New reference equations to improve interpretation of infant lung function

Rationale

With increasing use of infant pulmonary function tests (IPFTs) in both clinical and research studies, appropriate interpretation of results is essential.

Objectives

To investigate the potential bias associated with “normalising” IPF by expressing results as a ratio of body size and to develop reference ranges for tidal breathing parameters, passive respiratory mechanics (compliance [C_rs] and resistance [R_rs]) and plethysmographic functional residual capacity (FRC_p) for white infants during the first 2 years of life.

Methods

IPFTs were measured using the Jaeger BabyBody system and standardized protocols. Reference equations, adjusted for body size, age, and sex where appropriate, were created using multilevel modeling.

Results

The ratio of lung function to body length changes markedly with growth, thereby precluding its use for any outcome. While the ratio of tidal volume and C_rs to body weight remained relatively constant with growth, this was not the case for FRC_p. Even in healthy infants, a strong inverse relationship was observed between lung function/body weight and weight z‐score which could distort interpretation of results in growth‐restricted infants with lung disease, such as cystic fibrosis. Reference equations were derived from 153 healthy white infants on 232 test occasions (median age 35.5 weeks [range: 2.6–104.7]). Crown‐heel length was the strongest predictor of IPF.

Conclusions

When reporting IPF, use of size‐corrected ratios should be discouraged, with interpretation instead based on appropriate reference equations. The current equations are applicable to white infants and young children up to 2 years of age, studied using the same commercially available equipment. The extent to which these equations are applicable to infants and young children of other ethnic backgrounds or who are tested with different equipment needs to be established. Pediatr Pulmonol. 2013; 48:370–380. © 2012 Wiley Periodicals, Inc.     

Parental emotional functioning declines with occurrence of clinical complications in pediatric hematopoietic stem cell transplant

Purpose

Parents’ stress levels are high prior to their child’s hematopoietic stem cell transplant (HSCT) and during transplant hospitalization, usually abating after discharge. Nevertheless, a subgroup of parents continues to experience frequent anxiety and mood disruption, the causes of which are not well understood. The purpose of this study was to assess whether clinical complications of HSCT could explain variation in parents’ recovery of emotional functioning.

Methods

Pediatric HSCT recipients (n?=?165) aged 5–18 and their parents were followed over the first year post-transplant. Health-related quality of life assessments and medical chart reviews were performed at each time period (baseline, 45 days, 3, 6, and 12 months). We tested the association between clinical complications [acute and chronic graft versus host disease (aGVHD and cGVHD), organ toxicity, and infection] and longitudinally measured parental emotional functioning, as assessed by the Child Health-Ratings Inventories. The models used maximum likelihood estimation with repeated measures.

Results

In adjusted analyses covering the early time period (45 days and 3 months), aGVHD grade ≥2, intermediate or poor organ toxicity, and systemic infection were associated with decreases in mean parental emotional functioning of 5.2 (p?=?0.086), 5.8 (p?=?0.052), and 5.1 (p?=?0.023) points, respectively. In the later time period (6 and 12 months), systemic infection was associated with a decrease of 20 points (p?<?0.0001). cGVHD was not significantly associated.

Conclusions

When children experience clinical complications after HSCT, parental emotional functioning can be impacted. Intervening at critical junctures could mitigate potential negative consequences for parents and their children.     

Cortical reorganization in children with unilateral sensorineural hearing loss

Previous studies have shown evidence of cortical reorganization following unilateral sensorineural hearing loss (USNHL). In addition, study participants with right USNHL have shown greater deficits in academic and language performance compared with those with left USNHL. A preliminary functional magnetic resonance imaging investigation was performed on a small cohort of participants, four with left USNHL and four with right USNHL, using the paradigm of listening to random tones. While the participants with left USNHL displayed greater activation in the right superior temporal gyrus, those with right USNHL displayed greater activation in the left inferior frontal area immediately anterior to the superior temporal gyrus. The results provide preliminary evidence of disparate neural circuitry supporting auditory processing in participants with left and right USNHL.     

Are there gender differences in pain perception?

Chronic pain conditions are increasingly prevalent. However, very little is known about the relationship between pain and gender. The purposes of this study were to determine gender differences in pain threshold and tolerance among Chinese adults in Hong Kong and to examine the role of anxiety in pain perception. One hundred seventy-eight healthy, pain-free adults (89 men and 89 women) were recruited from a local university by convenience sampling to participate in the study. All participants completed the State and Trait Anxiety Inventory and underwent a laboratory pain task to determine their pain threshold and tolerance levels. Pain was assessed by using the Pain Intensity Verbal Rating Scale-Chinese version. Compared to men, women had a lower threshold (p < .001) and tolerance (p < .001) for pressure pain, and women reported more pain (p < .01) at the pain tolerance level. Higher trait anxiety scores were associated with higher pain report in men only (r [89] = .22, p = .04). The study indicated that gender differences in pain perception exist among the Chinese population in Hong Kong. A better understanding of the factors that contribute to gender differences in pain perception could reduce gender bias in pain management.     

Switching between abstract rules reflects disease severity but not dopaminergic status in Parkinson's disease

This study sought to disambiguate the impact of Parkinson's disease (PD) on cognitive control as indexed by task set switching, by addressing discrepancies in the literature pertaining to disease severity and paradigm heterogeneity. A task set is governed by a rule that determines how relevant stimuli (stimulus set) map onto specific responses (response set). Task set switching may entail reconfiguration in either or both of these components. Although previous studies have shown that PD patients are impaired at switching between stimuli, in the present study not all patients were impaired at switching entire task sets, that is, both stimulus and response sets: compared with controls, patients with unilateral signs (Hoehn & Yahr Stage I) demonstrated intact switching, even following withdrawal from dopaminergic medication, while bilaterally affected Stage II patients were impaired. The parametric measure of Unified Parkinson's Disease Rating Scale (UPDRS) score predicted increasing switch costs within the patient group. These findings suggest that switching entire task sets may be a function of extrastriatal, possibly non-dopaminergic pathology which increases as the disease progresses.     

Breath analysis by API/MS—human exposure to volatile organic solvents

Summary The expired breath of subjects, exposed for periods of ca. 90 min to atmospheres artificially contaminated with low levels of methanol, (ca. 100 ppm) toluene (ca. 50 ppm) or tetrachloroethylene, (ca. 50 ppm) was monitored during and after the exposure period using an atmospheric pressure ionization mass spectrometer, fitted with a direct breath analysis system. The retention of solvent by the subjects, estimated from steady state levels in the expired breath, averaged 82% of the inspired level for methanol, 83% for toluene and 87% for tetrachloroethylene. The elimination of unchanged solvent via respiration during the post exposure period followed first order kinetics with mean half life values of 24 min for methanol, 27 min for toluene and 79 min for tetrachloroethylene.