The Impact of High-Flow Nasal Oxygen in the Immunocompromised Critically Ill: A Systematic Review and Meta-Analysis

Abstract

BACKGROUND: High-flow nasal-cannula (HFNC) may be an oxygen modality useful for preventing invasive mechanical ventilation and mortality; however, its role in acute hypoxemic respiratory failure is not clearly defined. We sought to evaluate the impact of HFNC on mortality across immunocompromised subjects compared to alternative noninvasive oxygen therapies, namely conventional oxygen therapy and noninvasive ventilation (NIV). METHODS: We systematically searched the major databases to identify randomized, controlled trials (RCTs) or observational studies (until May 2018). We included studies reporting the use of HFNC in immunocompromised subjects and evaluated its impact on mortality and invasive mechanical ventilation. RESULTS: Upon review of 6,506 titles, 13 studies (1,956 subjects) fulfilled our inclusion criteria (4 RCTs, 9 observational studies). The predominant cause of immunocompromised status was cancer. Bacterial pneumonia was the most common cause of acute hypoxemic respiratory failure with a median P aO2 /F IO2 of 145 mm Hg (interquartile range 115-175). HFNC was used as the first oxygen strategy in 474 subjects compared to NIV (242 subjects) and conventional O 2 therapy (703 subjects). There was a 46% rate of invasive mechanical ventilation and 36% mortality. Mortality at the longest available follow-up was lower with HFNC compared to the oxygen therapy controls (NIV or conventional O 2 therapy) in 7 studies (1,429 subjects; relative risk 0.72, 95% CI 0.56-0.93, P ‫؍‬ .01). There was a lower rate of invasive mechanical ventilation with HFNC compared to the oxygen therapy controls across 8 studies (1,529 subjects, relative risk 0.81, 95% CI 0.67-0.96, P ‫؍‬ .02). These results were robust across a series of sensitivity analyses. CONCLUSIONS: There exists a need to develop a greater evidence base evaluating the utility of HFNC in immunocompromised subjects. In our exploratory analysis, HFNC was found to decrease mortality and use of invasive mechanical ventilation compared to alternative noninvasive oxygen controls. These results are meant to be exploratory. Higher-quality studies evaluating a more homogeneous population are needed to further elucidate its benefit.

Noninvasive Oxygenation Strategies in Adult Patients with Acute Respiratory Failure: A Protocol for a Systematic Review and Network Meta-analysis

“…The risk of bias will be assessed independently using the tools specified in the Cochrane Handbook for Systematic Reviews of Interventions for RCTs. [27][28][29][30] The following aspects will be assessed: This research will be done without patient involvement. Patients will not be invited to comment on the protocol design nor consulted to develop patient relevant outcomes.…”

“…(8) Furthermore, although previous systematic reviews and meta-analyses have explored the effectiveness of HFNC in patients with AHRF, these studies have often pooled control group data as "any other strategy", failing to account for the important physiologic and clinical differences of these alternative interventions. (28)(29)(30) Network meta-analysis (NMA) is a strategy to summarize the evidence of clinical studies which include multiple treatments. 31…”

Non-Invasive Oxygenation Strategies in Adult Patients with Acute Respiratory Failure: A Protocol for a Systematic Review and Network Meta-analysis

“…The risk of bias will be assessed independently using the tools specified in the Cochrane Handbook for Systematic Reviews of Interventions for RCTs. [27][28][29][30] The following aspects will be assessed:…”

“…(8) Furthermore, although previous systematic reviews and meta-analyses have explored the effectiveness of HFNC in patients with AHRF, these studies have often pooled control group data as "any other strategy", failing to account for the important physiologic and clinical differences of these alternative interventions. (28)(29)(30) Network meta-analysis (NMA) is a strategy to summarize the evidence of clinical studies which include multiple treatments. 31 The primary objective of this NMA is to assess the association between different non-invasive oxygenation strategies and all-cause mortality in adult patients with AHRF.…”

Effect of High-Flow Nasal Cannula Oxygen Therapy in Immunocompromised Subjects With Acute Respiratory Failure

“…16,17 Some systematic reviews and meta-analyses have reported that HFNC might decrease mortality and the use of invasive mechanical ventilation in immunocompromised subjects with ARF compared to other noninvasive oxygen strategies. 18,19 However, a recent meta-analysis, 20 which included a new large-scale trial, 21 found no benefit of HFNC over conventional oxygen therapy on mortality in immunocompromised subjects. These findings were consistent with another recent meta-analysis 22 that focused on a heterogeneous patient population, which included immunocompromised subjects.…”