Development of a closed-loop device for phrenic nerve stimulation to enable a new approach of intensive care ventilatory support – (DIA-STIM)

• Applicants: Dr. Thomas Breuer; Professor Dr.-Ing. Steffen Leonhardt
• Subject Area: Biomedical Systems Technology ; Anaesthesiology ; Medical Physics, Biomedical Technology
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 420664178

Mechanical ventilation (MV) is the only established method used as a life-saving intervention in patients with acute respiratory failure. During this ventilatory support, the diaphragm stays inactive and is threatened by a pathophysiological syndrome called "ventilator-induced diaphragmatic dysfunction" (VIDD), an important contributor to weaning failure aggravating morbidity and mortality of ventilated patients. Several studies indicated that maintaining a certain degree of diaphragmatic activity during MV (e.g. by phrenic nerve pacing) could preserve diaphragm function and inhibit its atrophy, which could result in fewer days on the ventilator. Conventional phrenic nerve stimulation has been established for years, especially in patients suffering from severe neurological pathologies like paraplegia. But so far these large-scale devices, which are implanted on the diaphragmatic surface using a transthoracic open approach, are limited to a selected patient cohort, with long-term dependency on this stimulation device. It can be concluded that in many difficult-to-wean patients, VIDD occurs before spontaneous breathing can be established. Till now, the adaptation of ventilator settings to patients’ breathing efforts is still a manual procedure in intensive care, which crucially depends on the presence of a bedside human therapist. As a problem-solving approach, immediate breath-by-breath adaption of respirator settings enabling prevention from unanswered breathing efforts combined with phrenic nerve-stimulated diaphragm activity could prevent VIDD in an acute or perioperative setting.Therefore, the proposed experiments will examine the feasibility of an immediate adaption of breathing efforts to mimic spontaneous breathing in perioperative intensive care; a clinical situation where spontaneous breathing has often been impossible in intubated patients till now. An ICU-compatible procedure of diaphragm stimulation could minimize patients’ need for MV. Hence, the proposed work will combine benefits from conventional phrenic pacing with temporary diaphragm stimulation in an automated regulation of the respiratory minute volume.

• DFG Programme: Research Grants