Reductions in dead space ventilation with nasal high flow depend on physiological dead space volume: metabolic hood measurements during sleep in patients with COPD and controls - Biselli, Paolo José Cesare; Fricke, Kathrin; Grote, Ludger; Braun, Andrew T; Kirkness, Jason; Smith, Philip; Schwartz, Alan; Schneider, Hartmut (European Respiratory Journal, 2018)