Perceptions of parents on the participation of their infants in clinical research

25 Years of translational research in the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC)

The Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) mother-child cohorts have provided a foundation of 25 years of research on the origins, prevention, and natural history of childhood asthma and related disorders. COPSAC's approach is characterized by clinical translational research with longitudinal deep phenotyping and exposure assessments from pregnancy, in combination with multi-omic data layers and embedded randomized controlled trials. One trial showed that fish oil supplementation during pregnancy prevented childhood asthma and identified pregnant women with the highest benefits from supplementation, thereby creating the potential for personalized prevention. COPSAC revealed that airway colonization with pathogenic bacteria in early life is associated with an increased risk of asthma. Further, airway bacteria were shown to be a trigger of acute asthma-like symptoms, with benefit from antibiotic treatment. COPSAC identified an immature gut microbiome in early life as a risk factor for asthma and allergy and further demonstrated that asthma can be predicted by infant lung function. At a molecular level, COPSAC has identified novel susceptibility genes, early immune deviations, and metabolomic alterations associated with childhood asthma. Thus, the COPSAC research program has enhanced our understanding of the processes causing childhood asthma and has suggested means of personalized prevention and treatment.

Reasons for participation in a child development study: Are cases with developmental diagnoses different from controls?

BACKGROUND

Current knowledge about parental reasons for allowing child participation in research comes mainly from clinical trials. Fewer data exist on parents' motivations to enrol children in observational studies.

OBJECTIVES

Describe reasons parents of preschoolers gave for participating in the Study to Explore Early Development (SEED), a US multi-site study of autism spectrum disorder (ASD) and other developmental delays or disorders (DD), and explore reasons given by child diagnostic and behavioural characteristics at enrolment.

METHODS

We included families of children, age 2-5 years, participating in SEED (n = 5696) during 2007-2016. We assigned children to groups based on characteristics at enrolment: previously diagnosed ASD; suspected ASD; non-ASD DD; and population controls (POP). During a study interview, we asked parents their reasons for participating. Two coders independently coded responses and resolved discrepancies via consensus. We fit binary mixed-effects models to evaluate associations of each reason with group and demographics, using POP as reference.

RESULTS

Participants gave 1-5 reasons for participation (mean = 1.7, SD = 0.7). Altruism (48.3%), ASD research interest (47.4%) and perceived personal benefit (26.9%) were most common. Two novel reasons were knowing someone outside the household with the study conditions (peripheral relationship; 14.1%) and desire to contribute to a specified result (1.4%). Odds of reporting interest in ASD research were higher among diagnosed ASD participants (odds ratio [OR] 2.89, 95% confidence interval [CI] 2.49-3.35). Perceived personal benefit had higher odds among diagnosed (OR 1.92, 95% CI 1.61-2.29) or suspected ASD (OR 3.67, 95% CI 2.99-4.50) and non-ASD DD (OR 1.80, 95% CI 1.50-2.16) participants. Peripheral relationship with ASD/DD had lower odds among all case groups.

CONCLUSIONS

We identified meaningful differences between groups in parent-reported reasons for participation. Differences demonstrate an opportunity for future studies to tailor recruitment materials and increase the perceived benefit for specific prospective participants.

Attitudes of Mothers Regarding Willingness to Enroll Their Children in Research

This study assessed mothers' perspectives regarding research involvement by their children, factors that might affect perceptions of research risks, and attitudes regarding willingness to enroll children in research. Participants completed a survey on Amazon Mechanical Turk. Mothers were less inclined to enroll children in research involving procedures posing higher risk (regression coefficient = -0.51). Mothers without mental health issues with children without health issues were more sensitive to risk than mothers without mental health issues with children with health issues (estimated difference = 0.49). Mothers with mental health issues were more willing than mothers without mental health issues to enroll children in research (regression coefficient = -0.90). Among mothers with mental health issues, having a child with a health issue was associated with increased willingness to enroll in research, compared with having children without health issues (estimated difference = 0.65).

Sharing longitudinal, non-biological birth cohort data: a cross-sectional analysis of parent consent preferences

BACKGROUND

Mandates abound to share publicly-funded research data for reuse, while data platforms continue to emerge to facilitate such reuse. Birth cohorts (BC) involve longitudinal designs, significant sample sizes and rich and deep datasets. Data sharing benefits include more analyses, greater research complexity, increased opportunities for collaboration, amplification of public contributions, and reduced respondent burdens. Sharing BC data involves significant challenges including consent, privacy, access policies, communication, and vulnerability of the child. Research on these issues is available for biological data, but these findings may not extend to BC data. We lack consensus on how best to approach these challenges in consent, privacy, communication and autonomy when sharing BC data. We require more stakeholder engagement to understand perspectives and generate consensus.

METHODS

Parents participating in longitudinal birth cohorts completed a web-based survey investigating consent preferences for sharing their, and their child's, non-biological research data. Results from a previous qualitative inquiry informed survey development, and cognitive interviewing methods (n = 9) were used to improve the question quality and comprehension. Recruitment was via personalized email, with email and phone reminders during the 14-day window for survey completion.

RESULTS

Three hundred and forty-six of 569 parents completed the survey in September 2014 (60.8%). Participants preferred consent processes for data sharing in future independent research that were less-active (i.e. no consent or opt-out). Parents' consent preferences are associated with their communication preferences. Twenty percent (20.2%) of parents generally agreed that their child should provide consent to continue participating in research at age 12, while 25.6% felt decision-making on sharing non-biological research data should begin at age 18.

CONCLUSIONS

These finding reflect the parenting population's preference for less project-specific permission when research data is non-biological and de-identified and when governance practices are highly detailed and rigourous. Parents recognize that children should become involved in consent for secondary data use, but there is variability regarding when and how involvement occurs. These findings emphasize governance processes and participant notification rather than project-specific consent for secondary use of de-identified, non-biological data. Ultimately, parents prefer general consent processes for sharing de-identified, non-biological research data with ultimate involvement of the child.

FeNO and Exercise Testing in Children at Risk of Asthma

BACKGROUND

Exercise testing is the gold standard for diagnosing exercise-induced bronchoconstriction in children, but requires considerable cooperation and medical resources. Therefore, fraction of exhaled nitric oxide (FeNO) has been proposed as a tool to predict the need for exercise testing.

OBJECTIVE

The objective of this study was to investigate the relationship between FeNO, exercise test results, and a history of respiratory symptoms during exercise in children at risk of asthma.

METHODS

FeNO measurement, exercise testing, and interview about respiratory symptoms during exercise were completed in 224 seven-year-old children from the at-risk Copenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ birth cohort. The associations between FeNO, exercise test results, and reported respiratory symptoms during exercise were analyzed adjusting for gender, respiratory infections, and inhaled corticosteroid treatment. The associations were also analyzed stratified by asthma and atopic status.

RESULTS

Of the 224 children, 28 (13%) had an established asthma diagnosis and 58 (26%) had a positive exercise test (≥15% drop in forced expiratory volume in 1 second [FEV₁] from baseline). FeNO and bronchial obstruction after exercise were linearly associated with a doubling of FeNO corresponding to a 2.4% drop in FEV₁ (95% confidence interval, 0.8-4.1; P < .01). However, a receiver operating characteristic curve analysis showed that the best cutoff of FeNO for predicting exercise test outcome among children who reported respiratory symptoms during exercise was 17 ppb, which only had 74% negative predictive value. There was no association between FeNO and reported respiratory symptoms during exercise (odds ratio = 1.3 [0.8-1.9]; P = .29) or reported symptoms during exercise and exercise test results (odds ratio = 1.0 [1.0-1.1]; P = .12).

CONCLUSIONS

A history of respiratory symptoms during exercise was not associated with either elevated FeNO or a positive exercise test in children at risk of asthma. FeNO and exercise test results were linearly associated traits, but FeNO could not reliably be used dichotomized to predict the need of exercise testing.

Deep phenotyping of the unselected COPSAC2010 birth cohort study

Background

We hypothesize that perinatal exposures, in particular the human microbiome and maternal nutrition during pregnancy, interact with the genetic predisposition to cause an abnormal immune modulation in early life towards a trajectory to chronic inflammatory diseases such as asthma and others.

Objective

The aim of this study is to explore these interactions by conducting a longitudinal study in an unselected cohort of pregnant women and their offspring with emphasis on deep clinical phenotyping, exposure assessment, and biobanking. Exposure assessments focus on the human microbiome. Nutritional intervention during pregnancy in randomized controlled trials are included in the study to prevent disease and to be able to establish causal relationships.

Methods

Pregnant women from eastern Denmark were invited during 2008–2010 to a novel unselected ‘COPSAC₂₀₁₀’ cohort. The women visited the clinic during pregnancy weeks 24 and 36. Their children were followed at the clinic with deep phenotyping and collection of biological samples at nine regular visits until the age of 3 and at acute symptoms. Randomized controlled trials of high‐dose vitamin D and fish oil supplements were conducted during pregnancy, and a trial of azithromycin for acute lung symptoms was conducted in the children with recurrent wheeze.

Results

Seven hundred and thirty‐eight mothers were recruited from week 24 of gestation, and 700 of their children were included in the birth cohort. The cohort has an over‐representation of atopic parents. The participant satisfaction was high and the adherence equally high with 685 children (98%) attending the 1 year clinic visit and 667 children (95%) attending the 2 year clinic visit.

Conclusions

The COPSAC₂₀₁₀ birth cohort study provides longitudinal clinical follow‐up with highly specific end‐points, exposure assessments, and biobanking. The cohort has a high adherence rate promising strong data to elucidate the interaction between genomics and the exposome in perinatal life leading to lifestyle‐related chronic inflammatory disorders such as asthma.

Factors influencing parents' decision to donate their healthy infant's DNA for minimal-risk genetic research

PURPOSE

To examine factors that influence a parent's decision to donate their healthy infant's DNA for minimal-risk genetic research.

DESIGN

Grounded theory, using semi-structured interviews conducted with 35 postpartum mother or mother-father dyads in an urban teaching hospital. Data were collected from July 2011 to January 2012.

METHODS

Audiorecorded semistructured interviews were conducted in private rooms with mothers or mother-father dyads 24 to 48 hr after the birth of their healthy, full-term infant. Data-driven content analysis using selected principles of grounded theory was performed.

FINDINGS

Parents' willingness to donate their healthy infant's DNA for minimal-risk pediatric genetic research emerged as a process involving three interacting components: the parents, the scientist, and the comfort of the child embedded within the context of benefit to the child. The purpose of the study and parents' perception of their commitment of time and resources determined their willingness to participate. The scientist's ability to communicate trust in the research process influenced parents' decisions. Physical discomfort of the child shaped parents' decision to donate DNA. Parental perception of a direct benefit to their child affected their willingness to discuss genetic research and its outcomes.

CONCLUSIONS

Significant gaps and misunderstandings in parental knowledge of pediatric genetic research may affect parental willingness to donate their healthy child's DNA.

CLINICAL RELEVANCE

Nurses knowledgeable about the decision-making process parents utilize to donate their healthy infant's DNA for minimal-risk genetic research and the factors influencing that decision are well positioned to educate parents about the role of genetics in health and illness and reassure potential research participants of the value and safeguards in pediatric genetic research.

Perceptions of academic health science research center personnel regarding informed consent processes and therapeutic misconception

INTRODUCTION

Instrumentation exists to measure voluntariness and misunderstanding in informed consent processes. However, research personnel's perspectives about using instrumentation to measure therapeutic misconceptions in research participants has not been reported. We designed a workshop to promote research personnel knowledge of emerging instrumentation and to study the perceptions of research personnel regarding such instruments.

METHODS AND FINDINGS

Two nationally recognized experts who have developed psychometric instruments to measure aspects of informed consent presented their recent findings to research personnel of the Medical University of South Carolina at a one-day workshop. Following the presentations, workshop attendees divided into two focus groups and shared their perceptions regarding the presentation content. Inductive thematic analysis detected themes related to informed consent processes including: investigator/provider role clarity; investigator transparency; therapeutic misconception; and screening subjects for understanding.

CONCLUSION

Our findings suggest future directions in applied, proactive empirical research to better understand investigator perceptions and practices related to transparency in research, and to develop instrumentation to detect risks to the integrity of informed consent in order to promote voluntariness and autonomy and minimize therapeutic misconception in research practices.

Parent perspectives on decisions to participate in a phase I hepatocyte transplant trial

We examined factors that affect decision-making for families presented with a phase I clinical trial of hepatocyte transplant as a potential alternative to liver transplant for their children among two groups: (i) families who were actually offered enrollment in the hepatocyte trial and; (ii) families whose children had liver transplants before the trial was available. We conducted semi-structured interviews about actual and hypothetical decision-making regarding trial participation and used grounded theory analysis to identify common themes. The most common motivator for participation was decline in the child's health. The most common deterrent was lack of data from prior hepatocyte transplants, particularly when compared with data available about liver transplant. Interviewees' point of comparison for evaluating relative benefits and risks of hepatocyte transplant oscillated between the alternative of doing nothing while waiting for a liver (the relevant alternative) vs. the alternative of getting a liver. These results suggest that families' reluctance to participate may result from misconceptions about severity of the child's disease, underestimating risks of liver transplant, or confusion about the role of hepatocyte transplant in the treatment pathway. Clarification of available treatment alternatives and associated risks as part of informed consent may improve the quality of decision-making regarding trial enrollment.

Parental comprehension of the benefits/risks of first-line randomised clinical trials in children with solid tumours: a two-stage cross-sectional interview study

OBJECTIVES

To analyse the parental understanding of informed consent information in first-line randomised clinical trials (RCTs) including children with malignant solid tumours and to assess parents' needs for decision-making.

DESIGN

Observational prospective study.

SETTING

3 paediatric oncology centres in the Parisian region in France.

PARTICIPANTS

53 parents were approached to participate in a RCT for their child with malignant solid tumour, over a 1-year period. 40 parents have been interviewed in our study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Parental understanding of information in RCTs, parents' needs for decision-making. Parents were questioned by a psychologist, independent of the paediatric oncology teams, using a semidirected interview, 1 (M1) and 6 months (M6) after the consent was sought.

RESULTS

18 parents (45%) did not understand the concept of randomisation. Half of the parents could explain neither the aim of the clinical trial nor the potential benefit to their child of inclusion. 35 parents (87.5%) expressed very few specific risks related to the trial. Being mostly French-speaking (p=0.03) and the reading of the information sheet by the parents (p=0.0025) improved their understanding. The parental comprehension did not differ between M1 and M6. The principal factors underlying their decision were confidence in the medical team (39%), wish to access to the best treatment (37%) and the best quality of life (37%).

CONCLUSIONS

Despite medical explanations, parents have limited knowledge in some areas in first-line RCTs and improvements of information process are required. The risks specific to the randomised trial are underestimated by parents and the unproven nature of the treatment is not well-known or understood.

Allergic rhinitis is associated with otitis media with effusion: a birth cohort study

BACKGROUND

Childhood otitis media with effusion is a common disease and a link to allergic diseases has been suggested.

OBJECTIVE

To investigate the association between atopic disease and otitis media with effusion diagnosed according to strict objective case definitions by age 6 years.

METHODS

We evaluated 291 children in the 6th year of life from the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) 2000 birth cohort. Otitis media with effusion was diagnosed based on tympanometric and objective evaluation. Asthma, eczema, allergic- and non-allergic rhinitis was diagnosed prospectively by pre-defined algorithms. Nasal mucosal swelling was assessed using acoustic rhinometry and nasal eosinophilia from scrapings. Analyses were performed using logistic regression and adjusted for dog, cat and smoking exposure, paternal atopy, household income, older siblings, gender and number of acute otitis media episodes.

RESULTS

Otitis media with effusion was diagnosed in 39% of the cohort and was associated with allergic rhinitis (aOR = 3.36, CI = 1.26-8.96, P = 0.02), but not with nasal mucosal swelling, nasal oeosinophilia, non-allergic rhinitis, asthma or eczema.

CONCLUSION

Otitis media with effusion is closely associated with allergic rhinitis presumably caused by allergic inflammation, but not mechanical nasal mucosal swelling. These findings warrant an increased awareness of otitis media with effusion in children with allergic rhinitis.

Parents' perceptions of their infants' participation in randomized controlled trials

OBJECTIVE

To explore parents' perceptions of their infants' participation in randomized control trials (RCTs) and the implications of the RCT for their infant and themselves.

DESIGN

A qualitative study using semistructured interviews.

SETTING

Participants were identified from neonatal intensive care unit (NICU) clinical registers and from responses to an advertisement put on the website of United Kingdom special care baby charity, BLISS. Interviews were conducted with parents face-to-face in their homes or over the telephone.

PARTICIPANTS

Sixteen parents of 12 infants born prematurely or with complications at full term and who had participated in one of three RCTs while receiving intensive care in one of seven NICUs.

METHODS

Interviews were audio-taped or digitally recorded, transcribed verbatim, and analyzed using systematic thematic analysis using WinMax qualitative software.

RESULTS

Five main themes emerged from the data. The themes were parents' immediate reactions to being approached about RCT enrollment, interactions between parents and clinicians upon the approach of enrollment and during the RCT, making the decision to enroll their infants, implications of the RCT for parents, and effects of the RCT on the infants.

CONCLUSIONS

Clinicians should be encouraged to approach parents about enrollment of their infants in clinical research given that parents reported mostly positive experiences related to this participation. However, appropriate measures should be taken to ensure that the individual needs of parents are being met throughout the entire research process from enrollment to follow-up.

Physical activity in young children is reduced with increasing bronchial responsiveness

BACKGROUND

Physical activity is essential for young children to develop adequately and for quality of life. It can be lower in children with subclinical asthma, and therefore methods to reveal subclinical reduction in physical activity in young children are warranted.

OBJECTIVE

We sought to study an association between physical activity in preschool children and objectively assessed intermediary asthma phenotypes.

METHODS

We studied 253 five-year-old children (127 girls) participating in the Copenhagen Prospective Studies on Asthma in Childhood. The main outcome measure was level of physical activity assessed objectively with accelerometers worn on an ankle for 4 weeks. Objective assessment of asthma intermediary phenotypes included prebronchodilator and postbronchodilator specific airway resistance, bronchial responsiveness to cold dry-air hyperventilation, and exhaled nitric oxide levels. Analyses were performed with generalized linear model and principal component analysis.

RESULTS

Physical activity was inversely associated with bronchial responsiveness (relative rate, 0.89; 95% CI, 0.83-0.95; P = .007) and significantly increased in the months of spring and summer (P < .001) and in boys (relative rate, 1.16; 95% CI, 1.09-1.25; P < .001). Physical activity was independent of asthma diagnosis, age, body mass index, baseline specific airway resistance, reversibility to beta(2)-agonist, sensitization, and exhaled nitric oxide level.

CONCLUSION

Physical activity in preschool children was reduced with increasing bronchial responsiveness. The reduced physical activity was subclinical and not realized by parents or doctors despite daily diary cards and close clinical follow-up since birth. This observation warrants awareness of even very mild asthma symptoms in clinical practice.

Seven-year-old children's perceptions of participating in a comprehensive clinical birth cohort study

While several studies have explored parents' perceptions of their children's participation in research, very few studies have described the children's own perceptions of their participation in research. The aim of this study was to describe children's perceptions of their participation in a comprehensive longitudinal clinical study. Semi-structured qualitative interviews were conducted with 17 children aged seven participating in the Copenhagen Prospective Study on Asthma in Childhood. The interviews were audiotaped, transcribed and analysed using the template analysis method. The children rated their experiences with venepunctures on a Wong-Baker faces scale. The regular visits to the hospital and comprehensive clinical tests did not seem to have affected the children negatively. In particular, the children would happily engage themselves in medical tests mimicking play (moving, walking, running or playing with a computer). A majority of the children, however, disapproved of the venepunctures and some even refused to have it done. The results of this study indicate that participation in even comprehensive paediatric research can be a positive experience to the participants, with the most popular tests being those that required active participation from the children.

How do parents experience being asked to enter a child in a randomised controlled trial?

Background

As the number of randomised controlled trials of medicines for children increases, it becomes progressively more important to understand the experiences of parents who are asked to enrol their child in a trial. This paper presents a narrative review of research evidence on parents' experiences of trial recruitment focussing on qualitative research, which allows them to articulate their views in their own words.

Discussion

Parents want to do their best for their children, and socially and legally their role is to care for and protect them yet the complexities of the medical and research context can challenge their fulfilment of this role. Parents are simultaneously responsible for their child and cherish this role yet they are dependent on others when their child becomes sick. They are keen to exercise responsibility for deciding to enter a child in a trial yet can be fearful of making the 'wrong' decision. They make judgements about the threat of the child's condition as well as the risks of the trial yet their interpretations often differ from those of medical and research experts. Individual parents will experience these and other complexities to a greater or lesser degree depending on their personal experiences and values, the medical situation of their child and the nature of the trial. Interactions at the time of trial recruitment offer scope for negotiating these complexities if practitioners have the flexibility to tailor discussions to the needs and situation of individual parents. In this way, parents may be helped to retain a sense that they have acted as good parents to their child whatever decision they make.

Summary

Discussing randomised controlled trials and gaining and providing informed consent is challenging. The unique position of parents in giving proxy consent for their child adds to this challenge. Recognition of the complexities parents face in making decisions about trials suggests lines for future research on the conduct of trials, and ultimately, may help improve the experience of trial recruitment for all parties.

Prenatal determinants of neonatal lung function in high-risk newborns

BACKGROUND

Neonatal lung function is suspected to be associated with wheezy disorders, but little is known about risk factors for the early lung function.

OBJECTIVES

To study prenatal determinants of neonatal lung function.

METHODS

This is a clinical, prospective birth cohort study of 411 newborns, the Copenhagen Prospective Study on Asthma in Childhood, in a single-center research clinic dedicated solely to this longitudinal birth cohort study. Lung function was determined at 1 month of age by infant spirometry (the raised volume rapid thoraco-abdominal compression technique) and bronchial responsiveness to methacholine by transcutaneous oxygen measurements. Risk factor analyses included anthropometrics; demographics; socioeconomic factors; parental atopic history; previous deliveries; exposures during the third trimester to the mother's smoking, alcohol, and medicines; third trimester pregnancy complications including mother's asthma status; and mode of delivery.

RESULTS

Lung function was determined in 404 neonates, age 6 weeks. Neonates with body mass index in the upper quartile had 14% lower baseline forced expiratory volume at 0.5 second, and neonates of mothers smoking during the third trimester had 7% lower baseline forced expiratory volume at 0.5 second. Sex or parental atopic disease did not affect the neonatal lung function and bronchial responsiveness. Maternal intake of paracetamol during the third trimester was associated with doubling of the bronchial responsiveness in the neonates, but the statistical significance may have been driven by outliers. Bronchial responsiveness exhibited a parabola development with tripling of bronchial responsiveness reaching the nadir at 3 months of age, but this needs replication in a study with repetitive measurements within individuals.

CONCLUSION

High body mass index in newborns and mothers smoking is associated with reduced neonatal lung function. This suggests that the association between body proportion and wheezing disorders may be a result of shared genes or prenatal nutrition.

Participation in environmental health research by placenta donation - a perception study

BACKGROUND

Much environmental health research depends on human volunteers participating with biological samples. The perception study explores why and how people participate in a placenta perfusion study in Copenhagen. The participation implies donation of the placenta after birth and some background information but no follow up.

METHODS

Nineteen semi-structured qualitative interviews were conducted with participants in the placenta perfusion study after donation of placenta. Observation studies were made of recruitment sessions.

RESULTS

The interviewed participants are generally in favour of medical research. They participated in the placenta perfusion study due to a belief that societal progress follows medical research. They also felt that participating was a way of giving something back to the Danish health care system. The participants have trust in medical science and scientists, but trust is something which needs to be created through "trust-work". Face-to-face interaction, written information material and informed consent forms play important parts in creating trusting relationships in medical research.

CONCLUSION

Medical research ethics do not only amount to specific types of written information material but should also be seen as a number of trust making performances involving researchers as well as research participants.

Feasibility of repetitive lung function measurements by raised volume rapid thoracoabdominal compression during methacholine challenge in young infants

BACKGROUND

The aim of the study was to evaluate the feasibility of lung function measurements by the raised volume rapid thoracoabdominal compression (RVRTC) technique during bronchial methacholine challenge in young infants.

METHOD

Four hundred two healthy infants were tested at 1 month of age with RVRTC during repeated methacholine challenges with quadrupling doses from 0.037 to 16.674 mumol.

RESULTS

Measurement of baseline lung function was successful in 99% and the provocative dose (PD) was achieved in 79% of infants by forced expiratory volume in 0.5 s (FEV(0.5)). Additionally, the PD was successfully measured in 87% by transcutaneous oxygen pressure. No serious adverse events were observed during testing or after discharge from the clinic. The methacholine dose range was appropriate as PD could be determined in the majority of infants. FEV(0.5) values in 21% of infants dropped > 40% during the test. Short-lasting, self-limiting episodes of hypoxemia of < 80% occurred in 1% of infants and bradycardia < 90 beats/min in 19% of infants. The most common observations by parents were changes in the patterns of sleeping (95%), eating (57%), and behavior (58%) of the infant after hospital discharge. The mean acceptability rating among parents was 8 on a scale from 1 to 10, with 13% rating < or = 5. It took one operator 3 h to complete the test, with the actual lung function testing accounting for half the time.

CONCLUSION

This very comprehensive experience with standardized measurements of lung function by RVRTC during methacholine challenge in young infants in a single center leads us to conclude that the test is feasible and safe to perform in asymptomatic young infants.