Noninvasive Positive Pressure Ventilation in Patients with Acute Respiratory Failure Secondary to Acute Exacerbation of Chronic Obstructive Pulmonary Disease.

Introduction Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a leading cause of poor quality of life and mortality in developing countries. Noninvasive positive pressure ventilation (NIPPV) remains the first-line intervention in hospitalized patients with acute respiratory failure (ARF) due to AECOPD. However, NIPPV may fail in some patients. This study was conducted to assess the frequency of NIPPV failure and clinical parameters and outcomes in AECOPD patients with failed NIPPV and their conversion to invasive positive pressure ventilation (IPPV). Methods This prospective observational study was conducted in the pulmonology unit of a tertiary care hospital in Pakistan. AECOPD patients with ARF who were candidates of NIPPV were included after securing informed consent. Their demographic characteristics, clinical parameters, and in-hospital outcomes were recorded on a semi-structured proforma. For statistical analysis, SPSS software version 22.0 for Windows (IBM, Armonk, NY) was used. Results With 24 hours of NIPPV, 73 (70.2%) patients improved and the remaining 31 (29.8%) were shifted to IPPV. Patients in the IPPV group had higher systolic blood pressure (BP) [133.8 mmHg (±21.2) vs. 121.1 mmHg (±8.3); probability value (p): <0.000] and lower diastolic BP [68.7 mmHg (±13.4) vs. 76.2 mmHg (±10.8); p: 0.003]. Their pH was more acidic [7.20 (±0.13) vs. 7.42 (±0.01); p: <0.000], heart rates were high [131.1 (±10.5) vs. 100.2 (±7.5); p: <0.000], and the percentage of oxygen saturation was low [90.7 (±3.0) vs. 93.4 (±4.5); p: 0.004]. Patients who were managed on NIPPV throughout their hospital stay required respiratory support for fewer days [3.2 (±1.3) vs. 4.1 (±1.8); p: 0.005], and their hospital stay was shorter [3.5 (±1.2) vs. 5.3 (±2.5) days; p: <0.000]. Mortality rate in the NIPPV group was significantly lower (1.4% vs. 12.9%; p: 0.01). Conclusions Deranged blood pressure, increased heart rate, acidemia, and a low percentage of oxygen saturation are crucial clinical and biochemical parameters that can predict the success of NIPPV with 24 hours of therapy in patients with AECOPD and secondary ARF. Patients who do not improve with 24 hours of NIPPV therapy usually have poor in-hospital outcomes including mortality.