{'fraction_non_alphanumeric': 0.06029506093649775, 'fraction_numerical': 0.06286080821039128, 'mean_word_length': 4.492957746478873, 'pattern_counts': {'":': 0, '<': 2, '<?xml version=': 0, '>': 5, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Relationship between response to inhaled salbutamol and methacholine bronchial provocation in children with suspected asthma

Fifty children (27 females, 23 males) ages 6–15 years who were referred for evaluation of suspected asthma had baseline FEV1 and FEF25‐75 of ⩾ 80% and FEF50 ⩾ 70% of predicted values. All had these tests repeated on the same day, after inhaling salbutamol. On a subsequent day PC‐20 (methacholine) was determined as an index of bronchial hyperreactivity (BH). Fourteen age‐matched healthy children (6 females, 8 males) were studied in a similar manner. There was no significant relationship between the PC20 and the change in FEF25‐75 or FEF50 following salbutamol. There was a negative correlation between the initial FEV1 (% predicted) and the percent change in FEV1 following salbutamol (P < 0.01). An increase in FEV1 of >6% occurred in 7/12 (58.3%) patients with PC20 ⩽ 0.25 mg/mL (Group I); in 7/24 (29.2%) patients with PC20 = 0.26–2.0 mg/mL (Group II); in only 1/14 (7.1%) patients with PC20 > 2.1 mg/mL (Group III) and in none of those asymptomatic (control) children with PC20 > 8.0 mg/mL (Group IV). All subjects who had a change in FEV1 > 6% after salbutamol had a PC20 < 8 mg/mL and this test detected the majority of patients with severe BH. However, although the sensitivity of the test was 100%, the predictive value was only 36%. We conclude that in the presence of a normal baseline FEV1 a change of > 6% following salbutamol inhalation is indicative of bronchial hyperreactivity. Pediatr Pulmonol 1991; 10:244–248.