Objective: To evaluate the long term efficacy and safety of long term home noninvasive positive pressure ventilation (HNPPV) in stable hypercapnic patients with chronic obstructive pulmonary disease (COPD).
Methods: Forty patients with stable severe COPD [arterial PaCO2>or=55 mm Hg (1 mm Hg=0.133 kPa)] after hospital discharge were divided into 2 groups: the HNPPV group (n=20) with conventional therapy and HNPPV, and the control group (n=20) with conventional therapy only. Parameters before and after 2 year follow-up observation were compared, which included dyspnea grade, scale for accessory muscle use, scoring for emotional disorders, lung function test, arterial blood gases, 6-min walking distance (6MWD), mean pulmonary arterial pressure (mPAP) by electrocardiography, mortality and hospitalization rates.
Results: The age, gender, height, weight, dyspnea grade, scale for accessory muscle use, anxiety scores, depression scores, 6MWD, mPAP, arterial PaCO2 and PaO2, FVC, FEV1, and hospitalization rates of the 2 groups on admission were similar (t values were 1.08, 1.15, 1.20, 1.09, 0.86, 0.54, 0.00, 0.00, 0.43, 0.96, 0.76, 0.38, 0.26, 0.24 and 0.87 respectively, all P>0.05). The mortality was reduced slightly by HNPPV but with no statistically significant difference (3/20 and 8/20, respectively, chi2=3.27, P>0.05). After 2 years, the difference of the dyspnea grade, scale for accessory muscle use, anxiety scores, depression scores, arterial PaCO2 and PaO2, 6MWD, mean pulmonary artery pressure, and hospitalization rates in the HNPPV group [2.4+/-0.5, 2.6+/-0.6, 6.9+/-2.1, 6.1+/-1.6, (49.5+/-2.2) mm Hg, (60.8+/-4.7) mm Hg, (213+/-45) m, (30.3+/-2.2) mm Hg, (1.4+/-0.4) times/year] was statistically significant compared to the control group [3.9+/-0.3, 4.8+/-0.4, 11.2+/-2.6, 11.6+/-2.1, (61.5+/-2.3) mm Hg, (52.8+/-2.4) mm Hg, (127+/-23) m, (36.4+/-2.3) mm Hg, (3.9+/-0.3) times/year] (t values were 9.53, 10.83, 4.92, 7.83, 14.07, 5.41, 6.07, 4.81 and 10.22 respectively, all P<0.01).
Conclusion: Long-term use of home noninvasive positive ventilation in patients with stable severe COPD is effective and safe.