Autotitrating Versus Standard Non-invasive Ventilation (NIV) in Acute Exacerbation of Respiratory Failure

Autotitrating Non-invasive Ventilation (NIV) Versus Standard NIV; a Randomised Crossover Trial in Patients With Acute Exacerbation of Chronic Respiratory Failure

The aim of the study is to compare the efficacy and tolerance of autotitrating non-invasive ventilation (NIV) versus standard NIV in patients admitted to hospital with acute exacerbation of chronic respiratory failure.

The investigators hypothesise that autotitrating NIV will ventilate patients with acute exacerbations of chronic respiratory failure as effectively as standard NIV.

The aim of the study is to compare the effect of two types of noninvasive ventilator (a small machine that assists breathing) in patients admitted to hospital with a sudden worsening of their existing breathing insufficiency, including an increase of carbon dioxide in the blood (hypercapnia) and acidity of the blood. Noninvasive ventilation (NIV) is standard therapy for patients with acute hypercapnic exacerbations (sudden worsening of existing breathing insufficiency) of both chronic obstructive pulmonary disease (COPD) and nonCOPD patients.

The most common type of NIV is bilevel pressure support which assists patient breathing by delivering different levels of air pressure during inspiration and expiration via a mask covering the nose or nose and mouth. Standard bilevel NIV (VPAP™) has been further developed to create a new automatically adjusting NIV (AutoVPAP™). Automatically adjusting NIV varies the inspiratory air pressure according to the airflow rates generated by the patient. This may improve patient comfort, hours of NIV use and recovery time.

Patients over the age of 18 admitted to Royal Brompton Hospital respiratory ward will be considered for entry into this randomised crossover study. If eligible for inclusion and willing to take part patients will be setup on automatically adjusting NIV or standard NIV, assigned in random order. After 24 hours on the first NIV the patient will be swapped to the alternative NIV for a further 24 hours of treatment.

Inclusion Criteria:

• patients admitted or transferred to Royal Brompton Hospital with acute exacerbation of chronic respiratory failure, or inpatients who suffer a deterioration in respiratory status, defined as 7.25 < pH < 7.35, PaCO2 > 6.0kPa, and respiratory rate > 20bpm

Exclusion Criteria:

• < 18 years old
• pH < 7.25
• need for immediate intubation
• uncontrolled cardiac failure
• hypotensive (systolic blood pressure < 90mmHg)
• acute myocardial infarction
• acute dysrhythmia
• other system failure (e.g. acute renal failure, liver failure)
• moderate or severe bulbar weakness
• inability to understand rationale and/or consent form for study