Parents and primary caregivers of children with asthma are limited in normal daily activities and experience anxieties and fears due to the child's illness. We have developed the Paediatric Asthma Caregiver's Quality of Life Questionnaire (PACQLQ) to measure these impairments. The objective of this study was to evaluate the measurement properties of the PACQLQ. A 9-week single cohort study was conducted with assessments at 1, 5 and 9 weeks. Participants in the study were primary caregivers of 52 children (age 7-17 years) with symptomatic asthma, recruited from notices in the local media and paediatric asthma clinics. Caregivers completed the PACQLQ, Impact-on-Family Scale and Global Rating of Change Questionnaires. Patients completed the Paediatric Asthma Quality of Life Questionnaire and an asthma control questionnaire. Spirometry and beta-agonist use were recorded. The PACQLQ was able to detect quality of life changes in those caregivers who changed (p < 0.001) and to differentiate these from the caregivers whose quality of life remained stable (p < 0.0001). The PACQLQ is reproducible in subjects who are stable (ICC = 0.84), and showed acceptable levels of longitudinal and cross-sectional correlations with the child's asthma status and health-related quality of life and with other measures of caregiver health-related quality of life. The PACQLQ functions well as both an evaluative and a discriminative instrument.

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. Thorax, 33,. Reproducibility and comparison of responses to inhaled histamine and methacholine. The efficiency of a standardised inhalation test procedure was studied by examining the reproducibility of responses to histamine and methacholine. In addition, the responses to the two agents were compared. Each set of duplicate tests was carried out on a separate day within one week, and all factors known or presumed to influence responses were carefully controlled. The results were expressed as the provocative concentration of the agent causing a 20% fall in forced expired volume in one second (PC20). Responses to histamine and methacholine were highly reproducible (coefficients of determination [r2] = 0 994 and 0 990 respectively).Responsiveness to histamine correlated closely with responsiveness to methacholine (r2 = 0 85).There was a small but significant cumulative dose effect with methacholine (P<0 01) but not with histamine. Side effects of throat irritation, flushing, and headache were more frequent with histamine than methacholine, and were dose-related. The high level of reproducibility indicates the efficiency of the test procedure. The similar severity of effects by agents with different mnechanisms of action suggests that the primary cause of non-specific bronchial hyperreactivity lies at the level of bronchial smooth muscle.Non-specific bronchial reactivity is the term used to indicate the responsiveness of the airways to chemical mediators, such as histamine, acetylcholine, and prostaglandin F2a, or to the synthetic analogues of acetylcholine, such as methacholine and carbachol. Its measurement is becoming increasingly important in clinical practice, epidemiology, and research.Non-specific bronchial reactivity is measured by inhalation tests, usually with histamine or methacholine. In the past different methods have been used, making critical analysis of results difficult. Recently Chai et al (1975) and Orehek and Gayrard (1976) have emphasised the importance of the standardisation of tests. Standardisation requires consideration of the many different factors that will influence the results.In this study we have standardised a simple inhalation test using histamine and methacholine. We have investigated the efficiency of the method by examining the reproducibility of responses over a short period. In addition we have compared the responsiveness to each agent and investigated the possibility of cumulative dose-effects and recorded side effects. Subjects and methods SUBJECTSThe patients were adults with asthma attending the regional chest and allergy unit. All had episodic dyspnoea or wheezing and documented variation in forced expired volume in one second (FEV1) of more than 20%, either spontaneously or after medication. None had features of any other respiratory disorder.Normal adults were volunteers from hospital staff. They had no present or past symptoms of rhinitis, asthma, or other respiratory disorder. They were non-smokers, non-atopic, and had normal spirometry. Non-atopic implied that they...