title: Preliminary observations of transtracheal augmented ventilation for chronic severe respiratory disease.
abstract: OBJECTIVE
  Evaluate the potential safety and efficacy of transtracheal augmented ventilation (TTAV), which is the transtracheal delivery of high flows of a humidified air-oxygen blend.
  
  
  METHODS
  The first of 2 observational studies evaluated patients before and after a 3-month intervention with the nocturnal (Noc) administration of TTAV at 10 L/min. Resting physiologic studies evaluated standard low-flow transtracheal oxygen (LFTTO), TTAV, and breathing without transtracheal flow via mouthpiece (MP). Patients also underwent nocturnal polysomnography, bronchoscopy, ventilatory drive evaluation, and treadmill exercise. The second study assessed the safety of Noc TTAV for up to 60 months. Each study evaluated 15 different transtracheal patients with severe lung disease.
  
  
  RESULTS
  Pleural pressure-time index and respiratory duty cycle were significantly lower (p < 0.05) when comparing MP to TTAV. TTAV contributed more (p < 0.05) than LFTTO to the total volume delivered to the lung (V(L)). Arterial blood gases and (V(L)) were unaltered by TTAV. Sleep quality and nocturnal oxygenation with TTAV were similar to LFTTO, and Noc TTAV had no effect on ventilatory drive. Bronchoscopy showed no evidence of substantial injury. Treadmill exercise tests showed a longer exercise time (p < 0.005) and greater total work (p < 0.05) following Noc TTAV. During exercise, the changes in slope for heart rate and pH were less steep (p < 0.05) following Noc TTAV. The 3-month study and a long-term evaluation showed that Noc TTAV was well-tolerated and safe, with a reported high compliance.
  
  
  CONCLUSIONS
  Patients with chronic hypoxemia and severe respiratory insufficiency may benefit from Noc TTAV.
authors.affiliation: Division of Pulmonary Sciences and Critical Care Medicine, Dept. of Medicine, University of Colorado Health Sciences Center, Denver CO 80231, USA. drkchristopher@home.com
authors.forename: K L
authors.initials: KL
authors.lastname: Christopher
authors.forename: D T
authors.initials: DT
authors.lastname: VanHooser
authors.forename: S J
authors.initials: SJ
authors.lastname: Jorgenson
authors.forename: L
authors.initials: L
authors.lastname: Winslett
authors.forename: S S
authors.initials: SS
authors.lastname: Diehl
authors.forename: D A
authors.initials: DA
authors.lastname: Young
authors.forename: H
authors.initials: H
authors.lastname: Shapiro
authors.forename: T L
authors.initials: TL
authors.lastname: Petty
mesh_terms: D000368:Aged; D001999:Bronchoscopy; D002908:Chronic Disease; D005080:Exercise Test; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D017286:Polysomnography; D012131:Respiratory Insufficiency / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics