PURPOSE: NIV is being increasingly used for management of type-II hypercapnic respiratory failure due to COPD and in type-I, hypoxemic respiratory failure.It's role in acute severe asthma is limited. However, NIV has shown some excellent result in type-II hypercapnic acidotic exacerbations of asthma which occurs due to respiratory muscle fatigue in patients of acute severe asthma.
METHODS: Thirty patients of acute severe asthma aged between 30-60 years, who presented with hypoxemic respiratory failure (Mean PaO2 = 51.7143 with SD of 4.2314) but rapidly progressed to hypercapnic respiratory failure due to respiratory muscle fatigue.Fourteen out of 30 patients gradually developed type-II respiratory failure (mean PCO2 of 64.3478, SD of 6.5969, p value < .05) in next 24-36 hours and did not respond to conventional β2 agonists. All the patients were put on high flow oxygen inhalation (4 -6 L./min.) with the help of venturi mask and added medications in the form of inhaled β2 agonist and oral corticosteroids were given, but a minimal response to first line management was observed with gradual rise in PCO2 levels and shift of pH towards acidic side.
RESULTS: NIV was initiated (IPAP of 3cm and EPAP of 12-14cm of H2O). This lead to gradual fall in PCO2 levels (mean PCO2 levels of 52.4862 with SD of 11.8442, p value < .05) after 48 hours of NIV. A decreased in CO2 levels was accompanied with normalization of pH values.12 out of 14 patients with type-II respiratory failure showed approximately normal ABG parameters in next 4 days of Non Invasive Ventilation and were weaned off successfully. Two patients died of respiratory acidosis.
CONCLUSION: In the present study best results were obtained in patients with type-II acidotic asthmatic exacerbations due to respiratory muscle fatigue. However the patients with type-I respiratory failure showed some less promising preliminary results.
CLINICAL IMPLICATIONS: Treatment with NIV reduced work load of breathing and improved respiratory muscle fatigue, thus shortened hospital stay and favorable treatment outcomes in severe asthmatic exacerbations.
DISCLOSURE: Sudhir Agarwal, No Financial Disclosure Information; No Product/Research Disclosure Information