Managing Respiratory Failure in Obstructive Lung Disease

Apnea-Hypopnea Index in Chronic Obstructive Pulmonary Disease Exacerbation Requiring Noninvasive Mechanical Ventilation with Average Volume-Assured Pressure Support

Introduction

This study intends to determine the Apnea-Hypopnea Index in patients hospitalized with acute hypercapnic respiratory failure from chronic obstructive pulmonary disease exacerbation, who require noninvasive ventilation with average volume-assured pressure support (AVAPS), as well as describes the clinical characteristics of these patients.

Materials and Methods

We designed a single-center prospective study. The coexistence of Apnea-Hypopnea Index and clinical, gasometric, spirometric, respiratory polygraphy, and ventilatory characteristics were determined. The clinical characteristics found were categorized and compared according to the Apnea-Hypopnea Index (AHI) < 5, AHI 5–15, and AHI >15. A p value <0.05 was considered statistically significant.

Results

During the study period, a total of 100 patients were admitted to the ICU with a diagnosis of acute hypercapnic respiratory failure due to COPD exacerbation. 72 patients presented with acute respiratory failure and fulfilled criteria for ventilatory support. Within them, 24 received invasive mechanical ventilation and 48 NIV. After applying the inclusion criteria for this study, 30 patients were eligible. An AHI >5 was present in 24 of the 30 patients recruited (80%). Neck circumference (cm), Epworth scale, and Mallampati score evidenced significant differences when compared to the patient's AHI <5, AHI 5–15, and AHI >15 (p < 0.05). Furthermore, patients with an AHI >5 had longer hospital admissions, prolonged periods on mechanical ventilation, and a higher percentage of intubation rates.

Conclusion

Apnea-Hypopnea Index and chronic obstructive pulmonary disease exacerbation are a frequent association found in patients with acute hypercapnic respiratory failure and COPD exacerbations that require NIV. This association could be a determining factor in the response to NIV, especially when AVAPS is used as a ventilatory strategy.

Steroid sparing effects of doxofylline

Glucocorticosteroids are widely used in the treatment of asthma and chronic obstructive pulmonary disease (COPD). However, there are growing concerns about the side effect profile of this class of drug, particularly an increased risk of pneumonia. Over the last two decades there have been many attempts to find drugs to allow a reduction of glucocorticosteroids, including xanthines such as theophylline. Use of xanthines has been shown to lead to a reduction in the requirement for glucocorticosteroids, although xanthines also have a narrow therapeutic window limiting their wider use. Doxofylline is another xanthine that has been shown to be of clinical benefit in patients with asthma or COPD, but to have a wider therapeutic window than theophylline. In the present study we have demonstrated that doxofylline produces a clear steroid sparing effect in both an allergic and a non-allergic model of lung inflammation. Thus, we have shown that concomitant treatment with a low dose of doxofylline and a low dose of the glucocorticosteroid dexamethasone (that alone had no effect) significantly reduced both allergen-induced eosinophil infiltration into the lungs of allergic mice, and lipopolysaccharide (LPS)-induced neutrophil infiltration into the lung, equivalent to a higher dose of each drug. Our results suggest that doxofylline demonstrates significant anti-inflammatory activity in the lung which can result in significant steroid sparing activity.