High Flow Through a Nasal Cannula and CPAP Effect in a Simulated Infant Model

The full text article is temporarily unavailable.

We apologise for the inconvenience. Please try again later.

Abstract:

BACKGROUND: Limited data are available to describe the CPAP effects that can be expected when using high flow with a traditional nasal cannula. OBJECTIVE: To describe the relationship between the pressure generated at the airway opening and flow through a nasal cannula using a simulated infant model. We hypothesized that positive pressure generated by a standard cannula at flows > 2 L/min would be minimal and clinically unimportant. METHODS: Nares were simulated with holes drilled in a plastic fixture. A nares template for CPAP prongs served as a sizing template for the holes. Small, medium, and large nares fixtures were constructed and connected to a lung simulator that simulated spontaneous breathing. Respiratory muscle pressure was simulated by setting a waveform and adjusting the amplitude to deliver a range of tidal volumes (VT) from 3 mL to 12 mL. Lung compliance and resistance were set at 0.5 mL/cm H2O and 125 cm H2O/L/s, respectively. Nasal cannulas were inserted in the model nares. We assured that the prong occlusion of the nares did not exceed 50%. Cannula flow was adjusted from 2‐6 L/min in 1-L/min increments. Data were averaged over 20 breaths. Mean airway pressure and percent change in VT were recorded. RESULTS: The greatest effect on VT (mean ± SD 0.16 ± 0.10 mL) and pressure change (mean ± SD 0.7 ± 0.5 cm H2O) occurred with the premature cannula. The least effect on pressure (mean ± SD 0.3 ± 0.22 cm H2O) and VT change (mean ± SD 0.01 ± 0.02 mL) occurred with the infant cannula. CONCLUSIONS: Clinically important pressures were not generated by high flows with a standard nasal cannula. The differences in spontaneous VT across all flows were negligible.

Keywords: high-flow nasal cannula; nasal CPAP; oxygen therapy; pediatric

Document Type: Research Article

DOI: http://dx.doi.org/10.4187/respcare.01204

Affiliations: Children’s Hospital Medical Center of Akron, Akron, Ohio. USA

Publication date: December 1, 2011

Related content

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more