Breath-holding test in subjects with near-fatal asthma. A new index for dyspnea perception

Breath-holding as model for the evaluation of EEG signal during respiratory distress

PURPOSE

Research describes the existence of a relationship between cortical activity and the regulation of bulbar respiratory centers through the evaluation of the electroencephalographic (EEG) signal during respiratory challenges. For example, we found evidences of a reduction in the frequency of the EEG (alpha band) in both divers and non-divers during apnea tests. For instance, this reduction was more prominent in divers due to the greater physiological disturbance resulting from longer apnea time. However, little is known about EEG adaptations during tests of maximal apnea, a test that voluntarily stops breathing and induces dyspnea.

RESULTS

Through this mini-review, we verified that a protocol of successive apneas triggers a significant increase in the maximum apnea time and we hypothesized that successive maximal apnea test could be a powerful model for the study of cortical activity during respiratory distress.

CONCLUSION

Dyspnea is a multifactorial symptom and we believe that performing a successive maximal apnea protocol is possible to understand some factors that determine the sensation of dyspnea through the EEG signal, especially in people not trained in apnea.

Utility of the breath-holding test in patients with systemic sclerosis

OBJECTIVES

Cardiopulmonary involvement is a major cause of death in patients with SSc. This study evaluated the clinical utility and reliability of breath-holding test (BHT) in evaluating cardiopulmonary function in patients with SSc.

METHODS

Seventy-two prospectively enrolled patients with SSc underwent BHT and the 6 min walk test (6MWT), along with measurements of the Borg dyspnoea scale and Scleroderma Health Assessment Questionnaire (SHAQ). Data on pulmonary function test and echocardiography were also collected. Validity was assessed based on the correlations between the best BHT and relevant clinical parameters. To assess the reliability of BHT, an additional 31 patients with SSc underwent BHTs twice within 2 week intervals.

RESULTS

Mean (s.d.) best BHT time was 38.4 (15.7) s, and 6MWT distance was 473.5 (95.5) m. BHT showed significant correlations with the Borg dyspnoea scale before (r = -0.367, P < 0.001) and after (r = -0.285, P = 0.016) testing, whereas 6MWT were correlated with the Borg dyspnoea scale after (r = -0.351, P = 0.002) but not before (r = -0.113, P = 0.343) testing. BHT time was correlated with diffusing capacity for carbon monoxide (%, r = 0.426, P < 0.001), forced vital capacity (litres, r = 0.373, P = 0.001), pulmonary arterial systolic pressure (mmHg, r = -0.272, P = 0.031) and SHAQ score (r = -0.470, P < 0.001), but not with left ventricular ejection fraction (%, r = -0.135, P = 0.263). BHT showed excellent reliability, with an intraclass correlation coefficient (2, 1) of 0.943 (95% CI: 0.88, 0.97).

CONCLUSION

BHT, a simple and less time-consuming test, shows excellent reliability and significant correlation with the Borg scale, SHAQ and pulmonary parameters. These results suggest that BHT might be a useful surrogate marker of pulmonary capacity in SSc patients.

TRIAL REGISTRATION NUMBER

NCT04484948.

Maximal Voluntary Breath-Holding Tele-Inspiratory Test in Patients with Chronic Obstructive Pulmonary Disease

Maximal voluntary inspiratory breath-holding time (MVIBHT) has proved to be of clinical utility in some obstructive ventilatory defects. This study aims to correlate the breath-holding time with pulmonary function tests in patients with chronic obstructive pulmonary disease (COPD) and to determine the feasibility of using a breath-holding test in assessing the severity of COPD.

A cross-sectional study including male patients with stable COPD were conducted. Patients with respiratory comorbidities and severe or unstable cardiac diseases were excluded. Patients were interviewed and examined. Six-minute walk test (6MWT) and plethysmography were performed.For MVIBHT collection, the subject was asked to inspire deeply and to hold the breath as long as possible at the maximum inspiratory level. This maneuver was repeated three times. The best value was used for further analysis.

A total of 79 patients (mean age: 64.2 ± 8) were included in this study. The mean value of MVIBHT was 24.2 ± 8.5 s. We identified a positive and significant correlations between MVIBHT and forced vital capacity (r = .630; p < .001) as well as MVIBHT and forced expiratory volume in 1 s (FEV1%) (r = .671; p < .001). A significant inverse correlation with total lung capacity (r = −.328; p = .019) and residual volume to total lung capacity ratio (r = −.607; p < .001) was noted. MVIBHT was significantly correlated to the distance in the 6MWT (r = .494; p < .001). The mean MVIBHT was significantly different within spirometric grades (p < .001) and GOLD groups (p = .002). At 20.5 s, MVIBHT had a sensitivity of 72% and specificity of 96% in determining COPD patients with FEV1 <50%.

Our results provide additional evidence of the usefulness of MVIBHT in COPD patients as a pulmonary function parameter.

Validation of a breath-holding test as a screening test for exercise-induced hypoxemia in chronic respiratory diseases

The detection of exercise-induced hypoxemia is important for evaluating disease status in patients with chronic respiratory diseases. The 6-min walk test (6MWT) is useful for detecting exercise-induced hypoxemia. This pilot study aimed to validate the breath-holding test (BHT) as a screening for exercise-induced hypoxemia and compare its utility with that of the 6MWT in patients with chronic respiratory diseases. Fifty-nine patients with chronic respiratory diseases underwent BHTs lasting 10, 15, and 20 s. Percutaneous oxygen saturation (SpO₂), pulse rate, and severity of dyspnoea were measured. The participants also underwent a 6MWT, a pulmonary function test, and analysis of arterial blood gas at rest. Multivariate linear regression analysis was performed to identify significant predictors of desaturation in the 6MWT. The minimum SpO₂ during the BHT (all durations) and 6MWT were significantly correlated. Receiver operating characteristic analysis revealed the optimal cut-off for predicting SpO₂ < 90% during the 6MWT as a minimum SpO₂ ≤ 94% during the 15-s BHT. Perceived dyspnoea and maximum pulse rate were significantly lower during the 15-s BHT than during the 6MWT. In the multivariate linear regression analysis, the minimum SpO₂ during the 15-s BHT (β, 0.565, p < 0.001) and %DLco (β, 0.255, p < 0.028) were independent predictors of desaturation in the 6MWT. The minimum SpO₂ during the 15-s BHT may be a useful measure for screening for exercise-induced hypoxemia in patients with chronic respiratory diseases. The BHT is easier to perform, more readily available, and better tolerated than the 6MWT.

Factors associated with discrepancies between poor dyspnea perception and abnormal lung function in 65 asthmatic patients

Background

Dyspnea is a subjective symptom of asthma whose perception is characterized by an interindividual variability. Poor dyspnea perception is usually associated with increased risk of exacerbation and may lead to inappropriate asthma management and under-treatment. We sought to identify factors associated with discrepancies between poor dyspnea perception and abnormal lung function in patients with moderate persistent asthma.

Methodology

65 patients, who attended their scheduled follow-up pulmonology consultation at Ibn Sina Hospital (Rabat - Morocco), underwent interrogation including modified Medical Research Council (mMRC) scale for dyspnea, physical examination and spirometry. Two groups, those with mMRC < 2 (poor dyspnea perceivers) and those with mMRC scale ≥ 2 were compared.

Results

Poor dyspnea perception was found in 21 patients (32.3%). Associated factors were male sex (p : 0.03), low socio-economic income (p : 0.01), an onset of symptoms greater than 10 years (p : 0.01), BMI ≥ 25 Kg/m2 (p : 0.04) and depression (p : 0.04).

Conclusion

The results revealed factors significantly associated with poor dyspnea perception despite an obstructive ventilatory disorder. These factors could usefully be considered to successfully manage asthma as well as the regular prescription of an objective test like spirometry.

Health Services Utilization Is Increased in Poor Perceivers of Bronchoconstriction and Hyperinflation in Asthma

BACKGROUND

Impaired symptom perception is often listed as a risk factor for life-threatening asthma, but there is limited evidence to support this.

OBJECTIVE

We aimed to determine whether impaired perception of bronchoconstriction (BC) and/or dynamic hyperinflation (DH) are risk factors for severe asthma exacerbations.

METHODS

In this prospective cohort study, individuals with asthma underwent high-dose methacholine challenge testing. Changes in forced expiratory volume in 1 second (FEV₁) (% predicted) and inspiratory capacity (IC) (% predicted) were measured to assess the degree of BC and DH, respectively, during high-dose methacholine bronchoprovocation. Participants rated dyspnea intensity during testing and were categorized as poor, normal, and over perceivers of BC and DH based on perception scores at standardized changes (20%, 30%, and 40%) in FEV₁ (% predicted) and IC (% predicted). We compared the rates of severe asthma exacerbations (defined as one of emergency department [ED] visit or hospitalization) between groups, using Ontario's administrative health databases.

RESULTS

Poor perceivers had higher rates of ED visits and hospitalizations as compared with normal perceivers at 4 of 6 threshold decreases in FEV₁ and IC studied. Poor perceivers of severe DH had a 6-fold increase in asthma exacerbations (odds ratio, 5.7; 95% confidence interval, 1.31-25.03).

CONCLUSIONS

Health services utilization is increased in individuals with asthma who have poor perception of BC and DH. Poor perceivers of severe DH appear to be at the highest risk of exacerbations.

Symptoms and perception of airway obstruction in asthmatic patients: Clinical implications for use of reliever medications

BACKGROUND

Asthma causes the unpleasant sensation of breathlessness (dyspnea) caused by airway obstruction. Patients with poor perception of airway obstruction are at risk of delay in seeking medical attention and undertreatment, which can lead to avoidable deaths. Conversely, those with heightened perception are at risk of overtreatment and iatrogenic adverse effects with reliever medications, anxiety, and unnecessary use of health care resources.

OBJECTIVE

We sought to review evidence about symptom misperception in asthmatic patients and how to identify and manage affected patients, particularly with regard to reliever medications.

METHODS

We conducted a systematic literature search for studies of perception of airway function in asthmatic patients. We searched the OVID (Medline and Medline [R] in process [PubMed]), Embase, and Adisearch/Odyssey databases, restricting our search to human studies published in English from 1990-2018, with no restrictions on age, sex, or racial origin.

RESULTS

We found that both underperception and overperception assessed during induced bronchoconstriction or bronchodilation or during changes in airway resistance were common across all age groups and that aging, disease severity, smoking, sex, ethnicity, psychologic factors, and medication are all associated with differences in perception. Importantly, airway inflammation was associated with impaired perception and a history of severe or near-fatal asthma. We also identified knowledge gaps, such as whether an individual patient's perception varies over time and the influence perception has on patients' use of reliever medication.

CONCLUSION

We found that abnormal perception of airway obstruction has important clinical implications for the management of patients with asthma.

Effect of Dyspnea Induced by Breath-holding on Maximal Muscular Strength of Patients with COPD

[Purpose] The purpose of the present study was to clarify the effect of dyspnea induced by breath-holding on maximum muscular strength of patients with COPD. [Subjects] This study recruited 14 COPD subjects via public posting. [Methods] Dyspnea was assessed by the modified Borg scale. The subject asked to stop breathing at end-expiration and to hold their breath with a nose clip for as long as possible. Both total breath-holding time and threshold time of dyspnea were measured with a chronograph. Dyspnea reserve time (DRT) was defined by subtracting the threshold time of perception dyspnea from total breath-holding time in order to calculate the 50% DRT. The muscular strengths of maximal handgrip contraction were measured at baseline, 50% threshold time of dyspnea (subliminal point of dyspnea), and the 50% DRT (supraliminal point of dyspnea). [Results] The maximal handgrip at the supraliminal point of dyspnea was significantly lower than the baseline and subliminal point of dyspnea values. There was no statistically significant difference in maximal muscular strength between baseline and the subliminal point of dyspnea value. [Conclusion] The present results demonstrate that dyspnea induced by breath-holding aggravates weakness in the maximum muscular strength of patients with COPD.

Impact of blunted perception of dyspnea on medical care use and expenditure, and mortality in elderly people

Dyspnea is an alarming symptom responsible for millions of patient visits each year. Poor perception of dyspnea might be reasonably attributed to an inappropriately low level of fear and inadequate earlier medical treatment for both patients and physicians, resulting in subsequent intensive care. This study was conducted to evaluate medical care use and cost, and mortality according to the perception of dyspnea in community-dwelling elderly people. We analyzed baseline data from a community-based Comprehensive Geriatric Assessment in 2002. The perception of dyspnea in 479 Japanese community-dwelling elderly people with normal lung function was measured in August 2002. The sensation of dyspnea during breathing with a linear inspiratory resistance of 10, 20, and 30 cmH(2)O/L/s was rated using the Borg scale. According to the perception of dyspnea, we divided the elderly into tertiles and compared all hospitalizations, out-patient visits, costs, and death through computerized linkage with National Health Insurance beneficiaries claims history files between August 2002 and March 2008. In-patient hospitalization days and medical care costs significantly increased with the blunted perception of dyspnea, resulting in an increase in total medical-costs with blunted perception of dyspnea. With low perception group as reference, the hazard ratios of all-cause mortality were 0.65 (95% CI 0.23-1.89) for intermediate perception group and 0.31 (0.10-0.97) for high perception group, indicating the mortality rate also significantly increased with the blunted perception of dyspnea after multivariates adjustment (p = 0.04). The blunted perception of dyspnea is related to hospitalization, large medical costs, and all-cause mortality in community-dwelling elderly people. These findings provide a rational for preventing serious illness with careful monitoring of objective conditions in the elderly.

Efeito do broncodilatador no tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos

OBJETIVO: Identificar o papel do broncodilatador no tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos (DVOs). MÉTODOS: Estudo caso-controle incluindo pacientes com DVOs e grupo controle. Foram realizadas espirometrias antes e após o uso de broncodilatador, assim como testes de apneia respiratória, utilizando-se um microprocessador eletrônico e um pneumotacógrafo como transdutor de fluxo. As curvas de fluxo respiratório foram exibidas em tempo real em um computador portátil, e os tempos de apneia voluntária inspiratória e expiratória máximos (TAVIM e TAVEM, respectivamente) foram determinados a partir do sinal adquirido. RESULTADOS: Um total de 35 pacientes com DVOs e 16 controles foram incluídos no estudo. O TAVIM sem o uso de broncodilatador foi significativamente menor no grupo DVO que no grupo controle (22,27 ± 11,81 s vs. 31,45 ± 15,73; p = 0,025), mas essa diferença não foi significativa após o uso de broncodilatador (24,94 ± 12,89 s vs. 31,67 ± 17,53 s). Os valores de TAVEM foram significativamente menores no grupo DVO que no grupo controle antes (16,88 ± 6,58 s vs. 22,09 ± 7,95 s; p = 0,017) e após o uso de broncodilatador (21,22 ± 9,37 s vs. 28,53 ± 12,46 s; p = 0,024). CONCLUSÕES: Estes resultados fornecem uma evidência adicional da utilidade clínica do teste de apneia na avaliação da função pulmonar e do papel do broncodilatador nesse teste.

Asthma history and presentation

Asthma is suspected from a history of key symptoms, including cough, wheezing, dyspnea, chest tightness, and increased mucus production. A positive family or personal history of atopic diseases and diseases that are comorbid with asthma, such as allergic rhinitis and rhinosinusitis, is also important. The differential diagnosis of asthma is broad and includes potentially life-threatening diseases. Pediatric asthma and psychiatric mimics require special attention to prevent misdiagnosis. Differentiating asthma from these other disease states by history alone is not always possible. Because accurate diagnosis is critical to successful treatment, objective testing by spirometry and methacholine challenge should be employed.