Perception of dyspnea in childhood asthma crisis by the patients and those in charge of them

Abstracts

OBJETIVO: Avaliar a correlação entre a percepção da dispneia durante uma crise de asma leve a moderada, por meio da escala modificada de Borg, com a medida do pico de fluxo expiratório (PFE). MÉTODOS: Estudo transversal de crianças e adolescentes que procuraram a emergência pediátrica devido a crise asmática, com dados coletados de julho de 2005 a junho de 2006. Foram registrados dados demográficos. Pacientes e seus responsáveis foram solicitados a graduar, individualmente, a dispneia do paciente por meio da escala modificada de Borg e, posteriormente, foi avaliada a medida do PFE. RESULTADOS: Foram avaliados 181 pacientes asmáticos, com idade média de 7,2 (±2,4) anos (4-12). A mãe procurou atendimento médico em 83,4% (151/181). Os sintomas incluíram tosse, em 68,5% (124/181), dispneia, em 47,0% (85/181), e sibilância, em 12,7% (23/181). Trinta e seis por cento (65/181) apresentavam crise leve, e 64,1% (116/181), moderada. Correlação negativa significativa foi evidenciada entre a percepção dos responsáveis e dos pacientes com dispneia e a medida do PFE dos pacientes (percentual previsto; r s = -0,240 e r s = -0,385, respectivamente). CONCLUSÃO: Pacientes e responsáveis demonstraram percepção limitada da gravidade da dispneia do paciente, evidenciando a necessidade de monitorar medidas objetivas, como a medida do PFE e o desenvolvimento de melhores meios de avaliação da dispneia.

Percepção; asma; dispneia

ORIGINAL ARTICLE

^IProfessora adjunta, Pediatria, Faculdade de Medicina, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Rio de Janeiro, RJ, Brazil Pneumologista pediátrica, Serviço de Pneumologia, Instituto de Puericultura e Pediatria Martagão Gesteira (IPPMG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil

^IIProfessora adjunta, Departamento de Pediatria, Faculdade de Medicina, UFRJ, Rio de Janeiro, RJ. Chefe do Serviço de Pneumologia, IPPMG, UFRJ, Rio de Janeiro, RJ, Brazil

^IIIMédica assistente, IPPMG, UFRJ, Rio de Janeiro, RJ, Brazil

^IVProfessor titular, Departamento de Pediatria, Faculdade de Medicina, UFRJ, Rio de Janeiro, RJ, Brazil

Correspondence

ABSTRACT

OBJECTIVE: To evaluate the correlation between perception of dyspnea during a mild to moderate asthma attack using the Modified Borg Scale (MBS) and peak expiratory flow rate (PEFR).

METHODS: This was a cross-sectional study conducted with children and adolescents who sought a pediatric emergency service due to an asthma attack. Data were collected from July 2005 to June 2006. Demographic data were recorded. Patients and those in charge of them were requested to grade, individually, the patient's dyspnea using the MBS; afterwards, the peak expiratory flow rate was measured.

RESULTS: 181 asthmatic patients were evaluated, with a mean age of 7.2 (± 2.4) years (range, 4-12). The mother sought medical aid in 83.4% of the cases (151/181). Patient symptoms included coughing in 68.5% (124/181), dyspnea in 47.0% (85/181), and wheezing in 12.7% (23/181). Thirty-six percent (65/181) had a mild attack, and 64.1% (116/181) a moderate one. A significant negative correlation was found between the patients' and accompanying adults' perceptions of patient's dyspnea and the PEFR (% predicted; r_s = -0.240 and r_s = -0.385, respectively).

CONCLUSION: Both the patients and those looking after them had a poor perception of the severity of the patient's dyspnea. This emphasizes the need to monitor objective measures such as the PEFR and to develop better ways of evaluating dyspnea.

Keywords: Perception, asthma and dyspnea.

Introduction

Perception can be defined as a conscious sensation of a physiological problem felt by the patient. It is the end result of a series of processes: activation of afferent terminals by physiopathological stimuli, transmission and processing of information by neuronal channels, interpretation in the cerebral cortex and acknowledgement by the patient. The term dyspnea is usually employed to describe unpleasant or uncomfortable respiratory sensations experienced by individuals.^1,2

Dyspnea is one of the main symptoms reported by the asthmatic patient, as is coughing, wheezing and the sensation of chest tightness. When diagnosing asthma, the presence of recurring episodes of airway obstruction and the exclusion of alternative diagnoses are of paramount importance. Thus, clinical data and laboratory examinations, in addition to the evaluation of lung function, via spirometry or the peak expiratory flow rate (PEFR) measure, are combined to confirm or exclude the disease and to evaluate severity classification.^3,4

In asthmatic individuals, there is strong evidence that the perception of dyspnea is associated with an increased respiratory effort generated by increased airway resistance. Thus, dyspnea quantification seems to be a good approach to determining the degree of airway obstruction.⁵ In addition to mechanical factors, Rosi et al.⁶ also emphasize the existence of a relationship between inflammation and the perception of dyspnea during bronchoconstriction.

Asthma attacks are classified according to their severity, and treatment should be started immediately. Asphyxia is identified as the main cause of death. Excessive treatment as the cause of death, although possible, is rare. A poor perception of the degree of airway obstruction has been identified, among other aspects, as a risk factor for the occurrence of very severe or fatal attacks.⁷

Choi et al.,⁸ studying asthmatic patients, showed that treatment with beta-2 agonist and corticosteroid improved the perception of dyspnea, even in elderly patients. Those authors emphasized the impact of an allergic component in the perception difficulty observed in some patients.

In spite of having more severe asthma attacks, some patients undervalue them and neglect their treatment. Conversely, other patients, with an exaggerated perception of their dyspnea, consume an excessive amount of drugs and medical resources.^3,7,9

There are both qualitative and quantitative methods available to determine the severity of dyspnea. The Modified Borg Scale (MBS) is one of those most used. The patient grades his or her degree of respiratory discomfort using a scale from zero to 10, with 10 being the maximum.¹⁰ Among other data, age, socioeconomic and cultural level and anxiety have been identified as factors involved in the perceptive variations reported. Because the treatment plan is determined by the symptoms described, monitoring objective measures, such as the PEFR, in poor perceivers acquires great importance in the patient's life.^1,11

Little is yet known about the accuracy of perception of respiratory difficulty in pediatric asthma.^9,11 Fritz et al.¹² have published a study on subjective and objective methods employed to evaluate respiratory perception, emphasizing its relevance in medical handling. Guyatt et al.,¹³ studying pediatric patients, observed that the perception of asthma by patients over 10 years old was more accurate than that referred by the people in charge of them.

Two studies have evaluated the perception of dyspnea in children with asthma and detected a high percentage of inadequate perception.^14,15 Cabral et al.¹⁶ showed that a large number of pediatric patients could not accurately perceive bronchial obstruction; those authors did not detect any association with age, sex, clinical severity or use of prophylactic medication. Fritz et al.,¹⁷ evaluating the correlation between PEFR measure and perception of external overload applied to the patient, have stressed the importance of in vivo studies and their greater possibility of practical application in identifying children at risk for greater asthma-related morbidity. Two recent studies have emphasized that the perception of bronchospasm severity can contribute to a delay in appropriate treatment.^18,19

The objective of this study was to evaluate the correlation between perception of dyspnea during a mild to moderate asthma attack using the MBS and PEFR.

Methodology

All the patients who sought the Institute of Puericulture and Pediatrics Martagão Gesteira (Instituto de Puericultura e Pediatria Martagão Gesteira, IPPMG), of the Universidade Federal do Rio de Janeiro (UFRJ), with a mild to moderate asthma attack, in the period between July 20, 2005 and June 30, 2006, in the working days of the researcher, were invited to take part in the study.

Inclusion criteria: Patients with the diagnosis of mild to moderate acute asthma, according to the Global Initiative for Asthma (GINA)⁴; an affirmative answer to the question "did the child present wheezing in the last 12 months?"²⁰; age between 4 and 12 years old.

Exclusion criteria: Patients with other conditions associated with the presence of dyspnea, such as cardiopathy, neuromuscular disease or other lung diseases; lack of cooperation or inability to execute the maneuvers requested; asthma classified as acute severe by the same criteria.⁴

In order to collect the data, a standardized sheet was filled in by the project author. The following items were recorded: the patient's age, sex and education level; symptom(s) which led to medical attendance; relationship of the person in charge with the child or adolescent and if he or she cared for the child when she/he was not at school; education level and socioeconomic classification of the person in charge according to criteria of the Brazilian Institute of Public Opinion and Statistics (Instituto Brasileiro de Opinião Pública e Estatística, IBOPE).²¹

The child's height and weight were recorded. Before starting the treatment, the patients were asked to score, without any intervention of the examiner, how dyspneic they felt, using the MBS, with scores available from zero to 10, being 10 the maximum value. The person in charge, without being aware of the patient's answer, proceeded likewise.

Afterwards, the patient was asked to blow three times, in discardable flow tubes, the device for measuring the PEFR (Mini-Wright Peak Flow Meter, Clement-Clarke International, Harlow, UK), and the best result was recorded.^3,4 The protocol of the study was approved by the local Research Ethics Committee and all those in charge signed the free informed term of consent (FITC).

Statistical analysis

Means and SDs of patients ages were recorded. The gender and education level of the patient and person in charge, relationship, if he or she looks after the child most of the time, classification of the IBOPE²¹ and of the acute asthm,^3,4 and complaint(s) which led to the medical attendance were described in absolute numbers and frequency. According to data distribution, Spearman's rank correlation coefficient (r_s ) was used to measure the degree of association between the perception (of the child and the person in charge) and the PEFR measure (PEFR % of predicted, related to the patient's height). Significance was set at 5%. The statistical analysis was processed by the software SAS 6.04 (SAS Institute, Inc., Cary, U.S.A.).

Results

Among the 181 patients, the mean age was 7.2 (±2.4) years, varying from 4 to 12 years old; 52.5% (95/181) were male. They all went to school.

The mother was responsible for seeking medical attendance in 83.4% (151/181) of the cases. There was an affirmative answer concerning looking after the patient in 93.4% (169/181). According to the criteria of the IBOPE of socioeconomic level, nobody in charge was in classes A1, A2 or E; 1.1% (2/181) belonged to class B1, and 4.4% (8/181) belonged to class B2. The classes C and D, together, accounted for 94.4% (171/181) of the population studied.

By the classification of the asthma crisis as per the GINA, 35.9% (65/181) had a mild attack, and 64.1% (116/181) a moderate attack. Coughing was reported in 68.5% (124/181), dyspnea in 47.0% (85/181), and wheezing in 12.7% (23/181). All the patients had one or more signs or symptoms characteristic of an asthma attack^3,4 (Table 1).

The mean score of dyspnea, by the MBS, of the patients and the accompanying adults was 3.5 and 4.1, with a standard deviation of 2.8 and 2.4, respectively. There was a significant inverse correlation between the patient's perception and the PEFR (% of predicted) (r_s = -0.240; p = 0.001; n = 181), as can be seen in Figure 1. There was also a significant inverse correlation between the perception of the accompanying adult and the PEFR (% of predicted) (r_s = -0.385; p = 0.0001; n = 181), as can be seen in Figure 2.

In the two scatter charts, the straight line drawn illustrates the trend of the relationship between the perception of dyspnea and the PEFR (% of predicted).

Subsamples were analyzed, in order to detect significant variations between the patient's perception and that of the person in charge, related to the age and gender of the child and adolescent; education level of the person in charge; classification of the asthma crisis. The patients were divided into two age ranges: 4-9 and 10-12 years old; and two asthma crisis groups: mild or moderate. Regarding education level, the people in charge were divided into two groups, up to or more than eight years of study (Table 2).

Discussion

This study showed a significant correlation between the perception of dyspnea of children and adolescents and those in charge of them and the PEFR measure (% of predicted). However, this correlation can be considered to be weak, as Spearman's rank correlation coefficient varies from -1 to 1, and the nearer it is to zero, the weaker is the relationship between the two variables. Those in charge showed better perception of the dyspnea than the patients studied.

The importance of a study performed in natural conditions should be pointed out, as it evaluates the perception of the dyspnea in vivo, in a situation very close to reality, in spite of the difficulties concerning an emergency room with spontaneous demand.^13,16

Cabral et al.,¹⁶ analyzing three different age ranges (6-9, 10-11 and 12-16 years old), concluded that the perception was not related to the age range. On the other hand, Guyatt et al.¹³ noted that the patients aged between 11 and 17 years old showed a better correlation of the capacity to evaluate asthma than those in charge of them. The authors emphasized that using the daily PEFR measure could bring additional benefit regarding the evaluation of the airway caliber. To analyze the age, the patients' results were subdivided into two age ranges: 4-9 and 10-12 years old. A significant inverse correlation was detected in the range from 4 to 9 years old (r_s = -0.321; p = 0.0001; n = 147); however, in the subgroup of 10 to 12 years old, no significant correlation was found between the patient's perception and the PEFR measure (% of predicted) (r_s = 0.102; p = 0.56; n = 34). This fact can be explained by the reduced number of patients in this age range or by their lower willingness to collaborate. Although widely used and recommended, using the PEFR measure does have limitations, as it is not familiar to all the patients, has an effort-dependent characteristic and may not reflect the involvement of the small airways accurately.^12,17 In spite of Yoos & McMullen²² reporting that adolescents have greater accuracy in the perception, Boulet et al.²³ had described poorer perception over time (10 years or more of disease) in asthmatic adults, and Chen et al.²⁴ point out that even children with more severe asthma can become accustomed to the symptoms and, as a result, be slower to perceive changes during exacerbations of asthma. Most of the studies in adults did not find any differences in gender perception. These findings were confirmed by studies in the pediatric population¹⁶ and are compatible with the results presented here.

The accompanying adults showed a significant inverse correlation between their perception of the patient's dyspnea and the PFER (% of predicted) (p < 0.01) (r_s = -0.326 and r_s = -0.442), although studies with adults have shown a greater difficulty in individuals with a low socioeconomic and educational level in the perception of dyspnea.²⁵ As anxiety seems to play an important role in the perceptive capacity, such variables may not be the only ones responsible for individual differences in perception.^22,26

No variation was shown in the perception between patients with a mild or moderate attack. Baker et al.¹⁵ described that the difficulty in perceiving changes in the degree of bronchial obstruction, induced by methacolin, was not significantly correlated with the hyperreactivity of the airway. We consider that the non-inclusion of patients with a severe asthma attack is a limitation of the study, but we should respect the patient's physical conditions and the ethical commitment of clinical research.

Issues concerning the improvement of the perception of symptoms of asthma with training and the best evaluation method remain inconclusive^17,27,28; nevertheless, all the patients studied went to school, so we suggest studies, in our setting, which evaluate the accuracy of the teachers in identifying students having an asthma attack, as well as their response to capacitation programs. A recent study showed that children whose caregivers did not have suitable knowledge of diagnosing asthma had a worse perception of dyspnea than those diagnosed by a doctor as being asthmatic.²⁹ Thus, clinical parameters added to the evaluation of the quality of life, lung function and inflammatory markers can be complementary in the management of the patient with asthma.³⁰

We concluded that the perception of dyspnea by the children and those in charge of them had a significant, but weak, correlation with the PFER measure (% of predicted). Further studies about more appropriate methods to evaluate perception of dyspnea and factors involved in poor perception are required, as well as how those factors can be modified in order to provide greater accuracy in perception.

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Perception of dyspnea in childhood asthma crisis by the patients and those in charge of them

Ana Alice Amaral Ibiapina Parente^I ; Maria de Fátima Pombo March^II; Lucia de Araujo Evangelista^III; Antonio Ledo Cunha^IV

Publication Dates

• Publication in this collection
  01 Feb 2012
• Date of issue
  Dec 2011

History

• Received
  31 Dec 2010
• Accepted
  24 Aug 2011