Measurement of AHR in children with A(H1N1)pdm09
infection
Studies on paediatric patients were carried out in accord with the
Declaration of Helsinki. This study enrolled paediatric participants
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)17. 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).