High-flow nasal cannula: Impact on oxygenation and ventilation in an acute lung injury model

Nemours Children's Clinic of Wilmington, The Nemours Foundation, Alfred I. duPont Children's Hospital, Primary Research Institution, Wilmington, Delaware 19803, USA.
Pediatric Pulmonology (Impact Factor: 2.7). 01/2011; 46(1):67-74. DOI: 10.1002/ppul.21326
Source: PubMed


High-flow nasal cannula therapy (HFNC) has been shown to be more effective than continuous positive airway pressure (CPAP) in reducing intubations and ventilator days. HFNC likely provides mechanisms to support respiratory efficiency beyond application of distending pressure. We reason that HFNC washout of nasopharyngeal dead space impacts CO(2) removal along with oxygenation. The aim of this study was to demonstrate the flow dependence of CO(2) reduction and improved oxygenation during HFNC and the dependence on leak around the nasal prongs.
Neonatal piglets (n=13; 2-6 kg) were injured with IV oleic acid and supported with HFNC at 2 through 8 L/min. High and low leak around the nasal prongs was accomplished by using single and double prong cannulae, respectively. Measurement of hemodynamic, respiratory and blood gas parameters were made at each setting following 10 min for physiologic equilibration. Tracheal pressures were recorded by transmural catheters.
With HFNC, CO(2) trended downward in a flow-dependent manner independent of leak. Oxygenation and tracheal pressures increased in a flow-dependent manner with the greatest effect during double prong. At 8 L/min, tracheal pressures did not exceed 6 ± 1 cmH(2) O.
HFNC improves gas exchange in a flow-dependent manner; double prong had greater impact on O(2;) single prong had greater impact on CO(2) elimination.

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