Neurophysiological Diagnosis for ICU Septic Shock Patients

• Nerve conduction study (Diagnostic test), also known as Peroneal nerve test (PENT test): Physical examination of muscle strength is conducted using the Medical Research Council (MRC) scale in 6 muscles bilaterally. Patients with an MRC score of less than 48 of 60 are diagnosed with critical illness polyneuromyopathy (CIPNM). The evaluation is completed by a routine neurological examination. In patients meeting the inclusion criteria, the screening Peroneal nerve test (PENT test) is performed on the day of study enrollment and subsequently in 1 week intervals until pathologic findings are detected or patient is discharged from the ICU. PENT measures the peroneal nerve Compound muscle action potential (CMAP) amplitude in one leg. If the PENT is normal, the contra-lateral peroneal nerve is measured. An abnormal condition is identified if the peroneal nerve CMAP amplitude is reduced below the normal limits of the participating centre in at least one leg. In Lausanne, the abnormal response is < 2,5 mV.

Primary outcomes

• Presence of ICU-acquired weakness in septic shock patients ventilated for more than 72 hours. [72 hours]: Medical Research Council strength scale

Secondary outcomes

• ICU length of stay [Up to 6 months]
• Hospital length of stay [Up to 6 months]
• Discharge destination [At discharge from hospital, up to 6 months]
• Length of ventilatory support [At extubation, up to 6 months]
• Extubation failure rate [up to 72 hours, after first extubation]: Patients requiring reintubation 72 hours after failed first extubation
• Time elapsed between endotracheal intubation and first out-of-bed mobilization [up to 6 months, at first out-of-bed mobilization]

Sex: All, ages: 18 Years to any

Inclusion Criteria:

• Patients admitted to the ICU with a septic shock and ventilated for more than 72 hours.

Exclusion Criteria:

* Hospitalization for more than 7 days before intubation.
* Functional disability at admission of ≥4 (Requires constant nursing care and attention, bedridden, incontinent) in the Modified Rankin Scale.
* Lower limb disorders precluding nerve conduction studies (NCV) and electromyography (EMG), such as clinical edema of the lower limbs, or fractures, amputation, and plaster casts of the lower limbs.
* Evidence of altered neuromuscular transmission at repetitive stimulation test either caused by neuromuscular blocking agents or disease.
* Burn patients admitted to ICU.
* Patient requesting withdrawal of therapies.

• Karin Diserens, PD-MER, Study director, NRA Unit. CHUV.