FIG. 15: This Figure show the trial design of the HOT-HMV trial, which was devised to select patients who had had a recent acute exacerbation of COPD requiring hospitalization and NIV support for decompensated hypercapnic respiratory failure.[1]

The aim of HOT-HMV was to assess patients in the acute phase of respiratory failure and bring these patients back for reassessment in the recovery phase, 2–4 weeks following resolution of the acidosis but before resolution of the acute exacerbation to the stable state, to ensure there was chronic hypercapnia.

Those patients meeting the criteria of persistent elevated PaCO2, which for study purposes was defined as PaCO2 >7 kPa in the recovery period with hypoxia, were randomized to receive either standard care with HOT alone or with the addition of HMV or home NIV. Home NIV was administered and titrated during an inpatient admission and patients were followed up at regular intervals over a 12-month period.