Factors leading to poor outcome of noninvasive positive pressure ventilation in acute exacerbation of chronic obstructive pulmonary disease

Predictors of success and failure of non-invasive ventilation use in type-2 respiratory failure

BACKGROUND

Non-invasive ventilation is widely used now a days in patients with hypercapnic respiratory failure. Non-invasive ventilation can be used in Intensive Care Unit setting and wards provided trained staff is there to monitor.

METHODS

This was a prospective observational study of 100 adult patients who were admitted with hypercapnic respiratory failure. Demographic information such as Age, Sex were recorded. Clinical parameters like Respiratory Rate, Heart Rate, Oxygen saturation and Arterial Blood Gas variables like pH, PaCO₂, HCO₃ were measured at the time of admission and at 1st hour, 4 hours and 24 hours after start of non-invasive ventilation. Outcome was recorded as success and failure with Non invasive ventilation.

RESULTS

Out of 100 patients, 76 (76%) managed successfully with non-invasive ventilation and 24 patients (24%) needed intubation and invasive mechanical ventilation in this study. Majority of patients (76%) were with clinical diagnosis of Chronic Obstructive Pulmonary Disease. Respiratory Rate and Heart Rate were significantly lower and showed significant improvement at 1st hour, 4 hours and 24 hours in patients who successfully improved with Non invasive ventilation. Oxygen saturation was found to be significantly higher among patients successfully managed with Non invasive ventilation (84.35 ± 8.55 vs 76.87 ± 7.33) as compared to patients who required intubation. pH was found to be significantly higher (7.28 ± 0.06 vs 7.23 ± 0.05) in patients showing good response to Non invasive ventilation and improvement in pH at 1st hour, 4 hours and 24 hours was observed in patients successfully managed with Non invasive ventilation. PaCO₂ level was found to be significantly lower and significant improvement in PaCO₂ at 1st hour, 4 hours and 24 hours was seen in patients with Non invasive ventilation success.

CONCLUSION

Improvement in clinical parameters like respiratory rate, heart rate, Oxygen saturation and improvement in ABG variables like pH, PaCO2 after 1st and 4 hours of start of Non invasive ventilation and maintaining the improvement at 24 hours are predictors of success of non-invasive ventilation in hypercapnic patients.

Non-invasive ventilation in children and adults in low- and low-middle income countries: A systematic review and meta-analysis

PURPOSE

We systematically reviewed the effects of NIV for acute respiratory failure (ARF) in low- and low-middle income countries.

MATERIALS AND METHODS

We searched MEDLINE, CENTRAL, and EMBASE (to January 2016) for observational studies and trials of NIV for ARF or in the peri-extubation period in adults and post-neonatal children. We abstracted outcomes data and assessed quality. Meta-analyses used random-effect models.

RESULTS

Fifty-four studies (ten pediatric/n=1099; 44 adult/n=2904), mostly South Asian, were included. Common diagnoses were pneumonia and chronic obstructive pulmonary disease (COPD). Considering observational studies and the NIV arm of trials, NIV was associated with moderate risks of mortality (pooled risk 9.5%, 95% confidence interval (CI) 4.6-14.5% in children; 16.2% [11.2-21.2%] in adults); NIV failure (10.5% [4.6-16.5%] in children; 28.5% [22.4-34.6%] in adults); and intubation (5.3% [0.8-9.7%] in children; 28.8% [21.9-35.8%] in adults). The risk of mortality was greater (p=0.035) in adults with hypoxemic (25.7% [15.2-36.1%]) vs. hypercapneic (12.8% [7.0-18.6%]) ARF. NIV reduced mortality in COPD (relative risk [RR] 0.47 [0.27-0.79]) and in patients weaning from ventilation (RR 0.48 [0.28-0.80]). The pooled pneumothorax risk was 2.4% (0.8-3.9%) in children and 5.2% (1.0-9.4%) in adults. Meta-analyses had high heterogeneity.

CONCLUSIONS

NIV for ARF in these settings appears to be effective.