Electromagnetic Stimulation of the Phrenic Nerve of Intubated Patients (STIMIT-I)

Electromagnetic Stimulation of the Phrenic Nerve to Generate Contraction of the Diaphragm in Anesthetized and Intubated Patients - a Proof-of-concept Study

Ventilator-induced diaphragmatic dysfunction is a common issue in critically ill patients. Muscle stimulation has shown to have beneficial effects in muscle groups on the extremities. A non-invasive way to stimulate the diaphragm would be the electromagnetic stimulation but it is currently unclear if that is feasible. In this proof-of-concept trial the primary aim is to show that it is possible to induce a diaphragmatic contraction leading to an inspiration with a sufficient tidal volume via an external electromagnetic stimulation of the phrenic nerve.

During the time of first spontaneous breathing trial 60% of mechanically ventilated patients present with diaphragmatic weakness or also know as ventilator-induced diaphragmatic dysfunction (VIDD). The damage to the diaphragm in terms of muscle atrophy has been shown as early as 12 hours after initiation of mechanical ventilation. Recently, a correlation between diaphragmatic atrophy and mortality could be established. Induction of diaphragmatic contractions via stimulation of the phrenic nerve would be a possible method to prevent or treat VIDD. A possible modality would be the non-invasive electromagnetic stimulation but feasibility has not been established. In this proof-of-concept trial the primary aim is to show that it is possible to induce a diaphragmatic contraction leading to an inspiration with a sufficient tidal volume via an external electromagnetic stimulation of the phrenic nerve.

When the stimulation locus is changed according to protocol the change of the triggered breath is measured in % to the original location.

Time between first successful N. phrenicus stimulation and identification of the optimal stimulation locus in seconds

Inclusion Criteria: ≥ 18 years of age American Society of Anaesthesiologists Classification I or II Exclusion Criteria: Chronic lung disease Preexisting diaphragmatic weakness Neurologic disease with known motor weakness Paralysis of the phrenic nerve Contraindication for any movement in the cervical vertebrae Conditions that limit the movement of the diaphragm e.g. ascites, increased intraabdominal pressure, adipositas. Inability to communicate in the official language Infections, lesions or stricture in the neck area Implanted cardiac devices e.g. pace maker, defibrillator, event recorder Implanted medical pumps e.g. left ventricular assist device Metal implants in the upper body Preganancy