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PubMed2002

Dyspnea, respiratory function and sputum profile in asthmatic patients during exacerbations.

Dyspnea is often used as a marker of asthma severity although a wide variation in dyspnea perception associated with bronchoconstriction (PB) has been described in asthmatic patients. Our hypothesis is that changes of airway inflammation, airway narrowing and hyperinflation may account for a part of the variability of breathlessness in spontaneous asthma attack. In asthmatic patients with exacerbation of the disease, we evaluated respiratory function, dyspnea (using visual Analogue Scale--VAS) and peak expiratory flow (PEF) values and variability (amplitude % mean), and sputum cellular and biochemical profile before (day I) and after (day II) therapy with i.v. corticosteroids and inhaled beta2-agonists, as appropriate. By day II, forced expiratory volume in 1 s (FEV1), inspiratory capacity (IC), PEF or VAS values and variability, sputum eosinophils and eosinophilic cationic protein (ECP) had improved. Improvement of dyspnea expressed as a decrease in VAS and reduction in variability of dyspnea sensation significantly correlated with increase in FEV1 %predicted value (%pv) (P=0.03; p=0.72 and P=0.02; p=0.74, respectively). No significant correlation was found between IC and VAS either in absolute values or as changes from days I and II, nor between sputum outcomes and PEF or VAS, regardless of how they were measured. We conclude that in acute asthmatic patients, dyspnea measurement, functional measurements and sputum analysis may be useful in monitoring disease activity, response to therapy and can provide different information on the state of the disease.

Acute Disease↗
PubMed2006

Radioiodine therapy in non-toxic multinodular goitre. The possibility of effect-amplification with recombinant human TSH (rhTSH).

There is no consensus regarding the optimum treatment of benign non-toxic goitre. L-thyroxine suppressive therapy is widely used, but there is poor evidence of its efficacy, and it may have serious adverse effects on health. Surgery is first choice in large goitres or if malignancy is suspected. 131I therapy results in a one-year goitre reduction of around 40% in multinodular goitres, usually with a high degree of patient satisfaction and improvement of the inspiratory capacity. The effect is attenuated with increasing goitre size. The risk of hypothyroidism is 22-58% within 5-8 years. A sufficient thyroid 131I uptake is mandatory for 131I therapy to be feasible and pre-stimulation with recombinant human TSH (rhTSH) increases this considerably. This leads to an increased absorbed thyroid dose by approx.75%, mainly in those patients with the lowest thyroid 131I uptake, and a more homogeneous intrathyroidal isotope distribution. Pre-stimulation with even a small dose of rhTSH seems to allow a reduction of the 131I activity while still achieving a mean goitre reduction of approximately 40% within a year. A significantly lower extrathyroidal radiation is achieved by this approach. With an unchanged 131I activity, rhTSH pre-stimulation improves the goitre reduction by 30-50%. However, this is at the expense of a higher rate of hypothyroidism, cervical pain and transient thyrotoxicosis. Of particular concern is the observation made in healthy persons, that rhTSH results in a transient average thyroid volume increase of 35%. A similar goitre swelling may cause problems in susceptible patients during rhTSH-augmented 131I therapy. Thus, this concept still needs a closer evaluation before routine use.

Administration, Cutaneous↗
PubMed2003

Inhalation profiles in asthmatics and COPD patients: reproducibility and effect of instruction.

Turbuhaler and Salbutamol-Diskus produce therapeutic doses at peak inspiratory flow (PIF) of >30 L/min. However, the optimum flow for Fluticasone-Diskus and Turbuhaler, in terms of total emitted dose and fine particle mass, is >60 L/min. The Turbuhaler achieved a higher output at this flow, as compared to Diskus. For pMDI 25 < PIF < 90 L/min, an actuation time of 0.0-0.2 sec is optimal. The aim of this study was to examine the incidence of optimum inhalation profiles, the effect of instruction, reproducibility, and the relationship between inhalation profiles and patient characteristics in stable asthmatics and mild/moderate/severe COPD patients. For each device, triplicate inhalation profiles were recorded during 6 sessions in a 10-week period. All patients achieved PIF > 30 L/min using Diskus. After instruction, all Diskus inhalations were performed with >60 L/min, except 7% of the inhalations of the severe COPD patients. At least 95% of the Turbuhaler inhalations was also performed with the minimum flow; however, 19% of the inhalations of the severe COPD patients were not optimally performed. The hand-lung coordination was inadequate in 40% of pMDI inhalation profiles, and 80% was performed with a too high flow. The reproducibility of PIF of both dry powder inhalers (DPIs) was very high (coefficient of variation = 4-10%). The reproducibility of the pMDI variables was lower (coefficient of variation = 9-18%). The major lung function variables predictive for PIF(diskus) and PIF(turbuhaler) were maximal inspiratory mouth pressure (MIP), PIF, and inspiratory capacity. No significant predictive lung function variables for PIF(pMDI) were found. Most patients performed reproducible optimum inhalation profiles through Diskus and Turbuhaler. However, in the severe COPD group, 7-19% of the patients were not able to generate the optimum flows through the DPIs. For these patients, a flow-independent aerosol delivery system might be more suitable. The majority of patients were using the pMDI incorrectly. Instruction had no effect. So, we concluded that the pMDI should not be used in these patient groups because of the coordination problems.

Administration, Inhalation↗
PubMed2001

Diaphragm movement before and after cholecystectomy: a sonographic study.

UNLABELLED: Respiratory disorders after abdominal surgery are commonly explained by changes in diaphragmatic movement that are difficult to demonstrate and quantify. Our aim was thus to quantify these changes using a noninvasive method. We used M-mode sonography for the prospective study to measure diaphragmatic amplitude in 14 patients before and after cholecystectomy. During quiet breathing, the diaphragm inspiratory amplitude (DIA) was significantly decreased after surgery from 1.4 +/- 0.2 cm to 1 +/- 0.1 cm and from 1.6 +/- 0.3 cm to 1.2 +/- 0.3 cm in the Laparoscopic and Open Cholecystectomy groups, respectively. The total time cycle of diaphragmatic motion decreased significantly in the two groups. The DIA also decreased significantly during deep breathing after cholecystectomy from 6.0 +/- 0.8 cm to 3.0 +/- 1.8 cm and from 6.1 +/- 1.3 cm to 3.1 +/- 1.6 cm in the Laparoscopic and Open Cholecystectomy groups, respectively. The six patients who underwent spirometric examination showed, during quiet breathing, a significant decrease in DIA without change in tidal volume, i.e., 0.51 +/- 0.08 L to 0.45 +/- 0.08 L. We found a significant decrease in DIA after cholecystectomy and a significant interindividual correlation between DIA during deep inspiration and inspiratory capacity. Using M-mode sonography techniques, we were able to demonstrate changes in diaphragmatic mobility after laparoscopic or open cholecystectomy. IMPLICATIONS: Cholecystectomy at times results in impaired respiratory and diaphragmatic functions. The techniques currently used to study these repercussions are both laborious and invasive. Our sonographic technique is completely noninvasive and can be used to study diaphragm morphology and movement in real time.

Adult↗
PubMed2001

Readmission to the intensive care unit after liver transplantation.

OBJECTIVE: We undertook this study to understand the factors at our transplant center that contribute to patients' return to the ICU after their liver transplant and their initial discharge from that unit. Patients who, after liver transplantation, fail discharge from the Intensive Care Unit (ICU) and must be readmitted to that unit may well utilize many more resources than those patients who are well enough to stay out of the ICU. DESIGN: A retrospective review of a prospectively maintained liver transplant research database followed by a retrospective review of (a subgroup) patient charts and contemporaneous controls. SETTING: A large metropolitan tertiary care center and adult liver transplant center. PATIENTS: A total of 1,197 consecutive adult patients who underwent their initial liver transplantation from 1984 to 1996. INTERVENTION: Readmission to the intensive care unit after adult liver transplantation and discharge from that unit. MAIN RESULTS: Only recipient age, pretransplant synthetic function labs (protime and albumin), bilirubin levels, and intraoperative blood product requirements could be statistically linked to the group requiring ICU readmission. The primary etiology for ICU readmission was cardiopulmonary deterioration. Readmission was associated with significantly lower patient and graft survivals. A detailed review of 23 patients transplanted from October 1994 to June 1996 was made, with special emphasis on cardiopulmonary status (hemodynamics, respiratory variables, and chest radiograph findings). This subgroup was compared with 30 temporally matched controls who were not readmitted to the ICU. Intravascular fluid overload and lower inspiratory capacity were significant factors related to ICU readmission. Readmitted patients had a longer hospitalization with higher hospital charges than the control group. CONCLUSIONS: We conclude that the most important means of preventing ICU readmission in liver transplantation patients is to optimize cardiopulmonary function and status. Close monitoring of fluid balance to avoid hypervolemia is essential. Readmitted patients have a greater resource utilization and have lower survival rates.

Adult↗
PubMed2000

Effects of short-term exposure to 0.2 ppm ozone on biomarkers of inflammation in sputum, exhaled nitric oxide, and lung function in subjects with mild atopic asthma.

To gain further insight into the kinetics of airway inflammatory response and explore the possibility of nitric oxide as a surrogate marker of the lower airway inflammatory response to ozone, nine subjects with mild atopic asthma were exposed to filtered air or 0.2 ppm ozone for 2 hours with intermittent exercise. Lung function was measured at baseline and immediately after exposures. Sputum induction was performed at 6 hours and at 24 hours after exposures, and exhaled nitric oxide levels were measured at baseline, immediately, 6, and 24 hours after both exposures. A significant decline in forced expiratory volume in one second and inspiratory capacity was detectable following exposure to ozone. In addition, a 2-fold increase was observed in the percentage of polymorphonuclear leukocytes 6 hours after exposure to ozone, with no changes in other biomarkers at this time point. By 24 hours after ozone exposure, the neutrophilia had subsided but there was an increase in albumin, total protein, myeloperoxidase, and eosinophil cationic protein. Exhaled nitric oxide levels, histamine, interleukin-8, and growth-related oncogene-alpha in sputum did not change significantly following ozone exposure. It was concluded that short-term ozone exposure induces an acute inflammatory response in asthmatic airways, characterized by early polymorphonuclear leukocyte influx followed by plasma extravasation and activation of eosinophils and neutrophils. Exhaled nitric oxide is not a useful marker for detecting inflammatory response to ozone in persons with mild asthma.

Administration, Inhalation↗
PubMed2004

Prediction equations for pulmonary function values in healthy young Iranians aged 8-18 years.

OBJECTIVE: Pulmonary function test (PFT) variables are dependent on height, age and gender. In addition, there is evidence of PFT variation in different ethnic groups. Prediction equations for PFT from a healthy, non-smoking, urban young population in the city of Mashhad (north-east Iran) have been derived. METHODOLOGY: Prediction equations for normal pulmonary function were derived from 336 healthy, non-smoking subjects, including 187 males (height 103-188.5 cm) and 149 females (height 104-183 cm) aged 8-18 years. The subjects underwent measurement of spirometric flow and volume. The following variables were measured: FVC, FEV1, maximal mid-expiratory flow (MMEF), PEF, maximal expiratory flow at 75, 50 and 25% of the FVC (MEF75, MEF50, and MEF25, respectively), tidal volume (VT), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), inspiratory capacity (IC), and vital capacity (VC). Regression analysis using height and age as independent variables was applied to provide predicted values for both genders. RESULTS: There were positive correlations for each pulmonary function variable with height and age. The largest positive correlations were found for FEV1 with height and age, in both genders. Comparison of PFT variables derived from the equations obtained in the present study showed significant differences to those calculated from several previously published equations (P < 0.001 for most variables). For example, the values of FVC and FEV1 derived from the equations obtained in the present study were 2.83 +/- 0.99 and 2.50 +/- 0.89 for males, and 2.41 +/- 0.54 and 2.19 +/- 0.53 for females, while the values derived from the equations of the European Community for Steel and Coal study were 3.12 +/- 1.06 and 2.62 +/- 0.89 for males and 2.79 +/- 0.67 and 3.35 +/- 0.57 for females, respectively. CONCLUSIONS: A set of PFT reference values and prediction equations for both genders has been derived using a relatively large, healthy, non-smoking Iranian young population, and has generated results that differ from several other prediction equations.

Adolescent↗
PubMed2007

Effects of bronchodilators on dynamic hyperinflation following hyperventilation in patients with COPD.

BACKGROUND AND OBJECTIVE: The present study was performed to examine the occurrence of dynamic hyperinflation following hyperventilation in COPD patients and former smokers without COPD, and the efficacy of short-acting anticholinergic agents (SAAC) and beta2-agonists (SABA) for lung hyperinflation following metronome-paced hyperventilation in COPD. METHODS: Fifty-nine patients with COPD, 20 ex-smokers without COPD and 20 healthy subjects who had never smoked were examined for dynamic hyperinflation by metronome-paced hyperventilation with respiratory rate increasing from 20 to 30 and 40 tidal breaths/min. Dynamic hyperinflation was evaluated as the decrease in inspiratory capacity (IC) following hyperventilation, and the effects of SAAC and SABA on dynamic hyperinflation were assessed. RESULTS: COPD patients showed a significant increase in end-expiratory lung volume and a decrease in IC following hyperventilation, and ex-smokers without COPD also showed mild but significant dynamic hyperinflation. Multiple stepwise linear regression analysis revealed that the carbon monoxide transfer coefficient (DLco/VA) and RV/TLC were significant and independent determinants of dynamic hyperinflation in COPD. Treatment with SAAC and SABA significantly increased IC at each respiratory rate, independently of the increases in FEV1. Furthermore, SABA significantly inhibited the decrease in IC due to hyperventilation. CONCLUSIONS: These findings suggest that lung hyperinflation following hyperventilation may be a useful method for detecting dynamic hyperinflation observed not only in patients with COPD but also in ex-smokers without COPD, and both SAAC and SABA are effective in reducing dynamic hyperinflation in COPD.

Administration, Inhalation↗
PubMed1999

Firing properties of single vasoconstrictor neurones in human subjects with high levels of muscle sympathetic activity.

1. Single-unit recordings were made from 19 postganglionic muscle vasoconstrictor axons via tungsten microelectrodes in the peroneal nerve in seven healthy subjects with many multi-unit sympathetic discharges at rest ('high group', 75 +/- 5 multi-unit bursts per 100 heart beats, mean +/- s.e.m.). The results were compared with previous data from 14 units in subjects with 21 +/- 2 multi-unit bursts per 100 heart beats ('low group'). 2. In the 'high group' the units fired spontaneously in 35 +/- 4 % of all cardiac intervals. One unit only ever fired once per cardiac interval, 14 units (74 %) generated maximally two to three spikes, and four units (21 %) up to four to five spikes. Of those cardiac intervals in which a unit fired, a single spike occurred in 78 %, two spikes in 18 %, three spikes in 4 % and four spikes in less than 1 % of cardiac intervals. Measured as the inverse of all interspike intervals, the mean rate was 0.33 +/- 0.04 Hz and the mean intraburst frequency 22.2 +/- 1.6 Hz. Most results were similar to those in the 'low group', but in the 'low group' heart rate was higher (64.5 vs. 50.4 beats min-1) and mean firing frequency was higher (0.49 +/- 0.06 Hz). 3. During increases of multi-unit burst activity evoked by sustained inspiratory-capacity apnoea the firing probability of nine units in the 'high group' increased from 33 +/- 6 to 56 +/- 3 % of the cardiac intervals. Simultaneously, the incidence of single spikes decreased and the incidence of multiple spikes per cardiac interval increased, resulting in an increase of mean firing frequency from 0. 23 +/- 0.04 Hz at rest to 1.04 +/- 0.14 Hz during the apnoea. 4. We conclude that single muscle vasoconstrictor neurones usually fire only a solitary spike during sympathetic bursts both in subjects with a high and in subjects with a low number of bursts at rest. Presumably, differences in the numbers of bursts are due mainly to differences in firing probability and recruitment of sympathetic fibres. During acute increases of multi-unit activity, both increases in discharge frequency and recruitment of additional neurones contribute to the increased intensity of an individual sympathetic burst.

Adult↗
PubMed1978

The pattern of stimulated breathing in man during non-elastic expiratory loading.

1. The pattern of breathing expressed as the relationship between tidal volume and the components of breath interval was studied in normal subjects during CO2 rebreathing, both under unloaded conditions and following the introduction of a non-elastic expiratory resistance. 2. Under unloaded conditions end-expiratory thoracic gas volume (FRC) measured plethysmographically did not alter during the course of the rebreathing experiment. Maximum tidal volume attained (VT, max.) was equal to or just less than the inspiratory capacity of the subject measured at rest. Expiratory reserve volume was not encroached upon even at the highest levels of ventilation. 3. Under loaded conditions the pattern of breathing was altered. VT, max. was diminished in all subjects and FRC showed a progressive rise during rebreathing which was proportional to the resistive load afforded by the artificial resistance. There were no consistent differences in the components of breath duration either at rest or on maximal ventilatory stimulation between the loaded and unloaded states. 4. It is suggested that the pattern of breathing adopted under conditions of expiratory non-elastic loading is influenced more by the secondary effects of breathing at an elevated lung volume, than by the effect of the non-elastic load per se.

Adult↗
PubMed2004

Effect of oxygen on recovery from maximal exercise in patients with chronic obstructive pulmonary disease.

BACKGROUND: The effects of oxygen on recovery from exercise in patients with chronic obstructive pulmonary disease (COPD) are not clearly known. A study was undertaken to determine whether oxygen given after maximal exercise reduced the degree of dynamic hyperinflation and so reduced the perception of breathlessness. METHODS: Eighteen patients with moderate to severe COPD performed maximal symptom limited exercise on a cycle ergometer. During recovery they received either air or oxygen at identical flow rates in a randomised, single blind, crossover design. Inspiratory capacity, breathing pattern data, dyspnoea intensity, and leg fatigue scores were collected at regular intervals during recovery. At a subsequent visit patients underwent a similar protocol but with a face mask in situ to eliminate the effects of instrumentation. RESULTS: When oxygen was given the time taken for resolution of dynamic hyperinflation was significantly shorter (mean difference between air and oxygen 6.61(1.65) minutes (95% CI 3.13 to 10.09), p = 0.001). Oxygen did not, however, reduce the perception of breathlessness during recovery nor did it affect the time taken to return to baseline dyspnoea scores in either the instrumented or non-instrumented state (mean difference 2.11 (1.41) minutes (95% CI -0.88 to 5.10), p = 0.15). CONCLUSIONS: Oxygen reduces the degree of dynamic hyperinflation during recovery from exercise but does not make patients feel less breathless than breathing air. This suggests that factors other than lung mechanics may be important during recovery from exercise, or it may reflect the cooling effect of both air and oxygen.

Adult↗
PubMed2006

Addition of salmeterol to existing treatment in patients with COPD: a 12 month study.

BACKGROUND: This study investigated the addition of salmeterol to existing treatment for exacerbations in patients with poorly reversible chronic obstructive pulmonary disease (COPD). METHODS: 634 patients aged >40 years with a history of COPD exacerbations (including at least two in the previous year) and poor reversibility of airflow obstruction (< or =10% predicted forced expiratory volume in 1 second) received either salmeterol 50 mug or placebo twice daily from a Diskus inhaler for 12 months. The primary outcome was the number of moderate and severe exacerbations. RESULTS: The median rate of moderate or severe exacerbations in the intent-to-treat (ITT) population was lower in the salmeterol group (0.00, range 0.0-9.8, n = 316) than in the placebo group (0.93, range 0.0-13.0, n = 318), but the difference was not statistically significant (p = 0.27). The median rate of exacerbations in the per protocol population (>90% compliance) was also found to be lower in the salmeterol group (0.00, range 0.0-5.0, n = 206) than in the placebo group (0.93, range 0.0-5.6, n = 195) and did reach statistical significance (p = 0.007). For secondary end points, patients receiving salmeterol had significant improvement in lung hyperinflation measured by inspiratory capacity which was evident at 4 weeks and maintained over 12 months (p = 0.035), and a significant improvement in health status measured by the St George's Respiratory Questionnaire at 12 months (p = 0.002). CONCLUSION: Salmeterol has a positive effect on symptoms and health status of patients with COPD when added to usual treatment. Exacerbations are only reduced in patients who comply with treatment.

Albuterol↗
PubMed2006

Combined physiological effects of bronchodilators and hyperoxia on exertional dyspnoea in normoxic COPD.

BACKGROUND: Studies examining the physiological interactions of oxygen (O(2)) and bronchodilators (BD) during exercise in chronic obstructive pulmonary disease (COPD) should provide new insights into mechanisms of exercise intolerance. We examined the effects of O(2) and BD, alone and in combination, on dyspnoea, ventilation (e), breathing pattern, operating lung volumes, and exercise endurance. METHODS: In a randomised, double blind, crossover study, 16 patients with COPD (mean (SE) FEV(1) 43(3)% predicted) performed pulmonary function tests and an incremental exercise test, then completed four visits in which they received either nebulised BD (ipratropium 0.5 mg + salbutamol 2.5 mg) or placebo (PL) with either 50% O(2) or room air (RA). After 90-105 minutes the patients performed pulmonary function tests, then breathed RA or O(2) during symptom limited constant load exercise at 75% peak work rate. RESULTS: With BD the mean (SE) increase in inspiratory capacity (IC) was 0.3 (0.1) l (p<0.05) at rest and during exercise, permitting greater tidal volume (Vt) expansion during exercise and a greater peak e. With O(2), e decreased during exercise as a result of decreased breathing frequency (F), with no significant change in IC. During exercise with BD+O(2), IC and Vt increased, F decreased, and e did not change. Dyspnoea decreased with all interventions at a standardised time during exercise compared with PL+RA (p<0.05). Endurance time was significantly (p<0.05) greater with BD+O(2) (10.4 (1.6) min) than with O(2) (8.5 (1.4) min), BD (7.1 (1.3) min) and PL+RA (5.4 (0.9) min). CONCLUSION: By combining the benefits of BD (reduced hyperinflation) and O(2) (reduced ventilatory drive), additive effects on exercise endurance were observed in patients with normoxic COPD.

Bronchodilator Agents↗
PubMed2006

Association between markers of emphysema and more severe chronic obstructive pulmonary disease.

BACKGROUND: The predominant emphysema phenotype is associated with more severe airflow limitation in patients with chronic obstructive pulmonary disease (COPD). A study was undertaken to investigate whether COPD patients, with or without emphysema quantitatively confirmed by high resolution computed tomography (HRCT), have different COPD severity as assessed by the BODE index (body mass index, airflow obstruction, dyspnoea, exercise performance) and inspiratory capacity to total lung capacity ratio (IC/TLC), and by different biological markers of lung parenchymal destruction. METHODS: Twenty six outpatients with COPD and eight healthy non-smokers were examined. Each subject underwent HRCT scanning, pulmonary function tests, cell counts, and measurements of neutrophil elastase, matrix metalloproteinase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1 in induced sputum, as well as measurement of desmosine, a marker of elastin degradation in urine, plasma and sputum. RESULTS: Patients with HRCT confirmed emphysema had a higher BODE index and lower IC/TLC ratio than subjects without HRCT confirmed emphysema and controls. Forced expiratory volume in 1 second (FEV(1)), FEV(1)/forced vital capacity ratio, and carbon monoxide transfer coefficient were lower, whereas the number of eosinophils, MMP-9, and the MMP-9/TIMP-1 ratio in sputum were higher in patients with emphysema. In COPD patients the number of sputum eosinophils was the biological variable that correlated positively with the HRCT score of emphysema (p = 0.04). CONCLUSIONS: These results suggest that COPD associated with HRCT confirmed emphysema is characterised by more severe lung function impairment, more intense airway inflammation and, possibly, more serious systemic dysfunction than COPD not associated with HRCT confirmed emphysema.

Aged↗
PubMed2006

Measurement of physiological recovery from exacerbation of chronic obstructive pulmonary disease using within-breath forced oscillometry.

BACKGROUND: Within-breath reactance from forced oscillometry estimates resistance via its inspiratory component (X(rs,insp)) and flow limitation via its expiratory component (X(rs,exp)). AIM: To assess whether reactance can detect recovery from an exacerbation of chronic obstructive pulmonary disease (COPD). METHOD: 39 subjects with a COPD exacerbation were assessed on three occasions over 6 weeks using post-bronchodilator forced oscillometry, arterial blood gases, spirometry including inspiratory capacity, symptoms and health-related quality of life (HRQOL). RESULTS: Significant improvements were seen in all spirometric variables except the ratio of forced expiratory volume in 1 s (FEV(1)) to vital capacity, ranging in mean (SEM) size from 11.0 (2.2)% predicted for peak expiratory flow to 12.1 (2.3)% predicted for vital capacity at 6 weeks. There was an associated increase in arterial partial pressure of oxygen (PaO(2)). There were significant mean (SEM) increases in both X(rs,insp) and X(rs,exp) (27.4 (6.7)% and 37.1 (10.0)%, respectively) but no change in oscillometry resistance (R(rs)) values. Symptom scales and HRQOL scores improved. For most variables, the largest improvement occurred within the first week with spirometry having the best signal-to-noise ratio. Changes in symptoms and HRQOL correlated best with changes in FEV(1), PaO(2) and X(rs,insp). CONCLUSIONS: The physiological changes seen following an exacerbation of COPD comprised both an improvement in operating lung volumes and a reduction in airway resistance. Given the ease with which forced oscillometry can be performed in these subjects, measurements of X(rs,insp) and X(rs,exp) could be useful for tracking recovery.

Female↗
PubMed1980

Respiratory function changes after asbestos pleurisy.

Six patients with radiographic evidence of diffuse pleural thickening after industrial asbestos exposure are described. Five had computed tomography of the thorax. All the scans showed marked circumferential pleural thickening often with calcification, and four showed no significant evidence of intrapulmonary fibrosis (asbestosis). Lung function testing showed reduction of the inspiratory capacity and the single-breath carbon monoxide transfer factor (TLCO). The transfer coefficient, calculated as the TLCO divided by the alveolar volume determined by helium dilution during the measurement of TLCO, was increased. Pseudo-static compliance curves showed markedly more negative intrapleural pressures at all lung volumes than found in normal people. These results suggest that the circumferential pleural thickening was preventing normal lung expansion despite abnormally great distending pressures. The pattern of lung function tests is sufficiently distinctive for it to be recognised in clinical practice, and suggests that the lungs are held rigidly within an abnormal pleura. The pleural thickening in our patients may have been related to the condition described as "benign asbestos pleurisy" rather than the interstitial fibrosis of asbestosis.

Adult↗
PubMed1983

Normal ventilatory movement of the right hemidiaphragm studied by ultrasonography and pneumotachography.

The ventilatory movement of the right dome of the diaphragm was studied over the range of the inspiratory capacity in 50 healthy adults in the supine position using simultaneous ultrasonography and pneumotachography. Regional differences were found in movement of the hemidiaphragm; there was greater movement of the middle and posterior thirds of the diaphragm than of the anterior third. A significant positive correlation was found between body weight and amount of diaphragm movement. An apparently greater degree of movement of the diaphragm was found in males than females; this may be related to weight. About 64% of diaphragm movement has occurred by the time midinspiratory capacity is reached. These data may help to define normal movement and also to differentiate abnormal from normal diaphragm movement.

Adult↗
PubMed1975

Relative contributions of rib cage and abdomen to breathing in normal subjects.

By use of the method of Konno and Mead and the respiratory magnetometer, the partition of respired gas volumes into rib cage and diaphragm-abdomen components was accomplished in 81 normal subjects including 32 young and middle-aged men, 29 young and middle-aged women, and 20 elderly men. Studied were isovolume maneuvers and the relaxation configuration over the inspiratory capacity range, quiet tidal breathing, increased amplitudes of slow breathing, rapid inspirations and expirations, and both quiet and forceful phonation. No major differences were noted between men and women or between the young and the elderly during any respiratory acts. During quiet breathing most normal subjects are abdominal breathers when supine and thoracic breathers when upright. Rapid respiratory maneuvers were accomplished mostly through rib cage displacement suggesting that rib cage muscles are capable of more rapid action than diaphragm and abdominal muscles. Data from deep breathing and rapid maneuvers supported the view that abdominal and rib cage muscles often act to optimize the mechanical (length-tension) advantage of the diaphragm.

Abdomen↗