Electromagnetic Stimulation of the Phrenic Nerve in Critically Ill Mechanically Ventilated Patients (STIMIT-II) (STIMIT-II)

Electromagnetic Stimulation of the Phrenic Nerve in Critically Ill Mechanically Ventilated Patients (STIMIT-II)

Electromagnetic Stimulation of the Phrenic Nerve to Generate Contraction of the Diaphragm in Critically Ill Mechanically Ventilated Patients - a Proof-of-concept Study (STIMIT-II)

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 in critically ill ICU patients via an external electromagnetic stimulation of the phrenic nerve, leading to an inspiration (i) with a sufficient tidal volume (3-6 ml/kg ideal body weight) and (ii) with verifiable muscular diaphragmatic contraction through ultrasound imaging.

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 in critically ill ICU patients via an external electromagnetic stimulation of the phrenic nerve, leading to an inspiration (i) with a sufficient tidal volume (3-6 ml/kg ideal body weight) and (ii) with verifiable muscular diaphragmatic contraction through ultrasound imaging.

15 patients in control group, 15 patients in interventional group with sequential design in term of daily frequency of non-invasive electromagnetic phrenic nerve stimulation, i.e. starting with 5 patients with 2 stimulation per day, followed by 5 patients with 3 stimulations and 5 patients with 5 stimulations per day

Percentage of non-feasible stimulation out of the total number of stimulations planned according to the investigation protocol.

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

Frequency of sufficient Tidal volume generated by electromagentical stimulation of the phrenic nerve (3-6 ml/kg ideal body weight)

Percentage of stimulated breaths above the cut-off Today volume (3-6 ml/kg ideal body weigh) out of the total number of stimulated breaths. Tidal volumes are measured by the mechanical ventilator.

Measurement of variance among the Tidal volumes stimulated during the experimental therapy intervention; Tidal volumes are measured by the mechanical ventilator.

sEMG amplitude and duration are measured by a device (sEMG Amplificator) connected to electrodes applied to the patient's chest during electromagnetic phrenic nerve stimulation.

Transpulmonary pressure is measured by the mechanical ventilator during electromagnetic phrenic nerve stimulation.

Occlusion pressure is measured by the mechanical ventilator during electromagnetic phrenic nerve stimulation.

Stimulated tracheal pressure is measured by the mechanical ventilator during electromagnetic phrenic nerve stimulation.

Progression of RSBI during 10 days after subject inclusion, based on the mechanical ventilation parameters (Tidal volume) and the ICU continuous monitoring system (Respiratory Rate).

Lung compliance is measured by the mechanical ventilator during electromagnetic phrenic nerve stimulation.

Lung resistance is measured by the mechanical ventilator during electromagnetic phrenic nerve stimulation.

Inclusion Criteria: Patients between 18 and 60 years old, hospitalized in ICU Mechanical ventilation < 36 h Prone to stay ventilated > 72 h Exclusion Criteria: Known neurological condition affecting motor neuron or muscle (e.g. ALS) Known paralysis of the phrenic nerve Proven or suspected spinal cord injury that contraindicates weight bearing on the spinal cord Conditions that limit diaphragm movement (high intra-abdominal pressure, ascites, obesity) Not able to read and understand the national language German Patients with Implanted cardiac support systems (pacemaker, implanted defibrillator) Patients with implanted medical pumps Pregnant patients Patients with skin lesions, infections or strictures in throat/neck area Patients with metallic implants