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PubMed2005

Pulmonary sarcoidosis: comparison of findings of inspiratory and expiratory high-resolution CT and pulmonary function tests between smokers and nonsmokers.

OBJECTIVE: The purpose of our study was to compare the high-resolution CT and pulmonary function test findings of smokers and nonsmokers with pulmonary sarcoidosis. MATERIALS AND METHODS: Full inspiratory and expiratory high-resolution CT of the thorax and pulmonary function tests were performed in 46 patients (23 smokers and 23 lifelong nonsmokers) with histologically proven sarcoidosis. The median interval between high-resolution CT and pulmonary function tests was 8 days (range, 0-27 days). High-resolution CT findings were categorized into six patterns, and the overall extent of each pattern was scored independently (high-resolution CT score). Correlation between each high-resolution CT score with each pulmonary functional parameter was performed using Spearman's rank correlation and stepwise multiple regression analysis. RESULTS: Air trapping on expiration (45/46 patients, 98%) and small nodules on inspiration (all 46 patients, 100%) were the most common findings. Smokers had a greater extent of emphysema than nonsmokers (p = 0.002). No significant difference was seen in the extent of air trapping, consolidation, ground-glass attenuation, reticular opacities, or small nodules between smokers and nonsmokers. On Spearman's rank correlation, the extent of air trapping negatively correlated with forced vital capacity in smokers (p < 0.05) but not in nonsmokers. The extent of small nodules negatively correlated with forced vital capacity and positively correlated with the ratio of forced expiratory volume in 1 sec to forced vital capacity in nonsmokers (p < 0.05, both) but not in smokers, respectively. On stepwise multiple regression analysis, the extent of air trapping on CT was independently associated with decreased forced vital capacity (p < 0.05), and cigarette smoking was the main determinant of decrease in maximum midexpiratory flow and forced expiratory flow at 50% of vital capacity (p < 0.01). CONCLUSION: Cigarette smoking confounds the correlation between the CT and pulmonary function test findings in patients with sarcoidosis. Therefore, smoking history must be taken into account when correlating the extent of parenchymal sarcoidosis on CT with functional impairment.

Adult↗

PubMed1994

Pulmonary function in spinal muscular atrophy.

We present the first prospective study on pulmonary function in spinal muscular atrophy patients. Seventy-seven spinal muscular atrophy patients, ages 5 to 18 years, from three centers, were studied with regard to forced vital capacity, using height as a predictor. Patients were categorized into four motor function categories. The highest-functioning group had normal or near-normal values, and those who sat with support had the lowest values. Those with intermediate function had intermediate values. Forced vital capacity was studied longitudinally in 40 spinal muscular atrophy patients for 1.1 to 4.4 years. Eighty-eight percent of patients grew in height, but only 35% showed an increase in height-adjusted forced vital capacity percent. In those patients with the least function, 100% lost height-adjusted forced vital capacity over time. In those patients with the highest function, 57% lost height-adjusted forced vital capacity. In addition, the basic forced vital capacity, not correlated to height, decreased in 43% of cases. These pulmonary function alterations appear to be important determinants for function and survival in spinal muscular atrophy patients.

Adolescent↗

PubMed1999

Spinal deformity, pulmonary compromise, and quality of life in osteogenesis imperfecta.

STUDY DESIGN: A cross-sectional radiologic and clinical study of patients with osteogenesis imperfecta. OBJECTIVES: To determine whether pulmonary compromise is more closely correlated with scoliosis, kyphosis, or chest wall deformity in the population with osteogenesis imperfecta, and to assess the impact of spinal deformity, chest wall deformity, and pulmonary function on quality of life. SUMMARY OF BACKGROUND DATA: The incidence of scoliosis in osteogenesis imperfecta is between 39% and 80%. Up to 60% of patients with osteogenesis imperfecta have significant chest wall deformities. Pulmonary compromise is the leading cause of death in adults with osteogenesis imperfecta. METHODS: Fifteen patients with osteogenesis imperfecta between the ages of 20 and 45 were evaluated with sitting or standing anteroposterior and lateral radiographs of the entire spine, pulmonary function testing, and a validated health self-assessment questionnaire (Short Form-36). Radiographs were evaluated for thoracic scoliosis, thoracic kyphosis, and chest wall deformity. Correlation analysis was performed. RESULTS: Thoracic scoliosis was strongly correlated with decreased predicted vital capacity (r = -0.76). Significant diminution in vital capacity below 50% occurred at a curve magnitude of 60 degrees. Kyphosis and chest wall deformity were not predictive of decreased pulmonary function. Physical health (PCS) was closely correlated with predicted vital capacity (r = 0.65; P < 0.01) and with scoliosis (r = -0.52; P < 0.05). CONCLUSIONS: Thoracic scoliosis of more than 60 degrees has severe adverse effects on pulmonary function in those with osteogenesis imperfecta. This finding may partly explain the increased pulmonary morbidity noted in adult patients with osteogenesis imperfecta and scoliosis compared with that in the general population.

Adult↗

PubMed1988

Dose response relation to oral theophylline in severe chronic obstructive airways disease.

OBJECTIVE: To evaluate measurement of the trapped gas volume as a measure of respiratory function in patients with chronic obstructive airways disease and their response to treatment with theophylline. DESIGN: Patients able to produce consistent results on testing of respiratory function spent two weeks having dosage of theophylline adjusted to give individual pharmacokinetic data. This was followed by random assignment to four consecutive two month treatment periods--placebo and low, medium, and high dose, as assessed by serum concentrations of theophylline. Respiratory function and exercise performance was assessed at the end of each two month period. SETTING: Chest unit in district hospital. PATIENTS: Thirty eight patients with chronic bronchitis and moderate to severe chronic obstruction to airflow were recruited; 33 aged 53-73 years completed the study. INTERVENTIONS: Dosage of oral theophylline increased during two week optimisation period to 800 mg daily unless toxicity was predicted, when 400 mg was given. Targets for the steady state serum theophylline concentrations were 5-10 mg/l in the low dose period, 10-15 mg/l in the medium dose, and 15-20 mg/l in the high dose period. ENDPOINTS: Respiratory function as measured by forced expiratory volume in one second, forced vital capacity, peak expiratory flow rate, slow vital capacity, and static lung volumes using helium dilution and body plethysmography from which trapped gas volume was derived. Exercise performance assessed by six minute walking test and diary cards using visual analogue scale. MEASUREMENTS AND MAIN RESULTS: The forced expiratory volume in one second, forced vital capacity, and peak expiratory flow rate changed only slightly (about 13%) over the range of doses. There was a linear dose dependent fall of trapped gas volume from 1.84 l (SE 0.157) to 1.42 l (0.152), 1.05 l (0.128), and 0.67 l (0.102) during the placebo and low, medium, and high dose treatment periods. Mean walking distance increased by up to 55.6 m (20%). There was a modest improvement in dyspnoea as the dose of theophylline was increased. Side effects were mostly minor but they became more frequent as the dose was increased. CONCLUSION: The fall in trapped gas volume may reflect an improvement in peripheral ventilation (associated with treatment with theophylline) which is less apparent in the more common tests of lung function used in patients with chronic obstructive airways disease.

Administration, Oral↗

PubMedDate not supplied

Dependent lung opacity at thin-section CT: evaluation by spirometrically-gated CT of the influence of lung volume.

OBJECTIVE: To evaluate the influence of lung volume on dependent lung opacity seen at thin-section CT. MATERIALS AND METHODS: In thirteen healthy volunteers, thin-section CT scans were performed at three levels (upper, mid, and lower portion of the lung) and at different lung volumes (10, 30, 50, and 100% vital capacity), using spirometric gated CT. Using a three-point scale, two radiologists determined whether dependent opacity was present, and estimated its degree. Regional lung attenuation at a level 2 cm above the diaphragm was determined using semiautomatic segmentation, and the diameter of a branch of the right lower posterior basal segmental artery was measured at each different vital capacity. RESULTS: At all three anatomic levels, dependent opacity occurred significantly more often at lower vital capacities (10, 30%) than at 100% vital capacity (p = 0.001). Visually estimated dependent opacity was significantly related to regional lung attenuation (p < 0.0001), which in dependent areas progressively increased as vital capacity decreased (p < 0.0001). The presence of dependent opacity and regional lung attenuation of a dependent area correlated significantly with increased diameter of a segmental arterial branch (r = 0.493 and p = 0.0002; r = 0.486 and p = 0.0003, respectively). CONCLUSION: Visual estimation and CT measurements of dependent opacity obtained by semiautomatic segmentation are significantly influenced by lung volume and are related to vascular diameter.

Adult↗

PubMedDate not supplied

Elective pneumonectomy for non-small cell lung cancer: factors affecting early operative mortality and morbidity.

BACKGROUND: The aim of this study was to investigate the factors influencing the morbidity and mortality of the non-small cell lung cancer (NSCLC) cases where pneumonectomy was performed. MATERIAL & METHODS: All 101 patients who had underwent a pneumonectomy for NSCLC between 1994-2001 in our hospital were included in the retrospective study. There were 97 males and 4 females with a mean age of 56+/-9.6. Factors affecting morbidity and mortality were analysed by univariate and multivariate analysis. RESULTS: The morbidity rate was 53% and the mortality rate was 9%. Morbidity was related to cardiopulmonary complications in 40% of the cases. The risk factors for cardiopulmonary morbidity with univariate analysis were age > 60 years (p = 0.004), FEV1 < 2 lt (p = 0.016), early bronchopleural fistula (p = 0.0001), tumour size > 4 cm (p = 0.033), vital capacity < 3.7 lt (p = 0.016), forced vital capacity < 3.5 lt (p = 0.033).. With multivariate analysis the risk factors cardiopulmonary morbidity were age (60 >) (p = 0.012) and tumour size > 4 cm (p = 0.043). The risk factors mortality with univariate analysis were right pneumonectomy (p = 0.025), respiratory morbidity (p = 0.0001), cardiac morbidity (p = 0.002), cell type (Epidermoid CA) (0.047), tumour size > 6 cm (p = 0.036), fluid infusion (p = 0.009), forced vital capacity < 78% (p = 0.039), forced expiratory volume in 1 second < 75% (p = 0.039), PO2 (p = 0.037), PCO2 > 42 mmHg (p = 0.023). CONCLUSION: Among the pneumonectomies performed for NSCLC, the causes of postoperative morbidity were multifactorial, however, multivariate analysis did not show any significant factor affecting the mortality, related to this procedure.

Adult↗

PubMedDate not supplied

Scoliosis and cor pulmonale.

Twenty patients with cor pulmonale due to scoliosis and associated spine deformities seen at the Twin Cities Scoliosis Center in the past 20 years have been reviewed. The average age was 37 years. The average scoliosis was 135 degrees and ranged from 90 degrees to 200 degrees. Fifteen patients were placed in halo traction, nine of whom went on to surgical stabilization. Of the nine patients having surgical treatment, five had postpoliomyelitis curves, two had congenital, one had infantile idiopathic, and one had frontometaphyseal dysplasia. The best results were in the postpoliomyelitis group, with an average pretreatment vital capacity of 595 cc and posttreatment vital capacity of 1071 cc; the average PaO2 increased from 55 to 64 mm Hg, and the average PaCO2 decreased from 52 to 43 mm Hg. The only death in the postpoliomyelitis group occurred six years postoperatively. Of the four nonpoliomyelitis patients having surgery, only one survived, the patient with frontometaphyseal dysplasia. The difference between the poliomyelitis and nonpoliomyelitis groups was striking. Patients with cor pulmonale due to spine deformity should have careful evaluation and a trial of halo traction. If the vital capacity improves, the PaO2 increases, and the PaCO2 decreases, then surgical stabilization can often be successfully accomplished. If these parameters do not improve in traction, then surgical treatment can be abandoned.

Adult↗

PubMed1999

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

PURPOSE: The aim of this article was to assess whether and to what extent pulmonary function recovered to normal degree postoperatively and to investigate the changes in pulmonary function after surgical correction and the value of surgical correction. METHODS: A total of 27 patients who could be questioned and examined in person at the outpatient department of our hospital were included in this study. Of these patents, 24 were boys and 3 were girls. Their ages ranged from 3 to 16 years (mean, 8.67) at follow-up. The mean age at surgery was 4 years, and mean years of follow-up was 6.8. Pulmonary functional measurements included in vital capacity (VC), total lung capacity (TLC), residual volume (RV), functional residual capacity (FRC), RV-TLC ratio, maximal voluntary ventilation (MVV), force ventilatory capacity (FVC), forced expiratory volume in one second (FEV1), maximal midexpiratory flow curve (MMEF), maximal expiratory flow in 75% vital capacity (V75), maximal expiratory flow in 50% vital capacity (V50), maximal expiratory flow in 25% vital capacity (V25), and breathing reserve ratio (BR). RESULTS: TLC, FRC, MVV, MMEF, V75, and V50 values were not different from the normal values. IVC, FVC, FEV1, and V25 values were decreased significantly compared with the normal values. The RV and RV-TLC were high in 87.5% cases. CONCLUSIONS: Preoperative symptoms obviously improved after operation. There was little airway obstruction in the patients postoperatively. The patients with pectus excavatum should be operated on as soon as possible.

Adolescent↗

PubMed1991

Pulmonary function in men after oxygen breathing at 3.0 ATA for 3.5 h.

As a pulmonary component of Predictive Studies V, designed to determine O2 tolerance of multiple organs and systems in humans at 3.0-1.5 ATA, pulmonary function was evaluated at 1.0 ATA in 13 healthy men before and after O2 exposure at 3.0 ATA for 3.5 h. Measurements included flow-volume loops, spirometry, and airway resistance (Raw) (n = 12); CO diffusing capacity (n = 11); closing volumes (n = 6); and air vs. HeO2 forced vital capacity maneuvers (n = 5). Chest discomfort, cough, and dyspnea were experienced during exposure in mild degree by most subjects. Mean forced expiratory volume in 1 s (FEV1) and forced expiratory flow at 25-75% of vital capacity (FEF25-75) were significantly reduced postexposure by 5.9 and 11.8%, respectively, whereas forced vital capacity was not significantly changed. The average difference in maximum midexpiratory flow rates at 50% vital capacity on air and HeO2 was significantly reduced postexposure by 18%. Raw and CO diffusing capacity were not changed postexposure. The relatively large change in FEF25-75 compared with FEV1, the reduction in density dependence of flow, and the normal Raw postexposure are all consistent with flow limitation in peripheral airways as a major cause of the observed reduction in expiratory flow. Postexposure pulmonary function changes in one subject who convulsed at 3.0 h of exposure are compared with corresponding average changes in 12 subjects who did not convulse.

Adult↗

PubMed1977

The interrelation of personality and postoperative factors.

A composite statistical analysis was made of the results from four trials comprising patients undergoing upper abdominal operations. It revealed a marked correlation between the neuroticism score as measured by a personality inventory before operation and the percentage vital capacity impairment found after operation. Neuroticism correlated also with pain as measured by a visual analogue scale. The vital capacity impairment and subjective pain readings were interrelated and both neuroticism and vital capacity impairment were related to the chest complication rate. Personality assessment before operation can identify one group of patients who will have marked pain and limitation of vital capacity after operation.

Abdomen↗

PubMed1981

Comparison study between acupuncture and pentazocine analgesic and respiratory post-operative effects.

The authors studied the effects of acupuncture and pentazocine on post-operative respiratory function and pain management on patients hysterectomized by means of a subumbilical midline incision. The acupunctural technique consisted of GB-26, St-36, Sp-6 and auricular Shen-Men bilateral electrostimulation for 40 minutes. The analgesic effect of acupuncture was equivalent to that of 30 mg pentazocine, yet the most important effect of acupuncture consisted in a net increase of vital capacity during the period of acupuncture analgesia that lasted for 3-4 hr after stimulation; contrariwise, pentazocine did not cause any vital capacity increment and vital capacity remained at the levels observed prior to narcotic administration.

Acupuncture Therapy↗

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↗

PubMed1985

Effects of pulmonary hemodynamics on lung function in adult patients with atrial septal defect.

To clarify the relationship of pulmonary function with differing severity of atrial septal defect (ASD) and to assess the effects of pulmonary hemodynamics on these functions, we classified 101 patients with adult ASD by their pulmonary arterial mean pressure (PAm) and pulmonary blood flow (Qp), and compared details of pulmonary functions between pairs of groups. Classification was by drawing lines at the PAm of 20 mmHg and the Qp of 10 L/min. Group I was the low pressure-low flow group, Group II the low pressure-high flow group, Group III the high pressure-low flow group, and Group IV the high pressure-high flow group. Vital capacity as the percentage of predicted (%VC) was low in Groups III and IV. There were no significant differences in the ratio of forced expiratory volume in one second to forced vital capacity (FEV1%), flow at 25% forced vital capacity and closing volume as the percentage of predicted (%V25, %CV/VC) between each group. Both maximum midexpiratory flow rate and flow rate at 50% forced vital capacity as the percentage of predicted (%MMEF, %V50) in Group III with the most severe ASD, were significantly low. Pulmonary diffusing capacities for carbon monoxide as the percentage of predicted (%DLco) exceeded 100% in all groups, and tended to decrease with increases of PAm without relation to Qp. Pulmonary dysfunctions in adult ASD were mainly due to restrictive changes accompanied by obstructive change in proportion to the decrease of VC. Peripheral airway obstructions are mild in ASD and these might be caused by lower pressure of left atrium and no existence of pulmonary venous congestion in ASD, even in the most severe group.

Adolescent↗

PubMed1984

Comparison of gallium-67 scanning, bronchoalveolar lavage, and serum angiotensin-converting enzyme levels in pulmonary sarcoidosis. Predicting response to therapy.

Patients with active pulmonary sarcoidosis underwent bronchoalveolar lavage, gallium scan, and serum angiotensin-converting enzyme (ACE) level determination prior to treatment with corticosteroids. Pulmonary function was tested before and after therapy. Increase in vital capacity after treatment ranged from 40 to 1,030 ml; 12 of the 16 patients studied had an increase of more than 200 ml. There was a close correlation between the percentage uptake of gallium scan and the increase of the vital capacity after therapy (r = 0.95, p less than 0.01). There was no relationship between the percentage of lymphocytes obtained on lavage and the changes in vital capacity with therapy (r = 0.05). There was a positive correlation between the changes in vital capacity and the ratio of T4(+):T8(+)lymphocytes (r = 0.62, p less than 0.05) and number of T4 (+) lymphocytes (r = 0.92, p less than 0.01) in the bronchoalveolar fluid. There was a low correlation between the pretreatment ACE level and the change in vital capacity (r = 0.368, p greater than 0.05).

Acetylcholinesterase↗

PubMed2003

[Pulmonary function test before and after operation of coronary artery by-pass surgery].

Respiratory complications after successful CABG operation continuous to have on influence on the immediate recovery of a patient. It was reported that the mortality risk of the CABG patients increased, proportional to the reduction of pulmonary function tests (PFT). In the present study we aimed to investigate PFT values (vital capacity: VC, total lung capacity: TLC, residual volume: RV, functional residual capacity: FRC, force expiratory volume first second: FEV1, force mid expiratory flow: FEF25-75, duration force expiratory flow in vital capacity 25%: FEF25, duration force expiratory flow in vital capacity 50%: FEF50, duration force expiratory flow in vital capacity 75%: FEF75, peak expiratory flow: PEF, RV/TLC, FEF/FIF, FEV1/FVC) and arterial blood gases (pH, PaCO2, PaO2, SaO2) pre- and postoperatively which undergo CABG. The PFT and arterial blood gases values of 20 patients, age between 39-74 years, were measured that were undergo CABG operation before a week and three months after.The measured PFT values of 20 patients were recorded by system 2400 computerized and sensor medix 6200 and arterial blood gases analysed by radiometer ABL 300. The results were compared by the time and periods of before and after CABG operation, statistically evaluated the pearson's correlation and Student's t-test. In the results the postoperative PFT values were significantly decreased (p< 0.05, p< 0.001). But the RV, RV% and RV/TLC values were not changed significantly. In arterial blood gases values were not significantly changes. To avoid the postoperative complications we suggested that should be done the PFT and arterial blood gases measurement preoperatively.

Adult↗

PubMed1976

An analysis of potential physiological predictors of respiratory adequacy following cardiac surgery.

More than 50 potential physiological and clinical predictors of postoperative respiratory adequacy were examined in an attempt to identify those few variables which, singly or in combination, best predicted the outcome of the first trial of spontaneous respiration following cardiac surgery. This trial was initiated when patients seemed hemodynamically stable and relatively alert following surgery. Analysis of data from 124 patients identified the following useful predictors: forced vital capacity, total lung capacity, and maximal mid-expiratory flow rate from preoperative pulmonary function tests; resting cardiac index from preoperative cardiac catheterization; postoperative compliance and resistance measured by a computer-based monitoring system; postoperative vital capacity per kilogram, and maximum inspiratory force, measured at the bedside prior to the weaning trial. Stepwise linear discriminant analysis indicated that vital capacity per kilogram and maximum inspiratory force were the most useful predictors, the dividing line between successes and failures being represented by a vital capacity per kilogram of 15 ml. and a maximum inspiratory force of 28 cm. H2O. Mean values of successes were 18.3 +/- 7 ml. per kilogram and 30.7 +/- 9 cm. H2O and, for failures, 11.9 +/- 4 ml. per kilogram and 24.3 +/- 8.4 cm H2O. These physiological variables assess patient effort acting upon an abnormal pulmonary system. Measurements of passive pulmonary mechanics, cardiac function, and the measurement of arterial blood gases were suprisingly poor predictors.

Airway Resistance↗

PubMed1987

Airway size is related to sex but not lung size in normal adults.

Within individuals, lung size as assessed by total lung capacity (TLC) or vital capacity (VC) appears to be unrelated to airway size as assessed physiologically by maximum expiratory flows (MEF). Green et al. (J. Appl. Physiol. 37: 67-74, 1974) coined the term dysanapsis (unequal growth) to express this apparent interindividual discrepancy between parenchymal and airway size. We have reexamined this discrepancy using both physiological and anatomic indexes of airway size. Airway area by acoustic reflectance (AAAR), peak expiratory flow rates (PEFR), MEF, and lung volumes were measured in 26 male and 28 female healthy nonsmoking adults. The effect of sex on these indexes of large airway size was significant when assessed in a subset of males and females whose TLC's were matched (5.0-6.5 liters). Within this subset, male AAAR was 2.79 +/- 0.45 cm2, whereas female AAAR was 1.99 +/- 0.67 cm2 (P less than 0.01). Male's PEFR and MEF after 25% of VC had been expired (MEF25) were 23% greater than those of females within this subset (P less than 0.05). For the entire group of subjects, once these sex-related differences had been accounted for, AAAR was not significantly related to TLC, whereas PEFR and MEF25 remained at best weakly related to TLC. We conclude that tracheal areas in males are significantly larger than those of females even after controlling for TLC and that after controlling for sex-related differences, tracheal size in adults is unrelated to lung size across a broad range of lung sizes.

Adult↗

PubMed2003

Peak inspiratory flows in children with cystic fibrosis.

OBJECTIVE: To show that in children with moderately severe cystic fibrosis lung disease: (i). inspiratory flow may be reduced; and (ii). peak inspiratory flow may be predicted from height, expiratory flow analysis or body mass index. METHODS: All children attending the Royal Children's Hospital, Melbourne, between May and July, 2001 who had cystic fibrosis, were aged > 5 years, were able to perform spirometry reproducibly and who had a forced expiratory volume in 1 s < 60% predicted were prospectively enrolled. Height, weight, peak inspiratory flow, forced expiratory volume in 1 s and forced vital capacity were recorded. Linear regression analysis was performed. RESULTS: The age range was 9.4-19.9 years. Sixteen boys and 11 girls were studied. All children had a peak inspiratory flow > 0.5 L/s. There was a significant relationship between peak inspiratory flow and forced vital capacity (R2 = 0.50) especially in boys (R2 = 0.65). In boys, peak inspiratory flow was significantly related to forced expiratory volume in 1 s (R2 = 0.47). There was no relationship between peak inspiratory flow and predicted values of expiratory flow, age, height, weight or body mass index. Logistic regression was used to predict the probability that peak inspiratory flow was < 2.0 L/s for a given forced vital capacity. If the forced vital capacity is > 2.5 L, peak inspiratory flow is likely to be > 2.0 L/s. CONCLUSIONS: In children with significant cystic fibrosis lung disease, peak inspiratory flow is likely to be > 0.5 L/s, which is required to activate dry powder inhalers. If the forced vital capacity is < 2.5 L, the peak inspiratory flow may be < 2.0 L/s, and a metered dose inhaler and spacer should be considered. Further studies that investigate the relationship between expiratory flow and peak inspiratory flow against an internal resistance are needed.

Child↗