Changing Demographics of Home Mechanical Ventilation Setups Following Acute Hypercapnic Respiratory Failure

INTRODUCTION: Obesity as the primary cause of acute hypercapnic respiratory failure (AHRF) receiving acute non-invasive ventilation (NIV) has doubled within a decade. We analysed the primary diagnoses for receiving home mechanical ventilation (HMV) upon discharge following an acute NIV episode. METHODS: Data were collected from the HMV quality database of our teaching hospital between January 2014 to February 2020 (period 1: pre-COVID-19) and August 2020 to December 2021 (period 2: post-COVID-19). Adults receiving HMV upon discharge following an acute NIV episode were included. One-year and two-year survival were recorded using the National Health Service (NHS) Spine Portal. Population characteristics recorded were age, sex, primary diagnosis requiring HMV (obesity, chronic obstructive pulmonary disease (COPD), neuromuscular disease (NMD), and chest wall deformity), and concomitant home oxygen use alongside HMV. The chi-squared test was performed to assess the significance of variations between period 1 and period 2. RESULTS: A total of 354 patients (298 in period 1 and 56 in period 2) received HMV upon discharge following an acute NIV episode: one-year survival was 280/354 (79%), and two-year survival was 227/354 (64%). There was no significant difference between age, sex, and home oxygen use. There was a significant increase in the number of patients receiving HMV for obesity-related respiratory failure (ORRF) (113/300 (37.7%) in period 1 vs. 30/56 (53.6%) in period 2; p=0.025). There was no difference in one-year and two-year survival within each of the diagnostic categories across the two periods. As regards two-year survival, COPD had the lowest (45/103, 44%), and NMD had the highest (55/71, 77%). DISCUSSION: There has been a significant rise in HMV utilisation due to obesity following an episode of AHRF. This is in keeping with the rise in obesity in the population. Further work is needed to confirm whether this trend is true several years post-COVID-19, to look at the effect of comorbidities on survival in respiratory failure, and to study respiratory failure because of combined COPD and obesity. CONCLUSION: In this single-centre retrospective observational study, there is a rise in HMV setups for ORRF following hospital admission for AHRF. Further multicentre work is needed to assess the significance of this trend and the impact of associated comorbidities on survival.