An early feasibility study to investigate the safety and feasibility of the Lungpacer Diaphragm Pacing Therapy System (DPTS) as a therapy to recondition and strengthen the diaphragm of patients who have been intubated and invasively mechanically ventilated for > or = 7 days, have failed two or more spontaneous breathing trials (SBT), and were not hypervolemic during the latest SBT.

Mechanical ventilation (MV) is a life saving technology but can also cause damage to the lungs and diaphragm such as ventilator induced diaphragmatic dysfunction (VIDD). Research has shown that after being on mandatory MV and sedated the diaphragm begins to atrophy within as little as 18 hours. The DPTS is a temporary therapy that consists of the Lungpacer IntraVenous Electrode Catheter (LIVE Catheter) and the lungpacer Control Unit (LCU) system. The LIVE Catheter is a proprietary central venous catheter that incorporates pacing electrodes in strategic areas that align with the left and right phrenic nerves in order to stimulate the nerves to recruit the diaphragm. The LIVE Catheter can also be used for fluid delivery like any other central venous catheter. This early feasibility trial will investigate the safety and feasibility of the DPTS as a therapy to recondition and strengthen the diaphragm by stimulating the diaphragm through daily sessions so the patient may be more quickly liberated from MV. The patient population includes those who have been mechanically ventilated for > or = to 7 days, have failed two or more SBTs, and were not hypervolemic during the latest SBT. Patients must have resolution of the initial indication for placement on MV before entering the trial.

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

Only investigators participating in this clinical trial will be able to see final de-identified participant data at the completion of the study and it will be available through Syntactx.