Predictors for Successful Non-Invasive Ventilation in Patients With Neuralgic Amyotrophy and Phrenic Nerve Involvement.

INTRODUCTION/AIMS: Phrenic nerve involvement in neuralgic amyotrophy (NA) may cause diaphragm paresis and respiratory impairment, for which chronic non-invasive ventilation (NIV) may be beneficial. Data on treatment success and predictors are lacking. This study evaluated NIV treatment success and its predictors in NA patients with diaphragm paresis. METHODS: Clinical data of all NA patients initiated on chronic NIV at the Centre of Home Mechanical Ventilation (Maastricht, the Netherlands) between September 2008 and April 2023 were retrospectively analyzed. Successful NIV use was defined as continued NIV or successful step-down due to clinical improvement. Cox proportional-hazards regression analyses were performed to identify predictors of successful outcome. RESULTS: Fifty-four patients (mean age 62.5 ± 10.9 years; 72.2% male) were included. Mean baseline postural decline in forced vital capacity (ΔFVC) was -35.1% ± 19.6%. Median NIV adherence was 6.4 [3.6-8.1] hours/day. Thirty-eight patients (70.4%) continued NIV during a mean follow-up of 4.9 years. Of these, six (11%) were successfully stepped down from NIV following clinical and/or functional improvement. Sixteen patients discontinued NIV because of lack of effect or intolerance. Baseline ΔFVC (sitting to supine) independently predicted successful NIV use (HR 0.947; 95% CI: 0.91-0.99). DISCUSSION: Chronic NIV was successful in most NA patients with diaphragm paresis, supporting its role as a long-term treatment option. Greater postural decline in FVC predicted treatment success, suggesting that postural spirometry may help identify patients most likely to benefit from NIV.