Background to Lungpacer® Therapy
Mechanical ventilation (MV) can be life-saving for many critically ill patients. However, MV can also be harmful to the patient:
- MV and sedation cause the disused diaphragm muscle to atrophy rapidly and profoundly (ventilator induced diaphragm dysfunction; VIDD*)
- Positive-pressure ventilation often damages the lungs (ventilator induced lung injury; VILI) and leads to ventilator-associated pneumonia (VAP)
- MV requires intubation and, whenever ventilation has to continue for longer than a week, a tracheostomy
- Ventilated patients are at high risk of contracting nosocomial (hospital-acquired) bacterial and fungal infections
VIDD, VILI and VAP are key contributing factors to the frequent difficulty in weaning patients from the ventilator. About 31% of patients on MV are categorized as ‘difficult to wean’ when they fail one or more spontaneous breathing trials or need to be re-intubated within 48 hours of extubation.
About 10% of ventilated patients require prolonged weaning periods, greater than 7 days. These patients alone account for 40% of total ICU patient-days and become the most expensive in-patients in North American hospitals**. When they become ventilator-dependent their risk of dying in the ICU increases 7-fold.
* Levine S, Nguyen T, et al. “Rapid Disuse Atrophy of Diaphragm Fibers in Mechanically Ventilated Humans” N Engl J Med 358: 1327-35, 2008.
** Dasta JF “Daily cost of an intensive care unit day: The contribution of mechanical ventilation” Crit Care Med 33: 1266-1271, 2005.
The Lungpacer® Diaphragm Pacing System
Lungpacer Medical Inc. is developing a novel therapeutic solution for preserving or restoring the integrity and strength of the diaphragm muscle in critically ill patients who require mechanical ventilation. The proprietary Lungpacer system is designed to activate the diaphragm using a temporary, minimally invasive, transvascular nerve stimulation approach that is expected to save many lives, improve surviving patient outcomes and greatly reduce hospital care costs.
Intravenously inserted Lungpacer electrodes are designed to rhythmically activate the diaphragm. In critically ill patients who have failed or would typically fail to wean and become ventilator-dependent, the pacing therapy is expected to prevent or reverse diaphragm muscle-disuse atrophy and maintain diaphragmatic endurance, thus facilitating weaning of patients from MV. In addition, the paced diaphragm is expected to restore negative pressure ventilation, thereby potentially providing a more physiological respiratory pattern and reducing the levels of positive pressure ventilation and its harmful effects on the lungs.
These potentially beneficial effects of transvascular diaphragm pacing are expected to result in faster patient recovery, a shorter stay in intensive care, improved health outcomes and lower hospitalization costs. Faster weaning will also increase the ability to treat additional patients with scarce mechanical ventilators, particularly during major emergencies such as flu pandemics.
Hoffer JA “Transvascular Nerve Stimulation Apparatus and Methods” PCT appl. No. WO2008/092246, priority date Jan 29, 2007.
Hoffer JA, Tran BD, Tang JK, Saunders JTW, Francis CA, Sandoval RA, Meyyappan R, Seru S, Wang HDY, Nolette MA, Tanner AC. “Diaphragm Pacing with Endovascular Electrodes”. IFESS 2010 – Int’l. Functional Electrical Stimulation Soc., 15th Ann. Conf., Vienna, Austria, pp 40-42, 2010.
Meyyappan R, Sandoval RA, Francis CA, Nolette MA, Tang J, Tindale L, Tran B, Afram BB, Coquinco B, Reynolds S, Hoffer JA. “Diaphragm pacing during controlled mechanical ventilation: pre-clinical observations reveal a substantial improvement in respiratory mechanics”. 17th Biennial Canadian Biomechanics Society Meeting, Burnaby, BC, June 6-9, 2012.