• Improvement in lung function defined as an increase of at least 50% in FEV1 as compared to baseline value on admission or an increase in FEV1 to > 60% of predicted value [ Time Frame: Time to discharge ]
  
• Intensive care unit length of stay [ Time Frame: Time to discharge ]
  
• Hospital length of stay [ Time Frame: Time to discharge ]
  

• Improvement in the clinical status [ Time Frame: Time to discharge ]
  
• Disappearance of pulsus paradoxus [ Time Frame: Time to discharge ]
  
• Improvement in arterial blood gases [ Time Frame: Time to discharge ]
  
• Improvement in oxygen saturation [ Time Frame: Time to discharge ]
  
• Requirements of FiO2 , medications. [ Time Frame: Time to discharge ]
  
• Need for mechanical ventilation [ Time Frame: Time to discharge ]
  

In the past, the mainstay of treatment for patients progressing to respiratory failure from acute asthma was intubation and mechanical ventilation. Newer strategies to prevent these intubations to prevent the inherent complications are being explored in form of various pharmacological means like heliox, magnesium sulfate etc. Non pharmacological strategies among which non invasive positive pressure ventilation (NIPPV) is one of the most challenging after showing success in patients with chronic obstructive airway disease (COPD) and cardiogenic pulmonary edema.

Data on efficacy of NIPPV in the management of AA is sparse but has the potential to improve the management of acute severe asthma. Noninvasive ventilation merits further studies in patients with AA, and some consensus panels have suggested that its widespread application in patients with asthma await such trials.The role of NIPPV is not yet clear and needs further studies and keeping this in view we planned this study to study the role of NIPPV in the management of acute asthma.

Inclusion Criteria:

1. History of asthma of at least 1 year
2. FEV1 < 50% of predicted (by age, height, and gender) or FEV1 < 200 L/minute
3. Respiratory rate > 30 breaths/min
4. All patients judged by the attending physician as having an acute attack of asthma ( Inability to speak in sentences in one breath, SaO2 < 92% ,pulsus paradoxus > 10 mm of Hg) -

Exclusion Criteria:

1. Smoking history of > 10 years
2. Chronic obstructive pulmonary disease
3. Endotracheal intubation
4. Room air saturation < 88 % or arterial PaO2 < 55 mm of Hg
5. Hemodynamic instability defined as systolic BP < 90 mm Hg
6. Altered state of consciousness
7. Congestive heart failure
8. Ischemic heart disease
9. Upper airway obstruction
10. Facial deformity
11. Pregnancy
12. Pulmonary infiltrates consistent with pulmonary edema or pneumonia