RT Journal Article SR Electronic T1 Oxygen supplementation in noninvasive home mechanical ventilation: the crucial roles of CO2 exhalation systems and leakages JF Respiratory Care FD American Association for Respiratory Care SP respcare.02596 DO 10.4187/respcare.02596 A1 Storre, Jan H A1 Huttmann, Sophie E A1 Ekkernkamp, Emelie A1 Walterspacher, Stephan A1 Schmoor, Claudia A1 Dreher, Michael A1 Windisch, Wolfram YR 2013 UL http://rc.rcjournal.com/content/early/2013/06/25/respcare.02596.abstract AB Background: When supplemental oxygen is added to noninvasive positive pressure ventilation (NPPV) using non-ICU ventilators, it is usually introduced with a preset flow rate into the ventilatory circuit at a site next to the ventilator; however, the impact of different CO2 exhalation systems and leaks on actual inspired FiO2 and gas exchange has not been elucidated. Methods: In a randomized, open-label, four-treatment (two-by-two), four-period crossover design, four daytime measurements (60 minutes each) were performed in 20 patients receiving home mechanical NPPV plus ≥2 L O2/min inserted proximally to the ventilator: active valve circuit or leak port circuit with or without artificial leakage (4mm I.D.). FiO2 at the ventilator, FiO2 at the mask, and blood gases were measured. Results: Overall, FiO2-mask (29±5%) was lower compared to FiO2-ventilator (34±4%), with a mean (95%CI) difference of 5.1 (4.2 to 5.9, p<0.0001)%. With the leak port circuit, FiO2-mask decreased by 3.2 (2.6 to 3.9, p<0.0001)% when compared to the active valve circuit. When artificial leakage was introduced into the circuit, FiO2-mask decreased by 5.7 (5.1 to 6.4, p<0.0001)%, PaO2 by 10.4 (3.1 to 17.7, p=0.006) mmHg, and PCO2 increased by 1.8 (0.5 to 3.3, p=0.008) mmHg. Conclusions: The use of leak port circuits and the occurrence of leakages around the interface significantly reduce FiO2-mask and negatively impact on gas exchange in patients receiving home mechanical NPPV and supplemental oxygen. Registered at: German Clinical Trials Register (DRKS); www.drks.de Registration number: DRKS00000449