SAA	Severe Acute Asthma
PICU	Paediatric Intensive Care Unit
TD-GC-MS	Thermal Desorption Gas Chromatography–Mass Spectrometry
VOC	Volatile Organic Compound
COPD	Chronic Obstructive Pulmonary Disease
MACU-PICU	Multisystem phenotyping in severe acute asthma at the PICU
PANDA	Paediatric Asthma Non-Invasive Diagnostic Approaches
IV	Intravenously
GINA	Global Initiative for Asthma
ACT	Asthma Control Test
ERS	European Respiratory Society
AMDIS	Automatic Mass Spectral Deconvolution and Identification System
MS-NIST	National Institute of Standards and Technology Mass Spectral Library
RT	Retention Time
PC	Principal Components