The use of increased nasal cannula (NC)
flow to deliver positive airway pressure
was initially described by Locke
et al5 in 1991 in 13 preterm infants.
They reported the potential to deliver
positive pressure with NC flows up to 2
L per minute (lpm), given a large NC
diameter (3 mm). They cautioned about
indiscriminate use of higher flow rates
via NC due to potential for unregulated
pressure delivery. Ten years later
Sreenan et al6 used the term “high-flow
nasal cannula” in reporting that NC
flows up to 2.5 lpm could be as effective
as nCPAP for treating apnea of prematurity,
and that delivered pressure
via NC flow could be regulated by using
esophageal pressure measurements.
Standard NC systems routinely use inadequately
warmed and humidified
gas, limiting use of higher flow rates
secondary to the risk of mucosal injury
and nosocomial infection.7–9 To circumvent
these concerns, heated, humidified
high-flow nasal cannula (HHHFNC)
systems were developed as possible
alternatives to nCPAP for noninvasive
respiratory support of neonates.