed in 50 cases of epidermoid bronchial cancers. Severe disorders take place in almost every patient. In one patient out of two, there is an old distension already existing prior to the cancer; in other patients gas exchange disorders can be improved by the intervention. Moreover, from some results a spreading of cancer towards the mediastinum is to be feared.

Adult↗
PubMed1999

[Flexible bronchoscopic implantation of Accuflex and Strecker stents in malignant bronchial stenoses].

Silicone and metal stents are available for the treatment of malignant bronchial stenoses. This project sought to compare the self-expanding nitinol Accuflex stent (Boston Scientific Corp; Watertown, Mass) with the passively expandable tantalum Strecker stent (Boston Scientific Corp; Watertown, Mass), both implanted by flexible bronchoscopy under local anesthesia and sedation. In 51 patients with malignant bronchial stenosis, 14 nitinol and 51 tantalum stents were used and stenoses of 75 to 100% were treated. The intervention was successful in all but one patient, a mean patency of 93% was achieved. In the follow-up period, the probability of survival was significantly lower in patients with total bronchus occlusion than in patients with stenotic alteration (44 vs 109 days; p < 0.05). In 10 patients, lung function analysis after stent implantation revealed a significant increase in PaO2 (65 vs 71 mm Hg; p < 0.01), inspiratory vital capacity (2.5 vs 2.7 L; p < 0.05), and FEV1 (1.8 vs 2.0 L; p < 0.05). Mucus retention was the main (39%) adverse factor in the early phase after stent implantation, whereas tumor penetration became the most frequent problem (67%) in the later phase. Recanalizing interventions were necessary in 18% of the cases in which tumor penetration occurred. Stent distortion occurred in 12 patients with Strecker and in none with Accuflex stents. In comparison to the Strecker stent, the self-expanding Accuflex stent is preferable owing to its excellent flexibility and faster delivery system. Both types of stents could be sufficiently deployed within the lesions and allowed for highly precise positioning. Furthermore, no general anesthesia was required. The fiber-bronchoscopy mode of implantation under sedation is very efficient even for tumor patients with severe impairment of their physical and respiratory condition.

Airway Obstruction↗
PubMed1999

[Control of respiration by inspiratory pressure support].

A reduction in arterial PCO2 is an important cause of respiratory muscle inhibition during pressure support (PS). A nonchemical inhibition of respiratory activity during PS has also been demonstrated. This nonchemical inhibition of inspiratory activity is not observed with all modes of mechanical ventilation. In fact, the higher is the initial flow rate provided by the ventilator, the more efficient the nonchemical inhibition of respiratory activity. Currently, PS is the ventilatory support technique which provides the highest initial inspiratory flow. However, these new physiological findings should facilitate the development of more effective ventilatory support techniques.

Carbon Dioxide↗
PubMed1997

[Measurement and clinical significance of inspiratory drive efficacy in patients with chronic obstructive pulmonary disease].

To study the relationship between VT/P0.1 and the function of inspiratory muscles, we performed the measurement of VT/P0.1 (inspiratory drive efficacy), MIP (maximal inspiratory mouth pressure) and MMIF (maximal midinspiratory flow) in 15 normal subjects and 60 patients with chronic obstructive pulmonary disease(COPD). The results indicated that VT/P0.1 decreased with the deterioration of COPD and it correlated highly and positively with MIP and MMIF. These suggest that VT/P0.1 can reflect the function of inspiratory muscles as well as MIP and MMIF can.

Aged↗
PubMed2000

[Maximum inspiratory flows in healthy children and asthmatics 4 to 8 years old. The implications for the inhalation of drugs in powder form].

Twenty-two asymptomatic asthmatic children and twenty-one healthy controls aged between 4 and 8 years old were studied in order to determine peak inspiratory flow (PIF) in baseline conditions through a Turbuhaler powder aerosol device. PIF was measured randomly on one of three days using computerized spirometry. In healthy children, baseline PIF ranged from 129 to 244 L/min; PIF through the Turbuhaler ranged from 72 to 99 l/min. In asthmatics, the ranges were 122 to 236 l/min and 79 to 102 l/min for baseline and Turbuhaler PIF, respectively. PIF was significantly related to age (p < 0.05). The difference between PIF through the Turbuhaler for asthmatic and healthy children was not significant. PIF of healthy and asthmatic Chilean children between 4 and 8 years of age exceeded the level required to obtain an optimum dose from this type of device. This study suggests that the aerosol powder doses produced by devices such as that used in this study can be used by children from age 4 and older.

Administration, Inhalation↗
PubMed1999

Spirometric impairments in undernourished children.

The present study elucidates the effect of undernutrition on pulmonary functions in children. The study was carried out in healthy normals, wasted, wasted and stunted children. Spirometry was performed with Vitalograph Compact-II spirometer. Wasted, wasted and stunted children showed lower lung volumes, forced mid expiratory flow time and inspiratory flow rates than healthy normals. Wasted and stunted children had lower VC, FVC and FIF50% than wasted children. The reduction in lung volumes and flow rates in wasted children may be due to ventilatory muscle wasting. But in wasted and stunted children along with muscular wasting diminished skeletal growth is also a reason for lower lung functions. No airflow limitation was observed in undernourished children.

Case-Control Studies↗
PubMed2000

[Titration of an effective positive pressure level in the treatment of obstructive sleep apnea syndromes using continuous positive pressure ventilation].

The efficacy of continuous airway positive pressure ventilation with a nasal mask mainly depends on the appropriateness of the effective positive pressure level. Conventionally, this level is determined from polysomnographic recordings using progressively increasing pressure levels to determine the point where episodes of apnea, hypopnea and snoring regress in all sleep phases and in all body positions. Since the first description of this method, many other titration methods have been proposed. Some use sophisticated signals such as the analysis of respiratory exertion level or limitation of inspiratory flow to provide a more precise titration which is particularly useful in cases where the classical titration method is insufficiently effective. Inversely, simplified methods have been examined from an economic point of view. These methods do not require the presence of a technician in a specialized laboratory where the waiting list for diagnostic tests is often long. Recordings during naps or short nights have been proposed for the more severe cases. Likewise titrations during simple polygraphy recordings or with an autoCPAP device have been shown to be effective in one-night laboratory recordings. Much work remains to be done to determine the effectiveness of these methods when used in the patient's home as well the long-term effects.

Humans↗