Disfunción de la pequeña vía aérea en niños con asma controlada

Introduction

Asthma is characterized by chronic inflammation of the central and distal airways. The aim of this study was to assess the small airway (SA) of children with moderate-severe asthma with normal FEV1.

The FEF25–75 and its Decline as a Predictor of Methacholine Responsiveness in Children

Background. Methacholine challenge (MCC) is an important diagnostic tool for asthma, especially in patients in whom routine pulmonary function testing (PFT) is normal or equivocal. The basis for a positive test per American Thoracic Society (ATS) guidelines is a methacholine concentration ≤ 16 mg/mL that causes a 20% decrease in forced expiratory volume in 1 second (FEV₁) (termed the PC20 for FEV₁). There is little information in the medical literature that utilizes other flow rates during MCC, including small airway function parameters such as the forced expiratory flow rate 25–75% (FEF_{25 ?75}). We question whether the FEF_{25 ?75} may be a useful parameter to monitor during MCC and whether it may be predictive of a positive MCC. Hypothesis. The baseline FEF_{25 ?75} and its decline during a MCC are useful in the interpretation of a MCC. Methods. We retrospectively analyzed all MCC performed at this institution between December 1998 and December 2006. Parameters reviewed included age, gender, race, weight, height, baseline PFT data including FVC, FEV₁, FEF_{25 ?75}, and forced expiratory time, methacholine PC20 for FEV₁, the relative changes from baseline for FEV₁ and FEF_{25 ?75} during the MCC, and clinical symptoms during the MCC. Results. A total of 532 MCC were completed during the 8-year study period in children 4 to 18 years of age. A total of 203 MCC (38%) were positive (defined by a PC20 ≤ 16 mg/mL) and 329 studies were negative (62%). The baseline % predicted FEF_{25 ?75} in positive MCC was 82.4 ± 21.9 vs. 98.7 ± 21.3 in the negative studies (p < 0.001). The FEF_{25 ?75}/FVC ratio in positive MCC was 0.82 ± 0.21 vs. 0.97 ± 0.23 in negative studies (p < 0.001). In the positive MCC, the decrease in FEF_{25 ?75} was much faster and of much greater degree than in the negative challenges. When a significant reduction in FEF_{25 ?75} was defined as greater than 10% by the second concentration of methacholine (0.25 mg/mL), the sensitivity for a positive MCC was 63%, the specificity was 71%, the positive predictive value was 57%, and the negative predictive value was 76%. A comparison of the baseline FEF_{25 ?75} to the PC20 for the positive MCCs revealed no statistical significance. Conclusions. The FEF_{25 ?75} and its decline during a MCC appear to be useful information and potentially predictive of a positive MCC. We suggest that the forced expiratory flow rate 25–75% (FEF_{25 ?75}) be considered as an adjunct to the FEV₁ to define a positive study.     

Baseline and post-bronchodilator interrupter resistance and spirometry in asthmatic children

In children unable to perform reliable spirometry, the interrupter resistance (R_int) technique for assessing respiratory resistance is easy to perform. However, few data are available on the possibility to use R_int as a surrogate for spirometry. We aimed at comparing R_int and spirometry at baseline and after bronchodilator administration in a large population of asthmatic children. We collected retrospectively R_int and spirometry results measured in 695 children [median age 7.8 (range 4.8–13.9) years] referred to our lab for routine assessment of asthma disease. Correlations between R_int and spirometry were studied using data expressed as z‐scores. Receiver operator characteristic curves for the baseline R_int value (z‐score) and the bronchodilator effect (percentage predicted value and z‐score) were generated to assess diagnostic performance. At baseline, the relationship between raw values of R_int and FEV₁ was not linear. Despite a highly significant inverse correlation between R_int and all of the spirometry indices (FEV₁, FVC, FEV₁/FVC, FEF_25–75%; P < 0.0001), R_int could detect baseline obstruction (FEV₁ z‐score ≤ ?2) with only 42% sensitivity and 95% specificity. Post‐bronchodilator changes in R_int and FEV₁ were inversely correlated (rhô = ?0.50, P < 0.0001), and R_int (≥35% predicted value decrease) detected FEV₁ reversibility (>12% baseline increase) with 70% sensitivity and 69% specificity (AUC = 0.79). R_int measurements fitted a one‐compartment model that explained the relationship between flows and airway resistance. We found that R_int had poor sensitivity to detect baseline obstruction, but fairly good sensitivity and specificity to detect reversibility. However, in order to implement asthma guidelines for children unable to produce reliable spirometry, bronchodilator response measured by R_int should be systematically studied and further assessed in conjunction with clinical outcomes. Pediatr Pulmonol. 2012. 47:987–993. © 2012 Wiley Periodicals, Inc.     

Post-bronchodilator Reversibility of FEV1 and Eosinophilic Airway Inflammation in COPD

Introduction

The relationship between bronchodilator responsiveness and eosinophilic airway inflammation has not been well documented in COPD. It has been investigated in this retrospective study. This issue has grown in importance due to increasing interest in the asthma-COPD overlap syndrome.

Dynamic Hyperinflation Correlates with Exertional Oxygen Desaturation in Patients with Chronic Obstructive Pulmonary Disease

Background

Dynamic hyperinflation (DH) causes exercise limitation and exertional dyspnea in patients with chronic obstructive pulmonary disease (COPD). Exertional desaturation (ED) also occurs commonly in COPD but neither routine physiologic parameters nor imaging predict ED accurately. In this study we evaluated the relationship between DH and ED during 6-min walk testing (6MWT).

Methods

We measured ED and DH in patients with stable COPD. SpO₂ was measured by continuous pulse oximetry during 6MWT. ED was defined as a decline in SpO₂ (ΔSpO₂) ≥4 %. DH was determined by measuring inspiratory capacity (IC) before and after the 6MWT using a handheld spirometer. DH was defined as ΔIC >0.0 L. We correlated DH and ED with clinical and pulmonary physiologic variables by regression analysis, χ ², and receiver operator curve (ROC) analysis.

Results

Thirty males [age = 65 ± 9.4 years, FEV₁ % predicted = 48 ± 14 %, and DLCO % predicted = 50 ± 21 % (mean ± SD)] were studied. ΔSpO₂ correlated with ΔIC (r = 0.49, p = 0.005) and age (r = 0.39, p = 0.03) by univariate analysis; however, only ΔIC correlated on multivariate regression analysis (p = 0.01). ΔSpO₂ did not correlate with FEV₁, FVC, FEF_25–75, RV, DLCO % predicted, BMI, smoking, BORG score, or distance covered in 6MWT. DH strongly correlated with ED (p = 0.001). On ROC analysis, DH had an area under the curve of 0.92 for the presence of ED (sensitivity = 90 %; specificity = 77 %, p < 0.001).

Conclusion

Routine pulmonary function test results and clinical variables did not correlate with ED in patients with stable COPD. Dynamic hyperinflation strongly correlates with exertional desaturation and could be a reason for this desaturation.     

Pulmonary function changes in children after transcatheter closure of atrial septal defect

This study was performed to assess changes in pulmonary function test (PFT) and pulmonary outcome after transcatheter closure of atrial septal defect (ASD) in pediatric patients. A total 55 pediatric patients undergoing transcatheter ASD closure received PFT at baseline (day before ASD closure), and at 3 days and 6 months after procedure. Forced vital capacity (FVC), forced expired volume in 1 sec (FEV₁), FEV₁ to FVC ratio (FEV₁/FVC), peak expiratory flow (PEF), and mean forced expiratory flow during the middle half of FVC (FEF_25–75) were measured. Individually, subjects were classified by spirometry as normal, obstructive or restrictive, to evaluate the effect of transcatheter closure on pulmonary outcome. These 55 children had significantly reduced mean PEF and FEF_25–75 (84 ± 24%, P = 0.040 and 76 ± 22%, P = 0.010, respectively) at baseline, with FEF_25–75 reduced significantly at 3 days and 6 months (78 ± 24%, P = 0.010 and 81 ± 24%, P = 0.040, respectively) after transcatheter closure. Six months after transcatheter closure of ASD, significant improvement was observed in mean FVC (94 ± 19% vs. 98 ± 15%, P = 0.034) and FEV₁ (90 ± 20% vs. 96 ± 19%, P = 0.008). Assessed individually, better pulmonary outcome was found in patients without pulmonary hypertension (PH) (χ² = 8.333, P = 0.044). PFT disturbance was observed in significant flow limitation in the peripheral airway of ASD patients. Improved PFT was found after transcatheter closure and better pulmonary outcome was observed in patients without PH. ASD children need monitoring pulmonary function and should receive transcatheter closure before PH develops. Pediatr Pulmonol. 2009; 44:1025–1032. ©2009 Wiley‐Liss, Inc.     

Effect of passive smoking,asthma, and respiratory infection on lung function in Australian children

We have calculated normal standards for lung function of Australian children and have estimated the effects on lung function of passive smoking, current asthma, past asthma, and a current respiratory infection. Three cross-sectional samples of children in school years 3–5 (aged 8–11 years) were studied. The 2765 children were from two rural regions of NSW and from the city of Sydney. Details of passive smoking and respiratory illness were collected by a questionnaire sent to parents. Forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV₁), peak expiratory flow rate (PEFR), and forced mid-expiratory flow rate (FEF_25–75%) were used as measures of lung function. Airway responsiveness was assessed by histamine inhalation test. Data from 1278 “normal” children were used in regression analysis to calculate prediction models for lung function. Passive smoking was associated with reduced FEV₁, PEFR, and FEF_25–75%. Children with current asthma had reduced FEV₁ and FEF_25–75% and children with past asthma had reduced FEF_25–75%. Children with a current respiratory infection had reduced FVC₁, FEV₁, PEFR, and FEF_25–75% The effects of these deficits on the future lung function of these children is not known but is likely to be important. Pediatr Pulmonol. 1994;18:323–329 © Wiley-Liss, Inc.     

Basal insulin glargine and microvascular outcomes in dysglycaemic individuals: results of the Outcome Reduction with an Initial Glargine Intervention (ORIGIN) trial

Aims/hypothesis

As glycaemia and the incidence of microvascular diabetes complications follow a log-linear relationship, it becomes increasingly difficult to demonstrate a microvascular benefit of glucose-lowering when the HbA_1c level is close to normal.

Methods

The Outcome Reduction with an Initial Glargine Intervention (ORIGIN) trial randomised 12,537 people with diabetes, impaired glucose tolerance or impaired fasting glucose to receive standard glycaemic care or standard care with the addition of basal insulin glargine (A21Gly,B31Arg,B32Arg human insulin), targeting a fasting plasma glucose level ≤5.3 mmol/l. Microvascular outcomes during a median follow-up of 6.2 years were examined in participants whose baseline HbA_1c was above or below the median of 6.4% (46.4 mmol/mol).

Results

Allocation to the insulin glargine group reduced the incidence of the primary microvascular composite outcome of kidney and eye disease in participants whose baseline HbA_1c level was ≥6.4% (46.4 mmol/mol; HR 0.90 [95% CI 0.81, 0.99]) but not in participants with a lower baseline HbA_1c (HR 1.07 [95% CI 0.95, 1.20]; p value for interaction 0.031). In people whose baseline HbA_1c level was ≥6.4% (46.4 mmol/mol), the median post-randomisation change in HbA_1c was ?0.65% (interquartile range ?0.16, ?0.91%) after allocation to insulin glargine and ?0.33% (?0.83, 0.13%) after allocation to standard care (median HbA_1c difference 0.33%; p?<?0.0001). A smaller median difference of 0.22% was noted in people whose baseline HbA_1c was <6.4% (p?<?0.0001).

Conclusions/interpretation

In patients with dysglycaemia, intervention targeting normal fasting glucose levels reduced HbA_1c and attenuated the risk of microvascular outcomes in participants with a baseline HbA_1c level ≥6.4% (46.4 mmol/mol). A neutral effect was seen in those with a lower baseline HbA_1c level.

Trial registration:

ClinicalTrials.gov NCT00069784     

Response–Dose Ratio is a Surrogate of Cumulative Provocative Dosage for Bronchial Provocation Tests in Asthma

Background

Response–dose ratio (RDR) and cumulative provocative dosage (PD) are useful indices reflecting airway responsiveness in asthma.

Objectives

To compare the diagnostic value of RDR and PD, by conducting leukotriene D₄ (LTD₄-BPT) and methacholine bronchial provocation test (MCh-BPT), in different asthma control levels.

Methods

Healthy subjects and asthmatic patients underwent LTD₄-BPT and MCh-BPT, at 2–14-day interval. This entailed assessment of the distribution characteristics, correlation, and diagnostic value of PD inducing 20 % fall in forced expiratory volume in one second (PD₂₀FEV₁) and the RDR, defined as FEV₁ fall (%) at the final step divided by the corresponding provocative dosage.

Results

Twenty uncontrolled, 22 partly controlled, 20 controlled asthmatics, and 21 healthy subjects were enrolled. Log₁₀RDR was positively correlated with log₁₀PD₂₀FEV₁ in both BPTs (all P < 0.05). Poorer asthma control was associated with significantly lower PD₂₀FEV₁ and higher RDR (both P < 0.05). The differences in PD₂₀FEV₁ and RDR between partly controlled and controlled asthma were unremarkable (both P > 0.05). Compared with log₁₀PD₂₀FEV₁, the log₁₀RDR yielded similar diagnostic values in both BPTs. A lower percentile of RDR (≤25th percentile) was associated with higher baseline FEV₁ (P < 0.05) and an increased proportion of well-controlled asthmatic patients. The combination of RDR and PD₂₀FEV₁ led to an increased diagnostic value compared with either parameter alone.

Conclusions

RDR is a surrogate of PD₂₀FEV₁ for BPTs in asthma. This finding was not modified by different asthma control levels or the types of bronchoprovocants.     

Common <Emphasis Type="Italic">SIRT1</Emphasis> variants modify the effect of abdominal adipose tissue on aging-related lung function decline

Lung function is an independent predictor of mortality and serves as an aging marker in never smokers. The protein sirtuin-1 of gene SIRT1 has profound anti-inflammatory effects and regulates metabolic pathways. Its suggested longevity effects on lower organisms remain poorly studied in humans. In 1132 never smokers of the population-based SAPALDIA cohort, we investigated associations between single nucleotide polymorphisms (SNPs; rs730821, rs10997868, rs10823116) of SIRT1 and aging-related lung function decline over 11 years in terms of change in forced expiratory volume in the first second (FEV₁), forced vital capacity (FVC), FEV₁/FVC ratio, and forced expiratory flow between 25 and 75 % of FVC (FEF_25–75) using multiple linear regression models. Interactions between the SIRT1 SNPs and adiposity parameters (body mass index (BMI), its change and weight gain) were tested by including multiplicative interaction terms into the models. SIRT1 polymorphisms exhibited no main effects, but modified the association between obesity measures and FEV₁/FVC and FEF_25–75 decline (p = 0.009–0.046). Per risk allele, FEV₁/FVC decline was accelerated up to ?0.5 % (95 % CI ?1.0 to 0 %) and ?0.7 % (?1.3 to ?0.2 %) over interquartile range increases in BMI (2.4 kg/m²) or weight (6.5 kg), respectively. For FEF_25–75 decline, corresponding estimates were ?57 mL/s (?117 to 4 mL/s) and ?76 mL/s (?1429 to ?9 mL/s). Interactions were not present in participants with genetically lowered C-reactive protein concentrations. Genetic variation in SIRT1 might therefore affect lung function and human longevity by modifying subclinical inflammation arising from abdominal adipose tissue.     

A review of tocilizumab treatment in 122 rheumatoid arthritis patients included in the Tsurumai Biologics Communication Registry (TBCR) Study

Objectives

Biologics have transformed the treatment of rheumatoid arthritis. Clinical remission is now the goal. We sought to verify whether the administration of tocilizumab—a biologic—can help to achieve current treatment goals.

Methods

Using data from the Tsurumai Biologics Communication Registry for 122 patients treated with tocilizumab, we evaluated changes in DAS28-ESR at 12 months after initiation, and also evaluated remission rates defined using conventional and new Boolean-based remission criteria. We divided 50 patients who had received tocilizumab as a first-line treatment into two groups [disease duration at baseline of 12 months or less (≤12 M) and more than 12 months (>12 M)].

Results

At 12 months after initiation, there was no difference in DAS28-ESR, and remission rates based on the conventional criterion were also comparable (50 % in both groups). However, under the new criterion, remission was 50.0 % in the ≤12 M group against 12.5 % in the >12 M group (p = 0.0181). Among the individual components of the new remission criterion, the small proportion of patients in the >12 M group with a patient global assessment (PtGA) of ≤1 had a particularly strong influence on the remission rate for that group, but this component was not as important for the ≤12 M group.

Conclusions

When used as a first-line biological drug for patients with early-stage RA (≤12 M), tocilizumab appears to provide high rates of remission under the Boolean-based remission criterion, which were strongly affected by the PtGA.     

Dual Bronchodilation with Indacaterol Maleate/Glycopyrronium Bromide Compared with Umeclidinium Bromide/Vilanterol in Patients with Moderate-to-Severe COPD: Results from Two Randomized,Controlled, Cross-over Studies

Purpose

To compare the efficacy and safety of two long-acting dual bronchodilator combinations: indacaterol/glycopyrrolate (IND/GLY) versus umeclidinium/vilanterol (UMEC/VI).

Methods

Studies A2349 and A2350 were replicate, randomized, double-blind, double-dummy, active-controlled, cross-over studies in patients with moderate-to-severe COPD. Patients were randomized to sequential 12-week treatments of twice-daily IND/GLY 27.5/15.6 μg and once-daily UMEC/VI 62.5/25 μg, each separated by a 3-week washout. The primary objective was to demonstrate non-inferiority of IND/GLY compared with UMEC/VI in terms of the 24-h forced expiratory volume in 1 s profile at week 12 (FEV₁ AUC_0–24). Rescue medication use, symptom control, and safety were assessed throughout.

Results

Both treatments delivered substantial bronchodilation over 12 weeks, with improvements in FEV₁ AUC_0–24h at week 12 of 232 and 185 mL for IND/GLY, and 244 and 203 mL with UMEC/VI in Studies A2349 and A2350, respectively. The primary efficacy objective of non-inferiority of IND/GLY relative to UMEC/VI was not met as the lower bound of the confidence interval for the LS treatment comparison was below the pre-specified non-inferiority margin of ?20 mL in both studies: ?26.9 and ?34.2 mL, respectively (LS mean between-treatment differences: ?11.5 and ?18.2 mL). Both drugs were well tolerated, with AE profiles consistent with their respective prescribing information.

Conclusions

IND/GLY and UMEC/VI provided clinically meaningful and comparable bronchodilation. Non-inferiority of IND/GLY to UMEC/VI could not be declared although between-treatment differences were not clinically relevant. The data support the use of IND/GLY as an efficacious and well tolerated treatment option in patients with COPD. (ClinicalTrials.gov NCT02487446 and NCT02487498)

     

Exhaled Nitric Oxide and Exercise-Induced Bronchospasm Assessed by FEV1, FEF25 − 75% in Childhood Asthma

The relationship between exhaled nitric oxide (eNO) and bronchial hyperresponsiveness (BHR) should be clarified. The aim of this study was to determine the relationship between eNO and exercise-induced bronchospasm (EIB) by estimation of the each lung parameter in asthmatic children who performed a bicycle ergometer exercise test. Twenty children with asthma were recruited. eNO concentration was examined by the recommended online method. To evaluate BHR, an exercise stress test was performed on a bicycle ergometer. The mean baseline eNO value was significantly correlated with the mean maximum % fall in forced expiratory volume in 1 second (FEV₁), forced expiratory flow between 25% and 75% (FEF25-75%) after exercise (r = 0.53, r = 0.65, respectively). eNO in the EIB-positive group was significantly higher than that in the EIB-negative group by assessing FEV₁, FEF_25?75% (p < 0.005, p = 0.005). We demonstrated that the most important lung parameter assessed the occurrence of EIB by a bicycle ergometer exercise test was not only FEV₁ but FEF_25?75%, which significantly correlated with eNO. This suggests that not only FEV₁ but FEF_25?75% can be used to evaluate the correlations between BHR (EIB) and airway inflammation (eNO) in asthmatic children. A low eNO is useful for a negative predictor for EIB.     

Comparison of the Bronchodilating Effects of Formoterol and Albuterol Delivered by Hydrofluoroalkane Pressurized Metered-Dose Inhaler

Objective

To compare the onset of bronchodilation with a new formoterol hydrofluoroalkane (HFA) pressurized metered-dose inhaler (pMDI) with albuterol (salbutamol) HFA pMDI.

Patients and methods

Thirty patients with stable mild or moderate asthma (23 using inhaled corticosteroids, mean FEV₁ 82% of predicted, ≥15% reversibility to terbutaline 1mg after 30 minutes) received formoterol HFA (Oxis®) 2 × 4.5µg, albuterol HFA (Ventoline® Evohaler®) 2 × l00µg, or placebo at three separate visits in this randomized, double-blind, double-dummy, three-way crossover study. FEV₁ was measured before and 3, 10, 20, 30 and 60 minutes after inhalation. Change in FEV₁ at 3 minutes after inhalation was the primary variable.

Results

Mean baseline FEV₁ was stable on all study days (range 2.92–2.94L). FEV₁ values at 3 minutes were: formoterol 3.22L (8% increase), albuterol 3.23L (9% increase) and placebo 2.99L (both p < 0.001 vs placebo). Maximum FEV₁ increased similarly with formoterol and albuterol, with no differences observed between the active treatments at any time point. Patients rated treatment effective at 3 minutes in 15 of 30, 19 of 30 and 7 of 30 cases with formoterol, albuterol and placebo, respectively. All treatments were well tolerated.

Conclusion

In stable, mild, or moderate asthma, formoterol 9µg and albuterol 200µg, both by HFA pMDI, provided equally rapid and effective bronchodilation.

     

Association of blood glucose control and pancreatic reserve with diabetic retinopathy in the Veterans Affairs Diabetes Trial (VADT)

Aims/hypothesis

The aim of this study was to test the hypothesis that intensive glycaemic control (INT) and higher plasma C-peptide levels in patients with poorly controlled diabetes would be associated with better eye outcomes.

Methods

The incidence and progression of diabetic retinopathy (DR) was assessed by grading seven-field stereoscopic fundus photographs at baseline and 5 years later in 858 of 1,791 participants in the Veterans Affairs Diabetes Trial (VADT).

Results

After adjustment for all covariates, risk of progression (but not incidence) of DR increased by 30% for each 1% increase in baseline HbA_1c (OR 1.3; 95% CI 1.123, 1.503; p?=?0.0004). Neither assignment to INT nor age was independently associated with DR in the entire cohort. However, INT showed a biphasic interaction with age. The incidence of DR was decreased in INT participants ≤55 years of age (OR 0.49; 95% CI 0.24, 1.0) but increased in those ≥70 years old (OR 2.88; 95% CI 1.0, 8.24) (p?=?0.0043). The incidence of DR was reduced by 67.2% with each 1 pmol/ml increment in baseline C-peptide (OR 0.328; 95% CI 0.155, 0.7; p?=?0.0037). Baseline C-peptide was also an independent inverse risk factor for the progression of DR, with a reduction of 47% with each 1 pmol/ml increase in C-peptide (OR 0.53; 95% CI 0.305, 0.921; p?=?0.0244).

Conclusions/interpretation

Poor glucose control at baseline was associated with an increased risk of progression of DR. INT was associated with a decreased incidence of DR in younger patients but with an increased risk of DR in older patients. Higher C-peptide at baseline was associated with reduced incidence and progression of DR.     

An Evaluation of Internal Medicine Residency Continuity Clinic Redesign to a 50/50 Outpatient–Inpatient Model

BACKGROUND

There have been recent calls for improved internal medicine outpatient training, yet assessment of clinical and educational variables within existing models is lacking.

OBJECTIVE

To assess the impact of clinic redesign from a traditional weekly clinic model to a 50/50 outpatient–inpatient model on clinical and educational outcomes.

DESIGN

Pre-intervention and post-intervention study intervals, comparing the 2009–2010 and 2010–2011 academic years.

PARTICIPANTS

Ninety-six residents in a Primary Care Internal Medicine site of a large academic internal medicine residency program who provide care for > 13,000 patients.

INTERVENTION

Continuity clinic redesign from a traditional weekly clinic model to a 50/50 model characterized by 50 % outpatient and 50 % inpatient experiences scheduled in alternating 1 month blocks, with twice weekly continuity clinic during outpatient months and no clinic during inpatient months.

MAIN MEASURES

1) Clinical outcomes (panel size, patient visits, adherence with chronic disease and preventive service guidelines, continuity of care, patient satisfaction, and perceived safety/teamwork in clinic); 2) Educational outcomes (attendance at teaching conference, resident and faculty satisfaction, faculty assessment of resident clinic performance, and residents’ perceived preparedness for outpatient management).

RESULTS

Redesign was associated with increased mean panel size (120 vs. 137.6; p?≤ 0.001), decreased continuity of care (63 % vs. 48 % from provider perspective; 61 % vs. 51 % from patient perspective; p ≤ ?0.001 for both; team continuity was preserved), decreased missed appointments (12.5 % vs. 10.9 %; p ≤ ?0.01), improved perceived safety and teamwork (3.6 vs. 4.1 on 5-point scale; p ≤ ?0.001), improved mean teaching conference attendance (57.1 vs. 64.4; p ≤ ?0.001), improved resident clinic performance (3.6 vs. 3.9 on 5-point scale; p ≤ ?0.001), and little change in other outcomes.

CONCLUSION

Although this model requires further study in other settings, these results suggest that a 50/50 model may allow residents to manage more patients while enhancing the climate of teamwork and safety in the continuity clinic, compared to traditional models. Future work should explore ways to preserve continuity of care within this model.     

The effect of transfusion on pulmonary function in patients with thalassemia major

Pulmonary involvement has been documented in thalassemia major (TM). We studied 12 patients with TM before and 24 hr after transfusion to evaluate the effect of transfusion on baseline lung function. Personal and family histories of respiratory illnesses were obtained by a questionnaire. Spirometry and carbon monoxide diffusion capacity (KCO) measurements were made. Blood gases (P, and S,) were determined on arterialized samples. Baseline expiratory volumes and flows were within normal range in all patients. Transfusion resulted in a significant reduction of forced expiratory volume in 1 sec (FEV₁) and forced expiratory flow between 25 and 75% vital capacity (FEF_25–75%). In two subgroups of patients identified by the questionnaire, those with no history of airway disease had normal baseline flows and no posttransfusion changes; those with history of airway obstruction had lower pretransfusion flows and significantly decreased posttransfusion FEV₁ and FEF_25–75%. The mean pretransfusion KCO value of 80% predicted for the whole group, significantly increased after transfusion (P < 0.05). Blood gases also significantly increased after transfusion (P < 0.05). When tested for the spirometric response to albuterol, patients with a history of asthma had a slightly greater increase in FEV₁ and FEF_25–75% than those who had never had asthma. We conclude that in our small study group, transfusion resulted in improved gas exchange and lung perfusion. The effect on flow limitation evident in some patients could, in part, be related to a preexisting bronchial hyperreactivity. Accurate evaluation of pulmonary function and of bronchial reactivity is advisable for patients with TM. Pediatr Pulmonol. 1994;18:139–143. © 1994 Wiley-Liss, Inc.     

Pulmonary function between 6 and 18 years of age

Pulmonary function of children aged 6–18 years is described based on 82,462 annual measurements of forced vital capacity (FVC), forced expired volume in 1 second (FEV₁), and forced expiratory flow between 25% and 75%of FVC (FEF_25–75%) from 11,630 white children and 989 black children. Median height, FVC, FEV₁ FEV₁/FVC₁ and FEF_25–75% for each 3 months of age are compared among race and sex subgroups. Race— and sex-specific percentile distributions of FVC, FEV₁, FEV₁/FVC, and FEF_25—75% are presented for each centimeter of height (growth curves). For the same height, boys have greater lung function values than girls, and whites have greater ones than blacks. Lung function increases linearly with age until the adolescent growth spurt at about age 10 years in girls and 12 in boys. The pulmonary function vs. height relationship shifts with age during adolescence. Thus, a single equation or the pulmonary function-height growth chart alone does not completely describe growth during the complex adolescent period. Nevertheless, race- and sex-specific growth curves of pulmonary function vs. height make it easy to display and evaluate repeated measures of pulmonary function for an individual child. Race-, sex-, and age-specific regression equations based on height are provided, which permit the evaluation of growth during adolescence with improved accuracy and, more importantly, in comparison with previous observations for the same child. © 1993 Wiley-Liss, Inc.     

A multifaceted community-based asthma intervention in Chicago: effects of trigger reduction and self-management education on asthma morbidity

Introduction. In the exercise challenge test (ECT), a drop in forced expiratory volume in the first second (FEV₁) of between 10 and 15% is the determinant variable for a diagnosis of exercise-induced bronchospasm. Hypothesis. The use of FEV₁ plus mean forced expiratory flow between 25% and 75% of the forced vital capacity (FEF_25–75%) may increase the sensitivity of the ECT in asthmatic children. Specific objective. To compare FEV₁ and FEF_25–75% changes in a group of asthmatic and healthy children. Methodology. This was a cross-sectional study. Asthmatics were categorized by their severity (GINA) and after 1 month without controller therapy, an ECT was done under standard protocol. As well, a questionnaire about rhinitis and asthma was conducted with the entire population. ROC curves were used for analysis. Results. A total of 147 children (34 healthy and 113 asthmatics, 18 and 58 males, respectively) were evaluated. Divided into healthy children and intermittent, mild and moderate persistent asthmatics, they had similar average ages (9.4, 9.48, 8.97, and 11.2 years, respectively). Using a 15% fall in FEV₁, we obtained 29% sensitivity and 100% specificity. However, when we used a 10% fall in FEV₁, sensitivity was 47% and specificity was 97%. Adding a 28% fall in FEF_25–75%, sensitivity was 52% and specificity was 94%. Conclusion. This study suggests that test sensitivity can increase by using a lower FEV₁ cut-off (10%) and adding a 28% fall in FEF_25–75%.