Peak flow variability and anxiety in asthmatics

Abstract

This study sought to establish how often circadian airflow measurements (Peak Expiratory Flow rate or PEF) and how many values were needed for asthma management. That is the primary aim was not only to investigate circadian airflow variability but also airflow variability among three blows done at the same time.;The secondary aim was to investigate the relationship of circadian airflow variability in asthmatics and their cognitive/affective state, i.e. the presence or absence of anxiety.;The study sample consisted of 34 asthmatic patients between the ages of 12--17. Each subject was randomly assigned to one of 3 groups. Group 1 (standard) took the PEF 'best value' measurement twice daily for 7 days. Group 2 (semistandard) took all values twice daily for 7 days. Group 3 (nonstandard) took PEF measurements (all values) 3 times daily during the week and 5 times on the weekend for 7 days. These measurements were self-administered and readings were obtained using a device known as a peak flow meter.;On the day of a patient's medical visit spirometry testing was done and the physician noted the severity rating. The ratings of mild, moderate, or severe were assigned based on the guidelines established by the National Heart, Lung, and Blood Institute. When the patient consented to participate in this study, he or she completed the Revised Children's Manifest Anxiety Scale and was given a data sheet to record PEF values and mail it back to the Department of Pediatric Pulmonology. The Revised Children's Manifest Anxiety Scale (Reynolds and Richmond, 1978) was administered by a psychologist (the principal investigator) who was blinded to the physician rated asthma severity. PEF measurements were generally taken at home.;It was hoped that this study would lead to establishing how often and how many values of airflow measurements should be taken to assess circadian airflow variability. It was hoped that by increasing the frequency of taking PEF measurements and keeping all the PEF values would uncover the circadian airflow variability that goes undetected with fewer measurements and less obtained values. Secondly, this study sought to determine whether asthmatic patients have a higher incidence of anxiety (as often reported in the literature as higher prevalence as compared to nonasthmatics), and how anxiety overlaps with their asthma disease. Since there is overlap between the symptoms of anxiety and symptoms of asthma, theoretically speaking, some misdiagnosis can occur. For example an asthmatic patient could have his or her anxiety under treated, or an asthmatic patient can have their asthma over treated. To date it is not clear that routine doses of anxiolytics can suppress one's ability to sense or respond to an asthma attack.;The results of this study found a significant positive F value of 5.65 between the three treatment groups in terms of percent peak flow expiratory variability which is significant at the .05 level of confidence interval. No positive correlation was found between peak flow variability and total anxiety score. No significant difference was found between percent PEF variability and asthma severity rating. No significant difference was obtained between total anxiety score and asthma severity rating.