Expiratory airflow limitation in adults born extremely preterm: A systematic review and meta-analysis

Extreme preterm (EP) birth, denoting delivery before the onset of the third trimester, interrupts intrauterine development and causes significant early-life pulmonary trauma, thereby posing a lifelong risk to respiratory health. We conducted a systematic review and meta-analysis to investigate adult lung function following EP birth (gestational age <28 weeks); comparing forced expiratory volume in first second (FEV1), forced vital capacity (FVC), and FEV1/FVC to reference values. Subgroup differences were explored based on timing of birth relative to surfactant use (1991) and bronchopulmonary dysplasia (BPD) status. Systematic searches were performed in Medline, EMBASE, Web of Science and Cochrane Central. Quality assessments were carried out using a modified Newcastle-Ottawa Scale for cohort studies. Sixteen studies encompassing 1036 EP-born adults were included, with 14 studies (n = 787) reporting data as %predicted, and 11 (n = 879) as z-score (not mutually exclusive). Overall mean [95 % confidence interval (CI)] %FEV1 was 85.30 (82.51; 88.09), %FVC was 94.33 (91.74; 96.91), and FEV1/FVC was 79.54 (77.71 to 81.38), all three with high heterogeneity. Overall mean (95 %CI) zFEV1 was -1.05 (-1.21; -0.90) and zFVC was. -0.45 (-0.59; -0.31), both with moderate heterogeneity. Subgroup analyses revealed no difference in FEV1 before versus after widespread use of surfactant, but more impairments after neonatal BPD. This meta-analysis revealed significant airflow limitation in EP-born adults, mostly explained by those with neonatal BPD. FEV1 was more reduced than FVC, and FEV1/FVC was at the lower limit of normal. Although at a group level, most adult EP-born individuals do not meet COPD criteria, these findings are concerning.

Diagnosis of vocal cord dysfunction/inducible laryngeal obstruction: An International Delphi Consensus Study

BACKGROUND

Vocal cord dysfunction/inducible laryngeal obstruction (VCD/ILO) is characterized by breathing difficulties in association with excessive supraglottic or glottic laryngeal narrowing. The condition is common and can occur independently; however, it may also be comorbid with other disorders or mimic them. Presentations span multiple specialties and misdiagnosis or delayed diagnosis is commonplace. Group-consensus methods can efficiently generate internationally accepted diagnostic criteria and descriptions to increase clinical recognition, enhance clinical service availability, and catalyze research.

OBJECTIVES

We sought to establish consensus-based diagnostic criteria and methods for VCD/ILO.

METHODS

We performed a modified 2-round Delphi study between December 7, 2021, and March 14, 2022. The study was registered at ANZCTR (Australian New Zealand Clinical Trials Registry; ACTRN12621001520820p). In round 1, experts provided open-ended statements that were categorized, deduplicated, and amended for clarity. These were presented to experts for agreement ranking in round 2, with consensus defined as ≥70% agreement.

RESULTS

Both rounds were completed by 47 international experts. In round 1, 1102 qualitative responses were received. Of the 200 statements presented to experts across 2 rounds, 130 (65%) reached consensus. Results were discussed at 2 international subject-specific conferences in June 2022. Experts agreed on a diagnostic definition for VCD/ILO and endorsed the concept of VCD/ILO phenotypes and clinical descriptions. The panel agreed that laryngoscopy with provocation is the gold standard for diagnosis and that ≥50% laryngeal closure on inspiration or Maat grade ≥2 define abnormal laryngeal closure indicative of VCD/ILO.

CONCLUSIONS

This Delphi study reached consensus on multiple aspects of VCD/ILO diagnosis and can inform clinical practice and facilitate research.

Prevalence and impact of exercise-induced laryngeal obstruction in asthma: a study protocol for a cross-sectional and longitudinal study

INTRODUCTION

Exercise-induced laryngeal obstruction (EILO) and exercise-induced asthma can cause troublesome respiratory symptoms that can be difficult to distinguish between. Further, there is now a growing appreciation that the two conditions may coexist, complicating the interpretation of symptoms. The primary aim of this study is to investigate the prevalence of EILO in patients with asthma. Secondary aims include evaluation of EILO treatment effects and investigation of comorbid conditions other than EILO in patients with asthma.

METHODS AND ANALYSIS

The study will be conducted at Haukeland University Hospital and Voss Hospital in Western Norway, and enrol 80-120 patients with asthma and a control group of 40 patients without asthma. Recruitment started in November 2020, and data sampling will continue until March 2024. Laryngeal function will be assessed at baseline and at a 1-year follow-up, using continuous laryngoscopy during high-intensity exercise (CLE). Immediately after the EILO diagnosis is verified, patients will be treated with standardised breathing advice guided by visual biofeedback from the laryngoscope video screen. The primary outcome will be the prevalence of EILO in patients with asthma and control participants. Secondary outcomes include changes in CLE scores, asthma-related quality of life, asthma control and number of the asthma exacerbations, as assessed between baseline and the 1-year follow-up.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Regional Committee for Medical and Health Research Ethics, Western Norway, (ID number 97615). All participants will provide signed informed consent before enrolment. The results will be presented in international journals and conferences.

TRIAL REGISTRATION NUMBER

NCT04593394.

Use of inhaled ipratropium bromide to improve exercise-induced laryngeal obstruction cannot be recommended

Introduction

Exercise-induced laryngeal obstruction (EILO) is a common cause of exertional breathing problems in young adults. Current management generally consists of breathing advice, speech therapy, inspiratory muscle training or supraglottoplasty in highly motivated subjects with supraglottic collapse. Inhaled ipratropium bromide (IB) is a muscarinic receptor antagonist used to treat asthma that is suggested in a few reports to improve EILO symptoms. The aim of the present study was to investigate effects of inhaled IB in EILO diagnosed by continuous laryngoscopy exercise (CLE) test and classified by CLE scores.

Methods

A randomised crossover trial was conducted at Haukeland University Hospital, Bergen, Norway, enrolling participants diagnosed with EILO defined by characteristic symptoms and CLE score ≥3 (range 0-12). Two consecutive CLE tests were performed within 2 weeks, one test with and one test without prior administration of inhaled IB in a randomised order. Main outcomes were the CLE score, dyspnoea measured using a modified BORG scale (range 0-10) and cardiopulmonary exercise data provided by the CLE test.

Results

20 participants (14 females) aged 12-25 years participated, and all ran to exhaustion on both tests. Mean CLE score, BORG score and peak oxygen consumption were similar in tests performed with and without IB; mean differences (95% confidence interval) were 0.08 (-0.28-0.43), 0.35 (-0.29-0.99) and -0.4 (-1.9-1.1) mL·kg^-1·min^-1, respectively.

Conclusion

Inhaled IB did not improve CLE score, dyspnoea or exercise capacity in subjects with EILO. The study does not support the use of inhaled IB to treat EILO.

Adjustments of non-invasive ventilation and mechanically assisted cough by combining ultrasound imaging of the larynx with transnasal fibre-optic laryngoscopy: a protocol for an experimental study

INTRODUCTION

Application of non-invasive positive airway pressure may provoke laryngeal responses that obstruct the airways, especially in patients with disturbed laryngeal control. To control and adjust for this, transnasal fibre-optic laryngoscopy (TFL) is used to visualise laryngeal movements during therapeutic interventions. Being an invasive procedure, this may be unpleasant for patients. The aim of this study is to evaluate if ultrasound (US) imaging of the larynx may be used as an alternative less invasive diagnostic tool for evaluating the upper airway responses to non-invasive ventilation (NIV) and mechanical insufflation-exsufflation (MI-E).

METHODS AND ANALYSIS

This protocol presents an experimental cross-sectional study of a novel method to study laryngeal responses in adult healthy volunteers (n=30). The participants will be assessed with simultaneous TFL and laryngeal US imaging (anterior and lateral approaches) during NIV and MI-E therapy. Additionally, airflow and pressure signals will be registered during the procedures. The primary outcome is whether laryngeal US is a feasible method to study laryngeal responses and, if so, to compare the laryngeal responses visualised with TFL and US. The participants' perception of the examinations will be recorded. Secondary outcomes include airflow curve shapes and calculated ventilation volumes during the interventions.

ETHICS AND DISSEMINATION

The study has been approved by The Regional Committee for Medical Research Ethics in Norway, and registered in ClinicalTrials.gov. Results will be disseminated through peer-reviewed journals, presentation of scientific abstracts at international medical conventions and oral presentations in relevant medical conventions.

TRIAL REGISTRATION NUMBER

NCT04586855.

Tracking of lung function from 10 to 35 years after being born extremely preterm or with extremely low birth weight

Background

Lifelong pulmonary consequences of being born extremely preterm or with extremely low birth weight remain unknown. We aimed to describe lung function trajectories from 10 to 35 years of age for individuals born extremely preterm, and address potential cohort effects over a period that encompassed major changes in perinatal care.

Methods

We performed repeated spirometry in three population-based cohorts born at gestational age ≤28 weeks or with birth weight ≤1000 g during 1982–85, 1991–92 and 1999–2000, referred to as extremely preterm-born, and in term-born controls matched for age and gender. Examinations were performed at 10, 18, 25 and 35 years. Longitudinal data were analysed using mixed models regression, with the extremely preterm-born stratified by bronchopulmonary dysplasia (BPD).

Results

We recruited 148/174 (85%) eligible extremely preterm-born and 138 term-born. Compared with term-born, the extremely preterm-born had lower z-scores for forced expiratory volume in 1 s (FEV₁) at most assessments, the main exceptions were in the groups without BPD in the two youngest cohorts. FEV₁ trajectories were largely parallel for the extremely preterm- and term-born, also during the period 25–35 years that includes the onset of the age-related decline in lung function. Extremely preterm-born had lower peak lung function than term-born, but z-FEV₁ values improved for each consecutive decade of birth (p=0.009). More extremely preterm—than term-born fulfilled the spirometry criteria for chronic obstructive pulmonary disease, 44/148 (30%) vs 7/138 (5%), p<0.001.

Conclusions

Lung function after extremely preterm birth tracked in parallel, but significantly below the trajectories of term-born from 10 to 35 years, including the incipient age-related decline from 25 to 35 years. The deficits versus term-born decreased with each decade of birth from 1980 to 2000.

Conundrums in the breathless athlete; exercise induced laryngeal obstruction or asthma?

PURPOSE

Exercise-induced bronchoconstriction (EIB) and exercise-induced laryngeal obstruction (EILO) are two disorders commonly considered when athletes complain of exertional dyspnea. They are highly different but often confused. We aimed to address this diagnostic challenge and its consequences in elite athletes.

METHODS

We included all athletes competing at national or international level, referred to our institution for workup for EILO during 2013-2016. We diagnosed EILO from video-recorded laryngoscopy performed during maximal cardiopulmonary treadmill exercise (CLE-test). Symptoms and previous diagnostic evaluations were obtained from referral letters and chart reviews.

RESULTS

EILO was diagnosed in 73/101 referred athletes, of whom 70/73 had moderate/severe supraglottic obstruction and 3/73 had primarily glottic obstruction with only minor supraglottic involvement. Of the 73 athletes with EILO, we were able to identify objective tests for asthma in 55 participants, of whom 22 had findings supporting asthma. However, 58/73 had used asthma therapy at some time previously, with current use in 28. Only three reported that asthma medication had improved their exercise related breathing problems, two of whom with tests confirming asthma. Treatment for EILO improved breathing problems in all but four.

CONCLUSIONS

Objective testing verified EILO in most of the referred athletes. EILO coexisting with asthma was common, and large proportions had used asthma medication; however, few reported effect on exercise related breathing problems. Unexplained persistent exertional dyspnoea must not lead to indiscriminate escalation of asthma treatment, but instead incite investigation for EILO, either as a co-morbidity or as a differential diagnosis.

Clinical responses following inspiratory muscle training in exercise-induced laryngeal obstruction

Purpose

Exercise-induced laryngeal obstruction (EILO) is relatively common in young people. Treatment rests on poor evidence; however, inspiratory muscle training (IMT) has been proposed a promising strategy. We aimed to assess laryngeal outcomes shortly after IMT, and to compare self-reported symptoms with a control group 4–6 years later.

Methods

Two groups were retrospectively identified from the EILO-register at Haukeland University Hospital, Norway; one group had received only information and breathing advice (IBA), and another additionally IMT (IBA + IMT). At diagnosis, all participants performed continuous laryngoscopy during exercise (CLE), with findings split by glottic and supraglottic scores, and completed a questionnaire mapping exercise-related symptoms. After 2–4 weeks, the IBA + IMT-group was re-evaluated with CLE-test. After 4–6 years, both groups were re-assessed with a questionnaire.

Results

We identified 116 eligible patients from the EILO-register. Response rates after 4–6 years were 23/58 (40%) and 32/58 (55%) in the IBA and IBA + IMT-group, respectively. At diagnosis, both groups rated symptoms similarly, but laryngeal scores were higher in the IBA + IMT-group (P = 0.003). After 2–4 weeks, 23/32 in the IBA + IMT-group reported symptom improvements, associated with a decrease of mainly glottic scores (1.7–0.3; P < 0.001), contrasting unchanged scores in the 9/32 without symptom improvements. After 4–6 years, exercise-related symptoms and activity levels had decreased to similar levels in both groups, with no added benefit from IMT; however, full symptom resolution was reported by only 8/55 participants.

Conclusion

Self-reported EILO symptoms had improved after 4–6 years, irrespective of initial treatment. Full symptom resolution was rare, suggesting individual follow-up should be offered.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00405-021-07214-5.

Exercise Training in Duchenne Muscular Dystrophy: A Systematic Review and Meta-Analysis

Objective: To evaluate the effects and safety of exercise training, and to determine the optimal [AQ7] exercise training intervention for people with Duchenne muscular dystrophy. Exercise training was compared with no training, placebo or alternative exercise training. Primary outcomes were functioning and health-related quality of life. Secondary outcomes were muscular strength, endurance and lung function.  Data sources: A systematic literature search was conducted in Medline, EMBASE, CINAHL, Cochrane Central, PEDro and Scopus.  Study selection and data extraction: Screening, data extraction, risk of bias and quality assessment were carried out. Risk of bias was assessed using the Cochrane Collaborations risk of bias tools. The certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation. Data synthesis: Twelve studies with 282 participants were included. A narrative synthesis showed limited or no improvements in functioning compared with controls. Health-related quality of life was assessed in only 1 study. A meta-analysis showed a significant difference in muscular strength and endurance in favour of exercise training compared with no training and placebo. However, the certainty of evidence was very low. Conclusion: Exercise training may be beneficial in Duchenne muscular dystrophy, but the evidence remains uncertain. Further research is needed on exercise training to promote functioning and health-related quality of life in Duchenne muscular dystrophy.

Breathing patterns in people with exercise-induced laryngeal obstruction

Exercise-induced laryngeal obstruction (EILO) is common, but we lack readily available diagnostic tools. The larynx represents an important point of resistance in the airways, and we therefore hypothesized that EILO is associated with characteristic breathing patterns possible to record from a standard incremental ergospirometry test. We studied 24 individuals with moderate/severe EILO and 20 individuals with no-EILO, mean (SD) age 17 (6.1) and 24 (6.4) years, respectively. EILO versus no-EILO was verified from maximal continuous laryngoscopy treadmill exercise (CLE) tests, which also included ergospirometry. We described the relationships between minute ventilation ( V ˙ E ) versus tidal volume (VT ) and V ˙ E versus carbon dioxide output ( V ˙ CO 2 ), using respectively quadratic and linear equations, and applied adjusted regression models to compare ergospirometry data and curve parameters. Compared to the no-EILO group, the group with EILO had prolonged inspiratory time (Tin ), lower breathing frequency (Bf ), lower V ˙ E , and lower inspiratory flow rate ( V ˙ in ) at peak exercise. Mathematical modeling of the breathing pattern relationships was feasible in both groups, with similar coefficients of variation. For V ˙ E versus VT , the mathematical curve parameters were similar. For V ˙ E versus V ˙ CO 2 , the slope was similar but the intercept was lower in the EILO group. EILO was associated with prolonged Tin , lower Bf , V ˙ E , and V ˙ E . The relationship between V ˙ E versus VT was similar, whereas for V ˙ E versus V ˙ CO 2 , the slope was almost parallel but shifted downward for the EILO group. Most ergospirometry data overlapped, except V ˙ in which discriminated between EILO and no-EILO in a promising way.

Upper Airway Assessment and Responses During Mechanically Assisted Cough

When the ability to cough is impaired, secretion clearance may be assisted and augmented with mechanical insufflation-exsufflation (MI-E). In some individuals, the efficacy of MI-E may be hampered by counterproductive upper airway reactions, where the airways close in response to positive pressures. To fully utilize the therapeutic potential inherent in the MI-E technology, we need a better understanding of the pathophysiology behind these untoward reactions. There is increasing interest in monitoring and measuring upper airway responses to MI-E and how such information can be used to optimize MI-E settings. The purpose of this narrative review is to increase the theoretical understanding of the larynx as a respiratory organ, summarize the current literature in the area, and provide insight into how this knowledge can affect current clinical practice.

Reliability of maximum oxygen uptake in cardiopulmonary exercise testing with continuous laryngoscopy

Aims

A cardiopulmonary exercise test (CPET) is the gold standard to evaluate symptom-limiting exercise intolerance, while continuous laryngoscopy performed during exercise (CLE) is required to diagnose exercise-induced laryngeal obstruction. Combining CPET with CLE would save time and resources; however, the CPET data may be distorted by the extra equipment. We therefore aimed to study whether CPET with CLE influences peak oxygen uptake (V′_O2peak) and other gas exchange parameters when compared to a regular CPET.

Methods

Forty healthy athletes without exercise-related breathing problems, 15–35 years of age, performed CPET to peak exercise with and without an added CLE set-up, in randomised order 2–4 days apart, applying an identical computerised treadmill protocol.

Results

At peak exercise, the mean difference (95% confidence interval) between CPET with and without extra CLE set-up for V′_O2peak, respiratory exchange ratio (RER), minute ventilation (V′_E) and heart rate (HR) was 0.2 (−0.4 to 0.8) mL·kg⁻¹·min⁻¹, 0.01(−0.007 to 0.027) units, 2.6 (−1.3 to 6.5) L·min⁻¹ and 1.4 (−0.8 to 3.5) beats·min⁻¹, respectively. Agreement (95% limits of agreement) for V′_O2peak, RER and V′_E was 0.2 (±3.7) mL·kg⁻¹·min⁻¹, 0.01 (±0.10) units and 2.6 (±24.0) L·min⁻¹, respectively. No systematic or proportional bias was found except for the completed distance, which was 49 m (95% CI 16 to 82 m) longer during CPET.

Conclusion

Parameters of gas exchange, including V′_O2peak and RER, obtained from a maximal CPET performed with the extra CLE set-up can be used interchangeably with data obtained from standard CPET, thus preventing unnecessary additional testing.

Cardiopulmonary exercise testing (CPET) with concurrent continuous laryngoscopy provides reliable measures for maximal oxygen consumption and other CPET datahttps://bit.ly/36wVJhb

Exercise Related Respiratory Problems in the Young-Is It Exercise-Induced Bronchoconstriction or Laryngeal Obstruction?

Complaints of breathlessness during heavy exercise is common in children and adolescents, and represent expressions of a subjective feeling that may be difficult to verify and to link with specific diagnoses through objective tests. Exercise-induced asthma and exercise-induced laryngeal obstruction are two common medical causes of breathing difficulities in children and adolescents that can be challenging to distinguish between, based only on the complaints presented by patients. However, by applying a systematic clinical approach that includes rational use of tests, both conditions can usually be diagnosed reliably. In this invited mini-review, we suggest an approach we find feasible in our everyday clinical work.

Predicting physical activity in a national cohort of children born extremely preterm

Predicting physical activity in a national cohort of children born extremely preterm.

OBJECTIVES

To compare physical activity among school-aged children born extremely preterm or with extremely low birthweight (EP/ELBW) to term-born children, and to identify early predictors for physical inactivity in the EP/ELBW-children.

METHODS

A national cohort born during 1999-2000 at gestational age < 28 weeks or birthweight <1000 g and term-born controls were assessed. EP/ELBW-children without neurodevelopmental disabilities were labeled "healthy". At five years, we examined the EP/ELBW-children's motor, mental and intellectual functioning using the Movement Assessment Battery for Children (MABC), The Strength and Difficulties Questionnaire (SDQ) and The Wechsler Preschool and Primary Scale of Intelligence-revised. At 11 years, the parents reported their children's physical activity (PA) in questionnaires.

RESULTS

Information was obtained from 231/372 EP/ELBW and 57/61 term-born children. At 11 years, EP/ELBW-children had fewer exercise events per week, were less engaged in team sports, had lower endurance, lower sports proficiency, and were less vigorous during PA than term-born children (p < 0.05). Low sports proficiency in the healthy EP/ELBW-children at 11 years was predicted (odds ratio; 95% confidence interval) by abnormal MABC-score (3.0; 1.0 to 8.7), and abnormal SDQ-score (4.0; 1.6 to 10.0) at 5 years. Lower endurance at PA was predicted by abnormal MABC-score (2.6; 1.0 to 6.6), abnormal SDQ-score (3.0; 1.4 to 6.5), and borderline intellectual functioning (4.2; 1.8 to 10.1).

CONCLUSIONS

Eleven-year-old EP/ELBW-children were less physically active than term-born. In healthy EP/ELBW-children, impaired motor coordination, borderline intellectual functioning and behavioral problems at 5 years of age predicted unfavorable PA habits at 11 years.

Severe Exercise-Induced Laryngeal Obstruction Treated With Supraglottoplasty

Introduction: Exercise induced laryngeal obstruction (EILO) is relatively common in adolescents, with symptoms often confused with exercise induced asthma. EILO often starts with medial or inward rotation of supraglottic structures of the larynx, whereas glottic adduction appears as a secondary phenomenon in a majority. Therefore, surgical treatment (supraglottoplasty) is used in thoroughly selected and highly motivated patients with pronounced symptoms and severe supraglottic collapse.

Aim: To investigate efficacy and safety of laser supraglottoplasty as treatment for severe supraglottic EILO by retrospective chart reviews.

Methods: The EILO register at Haukeland University Hospital, Bergen, Norway was used to identify patients who had undergone laser supraglottoplasty for severe supraglottic EILO, verified by continuous laryngoscopy exercise (CLE) test, during 2013–2015. Laser incision in both aryepiglottic folds anterior to the cuneiform tubercles and removal of the mucosa around the top was performed in general anesthesia. Outcomes were questionnaire based self-reported symptoms, and laryngeal obstruction scored according to a defined scheme during a CLE-test performed before and after surgery.

Results: Forty-five of 65 eligible patients, mean age 15.9 years, were included. Post-operatively, 38/45 (84%) patients reported less symptoms, whereas CLE-test scores had improved in all, of whom 16/45 (36%) had no signs of obstruction. Most improvements were at the supraglottic level, but 21/45 (47%) also improved at the glottic level. Two of 65 patients had complications; self-limiting vocal fold paresis and scarring/shortening of plica ary-epiglottica.

Conclusion: Supraglottoplasty improves symptoms and decreases laryngeal obstruction in patients with severe supraglottic EILO, and appears safe in highly selected cases.

Physiotherapy improves symptoms of exercise-induced laryngeal obstruction in young elite athletes: a case series

OBJECTIVE

A constricted, upper chest breathing pattern and postural dealignments habitually accompany exercise-induced laryngeal obstruction (EILO), but there are few effective treatments for athletes presenting with EILO. This case series was conducted to examine whether physiotherapy based on principles from the Norwegian psychomotor physiotherapy (NPMP) combined with elements of cognitive behavioural therapy can reduce laryngeal distress in athletes with EILO.

METHODS

Respiratory distress in four subjects was examined by interview prior to a physiotherapeutic body examination. Inappropriate laryngeal movements during exercise were measured by the continuous laryngoscopy exercise test, lung function was measured by flow-volume curves, and non-specific bronchial hyper-responsiveness was measured by a methacholine provocation test. History of asthma, allergy and respiratory symptoms was recorded in a modified AQUA2008 questionnaire. Parasympathetic activity was assessed by pupillometry. All data were gathered before and after 5 months of intervention.

RESULTS

Physiotherapy based on the principles from NPMP improved breathing problems in athletes with EILO. All athletes had less respiratory distress, improved lung function at rest and reduced inappropriate laryngeal movements during maximal exercise.

CONCLUSION

A diaphragmatic breathing pattern, a more balanced tension in respiratory muscles, and sound cervical alignment and stability may help to reduce adverse stress on the respiratory system and optimise the function of the larynx during high-intensity exercise. Our results suggest that understanding and management of EILO need to extend beyond structures located in the anterior neck and include factors influencing the whole respiratory system.

Exercise-induced laryngeal obstruction in athletes treated with inspiratory muscle training

Background

Exercise-induced laryngeal obstruction (EILO) is common in athletes and presents with dyspnoea, chest tightness, inspiratory stridor and sometimes panic reactions. The evidence for conservative treatment is weak, but case reports suggest effects from inspiratory muscle training (IMT). We aimed to explore effects from IMT used in athletes with EILO.

Method

Twenty-eight athletes, mean age 16.4 years, diagnosed with EILO at our clinic, participated in a 6-week treatment programme, using a resistive flow-dependent IMT device (Respifit S). Four athletes competed at international level, 13 at national and 11 at regional levels. Video-recorded continuous transnasal flexible laryngoscopy was performed from rest to peak exercise (continuous laryngoscopy exercise (CLE) test) and scored before and 2–4 weeks after the training period. Ergospirometric variables were obtained from this CLE set-up. Lung function was measured according to guidelines. Symptom scores and demographic variables were obtained from a questionnaire.

Results

After the treatment period, symptoms had decreased in 22/28 (79%) participants. Mean overall CLE score had improved after treatment (p<0.001), with the scores becoming normal in five athletes but worse in two. Most of the improvement was explained by changes at the glottic laryngeal level (p=0.009). Ergospirometric variables revealed significantly higher peak minute ventilation explained by higher tidal volumes and were otherwise unchanged.

Conclusion

This explorative study underlines the heterogeneous treatment response of EILO and suggests that IMT may become an efficient conservative treatment tool in subgroups, possibly contributing to better control of the vocal folds. The signals from this study should be tested in future controlled interventional studies.

Left vocal cord paralysis after patent ductus arteriosus ligation: A systematic review

CONTEXT

Extremely premature (EP) infants are at increased risk of left vocal cord paralysis (LVCP) following surgery for patent ductus arteriosus (PDA).

OBJECTIVE

A Systematical Review was conducted to investigate the incidence and outcomes of LVCP after PDA ligation in EP born infants.

DATA SOURCES

Searches were performed in Cochrane, Medline, Embase, Cinahl and PsycInfo.

STUDY SELECTION

Studies describing EP infants undergoing PDA surgery and reporting incidence of LVCP were included.

DATA EXTRACTION AND SYNTHESIS

Study details, demographics, incidence of LVCP, diagnostic method and reported outcomes were extracted. DerSimonian and Laird random effect models with inverse variance weighting were used for all analyses.

STUDY APPRAISAL

The Newcastle-Ottawa scale for observational studies was used for quality assessment.

RESULTS

21 publications including 2067 infants were studied. The overall pooled summary estimate of LVCP incidence was 9.0% (95% CI 5.0, 15.0). However, the pooled incidence increased to 32% when only infants examined with laryngoscopy were included. The overall risk ratio for negative outcomes was higher in the LVCP group (2.20, 95% CI 1.69, 2.88, p = 0.01) compared to the non-LVCP-group.

CONCLUSIONS

Reported incidence of LVCP varies widely. This may be explained by differences in study designs and lack of routine vocal cords postoperative assessment. LVCP is associated with negative outcomes in EP infants. The understanding of long-term outcomes is scarce. Routine laryngoscopy may be necessary to identify all cases of LVCP, and to provide correct handling for infants with LVCP.

Working Towards a Common Transatlantic Approach for Evaluation of Exercise-Induced Laryngeal Obstruction

Exertional dyspnea can be a manifestation of dysfunction in a variety of organ systems. Exercise-induced laryngeal obstruction (EILO), a condition previously known as vocal cord dysfunction and paradoxic vocal fold motion, is defined as inappropriate, reversible narrowing of the larynx during vigorous exercise. EILO is usually characterized by typical symptoms, which nevertheless frequently are confused with those of other conditions, including asthma. Laryngoscopy performed as symptoms evolve from rest to peak exercise is pivotal in patient work-up. Moving forward, laryngoscopy findings that definitively characterize EILO need to be defined as do objective measures that can quantitate absolute laryngeal measurements during exercise.

Mid-childhood outcomes after pre-viable preterm premature rupture of membranes

OBJECTIVES

Investigate cardiorespiratory outcomes in children surviving previable preterm premature rupture of membranes (PV-PPROM) before 22 weeks' gestational age (GA) with minimum 2 weeks latency.

STUDY DESIGN

Single institution, follow-up of retrospectively identified children who were born after PV-PPROM during 2000-2004, and individually matched preterm-born controls.

RESULTS

Eleven PV-PPROM and matched control children were included at mean age of 10.5 and 10.7 years. Rupture of membranes occurred at mean GA 18² and 27⁶ weeks and birth at 28³ and 28⁶ weeks, respectively. Compared to controls, the PV-PPROM group had significantly poorer lung function, findings on echocardiography indicating mild pulmonary hypertension, and lower peak oxygen consumption. Chart reviews suggested more motor difficulties and a tendency towards more problems with learning and attention.

CONCLUSION

The findings highlight a preterm-born sub-group in need of targeted long-term monitoring and possibly interventions regarding future cardiorespiratory and neurodevelopmental function.

Laryngeal response patterns influence the efficacy of mechanical assisted cough in amyotrophic lateral sclerosis

BACKGROUND

Most patients with amyotrophic lateral sclerosis (ALS) are treated with mechanical insufflation-exsufflation (MI-E) in order to improve cough. This method often fails in ALS with bulbar involvement, allegedly due to upper-airway malfunction. We have studied this phenomenon in detail with laryngoscopy to unravel information that could lead to better treatment.

METHODS

We conducted a cross-sectional study of 20 patients with ALS and 20 healthy age-matched and sex-matched volunteers. We used video-recorded flexible transnasal fibre-optic laryngoscopy during MI-E undertaken according to a standardised protocol, applying pressures of ±20 to ±50 cm H₂O. Laryngeal movements were assessed from video files. ALS type and characteristics of upper and lower motor neuron symptoms were determined.

RESULTS

At the supraglottic level, all patients with ALS and bulbar symptoms (n=14) adducted their laryngeal structures during insufflation. At the glottic level, initial abduction followed by subsequent adduction was observed in all patients with ALS during insufflation and exsufflation. Hypopharyngeal constriction during exsufflation was observed in all subjects, most prominently in patients with ALS and bulbar symptoms. Healthy subjects and patients with ALS and no bulbar symptoms (n=6) coordinated their cough well during MI-E.

CONCLUSIONS

Laryngoscopy during ongoing MI-E in patients with ALS and bulbar symptoms revealed laryngeal adduction especially during insufflation but also during exsufflation, thereby severely compromising the size of the laryngeal inlet in some patients. Individually customised settings can prevent this and thereby improve and extend the use of non-invasive MI-E.

Congenital laryngomalacia is related to exercise-induced laryngeal obstruction in adolescence

OBJECTIVES

Congenital laryngomalacia (CLM) is the major cause of stridor in infants. Most cases are expected to resolve before 2 years of age, but long-term respiratory prospects are poorly described. We aimed to investigate if CLM was associated with altered laryngeal structure or function in later life.

METHODS

Twenty of 23 (87%) infants hospitalised at Haukeland University Hospital during 1990-2000 for CLM without comorbidities and matched controls were assessed at mean age 13 years. Past and current respiratory morbidity was recorded in a questionnaire, and spirometry performed according to standard quality criteria. Laryngoscopy was performed at rest and continuously throughout a maximal treadmill exercise test (continuous laryngoscopy exercise test (CLE-test)), and scored and classified in a blinded fashion according to preset criteria.

RESULTS

In the CLM group, laryngeal anatomy supporting CLM in infancy was described at rest in nine (45%) adolescents. Eleven (55%) reported breathing difficulties in relation to exercise, of whom 7 had similarities to CLM at rest and 10 had supraglottic obstruction during CLE-test. Overall, 6/20 had symptoms during exercise and similarities to CLM at rest and obstruction during CLE-test. In the control group, one adolescent reported breathing difficulty during exercise and two had laryngeal obstruction during CLE-test. The two groups differed significantly from each other regarding laryngoscopy scores, obtained at rest and during exercise (p=0.001 or less).

CONCLUSIONS

CLM had left footprints that increased the risk of later exercise-induced symptoms and laryngeal obstruction. The findings underline the heterogeneity of childhood respiratory disease and the importance of considering early life factors.

Lung function after preterm birth: development from mid-childhood to adulthood

BACKGROUND

As a result of advances in perinatal care, more small preterm infants survive. There are concerns that preterm birth and its treatments may harm pulmonary development and thereby lead to chronic airway obstruction in adulthood.

OBJECTIVE

To assess the development of spirometric lung function variables from mid-childhood to adulthood after extreme preterm birth.

METHODS

Two population-based cohorts born at gestational age ≤28 weeks or with birth weight ≤1000 g performed lung function tests at 10 and 18 and at 18 and 25 years of age, respectively, together with matched term-born controls. The results are presented as z scores, normalised for age, sex and height. Longitudinal development was compared for groups born at term and preterm, split by a history of absence (n=20), mild (n=38) or moderate/severe (n=25) neonatal bronchopulmonary dysplasia (BPD).

RESULTS

The preterm-born cohorts, particularly those with neonatal BPD, had significantly lower forced expiratory volume in 1 s and mid-expiratory flow than those born at term at all assessments (z scores in the range -0.40 to -1.84). Within each of the subgroups the mean z scores obtained over the study period were largely similar, coefficients of determination ranging from 0.64 to 0.82. The pattern of development for the BPD subgroups did not differ from each other or from the groups born at term (tests of interaction).

CONCLUSIONS

Airway obstruction was present from mid-childhood to adulthood after extreme preterm birth, most evident after neonatal BPD. Lung function indices were tracking similarly in the preterm and term-born groups.

Exercise-induced laryngeal obstruction: natural history and effect of surgical treatment

The current follow-up study concerning the supraglottic type of exercise-induced laryngeal obstruction (EILO) was performed to reveal the natural history of supraglottic EILO and compare the symptoms, as well as the laryngeal function in conservatively versus surgically treated patients. A questionnaire-based survey was conducted 2-5 years after EILO was diagnosed by a continuous laryngoscopy exercise (CLE) test in 94 patients with a predominantly supraglottic obstruction. Seventy-one patients had been treated conservatively and 23 with laser supraglottoplasty. The questionnaire response rate was 70 and 100% in conservatively treated (CT) and surgically treated (ST) patients, respectively. A second CLE test was performed in 14 CT and 19 ST patients. A visual analogue scale on symptom severity indicated improvements in both the groups, i.e. mean values (± standard deviations) declined from 73 (20) to 53 (26) (P < 0.001) in the CT group and from 87 (26) to 25 (27) (P < 0.001) in the ST group. At follow-up, ST patients reported lower scores regarding current level of complaints, and higher ability to perform exercise, as well as to push themselves physically, all compared to CT patients (P < 0.001). CLE scores were normalized in 3 of 14 (21%) CT and 16 of 19 (84%) ST patients (Z = -3.6; P < 0.001). In conclusion, symptoms of EILO diagnosed in adolescents generally decreased during 2-5 years follow-up period but even more after the surgical treatment. Patients with supraglottic EILO may benefit from supraglottoplasty both as to laryngeal function and symptom relief.

Left vocal cord paralysis after extreme preterm birth, a new clinical scenario in adults

OBJECTIVE

The goal was to study the incidence and long-term consequences of left vocal cord paralysis (LVCP) after neonatal surgical treatment of patent ductus arteriosus (PDA) in a population-based cohort of adults who were born at gestational ages of ≤28 weeks or with birth weights of ≤1000 g in western Norway.

METHODS

Subjects with a history of neonatal PDA surgery were examined with transnasal flexible laryngoscopy, and those with LVCP were examined with continuous laryngoscopy during maximal treadmill exercise (continuous laryngoscopy exercise testing). All subjects underwent lung function testing, ergospirometry, and pulmonary high-resolution computed tomography. Symptoms were recorded with a questionnaire.

RESULTS

Forty-four (86%) of 51 eligible preterm infants participated in the study, 13 (26%) had a history of PDA surgery and 7 (54%) had LVCP, with the laryngeal appearances varying slightly. As a group, subjects with LVCP had significant airway obstruction, no decreases in aerobic capacity, and no obvious evidence of longstanding aspiration on high-resolution computed tomography scans. The continuous laryngoscopy exercise tests revealed increasing respiratory symptoms in parallel with increasing anteromedial collapse of the left aryepiglottic folds as the exercise load increased. Hoarseness and voice-related symptoms were the most typical complaints. Symptoms were attributed erroneously to other diseases for at least 2 subjects.

CONCLUSIONS

LVCP is not uncommon in young adults exposed to PDA surgery as preterm infants. The condition may be overlooked easily, and symptoms may be confused with those of other diseases. Laryngoscopy should be offered on the basis of liberal indications after PDA ligation.

Exercise induced dyspnea in the young. Larynx as the bottleneck of the airways

BACKGROUND

Exercise induced asthma may symptomatically be difficult to differentiate from exercise related obstruction in the upper airways, sometimes leading to diagnostic confusion and inappropriate treatment. Larynx accounts for a significant fraction of total airway resistance, but its role as a limiting factor for airflow during exercise has been hampered by lack of diagnostic tools. We aimed to study laryngeal function in exercising humans by transnasal laryngoscopy.

METHODS

Continuous video recording of the larynx was performed in parallel with continuous film recording of the upper part of the body and recording of breath sounds in subjects running to respiratory distress or exhaustion on a treadmill.

RESULTS

A successful examination was obtained in 20 asymptomatic volunteers and 151 (91%) of 166 young patients with a history of inspiratory distress or stridor during exercise. At rest, six patients had abnormal laryngeal findings. During exercise, a moderate or severe adduction of laryngeal structures was observed in parallel with increasing inspiratory distress in 113 (75%) patients. In 109 of these, adduction started within supraglottic structures, followed by adduction of the vocal cords in 88. In four patients, laryngeal adduction started in the vocal cords, involving supraglottic structures secondarily in three.

CONCLUSION

Larynx can safely be studied throughout a maximum intensity exercise treadmill test. A characteristic laryngeal response pattern to exercise was visualised in a large proportion of patients with suspected upper airway obstruction. Laryngoscopy during ongoing symptoms is recommended for proper assessment of these patients.

Better care of immature infants; has it influenced long-term pulmonary outcome?

AIMS

To assess whether lung function in late childhood had improved in subjects born extremely prematurely in the early 1990s compared to the early 1980s, and whether neonatal factors in the respective periods had different impact on long-term pulmonary outcome.

DESIGN

Population-based, controlled cohort study. Lung function was determined in 81 of 86 (94%) eligible subjects born with gestational age < or =28 weeks or birthweight < or =1000 g in Western Norway in 1982-85 (n=46) and 1991-92 (n=35), and in 81 matched control subjects born at term.

RESULTS

The incidence of bronchopulmonary dysplasia was similar in the two periods. At follow-up, airway obstruction, hyper-responsiveness and pulmonary hyperinflation were similarly increased in both preterm cohorts compared to matched controls. Furthermore, current lung function was similarly related to neonatal respiratory disease in both birth-cohorts: FEV1 was reduced with respectively 18.6% and 18.7% of predicted in preterms dependent on supplemental oxygen at 36 weeks postmenstrual age. Lack of antenatal treatment with corticosteroids and prolonged neonatal oxygen treatment predicted similar significant airway obstruction in the two birth-cohorts.

CONCLUSION

Preterms born in different eras of neonatology had similar long-term decreases in lung function. Long periods of oxygen supplementation are still required to salvage immature infants, and airway obstruction may still be a common long-term outcome.

Assessment of lung volumes in children and adolescents: comparison of two plethysmographic techniques

Thoracic gas volume (Vtg) can be measured with body plethysmography by either repetitive panting or one single inspiratory effort against a shutter occluding the airways. The panting technique is preferred, but may be demanding. We aimed to assess the precision of these two methods and the degree of agreement between them. Vtg and functional residual capacity (FRC) were measured in 155 subjects with a standard, commercially available plethysmograph, acting as a variable-pressure, constant-volume device when Vtg is determined. Total lung capacity (TLC) and residual lung volume (RV) were calculated subsequent to a full vital capacity manoeuvre. For non-asthmatic healthy subjects, the standard deviations (SD) of the differences between two replicate measurements of FRC, TLC and RV were respectively 0.16, 0.13 and 0.14 litres with the panting technique, and 0.18, 0.18 and 0.23 litres with the single inspiratory effort technique. In percentage of the respective lung volumes, the corresponding 1.96 SDs were 20%, 8% and 40% with the panting technique and 23%, 12% and 67% with the single inspiratory effort technique. Between the two techniques, 95% limits of agreement were 21% for FRC, 11% for TLC and 58% for RV. The variability of Vtg and FRC accounted for most of the variability of TLC and RV. In conclusion, the panting and the single inspiratory effort technique produced results that were comparable in magnitude, however with a better precision with the panting technique. The single inspiratory effort technique can be used as an alternative if the panting technique fails.

Exercise capacity in young adults with hypertension and systolic blood pressure difference between right arm and leg after repair of coarctation of the aorta

Coarctation of the aorta represents 5-7% of congenital heart defects. Symptoms and prognosis depend on the degree of stenosis, age at surgery, surgical method and the presence of other heart defects. Postoperative complications are hypertension, restenosis and an abnormal blood pressure response during exercise. This study includes 41 patients, 15-40 years old, operated in the period 1975-1996. All were exercised on a treadmill until maximal oxygen consumption was achieved. Blood pressure was measured in the right arm and leg before and immediately after exercise, and in the right arm during exercise. Oxygen consumption was monitored and we defined an aerobic phase, an isocapnic buffering phase and a hypocapnic hyperventilation phase. The resting systolic blood pressure correlates with the resting systolic blood pressure difference between right arm and leg. A resting systolic blood pressure difference between the right arm and leg of 0.13 kPa (1 mmHg) to 2.67 kPa (20 mmHg) corresponds with a slight increase in resting systolic blood pressure. This rise in blood pressure increases the aerobic phase of the exercise test, helping the patients to achieve higher maximal oxygen consumption. A resting systolic blood pressure difference of more than 2.67 kPa (20 mmHg) corresponds with severe hypertension and causes reduction in the aerobic phase and maximal oxygen consumption. Resting systolic blood pressure and resting systolic blood pressure difference between the right arm and leg are not indicators for blood pressure response during exercise. Exercise testing is important to reveal exercise-induced hypertension and to monitor changes in transition from aerobic to anaerobic exercise and limitation to exercise capacity.

Eosinophil cationic protein (ECP) in school children living in a mountainous area of Norway: a population-based study of ECP as a tool for diagnosing asthma in children with reference values

BACKGROUND

Most previous studies on eosinophil cationic protein (ECP) have been performed on carefully selected groups of asthmatic patients. Few studies based upon population cohorts have been reported. The primary objective of the present study was to assess the usefulness of serum eosinophil cationic protein (s-ECP) in the diagnosis of asthma in schoolchildren and determine reference values based on measurements in healthy children.

METHODS

The population consisted of 216 schoolchildren (aged 7-16 years) who in a previous questionnaire had reported asthma or asthma-like symptoms and a control group. The questionnaire study comprised the entire population of schoolchildren in Upper Hallingdal. After clinical assessment, blood samples, and skin prick tests, these subjects were then reclassified into four groups: atopic and nonatopic asthmatic and nonasthmatics. S-ECP was assessed in relation to atopy, asthma severity, allergen exposure, and sex.

RESULTS

The asthma group (n = 105) had significantly higher mean s-ECP level than the nonasthma group (n = 111) (13.3 vs 8.3 microg/l, P < 0.001), with no significant difference between atopic asthmatics and atopic nonasthmatics. Mean s-ECP levels in children with mild, moderate, or severe asthma were 12.1, 18.5, and 12.2 microg/l, respectively. The children with animal dander allergy demonstrated higher levels of s-ECP than children without this allergy (12.9 vs 9.1 microg/l, P = 0.001). The upper reference limit (determined as the 95th percentile in healthy children) of 19.1 microg/l, showed low sensitivity (24%) and high specificity (93%) for the diagnosis of asthma. The positive and negative likelihood ratios for the asthma diagnosis were found to be 3.2 and 0.83, respectively.

CONCLUSIONS

The highest s-ECP values were found among children with moderate asthma. Animal dander allergy resulted in elevated s-ECP. However, mean values were still below the reference value of 19.1 microg/l, and the sensitivity was low, suggesting that s-ECP is not a useful parameter for diagnosing asthma in population-based studies.

Asthma and allergy among schoolchildren in a mountainous, dry, non-polluted area in Norway

The aim of this study was to assess prevalence of asthma and allergy in the non-polluted mountain area of Upper Hallingdal, Norway. All schoolchildren (7-16 years) who in a previous questionnaire survey (n = 1177) reported 'sometime' asthma were enrolled in group I (n = 80), the 59 who reported asthma-like symptoms in the past 12 months formed group II, and 77 of the healthy controls were randomly selected as group III. All 216 children underwent clinical examination, skin prick test, spirometry, bronchial provocation (PD20 metacholine) and treadmill exercise test. Subsequently they were reclassified as (1) healthy, never had asthma or symptoms, (2) symptoms not confirmed as asthma, (3) previous asthma, now healthy, (4) current asthma. Lifetime asthma prevalence was 10.2%. Based upon clinical examination, the specificity and sensitivity of the questionnaire for asthma diagnosis were 88 and 74%, respectively. Forced vital capacity was significantly higher among the asthmatics (group 4 versus 1), whereas forced expiratory volume in one second (FEV1) and forced expiratory flow at 50% of vital capacity were similar in all groups. More than 10% reduction in FEV1 following treadmill-run was found in 20% of children. Children with current asthma compared to controls had significantly; lower mean values of PD20 (9.1 versus 16.5 micromol), higher eosinophil cationic protein (13.4 versus 7.7 micromol) and more frequent sensitization to animal dander (56% versus 10%). In conclusion, despite a favorable climate, little mite sensitization and low outdoor pollution, asthma prevalence was surprisingly high in Upper Hallingdal. Sensitization to animal dander was the most important contributing factor for current asthma.