Development and validation of a new affordable and easy-to-use phrenic nerve stimulation tool for diaphragm strength assessment in intensive care unit

In intensive care unit, various forms of sepsis, undernutrition, surgery, global inflammation, iatrogeny, and mechanical ventilation, contribute to the overall muscular involvement including the diaphragm.

Assessment of diaphragm dysfunction is a critical issue for patients under mechanical ventilation, providing prognosis information and leading to the best therapeutic choices.

Up to now, for sedated ventilated critical care patient, expensive magnetic phrenic nerve stimulation equipment is needed to evaluate diaphragm strength.

In this study, the investigators aim to develop an affordable easy-to-use phrenic nerve stimulation tool, with ultrasonography and a nerve stimulator usually used for neuromuscular transmission monitoring. Hypothesis is that phrenic pacing using this new method is equivalent to the Gold Standard.

Inclusion Criteria:

• ICU patient with invasive mechanical ventilation
• Sedated patient with a Richmond Agitation-Sedation Scale of -4 or -5

Exclusion Criteria:

• Contraindication for magnetic stimulation (Pacemaker)
• Hemodynamic or respiratory instability : PaO2/FiO2 < 200 mmHg, noradrenaline > 0,3 µg/kg/min, dobutamine > 10 µg/kg/min
• Neuromuscular disease or recent use of neuromuscular blocking agents (2h30) with a TOF ratio below 4/4 95%.
• Refusal of study participation or to pursue the study by the patient, no consent
• Pregnancy or breastfeeding
• Absence of coverage by the French statutory healthcare insurance system

Individual patient data will be made available upon a reasonable request

12 months after the main publication

Data are provided to qualified investigators free of charge. Required documents to request data include a summary of the research plan, request form, and institutional review board (IRB) review. Dataset will be shared after careful examination by the study board of investigators.