The expense of providing continuous oxygen therapy has prompted the development of oxygen-conserving devices. We studied the efficacy of a device that delivers a pulse of oxygen during inspiration only (Pulsair, CryO 2 Corp). Methods: Oxygen was delivered at three different flowrates (1, 2, and 3 L/min) by either continuous flow or pulsed delivery to 16 exercising patients who had chronic respiratory disease. Arterial blood samples were drawn via arterial line at each flowrate for both modes. Results: The arterial oxygen tension (PaO 2 ) achieved by the individual systems showed significant agreement at each flowrate. However, some patients did show lower oxygenation with pulsed delivery, particularly at higher flowrates. Consequently, we recommend that before a pulsed-flow device is prescribed, the patient undergo a simple exercise test with oximetry to ensure adequate oxygen delivery.
McDonnell et al. (Wed,) studied this question.