Background
Electromyography and nerve conduction studies (EMG-NCS) often yield nonspecific findings during the early stage of Guillain-Barré syndrome (GBS). Although useful for diagnosis, EMG-NCS are traditionally of little value in predicting a complicated clinical course, which is critical for timely decisions to initiate immunomodulatory treatment. We aimed to identify the early clinical and electrophysiologic predictors of respiratory failure, a prolonged hospital stay, and moderate-to-severe disability at discharge in GBS.
Methods
We retrospectively analyzed the clinical and electrophysiologic data of adult GBS patients who were hospitalized during the early course of the disease (<2 weeks from symptom onset).
Results
Eighty-one patients aged 47.5 ± 16.1 years were analyzed. The most common clinical variants were Miller-Fisher syndrome (30.9%) and classic sensorimotor GBS (25.9%). The clinical variant was not predictive of a complicated clinical course. Instead, specific clinical features such as dysautonomia (p = 0.006) and marked motor deficits (p = 0.002) were predictive of the primary composite outcome of respiratory failure and/or a prolonged hospital stay, with dysautonomia (p = 0.035) also predictive of moderate-to-severe disability at discharge. The most common abnormalities in EMG-NCS were bilateral absence of the H-reflex (86.4%) and F-wave abnormalities (44.4%). The presence of F-wave abnormalities was predictive of both respiratory failure (p = 0.032) and a prolonged hospital stay (p = 0.001).
Conclusions
Early F-wave abnormalities in GBS may serve as an electrophysiologic predictor of a complicated clinical course, suggesting that EMG-NCS can provide prognostic information to guide treatment decisions during the early stage of the disease.

Respiratory muscle weakness caused by neuromuscular disease can lead to both acute and chronic respiratory failure. Respiratory failure caused by Guillain-Barré syndrome and myasthenia gravis can potentially improve with disease-specific therapy. However, respiratory failure in amyotrophic lateral sclerosis is irreversible, and it may be necessary to provide full-time ventilation support along with additional assistance. Noninvasive ventilation is recommended for managing acute or acute-on-chronic hypercapnic respiratory failure caused by neuromuscular disease. It has also been effective in weaning patients off invasive mechanical ventilation. Although noninvasive ventilation offers numerous benefits over invasive mechanical ventilation, it is crucial to consider the specific contraindications and limitations of noninvasive ventilation and ensure its appropriate usage based on the patient's condition and needs. The timely recognition of neuromuscular respiratory failure is critical, as early intervention can be life-saving. This review focused on the clinical assessment and management of acute respiratory failure in neuromuscular diseases.