Procedure
muscle contractions, CM
CONTRACTION, BLIND
The medical, paramedical and physiotherapist teams involved in the care and decision to wean the patient from mechanical ventilation were not aware of the participant’s group allocation. Each morning, after the daily assessment for contraindications to transcutaneous electrical stimulation and diaphragm thickness measurement, blind investigators (CM and YC) positioned the electrodes according to the ultrasound location (see Additional file The stimulation applied to the TEDS group was a bidirectional current with a frequency of 50 Hz and an impulse width of 300 ms. The intensity was set to produce a palpable contraction of the muscles under the probes [The sham stimulation was a bidirectional current with a frequency of 2 Hz and a pulse duration of 300 microseconds; this did not produce muscle contractions but created some interference with the monitoring signals to ensure blinding of the nursing staff. The sham session lasted 20 min. TEDS or SHAM stimulation was applied until the first extubation attempt.The care and weaning protocols were standard practice on the ward and were identical between participants. The physicians who decided on patient care and ventilatory weaning were not aware of the randomisation or the daily diaphragmatic ultrasound measurements.