The type of valved holding chamber used with inhaled salbutamol can significantly influence clinical outcomes in preschool children with acute wheezing, according to a study undertaken in emergency departments across Finland.

Acute wheezing is a common reason for paediatric emergency visits and a multicentre randomised clinical trial conducted across four Finnish emergency departments examined whether a valved holding chamber with higher in vitro drug-delivery efficiency improved clinical outcomes compared with a lower-delivery device.

Published in JAMA Pediatrics, the investigator-initiated trial enrolled 80 children aged six months to four years (mean age 23.1 months; 64% male) presenting with moderate-to-severe wheezing respiratory distress, defined by a Respiratory Distress Assessment Instrument (RDAI) score of at least 6.

Recruitment took place between April 2019 and May 2025, with enrolment paused between March 2020 and July 2022 due to Covid-19 restrictions.

Children were randomised 1:1 to receive inhaled salbutamol via one of two commercially available valved holding chambers: VHC-1 (Optichamber Diamond), which has previously been shown to have high drug-delivery efficiency in laboratory testing, and VHC-2 (Babyhaler) – a device with substantially lower in vitro drug delivery but widely used in Finland.

Baseline characteristics, including respiratory distress scores, oxygen saturation and respiratory rate, were broadly comparable between groups.

Salbutamol was administered at a dose of 0.6 mg per treatment cycle, with up to three cycles given at 20-minute intervals and a fourth dose if clinically required. Physicians assessing treatment responses were blinded to the device used.

Heart rate after treatment did not differ significantly between groups, and no severe adverse events occurred. None of the children required intensive care or died during the study.

Improved outcomes via specific valved holding chamber

Children treated using the higher-delivery VHC-1 device showed significantly greater improvement in respiratory distress. After treatment, the mean RDAI score was 2.7 in the VHC-1 group compared with 6.8 in the VHC-2 group, a mean difference of −4.1 points (95% CI −5.4 to −2.7).

The reduction in RDAI score from baseline was also larger with VHC-1 (−8.6) than with VHC-2 (−3.2), corresponding to a mean difference of −5.4 points (95% CI −6.9 to −3.9).

Nearly all children receiving VHC-1 achieved a clinically meaningful improvement (98% vs 70%), an absolute risk difference of 28% and a number needed to treat (NNT) of 3.6.

Secondary outcomes demonstrated a similar trend. Hospitalisation occurred in 20% of children treated with VHC-1 compared to 50% of those receiving VHC-2 (absolute difference 30%; 95% CI 9.2–49; NNT 3.3).

Children treated with VHC-1 also showed a lower respiratory rate after treatment (42 vs 47 breaths per minute) and higher oxygen saturation (97% vs 94%). Fewer required a fourth dose of salbutamol in the emergency department (58% vs 80%).

Limitations and clinical implications

The authors noted that the clinical differences were consistent with laboratory evidence, showing wide variation in aerosol delivery between valved holding chamber devices.

Under simulated breathing conditions mimicking acute wheezing in young children, the higher-performing device delivered 43 μg of a nominal 100-μg salbutamol dose, compared with only 1.8 μg delivered by the lower-performing chamber.

Visual monitoring was necessary to ensure proper mask fit and inhalation technique, so blinding was not feasible for nurses and caregivers, which limited the findings.

Additionally, only two valved holding chamber models were assessed, and all participants were recruited in Finland, which may limit generalisability to other populations.

Nevertheless, the results suggested that valved holding chamber devices should not be viewed as interchangeable in paediatric inhalation therapy. Device choice can affect treatment response in young children with acute wheezing and should therefore be considered in clinical practice, the authors concluded.

They added that future guidelines should include device-specific recommendations and that improved performance testing of inhalation devices could help guide procurement and treatment strategies.

Reference
Csonka P et al. Valved Holding Chambers in Young Children With Acute Wheezing. JAMA Pediatr 2026;Feb 23:e256479.