Larynx during exercise: the unexplored bottleneck of the airways

Long-Term Outcomes of Respiratory Retraining Therapy for Exercise-Induced Laryngeal Obstruction

OBJECTIVE

To assess the long-term outcomes and efficacy of respiratory retraining therapy in patients with exercise-induced laryngeal obstruction (EILO).

METHODS

A retrospective chart review and prospective questionnaire-based survey were conducted on 88 patients who received respiratory retraining therapy for EILO at our institution over the past 5 years RESULTS: Thirty-four patients were included in the final analysis, with a mean age at symptom onset and age at initial evaluation of 13.67 ± 2.96 and 15.12 ± 3.48, respectively. We found a statistically significant difference in the pretreatment and post-treatment Dyspnea indices following respiratory retraining therapy, with a mean difference of 12.03 ± 7.18 (P < 0.001). When asked about the effectiveness of respiratory retraining therapy, the majority of patients (n = 28) reported improvement (13.3% "a little," 13.3% "somewhat better," 53.3% ("a lot better," and 13.3% complete resolution of symptoms. Only two patients (6.7%) responded that their breathing "did not get better." The most effective therapy techniques cited by patients were abdominal breathing (n = 10), ratio breathing (n = 5), and pursed lips or "straw" breathing (n = 5).

CONCLUSIONS

Respiratory retraining therapy represents an effective technique in both the short-term and long-term management of EILO. This therapy remains the first line in the management of EILO due to its ease of administration, non-invasive nature, and durable effect on breathing function.

Laryngeal response to high-intensity exercise in healthy athletes

Introduction

Exercise-induced laryngeal obstruction (EILO) is a common cause of exertional breathing problems. The current diagnostic approach rests on evaluation of laryngeal obstruction visualised by laryngoscopy performed continuously throughout a maximal exercise test (continuous laryngoscopy exercise (CLE) test) in patients who present with compatible symptoms. Laryngeal responses to high-intensity exercise in endurance athletes are not well described, potentially leading to inaccurate reference values and increasing the risk of misdiagnosing EILO.

Aim

To investigate laryngeal responses to high-intensity exercise in a healthy population of endurance athletes with no self-reported perception of respiratory problems.

Methods

A cross-sectional study was conducted at Haukeland University Hospital, Bergen, Norway, inviting amateur and professional athletes with no self-reported breathing problems who performed endurance training minimum four sessions weekly. Thirty-six eligible athletes completed a questionnaire detailing exercise habits and past and current respiratory symptoms. They performed a standardised CLE test from which cardiopulmonary exercise data and corresponding laryngeal responses were recorded. The CLE tests were evaluated in retrospect by two independent raters according to preset criteria providing a CLE score. The CLE score rates the severity of laryngeal obstruction during moderate and maximum exercise on the glottic and supraglottic regions on a scale ranging from 0 (no obstruction) to 3 (maximum obstruction).

Results

Twenty-nine (81%) athletes (15 females) aged 15-35 years completed a CLE test. Ten participants (33%) had a supraglottic CLE subscore of 2 or 3. Among these, two also had a glottic CLE subscore of 2 or 3. Notably, none had isolated glottic obstruction.

Conclusion

In healthy well-trained endurance athletes with no prior perception of respiratory symptoms, the laryngeal response to high-intensity exercise was diverse. Supraglottic laryngeal obstruction was observed in one-third of the athletes. The findings underline that a diagnosis of EILO should rest on observed laryngeal obstruction supported by compatible symptoms.

Are Questionnaires Helpful To Predict Exercise-Induced Bronchoconstriction (EIB) And Exercise-Induced Laryngeal Obstruction (EILO)?

OBJECTIVE

Exercise induced laryngeal obstruction (EILO) is an important differential diagnosis to exercise induced bronchoconstriction (EIB) and diagnosed via continuous laryngoscopy while exercising (CLE). However, availability of CLE is limited to specialized centres. And without CLE EILO is often misdiagnosed as EIB. Therefore it is essential to carefully preselect potential EILO candidates. Aim of this study was to investigate whether two short questionnaires -Asthma Control Test (ACT) and Dyspnea Index (DI) evaluating upper airway-related dyspnea- can differentiate between EIB and EILO.

METHODS

Patients with dyspnea while exercising were analysed with an exercise challenge in the cold chamber (ECC) to diagnose EIB in visit 1 (V1), as appropriate a CLE in visit 2 (V2, 4-6 weeks after V1) and ACT and DI in V1 and V2. EIB patients were treated with asthma medication after V1.

RESULTS

Complete dataset of 36 subjects were gathered. The ACT showed lower values in V2 in EILO compared to EIB patients. A lack of improvement in ACT in V2 after asthma medication of EIB patients is suspicious for additional EILO diagnosis. The DI showed higher values in V1 in EILO compared to EIB patients. A score≥30 can predict a positive CLE reaction.

CONCLUSION

ACT and DI are valuable tools in preselecting CLE candidates to assure timely diagnostic despite limited diagnostic capabilities.

Hypopharyngeal geometry impact on air-induced loads on the supraglottis

Exercise-induced laryngeal obstruction (EILO) describes paradoxical laryngeal closure during inspiration at high-intensity exercise. It is hypothesised that during intense activity, the air-induced loads on supraglottic walls overcome their internal stiffness, leading to the obstruction. Recent investigations have revealed that the air-induced loads on the supraglottic walls vary nonlinearly with increasing flow rate. It is, however, unclear whether certain geometric configurations of the hypopharynx and larynx may contribute to the predisposition to EILO. This study investigates the influence of hypopharyngeal and laryngeal geometry on upper respiratory tract airflow and air-induced forces. A computational fluid dynamics model is developed to study airflow through larynx. Four real, adult upper respiratory tracts with variable configurations are considered. Two steady, uniform inspiratory flow rates of 60 L/min and 180 L/min are considered. The analysis shows that geometries with a space lateral to the epiglottis (EpiS) and piriform fossae (PF) directs the hypopharyngeal and supraglottic pressure field to remain positive and increase with the flow rate. In geometries with EpiS and PF, pressure differential occurs around the aryepiglottic fold producing a net inward force over the region. The three-fold increase in flow rate induces near ten-fold increases in force over the region which may facilitate the closure. It is concluded that hypopharyngeal anatomy, particularly the piriform fossae, play a significant role in the obstruction of the supraglottic airway and should be considered in research and clinical assessment of EILO.

Airflow through the supraglottis during inspiration

Exercise-induced laryngeal obstruction is a paradoxical laryngeal closure during inspiration at high-intensity exercise, with supraglottic closure being most common. This study develops a model based on the computational fluid dynamics to investigate airflow velocity and pressure and the air-induced loads on the supraglottis at various inspiratory flow rates. It is found that at high flow rates, positive wall pressure is formed in the hypopharynx localise towards its lower region, while posterior supraglottic wall pressures shift from positive to negative. These findings suggest that high inspiratory flow rates may increase supraglottic pressure differentials, ultimately contributing in the collapse.

Exercise-Induced Dyspnea in Collegiate Athletes: Are We Missing the Diagnosis?

OBJECTIVES

Exercise-induced dyspnea (EID) can disrupt an athlete's participation and performance in their given sport. Differential diagnosis of EID is often completed using subjective report and may be inaccurate, therefore increasing the frustration and stress of the athlete. This nonexperimental research study was used to determine prevalence of EID and related respiratory symptoms in athletes at a small, Division I university.

METHODS

An anonymous survey was provided to athletes at Murray State University as they registered for participation in sports for the 2020-2021 school year. Data from this survey was analyzed as to reported physician-given diagnosis of a respiratory disorder as well as reported symptoms of EID.

RESULTS

Results showed that athletes with a physician-given diagnosis often did not report symptoms or responses to medications that support that diagnosis. Additionally, athletes frequently reported symptoms of EID without a formal diagnosis of a respiratory disorder.

CONCLUSIONS

These findings provide preliminary insight and pilot data that may be used to understand the prevalence of EID in collegiate athletes and the need for improved methods of diagnosis for etiologies of EID.

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.

The Need for Testing-The Exercise Challenge Test to Disentangle Causes of Childhood Exertional Dyspnea

Exertional dyspnea is a common symptom in childhood which can induce avoidance of physical activity, aggravating the original symptom. Common causes of exertional dyspnea are exercise induced bronchoconstriction (EIB), dysfunctional breathing, physical deconditioning and the sensation of dyspnea when reaching the physiological limit. These causes frequently coexist, trigger one another and have overlapping symptoms, which can impede diagnoses and treatment. In the majority of children with exertional dyspnea, EIB is not the cause of symptoms, and in asthmatic children it is often not the only cause. An exercise challenge test (ECT) is a highly specific tool to diagnose EIB and asthma in children. Sensitivity can be increased by simulating real-life environmental circumstances where symptoms occur, such as environmental factors and exercise modality. An ECT reflects daily life symptoms and impairment, and can in an enjoyable way disentangle common causes of exertional dyspnea.

Reported Symptoms Differentiate Diagnoses in Children with Exercise-Induced Respiratory Problems: Findings from the Swiss Paediatric Airway Cohort (SPAC)

BACKGROUND

Exercise-induced breathing problems with similar clinical presentations can have different etiologies. This makes distinguishing common diagnoses such as asthma, extrathoracic and thoracic dysfunctional breathing (DB), insufficient fitness, and chronic cough difficult.

OBJECTIVE

We studied which parent-reported, exercise-induced symptoms can help distinguish diagnoses in children seen in respiratory outpatient clinics.

METHODS

This study was nested in the Swiss Paediatric Airway Cohort, an observational study of children aged 0 to 17 years referred to pediatric respiratory outpatient clinics in Switzerland. We studied children aged 6 to 17 years and compared information on exercise-induced symptoms from parent-completed questionnaires between children with different diagnoses. We used multinomial regression to analyze whether parent-reported symptoms differed between diagnoses (asthma as base).

RESULTS

Among 1109 children, exercise-induced symptoms were reported for 732 (66%) (mean age: 11 years, 318 of 732 [43%] female). Among the symptoms, dyspnea best distinguished thoracic DB (relative risk ratio [RRR]: 5.4, 95% confidence interval [CI]: 1.3-22) from asthma. Among exercise triggers, swimming best distinguished thoracic DB (RRR: 2.4, 95% CI: 1.3-6.2) and asthma plus DB (RRR: 1.8, 95% CI: 0.9-3.4) from asthma only. Late onset of symptoms was less common for extrathoracic DB (RRR: 0.1, 95% CI: 0.03-0.5) and thoracic DB (RRR: 0.4, 95% CI: 0.1-1.2) compared with asthma. Localization of dyspnea (throat vs chest) differed between extrathoracic DB (RRR: 2.3, 95% CI: 0.9-5.8) and asthma. Reported respiration phase (inspiration or expiration) did not help distinguish diagnoses.

CONCLUSION

Parent-reported symptoms help distinguish different diagnoses in children with exercise-induced symptoms. This highlights the importance of physicians obtaining detailed patient histories.

Is the healthy respiratory system built just right, overbuilt, or underbuilt to meet the demands imposed by exercise?

In the healthy, untrained young adult, a case is made for a respiratory system (airways, pulmonary vasculature, lung parenchyma, respiratory muscles, and neural ventilatory control system) that is near ideally designed to ensure a highly efficient, homeostatic response to exercise of varying intensities and durations. Our aim was then to consider circumstances in which the intra/extrathoracic airways, pulmonary vasculature, respiratory muscles, and/or blood-gas distribution are underbuilt or inadequately regulated relative to the demands imposed by the cardiovascular system. In these instances, the respiratory system presents a significant limitation to O₂ transport and contributes to the occurrence of locomotor muscle fatigue, inhibition of central locomotor output, and exercise performance. Most prominent in these examples of an "underbuilt" respiratory system are highly trained endurance athletes, with additional influences of sex, aging, hypoxic environments, and the highly inbred equine. We summarize by evaluating the relative influences of these respiratory system limitations on exercise performance and their impact on pathophysiology and provide recommendations for future investigation.

Exercise-Associated Dyspnea and Stridor: Thinking Beyond Asthma

Breathlessness during sport can be caused by various cardiorespiratory conditions, but when associated with stridor, usually arises from an upper airway etiology. The term exercise-induced laryngeal obstruction (EILO) is now used to describe the phenomenon of transient glottic closure occurring in association with physical activity. Exercise-related laryngeal closure is most commonly encountered in athletic individuals and likely affects between 5% and 7% of all young adults and adolescents. The diagnosis of EILO is not always straightforward because features can overlap with exercise-induced asthma/exercise-induced bronchoconstriction. EILO can therefore remain misdiagnosed for years, and most patients receive inappropriate asthma therapy. In contrast with asthma, EILO symptoms are usually most prominent at maximal exercise intensity and resolve quickly on exercise cessation. It is important to recognize that EILO and asthma can coexist in a proportion of athletes. The criterion standard test for diagnosing EILO is continuous laryngoscopy during exercise testing, although eucapnic voluntary hyperpnea testing has also been used. Various surgical or pharmacological interventions can be used to treat EILO, but first-line treatment is breathing technique work. Further research is needed to establish the optimal treatment algorithm, and more work is needed to increase awareness of this important clinical entity.

Surgical intervention for exercise-induced laryngeal obstruction: A UK perspective

OBJECTIVES

Exercise-induced laryngeal obstruction (EILO) is a prevalent cause of exertional breathlessness and wheeze in young individuals. Typically diagnosed using the continuous laryngoscopy during exercise (CLE) test, treatment is largely based on breathing retraining promoting improved laryngeal function. In some cases, these techniques fail to alleviate symptoms, and surgical intervention with supraglottoplasty can be valuable in the supraglottic form of EILO. Globally, there is currently limited experience utilizing a surgical approach to EILO, and data regarding the optimum surgical technique and published outcomes and complication rates are thus limited.

STUDY DESIGN

Retrospective observational case series.

METHODS

In this report, we describe our experience as the only UK center undertaking supraglottoplasty for EILO. We report the surgical outcome of 19 patients (n = 16 female), mean age, 29.6 ± 13.1 years, referred for surgery with moderate to severe supraglottic EILO. Follow-up clinic ± CLE was performed within 4 months (median = 6 weeks), and CLE scores were evaluated before and following surgery.

RESULTS

We found a beneficial effect of surgery on supraglottic CLE scores (median score reducing from 3/3 to 1/3 postoperatively [P < .05] overall) with 79% (n = 15) of patients reporting an improvement in their exercise capacity. One patient developed an apparent increased tendency for glottic-level EILO following surgery; however, no voice- or swallowing-related complications were encountered.

CONCLUSIONS

This study is the first to report the UK experience, surgical technique, and outcome for EILO surgery. The findings indicate that EILO surgery appears to be a safe and effective option for individuals with moderate to severe supraglottic-type EILO who have failed initial conservative treatment.

LEVEL OF EVIDENCE

5 Laryngoscope, 130:E667-E673, 2020.

Exercise-induced laryngeal obstruction: Quality initiative to improve assessment and management

INTRODUCTION

Exercise-induced laryngeal obstruction (EILO) affects 2-3% of the general population and 5.1% of elite athletes. Symptoms arise during high-intensity exercise and resolve at rest. EILO is often misdiagnosed as exercise-induced asthma as both conditions can present with dyspnea, chest tightness and cough. The purpose of this quality initiative was to identify patient characteristics that predict a higher likelihood of EILO, streamline referrals for exercise-endoscopy testing and avoid unnecessary medications.

METHODS

A retrospective chart review included patients referred to a pediatric tertiary center between 2013 and 2018 for suspected EILO requesting exercise endoscopy. Data was collected from the patient chart and referral letters included age, sex, physical activity, medications, symptoms, and results of pulmonary and cardiac function tests.

RESULTS

Between 2013 and 2018, 35 patients (9 males and 26 females, aged 5-18 years) were referred. Only 18 patients developed symptoms during an exercise endoscopy test. The majority were female (15/18), older than 10 years (18/18) and were involved in competitive sports (16/18). Stridor was the most common complaint among all patients referred (24/35) and many reported anxiety and high stress (15/35). The majority (63%) were previously treated with asthma medication. Pulmonary and cardiac function testing was not predictive of EILO.

CONCLUSION

EILO is typically present in adolescent females involved in competitive sports. Anxiety and high stress was commonly noted. The majority were treated with asthma medication even though pulmonary function testing was normal. Recognition of this patient profile should improve timely access to appropriate diagnostic assessments, avoid unnecessary medical treatment, and promote a return to optimal athletic performance.

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.

Silsesquioxane polymer as a potential scaffold for laryngeal reconstruction

Cancer, disease and trauma to the larynx and their treatment can lead to permanent loss of structures critical to voice, breathing and swallowing. Engineered partial or total laryngeal replacements would need to match the ambitious specifications of replicating functionality, outer biocompatibility, and permissiveness for an inner mucosal lining. Here we present porous polyhedral oligomeric silsesquioxane-poly(carbonate urea) urethane (POSS-PCUU) as a potential scaffold for engineering laryngeal tissue. Specifically, we employ a precipitation and porogen leaching technique for manufacturing the polymer. The polymer is chemically consistent across all sample types and produces a foam-like scaffold with two distinct topographies and an internal structure composed of nano- and micro-pores. While the highly porous internal structure of the scaffold contributes to the complex tensile behaviour of the polymer, the surface of the scaffold remains largely non-porous. The low number of pores minimise access for cells, although primary fibroblasts and epithelial cells do attach and proliferate on the polymer surface. Our data show that with a change in manufacturing protocol to produce porous polymer surfaces, POSS-PCUU may be a potential candidate for overcoming some of the limitations associated with laryngeal reconstruction and regeneration.

Exercise-induced laryngeal obstruction in athletes: Contributory factors and treatment implications

Otherwise healthy adolescent athletes presenting with respiratory symptoms consistent with exercise-induced laryngeal obstruction (EILO) are frequently encountered in clinical practice. The symptoms are often incorrectly considered to result from exercise-induced asthma, and may be wrongly treated as such. Given the potential implications for health and performance if EILO is left untreated, a more comprehensive understanding of contributory mechanisms is essential in order to create appropriate treatment procedures. Informed by knowledge from physical therapy, as well as the fields of voice rehabilitation and vocal pedagogy, this theoretical article presents a novel way of understanding and managing EILO by exploring bodily mechanisms and structures that may disturb laryngeal function during strenuous exercise. Firstly, the status quo of the EILO diagnosis, its aetiology and treatment options are reviewed. Secondly, considerations associated with laryngeal structures and mechanisms, and their potential influence on laryngeal movement and sensitivity are examined. Thirdly, the manner in which postural de-alignment and breathing pattern may interfere with laryngeal functioning will be discussed. Finally, interventions for voice disorders and singing and the relevance of these for EILO are evaluated. It is argued that clients with EILO should undergo a thorough physical examination to identify constrictions in the body as a whole - such as postural de-alignments and a dysfunctional breathing pattern - as these are hypothesized as playing a critical role in laryngeal tightness during exercise. Physical therapists possess particular skills and competence with regard to examining breathing patterns and postural de-alignments, and should be included in the treatment process of EILO.

Laryngeal sensitivity testing in youth with exercise-inducible laryngeal obstruction

Exercise-inducible laryngeal obstruction (EILO) has been recognized as a not rare respiratory problem in youth practicing sports. The aim of the study was to test the mechanosensitivity of the larynx, and to identify the factors affecting it in a group of youth with proven EILO. Laryngeal sensory testing was performed in 54 adolescents and young adults with EILO. Laryngeal mucosal alterations were assessed according to the Reflux Finding Score (RFS). The data concerning diseases possibly affecting the upper airway, findings of previously performed flexible videolaryngoscopy during exercise, and RFS score were compared between the participants with laryngeal hyposensitivity and those with normal sensitivity. The participants with isolated vocal folds' adduction during an EILO attack were compared with those who demonstrated supraglottis collapse. Testing revealed an increased threshold for mechanical stimuli in 81.5% of participants. Among participants with hyposensitivity, there were significantly more participants with dysphagia during EILO attacks than among the participants with normal laryngeal sensitivity. The hyposensitivity group had a significantly higher RFS score compared with the other group. Isolated vocal folds' approximation was only observed in 11.9% of participants. These participants were younger and had asthma more frequently compared with the others. Only 16.9% of participants with EILO did not state symptoms related to gastroesophageal reflux. The decreased mechanosensitivity was detected in the majority of participants, suggesting that laryngopharyngeal reflux can be an important etiological factor. The problem of breathing difficulties during sport activities in youth can also be associated with the disproportionate growth of the respiratory tract.

Ergospirometry with concurrent fibre optic laryngoscopy: a randomised crossover study

Background: Patients suffering from exercise-induced laryngeal obstruction (EILO) are subjected to several exhausting tests. We aimed to assess the feasibility of using a single test to obtain diagnostic measurements for maximum oxygen uptake (VO₂max) and exercise-induced laryngeal obstruction (EILO).

Methods: Patients referred to the outpatient respiratory clinic at the University Hospital of Bispebjerg, Copenhagen with exercise-induced dyspnoea were evaluated for inclusion over 13 months. Eligible patients were aged 18–43 years, had a known EILO diagnosis (moderate or severe) and were inactive (self-reported activity) with less than 3 hours activity per week. In randomised order, all participants (n = 11) underwent three tests: a VO₂max test with and without concurrent laryngoscopy. VO₂max and EILO values from the two testing methods were compared.

Findings: There was no difference in VO₂max measured by ergospirometry with and without simultaneous continuous laryngoscopy during exercise (CLE) testing (mean difference −22 ml O₂･min⁻¹; 95% CI −125 to 81 ml O₂･min⁻¹; P = 0.647). EILO scores obtained during the CLE testing on the treadmill versus CLE testing on the ergometer bike revealed identical supraglottic scores in nine of the 11 participants (82%) with substantial agreement between the two types of test (x = 0.71). Glottic scores were identical in six of the 11 (55%), showing moderate agreement between test types (x = 0.38).

Conclusions: Based on our findings in inactive individuals, ergospirometry with laryngoscopy is feasible and well tolerated, yielding measurements for maximal oxygen uptake comparable to those of standard bike ergospirometry. Likewise, measurements of supraglottic EILO are comparable to those of the standard treadmill CLE test.

Eucapnic voluntary hyperventilation test in children

BACKGROUND

In children, exercise-induced dyspnea is a common symptom that can be due to dysfunctional breathing. EVH test has bee used especially in elite athletes as bronchoprovocation test. Currently, there are only few studies on the EVH test. New research methods are required alongside the traditionally used tests especially due to dysfunctional breathing disorder.

PURPOSE

The purpose of the "pilot study" was to study the usability of the EVH test with real time biofeedback in children of 10-16 years of age in the diagnostics of exercise-induced dyspnea.

METHODS

Six 10-16-year-old teenagers with history of exercise-induced dyspnea and three healthy control subjects were selected for the study. A 6-minute EVH test with realtime biofeedback was performed on the patients and the diagnosis was confirmed on the basis of clinical findings and spirometry follow-up either as normal, asthma or dysfunctional breathing.

RESULTS

The study was successful in the patients. In the spirometry follow-up, three patients had bronchoconstriction (FEV1 decline over 10%), dysfunctional breathing condition was observed in three patients and three control patients experienced no symptoms. Only two DFB-patients didn't reach the target level of minute ventilation due to a clinical symptom (inspiratory stridor).

CONCLUSION

The EVH test was successful in the 10-16-year-old children having participated in the study and the test was well tolerated. Through the study, it was possible to provoke both dysfunctional breathing disorder and bronchoconstriction in the symptomatic patients. Based on the pilot study, EVH test seems to be usable in the diagnostics of pediatric exercise-induced dyspnea but larger studies are warranted to confirm our preliminary findings.

Exercise-induced inspiratory symptoms in school children

BACKGROUND AND AIMS

Exercise-induced inspiratory symptoms (EIIS) have multiple causes, one of which is exercise-induced laryngeal obstruction (EILO). There is limited knowledge regarding EIIS in children, both in primary care practices and in pediatric asthma clinics. The aim of this study was to describe the feasibility of a diagnostic methodology and its results in a cohort of children with EIIS referred to our tertiary pediatric pulmonary center.

METHODS

This study analyzed consecutively collected data in children from East Denmark and Greater Copenhagen referred during a 3½ years period. The continuous laryngoscopy exercise (CLE) test directly visualizes the larynx using a flexible laryngoscope during a maximal exercise test. A post-test questionnaire evaluated the subjective impact of the examination.

RESULTS

The study included 60 children (37 girls/23 boys) with a mean age of 14 years (range 9-18). The feasibility of the CLE test was 98%; 18 children (35%) had EILO, while 33 children (61%) showed no abnormalities. Other laryngeal abnormalities were observed in three children before the exercise test. Asthma medication was successfully discontinued in 13 (72%) children with EILO. A significantly greater proportion of children shown to have EILO in the CLE test reported coping better with their EIIS than children with negative test (85% vs. 45%; P = 0.03).

CONCLUSIONS

Continuous laryngoscopy during exercise is feasible and useful for identifying children with EILO. A correct diagnosis of EILO can help relieve patient anxiety, improve their coping with symptoms, and prevent unnecessary long-term and potentially harmful asthma treatments involving high-dose inhaled steroids. Pediatr Pulmonol. 2016;51:1200-1205. © 2016 Wiley Periodicals, Inc.

Larynx during exercise: the unexplored bottleneck of the airways

Exercise-induced shortness of breath is not uncommon in otherwise healthy young people. Based on the presenting symptoms alone, it is challenging to distinguish exercise-induced asthma (EIA) from exercise-induced obstruction of central airways, sometimes leading to diagnostic errors and inadequate treatment. Central airway obstruction usually presents with exercise-induced inspiratory symptoms (EIIS) during ongoing exercise. EIIS tends to peak towards the end of an exercise session or immediately after its completion, contradicting symptoms of EIA typically peaking 3–15 min after the exercise has stopped. EIIS is usually associated with some form of laryngeal obstruction. Transnasal flexible laryngoscopy performed continuously throughout an incremental exercise test from rest to exhaustion or to intolerable symptoms is usually diagnostic, and also provides information that is important for further handling and treatment. Reflecting the complex anatomy and functional features of the larynx, exercise-induced laryngeal obstruction (EILO) appears to be a heterogeneous condition. Contradicting previous beliefs, recent literature suggests that laryngeal adduction in a majority of cases starts in supraglottic structures and that vocal cord adduction (VCD) most often occurs as a secondary phenomenon. However, EILO is poorly understood and more and better research is needed to unravel causal mechanisms. The evidence base for treatment of EILO is weak. Speech therapy, psychotherapy, biofeedback, muscle training, anticholinergic aerosols have all been applied, as has laser supraglottoplasty. Randomized controlled trials with well-defined and verifiable inclusion and success criteria are required to establish evidence-based treatment schemes.