Physiological effects of heated humidifiers versus heat and moisture exchangers in adult ARDS patients receiving invasive mechanical ventilation: A systematic review and meta-analysis.
Sanjay Singhal, Salvatore Notaro, R K Singh et al.
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In 30 seconds
This systematic review and meta-analysis compared heated humidifiers (HHs) with heat and moisture exchangers (HMEs) in adults with ARDS receiving invasive mechanical ventilation. Ten studies were included in the review, with paired physiological data available for selected outcomes. Compared with HMEs, HHs were associated with lower PaCO₂ (SMC -0.76, 95% CI -1.03 to -0.49; p < 0.001) and higher arterial pH (SMC 0.66, 95% CI 0.38-0.95; p < 0.001). PaO₂ did not differ significantly. No eligible comparative data addressed the prespecified primary outcome of artificial airway occlusion or other patient-centred clinical outcomes.
Key findings
- HHs were associated with lower PaCO₂ than HMEs (SMC -0.76, 95% CI -1.03 to -0.49; p < 0.001; I² = 0).
- Arterial pH was higher with HHs than HMEs (SMC 0.66, 95% CI 0.38-0.95; p < 0.001; I² = 0%).
- PaO₂ showed no significant difference between humidification methods (SMC -0.00, 95% CI -0.26 to 0.25; p = 0.98).
- No eligible comparative data were available for artificial airway occlusion or other patient-centred clinical outcomes.
Why it matters
Humidification choice may affect carbon dioxide clearance and arterial pH during lung-protective ventilation in ARDS. The findings suggest a physiological advantage for HHs on these measures, but they do not establish whether this translates into fewer airway obstructions or better patient-centred outcomes. Distinguishing physiological effects from clinical benefit is important when interpreting the evidence.
What to keep in mind
The evidence was based on a limited number of paired physiological studies, and no eligible comparative data addressed artificial airway occlusion or other patient-centred clinical outcomes.