Humidified high-flow nasal cannula (HHFNC) is widely used in children with bronchiolitis, but the optimal flow rate remains unclear. This study compared three different flow rates (1 L/kg/min, 2 L/kg/min, and 3 L/kg/min) to determine the most effective setting for respiratory support in bronchiolitis. The objective of this study was to ascertain the optimal flow rate of HHFNC required for management in children aged 1 month to 1 year diagnosed with moderate-to-severe bronchiolitis as per American Academy of Paediatrics (AAP) guidelines (2014) and graded for severity as per clinical respiratory score. A total of 90 children were enrolled, with 30 participants in each group. to compare three different flow rates of high-flow nasal cannula (HHFNC) therapy (1 L/kg/min, 2 L/kg/min, and 3L/kg/min) in children with bronchiolitis to determine the optimal setting for respiratory support. A randomized controlled trial was conducted at the Department of Paediatrics at a tertiary care centre. The participants were. Patients were randomly assigned to receive HHFNC at 1 L/kg/min, 2 L/kg/min, or 3 L/kg/min. Oxygen was delivered via a heated humidifier to maintain SpO2 between 94 and 97%. Primary outcome was treatment failure requiring escalation to invasive ventilation or PICU admission. Secondary outcomes included length of hospital stay, respiratory improvement, cardiac improvement, and adverse effects. Ninety children with bronchiolitis were randomized into three groups receiving HHFNC at 1, 2, and 3 L/kg/min. Group 1 showed significantly greater improvement in respiratory rate (18.4 ± 4.3/min; p = 0.01), heart rate (22.3 ± 6.2 bpm; p = 0.01), and SpO2 (3.5 ± 1.1%; p = 0.001) compared to Groups 2 and 3. PICU admission was lowest in Group 2 (13.3%) and highest in Group 3 (33.3%; p > 0.05). Adverse events were significantly more in Group 3 (26.7%) than Group 2 (16.7%; p = 0.001).Conclusion: HHFNC at 1 L/kg/min showed good clinical with fewer improvement adverse events, while 2 L/kg/min had the lowest PICU admissions and ventilation needs. In contrast, 3 L/kg/min was linked to higher complications and longer hospital stay.<Table Float="No" ID="Taba"> <tgroup cols="2"> <colspec align="left" colname="c1" colnum="1" /> <colspec align="left" colname="c2" colnum="2" /> <tbody> <row> <entry align="left" nameend="c2" namest="c1"> What is Known: • In management of children with acute bronchiolitis Humidified and heated air that is blended with oxygen and delivered through a nasal cannula (HHFNC) has emerged as mainstay of therapy to provide respiratory support with proven benefits like decreased work of breathing ,improved oxygenation, and reduced rates of intubation. • In a previously published work by Milesi et. al. HFNC flow rates of  3l/kg/min versus 2l/kg/min in infants up to six months age admitted to hospital with moderate to severe acute viral bronchiolitis were compared and both flow rates were comparable in clinical characterstics studied with more side effects seen with high flow rates. </entry> </row> <row> <entry align="left" nameend="c2" namest="c1"> What is New: • This study provides granular data on three different flow rates (1, 2, and 3 L/kg/min) of HHFNC, unlike many studies that compare only HHFNC vs. standard therapy. • This study also tries to provide the optimal balance between effectiveness and patient comfort (favouring 2 L/kg/min) and suggests that weaning success is higher with lower flow rates, reinforcing patient-friendly management strategies. </entry> </row> </tbody> </tgroup> </Table>

Comparison of 3 different flow rates of high-flow nasal cannula (1 L/kg/min versus 2 L/kg/min versus 3 L/kg/min) in management of children admitted with bronchiolitis: a randomized controlled trial

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发表日期：

2025年12月23日

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Manju Kaushik,
Kapil Bhalla

摘要

Humidified high-flow nasal cannula (HHFNC) is widely used in children with bronchiolitis, but the optimal flow rate remains unclear. This study compared three different flow rates (1 L/kg/min, 2 L/kg/min, and 3 L/kg/min) to determine the most effective setting for respiratory support in bronchiolitis. The objective of this study was to ascertain the optimal flow rate of HHFNC required for management in children aged 1 month to 1 year diagnosed with moderate-to-severe bronchiolitis as per American Academy of Paediatrics (AAP) guidelines (2014) and graded for severity as per clinical respiratory score. A total of 90 children were enrolled, with 30 participants in each group. to compare three different flow rates of high-flow nasal cannula (HHFNC) therapy (1 L/kg/min, 2 L/kg/min, and 3L/kg/min) in children with bronchiolitis to determine the optimal setting for respiratory support. A randomized controlled trial was conducted at the Department of Paediatrics at a tertiary care centre. The participants were. Patients were randomly assigned to receive HHFNC at 1 L/kg/min, 2 L/kg/min, or 3 L/kg/min. Oxygen was delivered via a heated humidifier to maintain SpO₂ between 94 and 97%. Primary outcome was treatment failure requiring escalation to invasive ventilation or PICU admission. Secondary outcomes included length of hospital stay, respiratory improvement, cardiac improvement, and adverse effects. Ninety children with bronchiolitis were randomized into three groups receiving HHFNC at 1, 2, and 3 L/kg/min. Group 1 showed significantly greater improvement in respiratory rate (18.4 ± 4.3/min; p = 0.01), heart rate (22.3 ± 6.2 bpm; p = 0.01), and SpO₂ (3.5 ± 1.1%; p = 0.001) compared to Groups 2 and 3. PICU admission was lowest in Group 2 (13.3%) and highest in Group 3 (33.3%; p > 0.05). Adverse events were significantly more in Group 3 (26.7%) than Group 2 (16.7%; p = 0.001).

Conclusion: HHFNC at 1 L/kg/min showed good clinical with fewer improvement adverse events, while 2 L/kg/min had the lowest PICU admissions and ventilation needs. In contrast, 3 L/kg/min was linked to higher complications and longer hospital stay.

What is Known:

• In management of children with acute bronchiolitis Humidified and heated air that is blended with oxygen and delivered through a nasal cannula (HHFNC) has emerged as mainstay of therapy to provide respiratory support with proven benefits like decreased work of breathing ,improved oxygenation, and reduced rates of intubation.

• In a previously published work by Milesi et. al. HFNC flow rates of 3l/kg/min versus 2l/kg/min in infants up to six months age admitted to hospital with moderate to severe acute viral bronchiolitis were compared and both flow rates were comparable in clinical characterstics studied with more side effects seen with high flow rates.

What is New:

• This study provides granular data on three different flow rates (1, 2, and 3 L/kg/min) of HHFNC, unlike many studies that compare only HHFNC vs. standard therapy.

• This study also tries to provide the optimal balance between effectiveness and patient comfort (favouring 2 L/kg/min) and suggests that weaning success is higher with lower flow rates, reinforcing patient-friendly management strategies.