2008 Readmission and One-year Survival of Patients with Chronic Hypercapnic Respiratory Failure on Non-invasive Home Mechanical Ventilation
Dr Yu Chin Wing
Department of Medicine, North District Hospital
Background
The use of non-invasive home mechanical ventilation (home NIV) has been increasing dramatically for chronic hypercapnic respiratory failure (CHRF). Studies on the readmission rate and poor prognostic factors of these patients were limited.
Primary Objective
To describe the characteristics and outcomes of patients with CHRF on home NIV
Secondary Objective
To analyse the risk factors for poor outcomes.
Methods
A retrospective cohort of CHRF patients with home NIV initiated in a local hospital from January 1999 to January 2007 was analysed.
Results
Seventy-six patients were eligible for analysis. The primary diagnoses included chronic obstructive pulmonary disease (COPD) in 60.5% (n=46), restrictive thoracic disorders (RTD) in 15.8% (n=12), obesity hypoventilation syndrome (OHS) in 9.2% (n=7), overlap syndrome in 7.9% (n=6), and mixed causes in 6.6% (n=5). The readmission rate at three months was 35.5% (27/76). Independent risk factors for readmission within three months were older age (adjusted odds ratio 3.37 for age > 70, p=0.037), need for regular inhaled corticosteroids upon discharge (adjusted odds ratio 3.84, 95% CI=1.15 -12.81, p=0.028) and home NIV started for difficulty in weaning hospital NIV (adjusted odds ratio 3.98, p=0.015). One-year survival was 81.6% (62/76) and the independent poor prognostic factors were readmission within three months (adjusted odds ratio 11.42, p=0.003) and high PaCO2 level on readmission or follow up after commencement of home NIV (adjusted hazard ratio 1.43 for every increase in one kPa of PaCO2, p=0.013).
Conclusion
Readmission rate of patients with CHRF treated with home NIV was high, while early readmission was associated with mortality. Early reassessment to optimize treatment may improve outcome.
