Clinical Trial: Combined High Frequency Oscillation and Tracheal Gas Insufflation for Severe Acute Respiratory Distress Syndrome

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Phase 1/Phase 2, Single-Center, Controlled Study of the Effectiveness of Combined High Frequency Oscillation and Tracheal Gas Insufflation in Improving the Clinical Course of Patients With Severe Acut

Brief Summary: In the past five years, there is a growing body of published evidence on the feasibility, and oxygenation and lung protection benefits of high frequency oscillation (HFO) in the acute respiratory distress syndrome (ARDS). The investigators have recently demonstrated the short term feasibility and additional benefits with respect to oxygenation of HFO combined with tracheal gas insufflation (TGI). In the present clinical trial, the investigators intend to test the hypothesis that HFO-TGI may result in improved respiratory physiology and clinical course compared to low tidal volume conventional mechanical ventilation in patients with severe ARDS.

Detailed Summary:

OBJECTIVES AND UNDERLYING HYPOTHESIS

High frequency oscillation (HFO) has beneficial physiological effects in acute respiratory distress syndrome (ARDS) [1-4]. A recent randomized controlled trial of HFO versus conventional mechanical ventilation (CMV) with traditional tidal volumes (10.1± 2.8 mL•kg-1 predicted body weight) reported a trend toward reduced 30-day mortality in the HFO arm (37% versus 52% in the CMV group; P = 0.10) [3]. To-date, HFO has not been compared to CMV with low tidal volumes (6.2 ± 1.1 mL•kg-1 predicted body weight) in ARDS [5], with respect to respiratory physiology and clinical course.

The main mechanisms of gas exchange during CMV are bulk convection and diffusion. [4, 6]. Tracheal gas insufflation (TGI) promotes CO2 elimination during CMV [7-9]. During HFO, additional gas exchange mechanisms comprise asymmetric velocity profiles, Taylor dispersion/turbulence, cardiogenic mixing, pendelluft effect, and collateral ventilation [4, 6].

We have recently shown that in patients with moderate-to-severe, primary ARDS, HFO combined with TGI (HFO-TGI) substantially improves oxygenation relative to both standard HFO and CMV according to the ARDS network protocol [5, 10]. Mean airway pressure (mPaw) was set at 1 cm H2O above the point of maximal curvature (PMC) of the expiratory pressure volume curve. During HFO-TGI, it is probably feasible to reduce mPaw, while still achieving PaO2 and peripheral oxygen saturation (SaO2) targets similar to those set by the ARDS network protocol [5]. This may result in reduced and non-traumatic ventilation pressures during HFO-TGI. Furthermore, if HFO-TGI-related gas exchange benefits are maintained during post-HFO-TGI CMV [10], then a reduction of ventilation pressures relative to the pre-HFO-TGI CMV ma
Sponsor: University of Athens

Current Primary Outcome:

  • Physiological variables (i.e. ventilation pressures and oxygenation) during the first 7-10 days following randomization [ Time Frame: 8-10 days post-randomization ]
  • Survival to days 28 and 60 post-randomization and to Hospital Discharge [ Time Frame: 28 days to more than 60 days post-randomization ]


Original Primary Outcome:

  • Survival to 28 days post-randomization
  • Survival to hospital discharge.
  • Ventilator-free days


Current Secondary Outcome:

  • Ventilator free days [ Time Frame: 28 days and 60 days ]
  • Number of Organ or system failure free days [ Time Frame: 28 days and 60 days ]
  • Occurence of Barotraumas/airway injury [ Time Frame: 28 days and 60 days ]


Original Secondary Outcome:

  • Number of days without organ system failure
  • Length of Intensive Care Unit Stay
  • Occurence of Barotraumas


Information By: University of Athens

Dates:
Date Received: December 26, 2006
Date Started: July 2006
Date Completion:
Last Updated: June 21, 2014
Last Verified: June 2014