Valved holding chambers vary significantly in the treatment of young children with respiratory distress

Acute wheezing is one of the most common reasons for emergency visits among preschool-aged children. The Finnish multi-centre CHAMBER trial demonstrated that the choice of VHC used to administer inhaled salbutamol, a bronchodilator, has a significant impact on treatment outcomes.

When a higher‑delivery VHC was used, 20% of children required hospital admission, compared with 50% when a lower‑delivery device was used. Children treated with the higher‑delivery chamber also had lower respiratory rates and higher oxygen saturation after treatment, indicating better physiological recovery.

A valved holding chamber is a tubular device attached to a pressurised metered‑dose inhaler that facilitates the delivery of aerosolised medicines. In children aged 0–3 years, the VHC is used with a face mask, while older children typically inhale the medicine without one. VHCs vary in shape, volume, valve design, electrostatic properties and mask fit, and these factors all influence how much medication ultimately reaches the lungs.

“Parents and clinicians often assume that VHCs are interchangeable, but our results show they are not. In small children with respiratory distress, the choice of device can make a major difference,” says Adjunct Professor Péter Csonka, principal investigator of the study. Csonka leads the Tampere Center for Child, Adolescent and Maternal Health Research (TamCAM) at Tampere University and works as Chief Paediatrician at the Terveystalo health clinic.

“Our findings are directly relevant to paediatric emergency care. By choosing a device that has been proven to deliver more medicine to the lungs of young children, we can reduce hospital admissions and improve the well-being of both children and their families,” adds Professor Terhi Ruuska-Loewald from Oulu University Hospital.

Previous laboratory studies had already shown that some VHCs deliver substantially less medication than others, but it had not been clear whether these laboratory differences would translate into tangible benefits in clinical practice.

“Many laboratory tests evaluating VHCs use steady flow profiles or simulate adult breathing patterns. A young child in respiratory distress, however, breathes rapidly and shallowly and has low lung capacity. The face mask may not fit ideally, and the child may cry or resist the treatment, all of which affect how much medicine actually reaches the lungs. Only a randomised clinical trial could determine whether these device‑related differences also influence symptom relief or the need for hospital care in clinical practice,” Csonka explains.

The CHAMBER trial confirmed that the differences observed in laboratory settings between VHCs are clinically meaningful. These performance differences also affect the delivery of other inhaled medications, underscoring the importance of choosing the right device in the treatment of paediatric respiratory diseases. This should be reflected both in device selection and user guidance.

The article Valved Holding Chambers in Young Children With Acute Wheezing: A Randomized Clinical Trial was published in the journal JAMA Pediatrics on 23 February 2026. The article is available online