Risk factors for lung function decline in a large cohort of young cystic fibrosis patients

OBJECTIVE

To identify novel risk factors and corroborate previously identified risk factors for mean annual decline in FEV1% predicted in a large, contemporary, United States cohort of young cystic fibrosis (CF) patients.

METHODS

Retrospective observational study of participants in the EPIC Observational Study, who were Pseudomonas-negative and ≤12 years of age at enrollment in 2004-2006. The associations between potential demographic, clinical, and environmental risk factors evaluated during the baseline year and subsequent mean annual decline in FEV1 percent predicted were evaluated using generalized estimating equations.

RESULTS

The 946 participants in the current analysis were followed for a mean of 6.2 (SD 1.3) years. Mean annual decline in FEV1% predicted was 1.01% (95%CI 0.85-1.17%). Children with one or no F508del mutations had a significantly smaller annual decline in FEV1 compared to F508del homozygotes. In a multivariable model, risk factors during the baseline year associated with a larger subsequent mean annual lung function decline included female gender, frequent or productive cough, low BMI (<66th percentile, median in the cohort), ≥1 pulmonary exacerbation, high FEV1 (≥115% predicted, in the top quartile), and respiratory culture positive for methicillin-sensitive Staphylococcus aureus, methicillin-resistant S. aureus, or Stenotrophomonas maltophilia.

CONCLUSIONS

We have identified a range of risk factors for FEV1 decline in a large cohort of young, CF patients who were Pa negative at enrollment, including novel as well as previously identified characteristics. These results could inform the design of a clinical trial in which rate of FEV1 decline is the primary endpoint and identify high-risk groups that may benefit from closer monitoring.

Outcomes of infants with indeterminate diagnosis detected by cystic fibrosis newborn screening

BACKGROUND AND OBJECTIVES

Cystic fibrosis transmembrane conductance regulator-related metabolic syndrome (CRMS) describes asymptomatic infants with a positive cystic fibrosis (CF) newborn screen (NBS) but inconclusive diagnostic testing for CF. Little is known about the epidemiology and outcomes of CRMS. The goal of this study was to determine the prevalence, clinical features, and short-term outcomes of infants with CRMS.

METHODS

We analyzed data from the US CF Foundation Patient Registry (CFFPR) from 2010 to 2012. We compared demographic, diagnostic, anthropometric, health care utilization, microbiology, and treatment characteristics between infants with CF and infants with CRMS.

RESULTS

There were 1983 infants diagnosed via NBS between 2010 and 2012 reported to the CFFPR. By using the CF Foundation guideline definitions, 1540 and 309 infants met the criteria for CF and CRMS, respectively (CF:CRMS ratio = 5.0:1.0). Of note, 40.8% of infants with CRMS were entered into the registry with a clinical diagnosis of CF. Infants with CRMS tended to have normal nutritional indices. However, 11% of infants with CRMS had a positive Pseudomonas aeruginosa respiratory tract culture in the first year of life.

CONCLUSIONS

CRMS is a common outcome of CF NBS, and some infants with CRMS may develop features concerning for CF disease. A substantial proportion of infants with CRMS were assigned a clinical diagnosis of CF, which may reflect misclassification or clinical features not collected in the CFFPR.

Short-term and long-term response to pulmonary exacerbation treatment in cystic fibrosis

BACKGROUND

Treatment of pulmonary exacerbations (PEx) in cystic fibrosis (CF) varies widely with no consensus on management practices or best indicators of therapeutic success. To design trials evaluating PEx treatment factors, we characterise the heterogeneity of PEx care in adults and paediatrics, and correlate it with measures of clinical response including short-term and long-term lung function changes, change in symptom severity score and time to next intravenous antibiotic therapy.

METHODS

Data were used from a prospective observational study of patients with CF ≥10 years of age enrolled at six sites between 2007 and 2010. All were started on intravenous antibiotics for a clinically diagnosed PEx. Analysis of variance, logistic and Cox regression were used to examine the association of treatment factors with short-term and long-term clinical response.

RESULTS

Of 123 patients with CF (60% women, aged 23.1±10.2 years), 33% experienced <10% relative improvement in FEV1 during treatment, which was associated with failing to recover baseline lung function 3 months after treatment (OR=7.8, 95% CI 1.9 to 31.6, p=0.004) and a longer time to next intravenous antibiotic (HR=0.48, 95% CI 0.27 to 0.85, p=0.011). Symptom improvement was observed but was not associated with subsequent lung function or time to next antibiotic therapy, which had a median recurrence time of 143 days.

CONCLUSIONS

Immediate symptomatic or respiratory response to PEx treatment did not have a clear relationship with subsequent outcomes such as lung function or intravenous antibiotic-free interval. These results can inform future research of treatment regimens for PEx in terms of interventions and outcome measures.

TRIAL REGISTRATION

NCT00788359 (www.clinicaltrials.gov).

Characterization of CD4 and CD8 T cell responses in MuSK myasthenia gravis

Muscle specific tyrosine kinase myasthenia gravis (MuSK MG) is a form of autoimmune MG that predominantly affects women and has unique clinical features, including prominent bulbar weakness, muscle atrophy, and excellent response to therapeutic plasma exchange. Patients with MuSK MG have predominantly IgG4 autoantibodies directed against MuSK on the postsynaptic muscle membrane. Lymphocyte functionality has not been reported in this condition. The goal of this study was to characterize T cell responses in patients with MuSK MG. Intracellular production of IFN-gamma, TNF-alpha, IL-2, IL-17, and IL-21 by CD4+ and CD8+ T cells was measured by polychromatic flow cytometry in peripheral blood samples from 11 Musk MG patients and 10 healthy controls. Only one MuSK MG patient was not receiving immunosuppressive therapy. Regulatory T cells (Treg) were also included in our analysis to determine if changes in T cell function were due to altered Treg frequencies. CD8+ T cells from MuSK MG patients had higher frequencies of polyfunctional responses than controls, and CD4+ T cells had higher IL-2, TNF-alpha, and IL-17. MuSK MG patients had a higher percentage of CD4+ T cells producing combinations of IFN-gamma/IL-2/TNF-gamma, TNF-alpha/IL-2, and IFN-gamma/TNF-alpha. Interestingly, Treg numbers and CD39 expression were not different from control values. MuSK MG patients had increased frequencies of Th1 and Th17 cytokines and were primed for polyfunctional proinflammatory responses that cannot be explained by a defect in CD39 expression or Treg number.

Sickle cell disease and complex congenital cardiac surgery: a case report and review of the pathophysiology and perioperative management

Sickle cell anemia and thalassemia are hemoglobinopathies rarely encountered in the United States. Compounded with congenital heart disease, patients with sickle cell disease (SCD) requiring cardiopulmonary bypass and open-heart surgery represent the proverbial “needle in the haystack”. As such, there is some trepidation on the part of clinicians when these patients present for complex cardiac surgery.

SCD is an autosomal, recessive condition that results from a single nucleotide polymorphism in the β-globin gene. Hemoglobin SS molecules (HgbSS) with this point mutation can polymerize under the right conditions, stiffening the erythrocyte membrane and distorting the cellular structure to the characteristic sickle shape. This shape change alters cellular transit through the microvasculature. As a result, circumstances such as hypoxia, hypothermia, acidosis or diminished blood flow can lead to aggregation, vascular occlusion and thrombosis. Chronically, SCD can give rise to multiorgan damage secondary to hemolysis and vascular obstruction.

This review and case study details an 11-year-old African-American male with known SCD who presented to the cardiothoracic surgical service with congenital heart disease consisting of an anomalous, intramural right coronary artery arising from the left coronary sinus for surgical consultation and subsequent surgical correction. This case report will include a review of the pathophysiology and current literature regarding preoperative, intraoperative and postoperative management of SCD patients.

Total artificial heart in the pediatric patient with biventricular heart failure

Mechanical circulatory support emerged for the pediatric population in the late 1980s as a bridge to cardiac transplantation. The Total Artificial Heart (TAH-t) (SynCardia Systems Inc., Tuscon, AZ) has been approved for compassionate use by the Food and Drug Administration for patients with end-stage biventricular heart failure as a bridge to heart transplantation since 1985 and has had FDA approval since 2004. However, of the 1,061 patients placed on the TAH-t, only 21 (2%) were under the age 18. SynCardia Systems, Inc. recommends a minimum patient body surface area (BSA) of 1.7 m(2), thus, limiting pediatric application of this device. This unique case report shares this pediatric institution's first experience with the TAH-t. A 14-year-old male was admitted with dilated cardiomyopathy and severe biventricular heart failure. The patient rapidly decompensated, requiring extracorporeal life support. An echocardiogram revealed severe biventricular dysfunction and diffuse clot formation in the left ventricle and outflow tract. The decision was made to transition to biventricular assist device. The biventricular failure and clot formation helped guide the team to the TAH-t, in spite of a BSA (1.5 m(2)) below the recommendation of 1.7 m(2). A computed tomography (CT) scan of the thorax, in conjunction with a novel three-dimensional (3D) modeling system and team, assisted in determining appropriate fit. Chest CT and 3D modeling following implantation were utilized to determine all major vascular structures were unobstructed and the bronchi were open. The virtual 3D model confirmed appropriate device fit with no evidence of compression to the left pulmonary veins. The postoperative course was complicated by a left lung opacification. The left lung anomalies proved to be atelectasis and improved with aggressive recruitment maneuvers. The patient was supported for 11 days prior to transplantation. Chest CT and 3D modeling were crucial in assessing whether the device would fit, as well as postoperative complications in this smaller pediatric patient.

The failing Fontan: what’s NEXT…?

The Fontan procedure represents the final stage of the transition to single ventricle physiology. Conversion of very complex congenital heart anatomy, such as hypoplastic left heart syndrome, double-outlet right ventricle or double-inlet left ventricle, to a single ventricle has grown in popularity as morbidity and mortality have improved. As these patients grow, survivors are at risk for impaired ventricular dysfunction, plastic bronchitis, protein-losing enteropathy and late failure. Late failing Fontan patients represent a particularly vexing scenario for clinicians, as the only durable treatment option is cardiac transplantation. However, in the short-term, some of these patients require support beyond medical management, with mechanical circulatory support via extracorporeal life support or a ventricular assist device. We report the successful bridge of an adolescent female post-Fontan conversion with late severe cardiac failure. The patient was initially resuscitated with extracorporeal life support, transitioned to a single Berlin Heart EXCOR® ventricular assist device and, subsequently, underwent successful cardiac transplantation.

Regional differences in the evolution of lung disease in children with cystic fibrosis

Progression of lung disease is a major event in children with cystic fibrosis (CF), but regional differences in its evolution are unclear. We hypothesized that regional differences occur beginning in early childhood. We examined this issue by evaluating 132 patients followed in the Wisconsin Neonatal Screening Project between 1985 and 2010. We scored chest X-rays obtained every 1-2 years with the Wisconsin chest X-ray system, in which we divided the lungs into quadrants, and gave special attention to ratings for bronchiectasis (BX) and nodular/branching opacities. We compared the upper and lower quadrant scores, and upper right and left quadrant scores, as patients aged using a multivariable generalized estimation equation (GEE) model. We did a confirmatory analysis for a subset of 81 patients with chest computerized tomography (CT) images obtained in 2000 and scored using the Brody scoring system. The chest X-ray analysis shows that the upper quadrants have higher BX (P<0.001) and nodular/branching opacities (P<0.001) scores than the lower quadrants. CT analysis likewise reveals that the upper quadrants have more BX (P=0.02). Patients positive for mucoid PA showed significantly higher BX scores than patients with non-mucoid PA (P=0.001). Chest X-ray scoring also revealed that the upper right quadrant has more BX (P<0.001) than the upper left quadrant, and CT analysis was again confirmatory (P<0.001). We conclude that pediatric patients with CF develop more severe lung disease in the upper lobes than the lower lobes in association with mucoid PA infections and also have more severe lung disease on the right side than on the left side in the upper quadrants. A variety of potential explanations such as aspiration episodes may be clinically relevant and provide insights regarding therapies.

The sensitivity of lung disease surrogates in detecting chest CT abnormalities in children with cystic fibrosis

RATIONALE

Chest CT scans detect structural abnormalities in children with cystic fibrosis (CF), even when pulmonary function tests (PFTs) are normal. The use of chest CT is limited in clinical practice, because of concerns over expense, increased resource utilization, and radiation exposure. Quantitative chest radiography scores are useful in detecting mild lung disease, but whether they are sensitive to the presence of CT scan abnormalities has not been evaluated.

OBJECTIVE

To determine in a cross-sectional study if quantitative chest radiography is a more sensitive marker of chest CT abnormalities than other lung disease surrogates.

METHODS

Brody chest CT scores were calculated for 81 children enrolled in the Wisconsin CF Neonatal Screening Project. We determined the sensitivity for Wisconsin (WCXR) and Brasfield (BCXR) chest radiography scores, PFTs, positive cultures for P. aeruginosa (PA), and parental report of symptoms to detect a Brody score worse than the median score for study participants.

MEASUREMENTS AND MAIN RESULTS

The mean FEV(1) for the study population was 91% predicted. Abnormal WCXR and BCXR scores had the highest sensitivity to detect a chest CT score worse than the median; abnormal PFTs, parental report of symptoms, and the presence of PA had much lower sensitivity (P < 0.001).

CONCLUSIONS

In this cross sectional study, quantitative chest radiography has excellent sensitivity to detect an abnormal chest CT and may have a role in monitoring lung disease progression in children with CF.

Comparing age of cystic fibrosis diagnosis and treatment initiation after newborn screening with two common strategies

BACKGROUND

Newborn screening (NBS) for CF has become widespread, although there are multiple strategies. Little is known about outcomes such as age of diagnosis after different NBS methods.

METHODS

We used the U.S. Cystic Fibrosis Foundation Patient Registry to identify infants with CF born between 2001 and 2008 in states that utilized NBS. We compared ages at diagnosis, genotyping, sweat test, and first visit to a CF Centre between states that used serial immunoreactive trypsinogen (IRT/IRT) levels and states that used IRT and DNA analysis (IRT/DNA).

RESULTS

We identified 1288 infants with CF. Compared to infants born in IRT/IRT states, infants born in IRT/DNA states were younger at the time of diagnosis (median 2.3 weeks versus 4.0 weeks in IRT/IRT states, p<0.001), genotyping (0.7 weeks versus 5.3 weeks, p<0.001), and initial CF Centre visit (5.9 weeks versus 7.7 weeks, p=0.008).

CONCLUSIONS

Although there is room to improve outcomes with both strategies, infants born in IRT/DNA states have treatment initiated at a younger age than infants born in IRT/IRT states.

Chest computed tomography scores of severity are associated with future lung disease progression in children with cystic fibrosis

RATIONALE

Most children with cystic fibrosis (CF) experience a slow decline in spirometry, although some children continue to be at risk for more significant lung disease progression. Chest computed tomography (CT) scans have been shown to be more sensitive to changes in lung disease than spirometry and may provide a means for predicting future lung disease progression.

OBJECTIVES

We hypothesized that Brody chest CT scan scores obtained in 2000 in a prospectively monitored cohort of children with CF would be associated with the most recent measures of lung disease severity.

METHODS

Brody chest CT scan scores were calculated for 81 children enrolled in the Wisconsin CF Neonatal Screening Project. Multivariable linear regression was used to determine associations between Brody scores and the most recent (age 21 yr or June 30, 2010, whichever was later) measures of CF lung disease.

MEASUREMENTS AND MAIN RESULTS

The mean observation time after the chest CT scan was 7.5 years. Brody chest CT scan scores were significantly associated with the most recent measures of spirometry (P < 0.001) and Wisconsin and Brasfield chest radiograph scores (P < 0.001). The strength of this association was much stronger than spirometry obtained near the time of the chest CT scan (P < 0.01) but not chest radiograph scores.

CONCLUSIONS

Chest CT scan scores are associated with future lung disease severity, and quantitative chest imaging(chest CT scan and chest radiograph scores) is more strongly associated with future lung disease severity than measures of spirometry. These findings may help clinicians identify patients at risk of future lung disease progression.

Chest computed tomography scores of severity are associated with future lung disease progression in children with cystic fibrosis

RATIONALE

Most children with cystic fibrosis (CF) experience a slow decline in spirometry, although some children continue to be at risk for more significant lung disease progression. Chest computed tomography (CT) scans have been shown to be more sensitive to changes in lung disease than spirometry and may provide a means for predicting future lung disease progression.

OBJECTIVES

We hypothesized that Brody chest CT scan scores obtained in 2000 in a prospectively monitored cohort of children with CF would be associated with the most recent measures of lung disease severity.

METHODS

Brody chest CT scan scores were calculated for 81 children enrolled in the Wisconsin CF Neonatal Screening Project. Multivariable linear regression was used to determine associations between Brody scores and the most recent (age 21 yr or June 30, 2010, whichever was later) measures of CF lung disease.

MEASUREMENTS AND MAIN RESULTS

The mean observation time after the chest CT scan was 7.5 years. Brody chest CT scan scores were significantly associated with the most recent measures of spirometry (P < 0.001) and Wisconsin and Brasfield chest radiograph scores (P < 0.001). The strength of this association was much stronger than spirometry obtained near the time of the chest CT scan (P < 0.01) but not chest radiograph scores.

CONCLUSIONS

Chest CT scan scores are associated with future lung disease severity, and quantitative chest imaging(chest CT scan and chest radiograph scores) is more strongly associated with future lung disease severity than measures of spirometry. These findings may help clinicians identify patients at risk of future lung disease progression.

Pulmonary exacerbations are associated with subsequent FEV1 decline in both adults and children with cystic fibrosis

BACKGROUND

Patients with cystic fibrosis (CF) frequently experience pulmonary exacerbations that may lead to a faster subsequent decline in pulmonary function; however, this relationship has not been clearly established. The purpose of this study was to determine the association between the frequency of pulmonary exacerbations and subsequent forced expiratory volume in 1 sec (FEV(1) ) decline in adults and children with CF.

METHODS

Cohort study of subjects followed in the Cystic Fibrosis Foundation Patient Registry from 2003 through 2006. Mixed effects modeling was used to estimate differences in rates of decline in FEV(1) in 2004-2006 for patients with 0, 1, 2, or 3+ pulmonary exacerbation(s) in 2003.

RESULTS

Of 8,490 subjects who met inclusion criteria, 60% had 0 exacerbations, 23% had 1, 10% had 2, and 7% had 3+ exacerbations in 2003. Compared to children with no pulmonary exacerbations in 2003, children with one or more exacerbations experienced a significantly (P < 0.001) greater rate of FEV(1) decline in 2004-2006. In contrast, among adults, only those with 3+ exacerbations in 2003 had a significantly (P = 0.01) greater rate of FEV(1) decline in 2004-2006 than those with no exacerbations in 2003.

CONCLUSIONS

There is a strong association between the frequency of pulmonary exacerbations and subsequent decline in pulmonary function. In adults, having 3+ exacerbations, and among children, having any exacerbations is associated with a greater rate of decline in the ensuing 3 years. Improved prevention, identification, and treatment of pulmonary exacerbations are likely to have long-term benefits for patients with CF, especially children.

Failure to recover to baseline pulmonary function after cystic fibrosis pulmonary exacerbation

RATIONALE

Patients with cystic fibrosis periodically experience pulmonary exacerbations. Previous studies have noted that some patients' lung function (FEV(1)) does not improve with treatment.

OBJECTIVES

To determine the proportion of patients treated for a pulmonary exacerbation that does not recover to spirometric baseline, and to identify factors associated with the failure to recover to spirometric baseline.

METHODS

Cohort study using the Cystic Fibrosis Foundation Patient Registry from 2003-2006. We randomly selected one pulmonary exacerbation treated with intravenous antibiotics per patient and compared the best FEV(1) in the 3 months after treatment with the best FEV(1) in the 6 months before treatment. Recovery to baseline was defined as any FEV(1) in the 3 months after treatment that was greater than or equal to 90% of the baseline FEV(1). Multivariable logistic regression was used to estimate associations with the failure to recover to baseline FEV(1).

MEASUREMENTS AND MAIN RESULTS

Of 8,479 pulmonary exacerbations, 25% failed to recover to baseline FEV(1). A higher risk of failing to recover to baseline was associated with female sex; pancreatic insufficiency; being undernourished; Medicaid insurance; persistent infection with Pseudomonas aeruginosa, Burkholderia cepacia complex, or methicillin-resistant Staphylococcus aureus; allergic bronchopulmonary aspergillosis; a longer time since baseline spirometric assessment; and a larger drop in FEV(1) from baseline to treatment initiation.

CONCLUSIONS

For a randomly selected pulmonary exacerbation, 25% of patients' pulmonary function did not recover to baseline after treatment with intravenous antibiotics. We identified factors associated with the failure to recover to baseline, allowing clinicians to identify patients who may benefit from closer monitoring and more aggressive treatment.

Return of FEV1 after pulmonary exacerbation in children with cystic fibrosis

RATIONALE

Lung function (FEV(1)) generally improves during treatment of pulmonary exacerbations in patients with cystic fibrosis (CF). However, it is unclear how often return to previous baseline FEV(1) is achieved.

OBJECTIVES

(1) To determine the proportion of pediatric patients with CF treated for a pulmonary exacerbation who fail to recover to baseline FEV(1) and (2) to identify factors associated with this failure.

METHODS

We performed a case-control analysis of patients from a single pediatric CF center admitted for their first pulmonary exacerbation in 2001-2006. Patients were considered to have recovered to baseline FEV(1) if their best FEV(1) within the 3 months following treatment was >or=95% of the best FEV(1) during the 6 months prior to treatment. Logistic regression was used to estimate associations between clinical characteristics and failure to regain baseline FEV(1).

RESULTS

Of 104 patients, 24 (23.1%) did not recover to baseline FEV(1). The adjusted odds ratio of failure to recover to baseline FEV(1) was 1.49 (95% confidence interval [CI] 1.20, 1.86) for every 5% greater decline in FEV(1) from baseline to admission. In exploratory analyses, the adjusted odds ratios for the failure to recover to baseline were also significantly higher for patients who were evaluated in our CF clinic more frequently between the baseline measurement and admission, were younger, or were insured by Medicaid.

CONCLUSIONS

Approximately one in four patients with CF failed to recover to baseline lung function after a pulmonary exacerbation despite treatment with intravenous antibiotics. Failure to recover to baseline was associated with the degree of decline in FEV(1) that had occurred prior to hospital admission, suggesting opportunities for earlier intervention to improve lung function outcomes. Additional studies are needed to determine how the failure to recover to baseline affects subsequent FEV(1) decline.

Athletic trainers' experience and comfort with evaluation and management of asthma: a pilot study

BACKGROUND

Approximately 10% to 50% of competitive athletes experience asthma symptoms with exercise, due to either chronic asthma or exercise-induced bronchospasm. Early recognition and management of asthma symptoms may improve athletic performance and quality of life for athletes with asthma or exercise-induced bronchospasm. Athletic trainers may have frequent opportunities to identify asthma symptoms and assist athletes with management.

OBJECTIVE

To survey athletic trainers about their experience and comfort with evaluation and management of asthma symptoms in athletes and identify athletic trainer characteristics associated with higher comfort levels.

DESIGN AND SETTING

A 2005 cross-sectional survey of National Athletic Trainers' Association and Illinois Athletic Trainers Association members.

PARTICIPANTS

A total of 304 athletic trainers.

DATA COLLECTION AND ANALYSIS

Respondents completed a Web-based survey reporting years of experience, competitive level of athletes supervised, satisfaction with asthma education, experience evaluating asthma symptoms, and comfort managing asthma.

RESULTS

Response rate was 13.9% (304 of 2,175). At least 23% of respondents evaluated asthma symptoms five or more times the previous year. Respondents working exclusively with junior high and/or high school athletes evaluated asthma symptoms more frequently than those working exclusively with college and/or professional athletes. Fifty-eight percent of respondents were unsatisfied with their asthma education. Only 25.3% were "very" comfortable managing asthma. Respondents with higher comfort levels evaluated asthma symptoms more frequently (p < 0.01, r = 0.18) and were more likely to be satisfied with their asthma education (p < 0.001). Over 95% of respondents endorsed more asthma education in athletic training curricula.

CONCLUSIONS

Results of this pilot study indicate that athletic trainers have opportunities to help athletes manage asthma symptoms that can compromise athletic performance or limit sports participation. However, few athletic trainers are very comfortable managing asthma, and most are unsatisfied with their asthma education. Further study is needed to determine the effect of enhanced asthma education on athletic trainers' comfort and skills with asthma evaluation and management.

Reproducibility of spirometry during cystic fibrosis pulmonary exacerbations

OBJECTIVES

To compare the within day variation of spirometry between hospital admission, discharge, and outpatient follow up among children with cystic fibrosis (CF) hospitalized for a pulmonary exacerbation.

HYPOTHESIS

Within day variation of spirometry will be greater at hospital admission than at hospital discharge or outpatient follow up.

METHODS

We performed a retrospective review of spirometry data for all patients with CF >or=6 years old admitted to our pediatric CF center for a pulmonary exacerbation in 2004 or 2005. For patients who had previously performed spirometry successfully, measurements were used from one admission only during 2004-2005 if the spirometry occurred within 3 days of hospital admission, 3 days of discharge, or at a follow up clinic visit when well. We compared the within day coefficients of variation (CV) for FVC, FEV(1), and FEF(25-75) between time points using the Wilcoxon signed rank-test. We also determined the change in spirometry that is likely to be beyond measurement variability during inpatient treatment of a pulmonary exacerbation.

RESULTS

Spirometry data were available from 40 subjects at admission and follow up and 35 at hospital discharge. There was no significant difference in CV at admission, discharge, and follow up for FVC, FEV(1), or FEF(25-75). The mean (SD) CV was 3.1% (2.7) for FVC, 3.2% (2.1) for FEV(1), and 9.7% (7.0) for FEF(25-75) at admission, 2.8% (2.2) for FVC, 3.1% (2.1) for FEV(1), and 8.1% (6.7) for FEF(25-75) at discharge, and 2.7% (1.7) for FVC, 2.8% (2.0) for FEV(1), and 8.4% (7.8) for FEF(25-75) at follow up. These are similar to previous reports of outpatients with CF. The improvement in spirometry that exceeded measurement variability for our cohort was 80 ml for FVC, 70 ml for FEV(1), and 220 ml/sec for FEF(25-75).

CONCLUSIONS

The presence of an acute pulmonary exacerbation in children and adolescents with CF does not substantially contribute to the within day variation in spirometry. Within day variation of spirometry for children with CF during pulmonary exacerbations is similar to previously reported values from clinically stable CF patients.

An unusually brilliant transient in the galaxy M85

Historically, variable and transient sources have both surprised astronomers and provided new views of the heavens. Here we report the discovery of an optical transient in the outskirts of the lenticular galaxy Messier 85 in the Virgo cluster. With a peak absolute R magnitude of -12, this event is distinctly brighter than novae, but fainter than type Ia supernovae (which are expected in a population of old stars in lenticular galaxies). Archival images of the field do not show a luminous star at that position with an upper limit in the g filter of about -4.1 mag, so it is unlikely to be a giant eruption from a luminous blue variable star. Over a two-month period, the transient source emitted radiation energy of almost 10(47) erg and subsequently faded in the optical sky. It is similar to, but six times more luminous at peak than, an enigmatic transient in the galaxy M31 (ref. 1). A possible origin of M85 OT2006-1 is a stellar merger. If so, searches for similar events in nearby galaxies will not only allow study of the physics of hyper-Eddington sources, but also probe an important phase in the evolution of stellar binary systems.

Quantitative myasthenia gravis score: assessment of responsiveness and longitudinal validity

We prospectively tested the quantitative myasthenia gravis score (QMG) for responsiveness and longitudinal construct validity in 53 patients with myasthenia gravis. Index of responsiveness was high. Longitudinal construct validity was confirmed by the correlation between changes in QMG and manual muscle testing and by a difference in QMG changes across patients that were clinically unchanged, improved, or worse between two visits. Our results support QMG use for assessing clinical change in trials.