What is it?
Apneic oxygenation (ApOx) is a passive flow of oxygen into the alveoli during apnea, typically at 15 liters per minute (LPM) via a nasal cannula. The procedure is quickly gaining traction in the clinical and pre-hospital settings because it is both safe and simple. Overall, apneic oxygenation aims to increase the length of the time that the patient remains oxygenated during intubation attempts.
Does it work?
The Mayo Clinic has completed a research study that reviewed a total of 14 studies that met their criteria. Of these 14 studies, 6 were from the Intensive Care Unit (ICU), 6 were from the Emergency Department (ED), and 2 were mixed from the ICU/ED. There were a total of 2,023 total patients in the 14 studies - 1,168 whom did receive apneic oxygenation and 855 patients who did not.
The study found that apneic oxygenation:
Increased peri-intubation oxygen saturation
Increased first-pass success rates with endotracheal intubation
Decreased incidence of hypoxia
Decreased length in ICU stays
Do I need a high-flow nasal cannula?
Flowing 15 liters per minute of oxygen through a "regular" nasal cannula is not a
typical procedure. However, it can be done. A "regular" nasal cannula, CapnoLine nasal cannula and of course, a high-flow nasal cannula can be used for ApOx.
Something worth mentioning is that the CapnoLine packaging shows a flow rate of 5L/minute or less (see picture below). However, this does not speak to the maximum amount of liters per minute that can be administered through this nasal cannula. Instead, manufacturer
directions state that a flow rate of greater than 5 LPM will cause CO2 wash out and will not allow the device to monitor carbon dioxide as intended.
What are the caveats?
Patients with shunt physiology (pneumonia, pulmonary edema, etc.) may not benefit from apneic oxygenation as much as a patient without shunt physiology. The pulmonary shunting in these patients decreases the ability for the hemoglobin to be continuously saturated. These patients benefit more from positive-end-expiratory-pressure (PEEP) more so than continuous high flow oxygen.