Percutaneous Temporary Placement of a Phrenic Nerve Stimulator for Diaphragm Pacing (RESCUE1)

Inclusion Criteria: * 18 years of age or older * have been mechanically ventilated for \> or = 7 days and have not met criteria for successful weaning during this period; and * have failed at least two SBTs, one of which is the study specific SBT. (Self-extubation with subsequent reintubation within 48 hours is considered a failed SBT). Exclusion Criteria: * currently on extracorporeal membrane oxygenation (ECMO); * weaning failure due to hypervolemia; * known anatomy that prevents insertion of the LIVE Catheter into the left subclavian vein; * history of congenital heart disease; * clinically overt congestive heart failure; * pre-existing neuromuscular diseases that could affect the respiratory muscles; * pleural effusions occupying greater than one third of the pleural space on either side; * BMI \> or = 40; * known or suspected phrenic nerve paralysis; * any electrical device (implanted or external) that may be prone to interaction with or interference from the Lungpacer DPTS including neurological pacing/stimulator devices, cardiac pacemakers and defibrillators; * bacteremia (blood cultures must be negative for 48 hours); * current haemodynamic instability, shock or severe sepsis; * terminally ill with 6 months or less life expectancy or not committed to full care; * known or suspected to be pregnant or lactating; and * actively participating in another clinical study