Portable pulse-dose oxygen concentrators should not be used with noninvasive ventilation.

An increasing number of patients, mainly COPD and overlap-syndrome patients, simultaneously use home oxygen therapy and noninvasive ventilation (NIV) at night. Usually the oxygen source is a stationary concentrator. We report a patient who, without a medical recommendation, was using a portable oxygen concentrator during nocturnal NIV. In the laboratory, with the patient, we tested the portable oxygen concentrator's triggering and oxygen delivery, with the supplemental oxygen connected at 3 different positions: near the ventilator, near the exhalation valve, and on the nasal mask port. We also tested the concentrator's triggering capacity by placing the nasal prongs and the nasal mask independently. We tested ventilator inspiratory pressures of 10, 14, and 18 cm H(2)O, and expiratory pressures of 4 and 6 cm H(2)O. The portable oxygen concentrator did not detect the patient's inspiratory effort or deliver the required oxygen flow at any of the tested settings. We recommended that the patient not use the portable oxygen concentrator during nocturnal NIV.