"Electromagnetical Stimulation of Phrenic Nerve to Generate Contraction of the Diaphragm"

"Electromagnetical Stimulation of the Phrenic Nerve to Generate Contraction of the Diaphragm in Healthy Subjects and Anaesthetized and Intubated Patients - a Feasibility Study"

The scientific study is intended to show that external non-invasive electromagnetic stimulation can be used to safely and effectively stimulate the phrenic nerve in awake healthy subjects as well as in ventilated, anesthetized patients and that the stimulation can generate a diaphragmatic contraction that generates significant breath volume - a Controlled Own Breath (COB).

Also of interest is the reproducibility of the generated diaphragmatic movements and the reliability of different feedback signals for detecting the generated diaphragmatic contraction. This applies to inspiration and expiration detection for subsequent synchronization mechanisms of the magnetic stimulator for patient-initiated breathing as well as to contraction intensity. Further, the characterization of the position finding process is of great importance, so that technical developments can further simplify the process of coil positioning in the future. The possible occurrence of discomfort and pain sensation will also be investigated in awake healthy volunteers. Different stimulation protocols will be used.

Finally, it will be investigated whether an adjusted coil position still triggers reproducible diaphragmatic contractions after removal and repositioning in the same configuration. The knowledge gained will be used to further develop the technique and to prepare a study in critically ill, ventilated patients where the diaphragmatic muscle is to be treated preventively by stimulating the phrenic nerve, in order to prevent atrophy of the muscle.

Inclusion Criteria:

• Persons aged > 18 years
• Applicable for Group 2: planned for elective surgery
• No relevant pre-existing conditions - corresponding to American Society of Anesthesiologists (ASA) level of I-II.
• Written informed consent by the patient for participation in the study given

Exclusion Criteria:

• chronic lung diseases (bronchial asthma, COPD)

• known diaphragmatic weakness

• known neurological conditions with motor muscle weakness

• known paralysis of the phrenic nerve

• conditions that limit the mobility of the diaphragm (high intra-abdominal pressure, ascites, BMI >30)

• not able to read and understand the national language German

• skin lesions, infections or strictures in the neck area

• persons with Implanted cardiac support systems (pacemaker, implanted defibrillator)

• persons with implanted medical pumps

• pregnant women

• persons deprived of liberty by administrative or judicial decision or under legal guardianship.

• Participation in another clinical trial

• Applicable for group 2 (intubated and mechanically ventilated) patients: Exclusion criteria at the time of stimulation:

  • Unstable patient after induction of anesthesia and intubation