PSV Versus ASV With Intellisync Mode for Delivery of NIV in AECOPD

Acute exacerbation of chronic obstructive pulmonary disease (COPD) is defined acute worsening of respiratory symptoms requiring additional therapy. COPD exacerbations affects the health status and quality of life of affected patients. The inpatient mortality during exacerbation is 3 to 4% while, intensive care unit (ICU) mortality approaches 43 to 46%. Each episode of exacerbation increases the risk of mortality subsequently(1) Non-invasive ventilation (NIV) therapy has established role in mild to moderate exacerbations of COPD. But the use of NIV therapy outside of acute exacerbation is uncertain(2) NIV use has been shown to prevent endotracheal intubation and improved hospital and ICU survival. NIV decreases the work of breathing by unloading the respiratory muscles through assisting the inspiratory phases and counterbalancing the intrinistic positive end expiratory positive pressure (ipeep)(3). NIV is delivered through face mask, although newer interfaces like helmet available(3). Tradionally pressure targeted mode is used in NIV therapy and is often given intermittently rather than continuously(4). NIV therapy via face mask was first used by Meduri et. Al in acute respiratory failure patients. Subsequent multiple randomized control trials established the role of NIV therapy in better gas exchange, reducing PCO2, reducing endotracheal intubation thereby reducing mortality, length of stay in hospital(3). NIV-PSV (pressure support ventilation) consists of 2 pressures. IPAP (inspiratory positive airway pressure) and EPAP (expiratory positive airway pressure) or PEEP. Pressure support is usually the pressure added above PEEP. Pressure support is usually started with 8-10 cm H2O to obtain a tidal volume of 6-8ml/kg ideal body weight. EPAP/PEEP is adjusted to counterbalance the iPEEP. It is usually kept at 4-6cm H2O. Fio2 is kept to maintain saturation of 88-92%. Inspiratory trigger is usually set at 1 L/min. Expiratory trigger kept at 50%. Back up rate should always