High-flow nasal cannulae for respiratory support in adult intensive care patients.

backgroundHigh-flow nasal cannulae (HFNC) deliver high flows of blended humidified air and oxygen via wide-bore nasal cannulae and may be useful in providing respiratory support for adult patients experiencing acute respiratory failure in the intensive care unit (ICU).

objectivesWe evaluated studies that included participants 16 years of age and older who were admitted to the ICU and required treatment with HFNC. We assessed the safety and efficacy of HFNC compared with comparator interventions in terms of treatment failure, mortality, adverse events, duration of respiratory support, hospital and ICU length of stay, respiratory effects, patient-reported outcomes, and costs of treatment. SEARCH

methodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 3), MEDLINE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Web of Science, proceedings from four conferences, and clinical trials registries; and we handsearched reference lists of relevant studies. We conducted searches from January 2000 to March 2016 and reran the searches in December 2016. We added four new studies of potential interest to a list of 'Studies awaiting classification' and will incorporate them into formal review findings during the review update. SELECTION CRITERIA: We included randomized controlled studies with a parallel or cross-over design comparing HFNC use in adult ICU patients versus other forms of non-invasive respiratory support (low-flow oxygen via nasal cannulae or mask, continuous positive airway pressure (CPAP), and bilevel positive airway pressure (BiPAP)). DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. MAIN

resultsWe included 11 studies with 1972 participants. Participants in six studies had respiratory failure, and in five studies required oxygen therapy after extubation. Ten studies compared HFNC versus low-flow oxygen devices; one of these also compared HFNC versus CPAP, and another compared HFNC versus BiPAP alone. Most studies reported randomization and allocation concealment inadequately and provided inconsistent details of outcome assessor blinding. We did not combine data for CPAP and BiPAP comparisons with data for low-flow oxygen devices; study data were insufficient for separate analysis of CPAP and BiPAP for most outcomes. For the primary outcomes of treatment failure (1066 participants; six studies) and mortality (755 participants; three studies), investigators found no differences between HFNC and low-flow oxygen therapies (risk ratio (RR), Mantel-Haenszel (MH), random-effects 0.79, 95% confidence interval (CI) 0.49 to 1.27; and RR, MH, random-effects 0.63, 95% CI 0.38 to 1.06, respectively). We used the GRADE approach to downgrade the certainty of this evidence to low because of study risks of bias and different participant indications. Reported adverse events included nosocomial pneumonia, oxygen desaturation, visits to general practitioner for respiratory complications, pneumothorax, acute pseudo-obstruction, cardiac dysrhythmia, septic shock, and cardiorespiratory arrest. However, single studies reported adverse events, and we could not combine these findings; one study reported fewer episodes of oxygen desaturation with HFNC but no differences in all other reported adverse events. We downgraded the certainty of evidence for adverse events to low because of limited data. Researchers noted no differences in ICU length of stay (mean difference (MD), inverse variance (IV), random-effects 0.15, 95% CI -0.03 to 0.34; four studies; 770 participants), and we downgraded quality to low because of study risks of bias and different participant indications. We found no differences in oxygenation variables: partial pressure of arterial oxygen (PaO AUTHORS'

conclusionsWe were unable to demonstrate whether HFNC was a more effective or safe oxygen delivery device compared with other oxygenation devices in adult ICU patients. Meta-analysis could be performed for few studies for each outcome, and data for comparisons with CPAP or BiPAP were very limited. In addition, we identified some risks of bias among included studies, differences in patient groups, and high levels of statistical heterogeneity for some outcomes, leading to uncertainty regarding the results of our analysis. Consequently, evidence is insufficient to show whether HFNC provides safe and efficacious respiratory support for adult ICU patients.