Management of an older patient with Stenotrophomonas maltophilia: is it an emerging pathogen in cystic fibrosis?
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
P T Bye
Publications and source records attributed to P T Bye.
Low-flow oxygen and bilevel ventilatory support: effects on ventilation during sleep in cystic fibrosis.
We measured ventilation in all sleep stages in patients with cystic fibrosis (CF) and moderate to severe lung disease, and compared the effects of low-flow oxygen (LFO2) and bilevel ventilatory support (BVS) on ventilation and gas exchange during sleep. Thirteen subjects, age 26 +/- 5.9 yr (mean +/- 1 SD), body mass index (BMI) 20 +/- 3 kg/m2, FEV1 32 +/- 11% predicted, underwent three sleep studies breathing, in random order, room air (RA), LFO2, and BVS +/- O2 with recording of oxyhemoglobin saturation (SpO2) (%) and transcutaneous carbon dioxide (TcCO2) (mm Hg). During RA and LFO2 studies, patients wore a nasal mask with a baseline continuous positive airway pressure (CPAP) of 4 to 5 cm H2O. Minute ventilation (V I) was measured using a pneumotachograph in the circuit and was not different between wake and non-rapid eye movement (NREM) sleep on any night. However, V I was reduced on the RA and LFO2 nights from awake to rapid eye movement (REM) (p < 0.01) and from NREM to REM (p < 0.01). On the BVS night there was no significant difference in V I between NREM and REM sleep. Both BVS and LFO2 improved nocturnal SpO2, especially during REM sleep (p < 0.05). The rise in TcCO2 seen with REM sleep with both RA and LFO2 was attenuated with BVS (p < 0.05). We conclude that BVS leads to improvements in alveolar ventilation during sleep in this patient group.
Adult↗
Predicting sleep-disordered breathing in patients with cystic fibrosis.
STUDY OBJECTIVES: To examine predictors of sleep-disordered breathing in patients with cystic fibrosis (CF) and moderate-to-severe lung disease using a comprehensive evaluation of both sleep and daytime function. DESIGN: Cross-sectional analysis of sleep studies, lung function, respiratory muscle strength, and evening and morning arterial blood gas measurements in patients with stable CF. A questionnaire addressing sleep quality was administered. Forward stepwise regression analysis was used to identify the parameters that best predict sleep-related desaturation, hypercapnia, and respiratory disturbance. SETTING: Sleep investigation unit and lung function laboratory. PATIENTS: Thirty-two patients with CF and FEV(1) < 65% predicted, in stable clinical condition. Patients were aged 27 +/- 8 years (mean +/- 1 SD) with FEV(1) of 36 +/- 10% predicted, evening PaO(2) of 68 +/- 8 mm Hg, and PaCO(2) of 43 +/- 5 mm Hg. RESULTS: Evening PaO(2) (p < 0.0001) and morning PaCO(2) (p < 0.01) were predictive of the average minimum oxyhemoglobin saturation per 30-s epoch of sleep (r(2) = 0.74; p < 0.0001). Evening PaO(2) (p < 0.001) was predictive of the rise in transcutaneous carbon dioxide (TcCO(2)) seen from non-rapid eye movement (NREM) to rapid eye movement (REM) sleep (r(2) = 0.37; p < 0.001). In addition, there was some relationship between expiratory respiratory muscle strength and the REM respiratory disturbance index (r(2) = 0.22; p < 0.01). CONCLUSION: Evening PaO(2) was found to contribute significantly to the ability to predict both sleep-related desaturation and the rise in TcCO(2) from NREM sleep to REM sleep in this subgroup of patients with CF.
Adult↗
Effect of a short course of rhDNase on cough and mucociliary clearance in patients with cystic fibrosis.
The aim of the study was to measure the effect of a short course of recombinant human deoxyribonuclease I (rhDNase) on ciliary and cough clearance in a group of cystic fibrosis patients, using a radioaerosol and gamma camera technique. Patients were initially randomized to receive either rhDNase (2.5 mg qd) or placebo. Following the measurement of baseline clearance, patients were given a 7-day course of either rhDNase or placebo. The patient then returned on the seventh day for follow-up clearance measurements. This was followed by a 2-week washout period before the whole process was repeated with the alternative inhalation solution. On each of the study days, mucociliary clearance was initially measured for a period of 60 min (IC). This was followed by cough clearance (CC) measurements for 30 min, during which patients were requested to cough a total of 120 times. Post-cough clearance (PCC) was then measured for a further 60 min. Thirteen patients completed the study. Patients' age ranged between 18-38 years, and they had baseline values of FEV(1) of 27-103% of predicted values. Following completion of the course of rhDNase, there was a mean percent increase from baseline of 7.5% for FEV(1) and 5.4% for FVC% (P = 0. 03). There was a small, nonsignificant increase in IC (6.2 +/- 3.6%) on the rhDNase arm compared with the placebo arm (-2.3 +/- 2.9%), P = 0.1. No changes were seen in either CC (1.0 +/- 3.2% [rhDNase] vs. 1.9 +/- 2.4% [placebo], P = 0.9) or PCC (-0.7 +/- 1.5% [rhDNase] vs. 0.9 +/- 1.7% [placebo], P = 0.3). Patients who achieved a 10% or greater improvement in FEV(1) (n = 5) in response to rhDNase did not show any greater change in clearance than nonresponders. In conclusion, we were unable to demonstrate any improvements in either ciliary or cough clearance in response to a short course of rhDNase. The mechanism of action of this drug in vivo remains uncertain.
Administration, Inhalation↗
Regional mucociliary clearance in patients with cystic fibrosis.
This paper reports on a large retrospective analysis of mucociliary clearance (MCC) studies in a group of 59 patients with cystic fibrosis (CF) and 17 age-matched healthy subjects. As many of the CF patients were studied on multiple occasions, a total of 184 patient studies are presented. MCC was measured using a radioaerosol and gamma camera technique. In addition to whole lung clearance, MCC was measured from the central, intermediate, peripheral, basal, mid and apical regions of the lung. MCC was markedly decreased in the CF patient group. Not only was whole lung clearance (14.2 +/- 1.4% vs. 28.0 +/- 3.7%) impaired, but also clearance from the central (19.1 +/- 1.9% vs. 35.6 +/- 4.3%), intermediate (10.7 +/- 1.6% vs. 25.5 +/- 3.7%), apical (12.4 +/- 2.6% vs. 31.6 +/- 4.6%) and mid (14.0 +/- 1.9% vs. 30.4 +/- 4.0%) regions. Attempts were made to identify factors that may have influenced MCC in both the normal subjects and CF patients. Age, gender, body mass index, patient genotype, penetration index, spontaneous cough, and various lung function parameters were entered into a stepwise multiple regression model, but none of the factors proved to be statistically important in determining MCC. Both intrasubject repeatability and intersubject variability estimates are presented for the patients and normal subjects that had multiple studies. The values were found to be remarkably similar for both CF patients and normal subjects and for both intra- and intersubject repeatability. With marked deviation from normal ranges and good repeatability, the measurement of MCC in CF patients would seem to be a valuable outcome measure for clinical trials involving new pharmaceuticals and physical therapy designed to improve removal of secretions from the airways.
Adolescent↗
Cepacia syndrome occurring following prolonged colonisation with Burkholderia cepacia.
Explore the source record for details and available documents.
Adult↗
The effect of inhaled mannitol on bronchial mucus clearance in cystic fibrosis patients: a pilot study.
It has been postulated that hypertonic saline (HS) might impair the antimicrobial effects of defensins within the airways. Alternative non-ionic osmotic agents such as mannitol may thus be preferable to HS in promoting bronchial mucus clearance (BMC) in patients with cystic fibrosis (CF). This study reports the effect of inhalation of another osmotic agent, dry powder Mannitol (300 mg), compared with its control (empty capsules plus matched voluntary cough) and a 6% solution of HS on BMC in 12 patients with cystic fibrosis (CF). Mucus clearance was measured using a radioaerosol/gamma camera technique. Post-intervention clearance was measured for 60 min, followed by cough clearance for 30 min. Neither mannitol nor HS improved BMC during the actual intervention period compared with their respective controls. However during the post-intervention measurement there was a significant improvement in BMC for both the mannitol (8.7+/-3.3% versus 2.8+/-0.7%) and HS (10.0+/-2.3% versus 3.5+/-0.8%). There was also a significant improvement in cough clearance with the Mannitol (9.7+/-2.4%) compared with its control (2.5+/-0.8%). Despite premedication with a bronchodilator, a small fall in forced expiratory volume in one second (FEV1) was seen immediately after administration of both the mannitol (7.3+/-2.5%) and HS (5.8+/-1.2%). Values of FEV1 returned to baseline by the end of the study. Inhaled mannitol is a potential mucoactive agent in cystic fibrosis patients. Further studies are required to establish the optimal dose and the long-term effectiveness of mannitol.
Administration, Inhalation↗
End-expiratory lung volume during arm and leg exercise in normal subjects and patients with cystic fibrosis.
There are no reports concerning the regulation of end-expiratory lung volume (EELV) and flow-volume relationships during upper limb exercise in health and disease. We studied EELV during such exercise in 22 adults with cystic fibrosis (CF) and nine age-matched healthy control subjects. Subjects with CF were grouped according to the severity of their lung disease, as follows: mild = FEV1 > 80% predicted; moderate = FEV1 40 to 80% predicted, and severe = FEV1 < 40% predicted. EELV was calculated from measurements of inspiratory capacity (IC) made at each workload during an incremental arm and leg ergometer test to peak work capacity. In the control group, the decrease in EELV was significantly smaller for arm than for leg exercise at peak work (-0.13 L versus -0.53 L, p < 0.001) and for arm than for leg exercise at an equivalent submaximal ventilation (-0.13 L versus -0.46 L, p < 0.01). In the groups with moderate and severe CF, arm exercise resulted in an increase in EELV from resting levels (dynamic hyperinflation) that was not significantly different from the increase observed for leg exercise. For CF subjects there was a significant inverse relationship between FEV1 and changes in EELV from rest to peak arm exercise (r = -0.46, p < 0.05). In normal subjects, there was a difference in the EELV response for arm versus leg exercise. In CF subjects with airflow limitation, dynamic hyperinflation occurred with both forms of exercise.
Adolescent↗
How to stop ACE-inhibitor-induced cough.
Explore the source record for details and available documents.
Angiotensin-Converting Enzyme Inhibitors↗
Effect of increasing doses of hypertonic saline on mucociliary clearance in patients with cystic fibrosis.
BACKGROUND: Patients with cystic fibrosis are known to have decreased mucociliary clearance. It has previously been shown that inhalation of a 7.0% solution of hypertonic saline significantly improved mucociliary clearance in a group of adult patients with cystic fibrosis. The aim of this study was to measure the response to increasing concentrations of inhaled hypertonic saline. METHODS: Ten patients (seven men) of mean (SE) age 22 (4) years and mean forced expiratory volume in one second (FEV1) 52.0 (6.7)% predicted completed the study. Mucociliary clearance was measured using a radioaerosol technique for 90 minutes after the interventions which comprised 0.9% NaCl + voluntary cough (control), 3.0% NaCl, 7.0% NaCl, and 12% NaCl. RESULTS: There was a significant increase in the amount of activity cleared from the right lung with all concentrations of hypertonic saline (HS) compared with control. The amount cleared at 90 minutes on the control day was 12.7% (95% confidence interval (CI) 9.8 to 17.2) compared with 19.7% (95% CI 13.6 to 29.5) for 3% HS, 23.8% (95% CI 15.9 to 36.7) for 7% HS and 26.0% (95% CI 19.8 to 35.9) for 12% HS. The improvement in mucociliary clearance was not solely due to coughing as the number of coughs recorded on the control day exceeded that recorded on any other day. The hypertonic saline did not induce a clinically significant change in FEV1. CONCLUSIONS: Within the range of concentrations examined in this study, the effect of hypertonic saline appears to be dose dependent. Inhalation of hypertonic saline remains a potentially useful treatment for patients with cystic fibrosis.
Administration, Inhalation↗
Evaluation of supported upper limb exercise capacity in patients with cystic fibrosis.
Physiological responses to upper limb exercise have not been well documented in patients with cystic fibrosis (CF). This is the first study to quantify ventilatory responses to supported incremental upper limb exercise in this patient group. Twenty-four subjects with CF, with a wide range of pulmonary impairment, and ten normal control subjects were studied. Subjects performed pulmonary function tests and incremental arm and leg exercise to peak work capacity on an arm crank and bicycle ergometer. All subjects performed less work with the arms than legs. At an equivalent oxygen consumption, ventilation was higher for arm work than leg work. This higher ventilation was achieved mainly through a higher frequency of breathing. Only CF subjects with severe pulmonary impairment (FEV1 < 40% predicted, FEF25-75% < 20% predicted) had a reduced arm work capacity compared with control subjects. At peak arm work, these subjects had a mean ventilation to maximum voluntary ventilation ratio (VE/MVV) of 106% +/- 25, while maximum heart rate was less than 80% predicted. Despite the high ventilatory requirement for arm exercise, arm work capacity was well maintained in subjects with CF until severe lung disease impaired the ability to further increase ventilation.
Adolescent↗
Simultaneous emission and transmission measurements as an adjunct to dynamic planar gamma camera studies.
Anatomical imaging provides useful information which complements functional imaging performed using a gamma camera. We have previously used transmission measurements in single-photon emission tomography acquired simultaneously with the emission scan using either a plane flood source or a moving line source for attenuation and scatter correction. This approach is equally applicable in planar imaging and provides useful information to assist in detecting patient motion and in defining regions of interest in dynamic studies. We have adapted a moving transmission line source to acquire dynamic geometric mean measurements in the study of the mucociliary clearance of inhaled technetium-99m labelled colloids with a single-headed rotating gamma camera. The line source makes a return pass for each emission acquisition frame (alternating anterior/posterior views), each pass being initiated by a signal from the gamma camera. The result is a dynamic sequence of emission and transmission measurements obtained from a single acquisition. In this application transmission measurements are used to define the lung outline for clearance determination and to check for subject movement throughout the duration of the study.
Gamma Cameras↗
Effect of hypertonic saline, amiloride, and cough on mucociliary clearance in patients with cystic fibrosis.
In patients with cystic fibrosis (CF), dehydration of airway secretions leads to a decrease in mucociliary clearance (MCC). We examined the acute effect of MCC of a single administration by aerosolization of hypertonic saline (7%) (HS), amiloride (0.3% in 0.12% NaCl) (AML) and a combination of AML and HS (AML + HS) in 12 patients with CF using a radioaerosol technique. Isotonic saline [0.9%] (IS) was used as a control solution. As both the AML and HS solutions induced cough in some patients, the last nine patients studied also underwent a cough clearance day. This was to eliminate the possible confounding effect of cough on MCC measurement. Patients ranged from 18 to 28 yr (mean +/- SD, 22 +/- 3) with an FEV1 of 27 to 112% predicted (61 +/- 30%). Following deposition of the radioaerosol, baseline clearance was assessed for 30 min. This was followed by a 30-min intervention period. Assessment of post-intervention clearance for a further 30 min was then performed. Comparison of the amount of radioaerosol cleared from the right lung was made at 60 min (%C60) and 90 min (%C90) using repeated measures ANOVA. The percent cleared at 60 and 90 min was significantly increased with HS (%C60 = 26.5%, %C90 = 29.4%) and the combination of AML + HS (%C60 = 23.1%, %C90 = 27.4%) compared with both IS (%C60 = 14.7%, %C90 = 17.5%) and COUGH (%C60 = 18.0%, %C90 = 19.5%), p < 0.01. Inhalation of hypertonic saline is a potentially useful treatment in patients with cystic fibrosis.
Adolescent↗
Ventilatory mechanics at rest and during exercise in patients with cystic fibrosis.
Ventilatory mechanics were measured at rest and during steady-state (25%, 50%, 75%) and maximal exercise (W-Max) on a cycle-ergometer in eight adult patients (FEV1 22 to 114% of predicted) with cystic fibrosis (CF). Tidal flow-volume loops were measured at rest and during exercise and placed within the maximal pre- and postexercise flow-volume loops, based on measured end-expiratory lung volume (EELV). The degree of flow limitation was expressed as the percentage of the tidal flow-volume loop that met the expiratory boundary of the maximal loop (TFVL%). Pressure-volume relationships were assessed by measurement of transpulmonary pressure (PTP). Peak inspiratory PTP was compared with maximal inspiratory pressures at rest and during exercise (Pcap(i)) at the equivalent lung volume. The maximal effective expiratory pressure (Pmax(e)) was determined using the orifice technique. Three patients with milder disease (FEV1 114, 98, 89% of predicted) did not show any flow limitation at rest or 50% W-Max but two did show some flow limitation at W-Max (0, 3, 23 TFVL%) with a decrease in EELV (-400, -200, -300 ml). There was considerable reserve for inspiratory and expiratory pressure generation at W-Max. Flow limitation was noted at rest in three patients and at 50% W-Max in the five patients with more severe airways obstruction. The increased flow was achieved by an increase in EELV in all five patients (+400, +430, +330, +150, +700 ml at W-Max). Pcap(i) was reached in two patients (-28, -36 cm H2O), while Pmax(e) was exceeded by four patients suggesting inefficient pressure generation. Expiratory flow limitation, hyperinflation, and pressure swings approaching capacity severely compromised the capacity to generate ventilation in some patients with CF.
Adolescent↗
Large lungs and growth hormone: an increased alveolar number?
Previous physiological studies suggest that increased lung growth in patients with acromegaly is associated with either a normal or above normal pulmonary transfer factor. These findings can be interpreted to suggest either alveolar hypertrophy or hyperplasia as the mechanism for lung growth in this condition. Since the ventilated airspaces retain normal elastic properties, we wanted to determine whether the mechanism for lung growth in acromegaly is the result of an increased alveolar number rather than size. Measurements of pulmonary distensibility (K) (an index of alveolar size), elastic recoil, single-breath carbon monoxide transfer factor and carbon monoxide transfer coefficient (KCO), pulmonary capillary blood volume and alveolar membrane diffusing capacity, together with chest width, were compared in nonsmoking, acromegalic and normal men and women, with and without an increased lung size. Pulmonary transfer factor was normal for all groups studied, regardless of lung size. However, KCO was inversely related to total lung capacity (% predicted) for all subjects and KCO (% predicted) was inversely related to chest width in men. Pulmonary capillary blood volume (% predicted) was inversely related to total lung capacity (% predicted) for subjects with large lungs. Pulmonary distensibility (K), membrane diffusing capacity and elastic recoil were within the normal range. These findings suggest normal alveolar size, alveolar membrane surface area and mechanical function in subjects with large lungs. They also suggest that KCO may not be a reliable guide to the interpretation of the mechanism of lung growth in individuals with disproportionately large lungs, and may be reduced because not all the alveoli are perfused. The normal values for pulmonary distensibility found in all our individuals with large lungs, including acromegalics, suggest that lung growth has been achieved by an increased alveolar number rather than size. However, morphometric studies of the lungs of nonsmoking, acromegalic subjects without lung disease, are required to substantiate this finding.
Acromegaly↗
Pulmonary capillary recruitment during exercise after detraining in a young man with small lungs.
Explore the source record for details and available documents.
Adult↗
The effect of a comprehensive, intensive inpatient treatment program on lung function and exercise capacity in patients with cystic fibrosis.
BACKGROUND AND PURPOSE: The purpose of this investigation was to measure the effects of a 10- to 14-day comprehensive, intensive hospital treatment program on peak exercise capacity, endurance capacity, respiratory function, weight change, and maximum inspiratory and expiratory mouth pressures in patients with cystic fibrosis with a pulmonary exacerbation. SUBJECTS: Fourteen young adults with cystic fibrosis admitted to a hospital for an exacerbation of their pulmonary disease were studied. METHODS: Subjects performed pulmonary function tests, inspiratory and expiratory mouth pressure tests, and stationary bicycle exercise tests at admission and discharge. Comprehensive therapy provided during the hospital admission consisted of intravenous antibiotics, physical therapy, high-calorie diet, and daily medical review. RESULTS: The patients showed improvements in forced expiratory volume in 1 second (46%-55% of predicted values) and forced vital capacity (62%-68% of predicted values). Maximum inspiratory and expiratory mouth pressures also improved (118%-131% and 78%-92% of predicted values, respectively). There was a mean weight gain of 2 kg. Maximum work capacity on a bicycle ergometer improved from a mean of 45% to 52% of predicted values. The most impressive result was the marked increase in exercise endurance time from a mean of 9.5 minutes on admission to 16.6 minutes at discharge. CONCLUSION AND DISCUSSION: This study indicates that young adults with cystic fibrosis and an exacerbation of their pulmonary disease obtain measurable benefits from a comprehensive, intensive treatment program, particularly improvement in their capacity for endurance exercise.
Adolescent↗
Mucociliary clearance in patients with cystic fibrosis and in normal subjects.
The aim of this study was to examine baseline mucociliary clearance (MCC) in patients with cystic fibrosis (n = 30; mean +/- SEM age, 23 +/- 1 yr; FEV1, 68 +/- 5% pred; range, 14 to 126%) and a group of normal subjects (n = 12; mean age, 27 +/- 1 yr) after an aerosol deposition of 99mTc-sulphur colloid (mass median diameter, 4.8 microns; geometric standard deviation, 1.6). Dynamic geometric mean images were formed from gamma camera data, and the percent clearance of activity after 60 min (%C60) was calculated for the whole right lung. Initial deposition of the aerosol was determined in terms of the penetration index, the ratio of peripheral to central activity. For normal subjects, an increase in mean inspiratory flow rate (MIFR) (49 +/- 5 versus 21 +/- 3 L/min, p < 0.05) resulted in an increase in whole right lung MCC (%C60, 31 +/- 4 versus 18 +/- 2%; p < 0.05). When aerosol delivery was controlled (MIFR, 34 +/- 5 versus 36 +/- 5 L/min), there was excellent reproducibility between studies (whole lung %C60, 34 +/- 8 versus 31 +/- 7; NS). The measurement of MCC was highly reproducible in six patients studied on four occasions with a mean coefficient of variation of 3.3 +/- 1%. A breathing pattern to accentuate central deposition was utilized in the patient studies (MIFR, 49 +/- 4 L/min).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗