Infant pulmonary function testing

Quantifiable features of a tidal breathing phenotype in dogs with severe bronchomalacia diagnosed by bronchoscopy

Dynamic lower airway obstruction is the primary component of canine bronchomalacia, but the ventilatory function remains underinvestigated. This prospective study analyzed tidal breathing characteristics in 28 dogs, comprising 14 with severe bronchomalacia diagnosed by bronchoscopy versus 14 without respiratory disease. Spirometry was conducted in all dogs. Bronchoscopy with bronchoalveolar lavage or brush under anesthesia was performed in 14 dogs with cough and expiratory effort. Severe bronchomalacia was defined by the severity of collapse and total number of bronchi affected. Ventilatory characteristics were compared between groups. Results revealed that dogs with severe bronchomalacia had lower minute volume (218 vs 338 mL/kg, p = .039) and greater expiratory-to-inspiratory time ratio (1.55 vs 1.35, p = .01) compared to control dogs. The tidal breathing pattern of dogs with bronchomalacia was different from that of normal dogs, and the pattern differed from the concave or flat expiratory curves typical of lower airway obstruction. Compared to control dogs, dogs with severe bronchomalacia had a significantly prolonged low-flow expiratory phase (p < .001) on the flow-time plot and a more exponential shape of the expiratory curve (p < .001) on the volume-time plot. Flow-time index ExpLF/Te (>0.14) and volume-time index Vt-AUCexp (≤31%) had a high ROC-AUC (1.00, 95% confidence interval 0.88 to 1.00) in predicting severe bronchomalacia. In conclusion, the tidal breathing pattern identified here indicates abnormal and complicated ventilatory mechanics in dogs with severe bronchomalacia. The role of this pulmonary functional phenotype should be investigated for disease progression and therapeutic monitoring in canine bronchomalacia.

Evaluation of Children with Malignancies for Blood and Marrow Transplantation: A Report from the ASTCT Committee on Practice Guidelines

Evaluation of a candidate for hematopoietic cell transplantation (HCT) is a complex process with substantial intercenter variability. Although literature providing guidance for evaluating the eligibility of adults is well established, similar guidance for children is lacking. To address gaps between adult recommendations and the specific needs of children, we convened a panel of pediatric HCT experts from a wide geographic range of American Society of Transplantation and Cellular Therapy (ASTCT) member institutions to offer recommendations for pediatric-focused pre-HCT evaluation. In this report from the ASTCT Committee on Practice Guidelines, we present a practical framework for evaluating children with malignancies who are candidates for HCT. We also highlight key differences from adults and emphasize areas of unmet need that require additional research to delineate best practices.

Forced deflation pulmonary function test: a novel method to evaluate lung function in infants and young children

We describe the safety and feasibility of a forced deflation pulmonary function test (dPFT) in infants and young children. Fifty-two dPFT studies were performed in 26 patients (median age, 1.4 years). Forced vital capacity (FVC) and forced expiratory flow (FEF₇₅ ) were normal in all except one case, but respiratory system compliance (Crs) was reduced in 24% patients. There were no significant differences in pre-blood and marrow transplantation FVC, FEF₇₅ , and Crs between those patients who did and those who did not have posttransplant pulmonary complications. A larger study is needed to determine the prevalence and significance of PFT abnormalities in this age group.

Pre-transplant lung function is predictive of survival following pediatric bone marrow transplantation

BACKGROUND

Pulmonary toxicity is well described in recipients of bone marrow transplants (BMT), and accounts for a sizeable proportion of post-transplant mortality. The majority of the data on post-transplant pulmonary function is from adults, although several small pediatric case series have been described. In adults, pre-transplant lung function has been predictive of post-transplant respiratory failure and mortality. This use of pulmonary function testing, that is, for pre-transplant risk counseling, is novel but has never been applied to pediatric patients. We hypothesized that in children, as in adults, pre-transplant pulmonary function would also be predictive of outcome post-transplantation morbidity.

PROCEDURE

Retrospective database analysis of pulmonary function tests of patients undergoing first myeloablative BMT at two large children's hospitals.

RESULTS

Two hundred seventy-three subjects had at least one pre-transplant PFT, and 317 subjects had at least one post-transplant PFT available for analysis. While the majority of patients had normal or mildly reduced pre-transplant flows and lung volume, 25% had moderately or severely reduced diffusion. All lung function parameters decreased post-transplant with a slow improvement over ensuing years. The Lung Function Score, a combined measurement of FEV(1) and DLCO, was highly associated with post-transplant survival. Hazard ratios for mortality (compared to the best LFS) ranged from 1.654 to 2.454.

CONCLUSIONS

Lung function prior to bone marrow transplant, especially diffusing capacity, is frequently abnormal. Lung function frequently decreases shortly post-transplant and tends to improve over time, but frequently remains abnormal even years after transplant. Post-transplant survival is related to pre-transplant lung function.

Posttransplant monitoring of pediatric lung transplant recipients

PURPOSE OF REVIEW

This article reviews current trends in pediatric lung posttransplant management, reveals pitfalls that exist, and introduces additional parameters that may have an impact on long-term survival.

RECENT FINDINGS

A number of parameters are monitored after transplantation to prevent or identify early complications related to lung transplantation in hope of reducing morbidity and mortality. These include routine laboratory studies, imaging, and monitoring of drug levels and lung function. Drug monitoring allows individualization of a patient's immunosuppressive therapy; however, drug levels alone may not reflect the patient's immune status. ImmuKnow is a general immune-monitoring assay that may help guide therapy. Two major complications are rejection and infection, and bronchoscopy is used to differentiate these two entities. Silent rejection may occur and increase the chance of developing bronchiolitis obliterans; therefore, many centers perform surveillance bronchoscopies. Recently, de-novo anti-histocompatibility locus antigen antibodies and gastroesophageal reflux have been associated with poor outcomes, and many centers are monitoring these entities as part of care following lung transplant.

SUMMARY

There has been little improvement in long-term outcomes of lung transplantation. Current monitoring methods are utilized to maintain or improve outcomes and recently additional monitoring parameters have been identified which hopefully will improve long-term outcomes.

[Wheezing in infants and toddlers: new insights]

Wheezing in infants and toddlers is a common symptom, and these patients are difficult to approach--both diagnostically and therapeutically. Congenital conditions causing wheezing disorders should not be missed and--not all wheezy bronchitis is or will become asthma. Results from longitudinal studies indicate that the term "asthma" includes different phenotypes: so-called transient early wheezing, non atopic wheezing and atopic wheezing (asthma). Transient early wheezing is generally accepted to define recurrent wheezing in non-atopic babies or toddlers and tends to disappear by the age of 3. The primary risk factor is reduced pulmonary function since birth. The most common cause for non-atopic wheezing is viral infection, most frequently caused by respiratory syncytial virus. Infection with respiratory syncytial virus is a risk factor for ongoing wheeze during childhood but resolves in most children by the age of 13. Asthma can start at any age and is determined by a more chronic condition, provoked by a number of triggers in addition to viruses, frequently associated with a family history of atopy, early allergic sensitization and concomitant atopic dermatitis. Only asthma seems to be a progressive disease; and there is evidence from long-term studies that if anti-inflammatory interventions are started late, it might be too late to alter the natural course of the disease with its decline in pulmonary function. On the other hand, there is no evidence that small children with non-atopic wheezy bronchitis would benefit from long-term therapy with anti-inflammatory treatment; in this group a therapeutic trial with bronchodilators is sufficient. The diagnostic and therapeutic challenges of diagnosing asthma in this age group are considerable and require a comprehensive approach.