Measurement of AHR in children with A(H1N1)pdm09
infection
Studies on pediatric patients were carried out in accord with the
Declaration of Helsinki. This study enrolled pediatric asthmatic
patients with A(H1N1)pdm09 infection and hypoxia
(SpO2≤90%) within the first day of fever admitted to
Fukuokahigashi Medical Center between September 2009 and December 2010.
Bronchial asthma was diagnosed according to the Japanese Pediatric
Guidelines for the Treatment and Management of Bronchial Asthma 2008
(JPGL 2008)15. The participants were diagnosed with
A(H1N1)pdm09 infection by polymerase chain reaction (PCR) at Fukuoka
Institute of Health and Environmental Sciences. AHRs were measured at 1
and 3 months after discharge. Anti-inflammatory drugs and
bronchodilators were prohibited 1 month after discharge. Increasing
concentrations of acetylcholine (39, 78, 156, 312, 625, 1,250, 2,500,
5,000, 10,000, and 20,000 µg/mL) were inhaled by a nebulizer until the
forced expiratory volume in 1 second (FEV1.0) was
reduced by 20% from a post-nebulized saline value.
FEV1.0 was measured using a spirometer (HI-801, CHEST
M.I., Inc., Tokyo, Japan). AHR was defined as the provocative
concentration causing a 20% fall in FEV1.0(PC20). This study was approved by the institutional
review board of Fukuokahigashi Medical Center (2020-rin-8). Parents were
explained this study and signed informed consent.