Introduction: Severe Guillain-Barré syndrome (GBS) patients may not show improvement after a single course of intravenous immunoglobulin (IVIg) therapy. Current treatment options include either a second course of IVIg or therapeutic plasma exchange (TPE). This systematic review aims to evaluate the current literature on the use of a second course of IVIg or TPE in patients who fail to show clinical improvement after the first IVIg course. Methods: We searched PubMed, Embase and Medline databases up until 26 October 2023. Studies that evaluated adult patients with confirmed GBS who have failed one full course of IVIg and subsequently received either repeat IVIg or TPE were included. Risk of bias was performed using study-specific checklists. A narrative synthesis of results is presented. Results: A total of 37 articles were identified (1 randomised controlled trial (RCT), 3 observational and 33 case reports/series), consisting of 422 patients in total. 12 studies evaluated repeat IVIg and 24 studies evaluated TPE after IVIg. There was no superiority of a repeat course of IVIg or TPE in all clinical outcome measures. Conclusions: The evidence suggests with a low degree of certainty that there is no beneficial effect of further IVIg in unresponsive GBS. The quality of evidence regarding TPE after IVIg is insufficient to suggest any efficacy due to a lack of RCTs. We recommend standardised case reporting with consideration for a multinational case registry and RCTs to determine the efficacy of TPE after initial IVIg unresponsiveness.

Background: There is limited evidence regarding the management of acute life-threatening asthma in intensive care units (ICUs), and few guidelines have details on this. We aimed to describe the characteristics, management, and outcomes of adults with life-threatening asthma requiring ICU admission. Methods: In this single-centre retrospective observational study, we included consecutive adults with acute asthma requiring ICU admission between 1 January 2016 and 31 December 2023. Our primary outcome was requirement for invasive mechanical ventilation (IMV). Results: We included 100 patients (median age 42.5 years, 67% female). The median pH, PaCO₂, and white cell count (WCC) on ICU admission were 7.37, 39 mmHg, and 13.6 × 109/L. There were 30 patients (30%) who required IMV, and the best predictors of IMV requirement were pH (AUC 0.772) and PaCO₂ (AUC 0.809). In univariate analysis, IMV requirement was associated with both increasing WCC (OR 1.14) and proven bacterial infection (OR 8.50). A variety of respiratory support strategies were utilised, with 38 patients (38%) receiving only non-invasive respiratory support. Conclusions: Our data highlight key characteristics which may be risk factors for acute asthma requiring ICU admission and suggest that pH, PaCO₂, and WCC are prognostic markers for disease severity. Our overall outcomes were good, with an IMV requirement of 30% and a 28-day mortality of 1%.