This systematic review produced by Corley and colleagues was published online in Cochrane Library in May 2017.
Background: A common reason for intensive care unit (ICU) admission is the need for breathing (or respiratory) support. HFNC are small plastic tubes that sit inside the nostrils and deliver a heated mix of air and oxygen at high flow rates to patients requiring breathing support. They are used frequently in the ICU, yet no clear evidence shows whether they provide patients with long-term benefits such as reduced ICU stay or improved chances of survival.
Study characteristics: The evidence is current to March 2016. We included in the review 11 studies with 1972 participants. Most participants had respiratory failure, or had just been taken off an artificial breathing machine. Included studies compared HFNC with low-flow oxygen given through face masks, through low-flow cannulae, or through devices that use mild pressure to aid oxygen delivery. We reran the search in December 2016 and will deal with any studies of interest when we update the review.
Key results: We found no evidence that HFNC reduced the rate of treatment failure or risk of death compared with low-flow oxygen devices. We found no evidence of any advantages for HFNC in terms of adverse event rates, ICU length of stay, or duration of respiratory support. We observed no differences in participants’ blood oxygen levels or carbon dioxide blood levels, and we noted that any differences in breathing rates were small and were not considered clinically important. Studies reported no differences in patient-rated measures of comfort. Only one study found evidence of less dry mouth when HFNC was used.
Quality of evidence: Most studies had reported methods inadequately, and we did not know whether risk of bias may have affected study results. We identified few eligible studies and noted some differences among participants within our included studies, particularly in reasons for requiring respiratory support. We used the GRADE system to rate the evidence for each of our outcomes, and we judged all evidence to be of low or very low quality.
Conclusion: We were not able to collect sufficient evidence from good quality studies to determine whether HFNC offer a safe and effective way of delivering respiratory support for adults in the ICU.