Clinical Study

Clinical Study

Respiratory Care Journal

April 2016; Editor’s Choice Study

The Study measured the effects on oxygen concentrations entering the airway when one nasal passage becomes blocked, a common occurrence of the “nasal cycle.” Here the authors found that the “traditional nasal cannula may be inefficient in the presence of the nasal cycle.” The authors concluded that “traditional nasal cannula usage in the presence of the human nasal cycle may result in oxygen waste for the patients receiving long-term oxygen therapy and a failure to deliver the prescribed amount of oxygen to the patient.”

“Right Versus Left Prong Nasal Cannula Flow Delivery and the Effects of Nasal Cycling on Inspired FIO2 in an Adult Model”

Authors: S. Gregory Marshall PhD, RRT, RPSGT, RST; Nicholas R. Henry MSc, RRT-ACCS, RRT-NPS AE-C; and Christopher J. Russian PhD, RRT-NPS, RPSGT, RST

The Nasal Cycle

  • Nasal cycle was first reported over 100 years ago – Nearly 80% of the health population appear to exhibit a regular nasal cycle day and night. It is present in infants, children, adults, and the majority of mammals as well (rats, rabbits, dogs, cats).
  • The nose is separated into 2 independent passages, and the phenomenon known as nasal cycling is the spontaneous change in unilateral airflow as a result of congestion and decongestion of the right or left nasal venous sinuses. The right and left prong of the nasal cannula is designed to deliver oxygen to its respective naris. There are no previous studies comparing right and left prong oxygen flow for nasal cannula adjuncts at various therapeutic flow settings.

Testing Methods

  • Oxygen flow from Right and Left Nasal Cannula prongs were measured simultaneously using thermal mass flow meters. 5 cannulas from different manufacturers were used.
  • An adult mannequin head with correct airways was connected to a test lung.
  • To accurately imitate the human nasal cycle, data was recorded with a) both nasals open, b) the right side blocked with left side open, and c) the left side blocked with right side open


  • There were statistical differences between right and left nasal cannula prong oxygen flows

  • No significant differences in nasal cannula flow between the differences in 5 cannulas from different manufacturers.

  • Significant differences when alternative nostrils were blocked and the other open.


  • Evaluating the flow of oxygen from nasal cannula prongs comparing 5 brands of nasal cannula devices revealed a statistically significant difference between right and left nasal cannula prong flow; however, the difference may not be clinically important. Delivering oxygen by nasal cannula during nasal cycling, causing a completely obstructed naris, may be insufficient for oxygen patient demands. Traditional nasal cannula usage in the presence of the human nasal cycle may result in oxygen waste for patients and fail to deliver the prescribed amount of oxygen to the patient. Because of this, clinicians should consider the effects of nasal cycling when delivering low-flow oxygen by nasal cannula.