Background: In infants, a high-flow nasal cannula (HFNC) generates continuous positive pressure on the upper airway. This study aimed to evaluate the association between pharyngeal pressure and flow rate, and the association between pharyngeal pressure and bodyweight for two types of HFNC devices commonly used in preterm infants: the Optiflow Junior, hereafter "FP" (Fisher & Paykel, Auckland, New Zealand), and the Precision Flow, hereafter "VT" (Vapotherm, Exeter, NH, USA).
Methods: Pharyngeal pressure measurements were performed in 12 preterm infants who received HFNC support. Flow rates of 1 to 4 L/kg/min were studied.
Results: The median weight at the time of measurement was 1,290 g (range, 953-1,932 g). The FP was used in eight infants and the VT in four. In both of the groups, the flow rate and pharyngeal pressure appeared to be positively correlated except for the premature cannula in the FP group. At a flow rate of ≥2 L/kg/min, there was a positive correlation between the bodyweight and pharyngeal pressure in infants with premature and neonatal cannulas in the FP group. Conversely, at the same flow rate, there was a negative correlation between the bodyweight and pharyngeal pressure in infants with a SOLO cannula in the VT group.
Conclusions: In preterm infants, the flow rate and pharyngeal pressure were positively correlated in many HFNC cannulas. However, the pharyngeal pressure and bodyweight appeared to be positively and negatively correlated in the FP and VT groups, respectively. Future studies with larger sample sizes should further investigate this issue.
Keywords: cannula; continuous positive airway pressure; infant; newborn; sample size.
© 2021 Japan Pediatric Society.