Humidified Non-Invasive Ventilation vs. High-Flow Therapy to Prevent Reintubation in Obese Patients
SFY – Hernández et al. AJRCCM 2025. DOI: 10.1164/rccm.202403-0523OC
What was it?
Multicenter randomized trial comparing humidified non-invasive ventilation (NIV) with high-flow nasal cannula (HFNC) therapy to prevent reintubation in obese ICU patients at intermediate risk of hypoxemic extubation failure.
The Devil in the details!
- 757 received either HFNC or NIV 48 hours post-extubation
- They wanted to see whether the interventions had any effect on the likelihood of reintubation within 7 days.
The Results!
- No significant difference in reintubation rates
- (NIV: 19.1% vs. HFNC: 22.8%)
- No significant difference in secondary outcomes like respiratory failure, ICU stay, and mortality.
- NIV was linked to more adverse events
- Discomfort (42.9% vs. 0% for HFNC)
- ICU LOS (Median 11 days in NIV group vs. 6.5 days in HFNC group
They Concluded
- The study concludes that NIV does not significantly decrease reintubation rates compared to HFNC
Gripe point summary!
It provides a focused comparison of NIV and HFNC in obese patients but:
- limited by its small sample size
- lack of blinding
- narrow patient selection
- confounding factors
If you want to see more arguments against it, see here
Our Summary:
In obese ICU patients at risk for extubation failure, humidified NIV and HFNC showed comparable reintubation rates (19.1% vs. 22.8%) within 7 days. While both strategies had similar outcomes, HFNC was better tolerated, suggesting it as a viable alternative to NIV.
Who’s worked on this before?
- Thille et al. 2024 – Thille et al. 2024 – Post-hoc analysis of three large randomized controlled trials evaluating prophylactic NIV post-extubation in obese patients; findings indicated NIV’s benefit, though not consistently statistically significant.
- Thille et al. 2019 (HIGH-WEAN) – Thille et al. 2019 (HIGH-WEAN) – In 641 patients, alternating HFNC with NIV lowered reintubation risk by day 7 compared to HFNC alone.
- De Jong et al. 2023 (EXTUB-OBESE) – De Jong et al. 2023 (EXTUB-OBESE) – In 981 patients, NIV reduced extubation failure risk compared to oxygen therapy, primarily due to oxygen therapy patients switching to NIV.
- Stéphan et al. 2015 (BIPOP) – Stéphan et al. 2015 (BIPOP) – In 830 patients post-cardiothoracic surgery, high-flow nasal oxygen therapy was non-inferior to BiPAP for respiratory failure.
Further gripes
The 2024 Hernández study, titled “Humidified Noninvasive Ventilation versus High-Flow Therapy to Prevent Reintubation in Obese Patients: A Randomized Clinical Trial,” aimed to compare the effectiveness of noninvasive ventilation (NIV) with active humidification versus high-flow nasal cannula (HFNC) in preventing reintubation in obese patients (BMI ≥ 30 kg/m²) at intermediate risk of extubation failure. While the study provides valuable insights, several weaknesses can be identified based on the available information and critical analysis:
- Limited Sample Size and Statistical Power:
- The study included 144 patients (72 in each group), which may be underpowered to detect statistically significant differences in reintubation rates. The observed difference in reintubation rates (23.6% for NIV vs. 33.3% for HFNC) was not statistically significant (p-value not provided in the summary, but noted as non-significant). A larger sample size might have clarified whether the observed trend was meaningful or due to chance.
- Narrow Patient Selection:
- The study focused on patients with three or fewer risk factors for reintubation and excluded those with hypercapnia at the end of the spontaneous breathing trial. This restricts the generalizability of the findings to a specific subset of obese patients, potentially excluding those at higher risk or with different respiratory failure profiles (e.g., hypercapnic respiratory failure). This limits the applicability of the results to broader ICU populations.
- Lack of Blinding:
- The trial was unblinded, meaning clinicians and patients were aware of the assigned treatment (NIV or HFNC). This could introduce bias in clinical decision-making, such as the threshold for reintubation or the management of respiratory distress, potentially influencing the primary outcome.
- Short Duration of Intervention:
- The intervention was applied for only 48 hours post-extubation. Some patients may develop respiratory failure beyond this period, and the study’s design may not capture the long-term impact of NIV versus HFNC on extubation outcomes. This short timeframe could underestimate the effectiveness of either strategy in preventing late extubation failures.
- Heterogeneity in NIV Application:
- The study used NIV with active humidification, but details on the specific settings (e.g., pressure support levels, positive end-expiratory pressure, or duration of NIV sessions) were not fully described in the provided summary. Variability in NIV application (e.g., patient tolerance, mask fit, or compliance) could affect outcomes and introduce inconsistency, a known challenge with NIV in obese patients.
- Primary Outcome Focus:
- The primary outcome was reintubation within 7 days, but the study did not report significant differences in secondary outcomes like ICU length of stay, hospital mortality, or patient comfort. The lack of improvement in these patient-centered outcomes raises questions about the clinical significance of NIV’s potential benefits, even if reintubation rates were reduced.
- Potential Confounding Factors:
- The study was conducted in only two Spanish ICUs, which may limit generalizability due to differences in clinical practice, patient demographics, or ICU protocols. Additionally, factors such as comorbidities, severity scores, or the presence of undiagnosed obstructive sleep apnea (common in obese patients) were not fully addressed as confounders in the provided summary, though severe obesity and comorbidities were noted as risk factors for reintubation.
- Comparison to Prior Studies:
- The study’s findings contrast with some prior research, such as Thille et al. (2022), which found NIV alternating with HFNC significantly reduced reintubation rates in obese patients. The Hernández study’s failure to show a significant difference may reflect differences in patient populations, NIV protocols, or study design, but these discrepancies were not thoroughly explored, limiting the ability to contextualize the results.
- Exclusion of Hypercapnic Patients:
- By excluding patients with hypercapnia (PaCO2 ≥ 50 mmHg), the study may have missed a subgroup where NIV is particularly beneficial, as prior studies suggest NIV is more effective in hypercapnic respiratory failure. This exclusion could bias the results toward null findings, underestimating NIV’s potential benefits in a broader obese population.
- Tolerance and Compliance Issues:
- NIV tolerance is a known issue, particularly in obese patients due to mask discomfort or claustrophobia. The study does not provide detailed data on patient compliance or reasons for treatment discontinuation, which could significantly impact the effectiveness of NIV compared to HFNC, which is generally better tolerated.
In summary, the 2024 Hernández study provides a focused comparison of NIV and HFNC in obese patients but is limited by its small sample size, lack of blinding, narrow patient selection, and potential confounding factors. These weaknesses suggest caution in interpreting the findings and highlight the need for larger, more inclusive trials to clarify the role of NIV versus HFNC in preventing extubation failure in this population.
Written by Dr Jonny Wilkinson
