© 2006 American Thoracic Society
The Low-Flow or High-Flow Oxygen Delivery System and a Low-Flow or High-Flow Nonrebreather MaskFrom the Authors:We thank Dr. Agarwal for the opportunity to further describe our method of oxygen delivery (1). Dr. Agarwal's concern is with respect to the FIO2 delivered with the usual method, particularly if the flow provided is inferior to the patient's demand (i.e., minute ventilation and peak inspiratory flow rate) (2). In fact, we used a balloon with an oxygen reservoir bag having a volume of 2,600 ml, greater than the tidal volume of a patient in acute respiratory failure. Rarely, the reservoir collapsed because of inadequate flow, indicating that for the majority of our patients, the minute ventilation never exceeded 15–20 L/min. Although we were unable to determine the FIO2 delivered to the patients in the control group, we speculate that the effective FIO2 was maintained between 0.8 and 1.0 in the control arm and that imposed work of breathing was minimal. As stated in our article (1), we compared noninvasive ventilation (NIV) as a new preoxygenation method to the usual method using a nonrebreather face mask with a balloon and an oxygen reservoir bag, which is the preoxygenation method widely used in the intensive care units (3). Nevertheless, we postulate that the significant improvement in oxygenation observed after 3 min of preoxygenation using NIV was not only attributable to the high delivered oxygen concentration but also to the recruitment of collapsed alveoli (1, 4).
University Hospital of Montpellier and Saint Eloi Hospital, Montpellier University, Montpellier, France
Avicenne Hospital, Paris 13 University–AP-HP, EA 3409, Bobigny, France FOOTNOTES Conflict of Interest Statement: Neither author has a financial relationship with a commercial entity that has an interest in the subject of this manuscript. REFERENCES
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