Please select the eligibility criteria that correspond to the clinical trial below.
Title: Phase II/Phase III Study of the Effect of Combined High-frequency Oscillation and Tracheal Gas Insufflation on the Survival to Hospital Discharge of Patients With Severe Acute Respiratory Distress Syndrome
Brief Summary: The investigators have recently demonstrated the beneficial effects of combined high-frequency oscillation (HFO) and tracheal gas insufflation (TGI) on the respiratory physiology \[1,2\] of patients with severe acute respiratory distress syndrome (ARDS) (NCT00416260). Preliminary short-term survival results were also encouraging. Consequently, in the present clinical trial, the investigators intend to increase the size of the studied population, in order to evaluate the effect of HFO-TGI on survival with adequate statistical power. Furthermore, the investigators intend to elucidate the mechanism of the HFO-TGI-related physiological benefit.


Options:
A: Inclusion Criteria:

* Acute onset of respiratory failure, with fewer than 2 weeks of new pulmonary symptoms;
* Endotracheal intubation or tracheostomy;
* Hypoxaemia - defined as a partial pressure of oxygen in arterial blood (PaO2)/fraction of inspired oxygen (FiO2) less than or equal to 200mmHg on FiO2 greater than or equal to 0.5, regardless of positive end expiratory pressure (PEEP)
* Bilateral alveolar consolidation (airspace disease) seen on frontal chest radiograph

In addition, to qualify for randomization, patients are assessed on the following ventilator settings:

* Mode: pressure control or volume control or pressure support
* FiO2 greater than 0.6 (or higher if necessary to keep pulse oximetric saturation \[SpO2\] greater than 90%)
* PEEP greater than 10 cm H2O (or greater if necessary to keep SpO2 greater than 90%)
* Tidal volume 6 ml/kg predicted body weight (PBW)

After at least 30 minutes on these settings, we sample arterial blood to assess oxygenation. If PaO2 is less than or equal to 200 mmHg, the patient qualifies for randomization; if PaO2/FiO2 greater than 200 mmHg, standardized hypoxaemia assessments are repeated at least once daily for the following 72 hours (providing eligibility criteria are still met).

Exclusion Criteria:

* Remaining duration of mechanical ventilation less than 48 hours, as judged by the attending physician
* Primary cause of acute respiratory failure judged by attending physician to be circulatory overload due to, for example, congestive heart failure, hyper-resuscitation, or need for dialysis
* Suspected pulmonary haemorrhage syndrome
* Lack of commitment to ongoing life support (note that this does not include the presence of a "Do Not Resuscitate" order alone, if there is a commitment to ongoing life support
* Aged less than 16 years or greater than 85 years
* Weight less than 35 kg
* Severe chronic respiratory disease, as indicated by any of:
* Baseline forced expiratory volume in one second (FEV1) less than 20 ml/kg predicted body weight
* Pre-existing chronic interstitial lung disease with chronic interstitial infiltration on chest x-ray
* Documented chronic carbon dioxide (CO2) retention (partial pressure of carbon dioxide in arterial blood \[PaCO2\] less than 50 mmHg) and/or chronic hypoxaemia(PaO2 less than 55 mmHg on FiO2=0.21)
* Chronic restrictive, obstructive, neuromuscular, chest wall or pulmonary vascular disease resulting in severe exercise restriction (e.g., unable to climb stairs or perform household duties), secondary polycythaemia, severe pulmonary hypertension (mean pulmonary arterial pressure \[PAP\] greater than 40 mmHg), or ventilator dependency
* Morbid obesity - defined as greater than 1 kg/cm body height
* Underlying pre-existing condition with expected 6-month mortality greater than 50%
* Neurological conditions with risk of intracranial hypertension (where hypercapnia should be avoided)
* Neuromuscular disease that will result in prolonged need for mechanical ventilation, including (but not limited to):
* Guillain Barre syndrome
* Cervical spinal cord injury
* Previous randomization in this trial
* All inclusion criteria present for greater than 73 hours in study intensive care unit (ICU)
* On HFO at the time of screening
B: Inclusion Criteria:

* Invasive mechanical ventilation
* Acute respiratory insufficiency (within past 28 days)
* Bilateral infiltrates on frontal chest radiograph
* Hypoxemia, defined as PaO2/FiO2\<=250

Exclusion Criteria:

* Primary cause of respiratory failure is cardiac
* Anticipated duration of mechanical ventilation \< 48 hours
* Inability to wean other experimental ventilation strategies
* Severe chronic respiratory disease
* Neuromuscular disease that will prolong mechanical ventilation
* Conditions where hypercapnia-induced intracranial hypertension should be avoided
* Morbid obesity (\> 1Kg per cm body weight)
* Pregnancy
* Very unlikely to survive and lack of commitment to life support Underlying irreversible condition with 6 month mortality \>= 50%
* Greater than 48 hours elapsed since first eligible
* Current participation in competing trial
* Lack of physician, patient or proxy consent
C: Inclusion Criteria:

* Age 18-75 years
* Body weight \> 40 kg
* Endotracheal intubation and mechanical ventilation
* Diagnosis of ARDS established within preceding 72 h
* Severe oxygenation disturbances: PaO2/FiO2 \<150 mm Hg sustained for 12 h, despite being ventilated with PEEP ≥8 cm H2O

Exclusion Criteria:

* Active air leak or recent severe air leak (severe air leak: \> 1 chest tube per hemithorax with persistent gas leak for \> 72 h)
* Severe hemodynamic instability (i.e., systolic arterial pressure \< 90 mm Hg despite volume loading and norepinephrine infusion at ≥ 0.5 μg/kg/min)
* Significant heart disease (i.e., ejection fraction \<40 %, and/or history of pulmonary edema, and/or active coronary ischemia or myocardial infarction)
* Significant chronic obstructive pulmonary disease (COPD) or asthma {i.e., previous admissions for COPD/asthma, chronic corticosteroid therapy for COPD/asthma, and documented chronic CO2 retention leading to a baseline PaCO2 of \> 50 mm Hg (for COPD)}
* Uncontrollable intracranial hypertension (i.e., intracranial pressure \>20 mm Hg despite deep sedation, analgesia, hyperosmolar therapy, and minute ventilation titrated to PaCO2 = 35 mm Hg)
* Chronic Interstitial Lung Disease associated with bilateral pulmonary infiltrates
* Lung biopsy or resection on current admission
* Immunosuppression caused by

  * neutropenia \[i.e., polymorphonuclear leukocyte count \< 1,000/μL (1 x 1012/L)\] after chemotherapy or bone marrow transplantation for hematologic cancers
  * corticosteroid or cytotoxic therapy for a nonmalignant disease
  * the acquired immunodeficiency syndrome
* Inability to wean from prone positioning or inhaled nitric oxide
* Pregnancy or morbid obesity (body mass index \>40 kg/m2)
* Enrollment in another interventional study
* Crossover from the CMV-group to the HFO-TGI-group at \> 72 h after the onset of the severe oxygenation disturbances
D: Inclusion Criteria:

* Mechanical ventilation through an endotracheal tube
* Bilateral infiltrates consistent with pulmonary edema
* PaO2/FiO2 \< 300 mmHg
* No clinical evidence of left atrial hypertension. If measured, pulmonary artery occlusion pressure \< 18 mmHg
* Criteria 1, 2 et 3 jointly present for less than 48 hours
* Written informed consent obtained from the patient or surrogate

Exclusion Criteria:

* Age \< 18 years
* Pregnancy
* Expected duration of mechanical ventilation through an endotracheal tube \< 48 hours
* Participation in other trials within the previous 30 days
* Increased intracranial pressure
* Severe chronic respiratory disease
* Morbid obesity (weight \> 1kg/cm)
* Sickle cell disease
* Bone marrow transplant or chemotherapy-induced neutropenia
* Extended burns (\> 30 % total body surface area)
* Severe chronic liver disease (Child-Pugh score C)
* Pneumothorax

Answer: C