A summary of included studies
| Author (year) | Patient group design | OPEP device | Treatment duration | Follow-up | Control | Results of OPEP group compared with corresponding groups |
| Aggarwal (2010)24 | Hospitalised AECOPD RCT | Flutter n=15 | 15 mins, 3 x per day, for 5 days | Every day |
Control 1: ACBT n=15 Control 2: pursed lip breathing n=15 | Flutter and ACBT had the same effect on lung function compared with pursed lip breathing (ΔPEFR; +30 L/min) Flutter reduced hospital stay compared with ACBT and pursed lip breathing (3/5/5 days). |
| Cegla (2002)25 | Stable COPD FEV1 40%±14% RCT | RC-Cornet plus UC n=25 | >5 mins, 3 x per day, for 2 years | Every 3 months | UC n=25 | RC-Cornet had the same effect as UC on lung function (ΔFVC%; predicted +2%) RC-Cornet reduced antibiotic use compared with UC (12/25 vs 24/25) RC-Cornet reduced exacerbations over 2 years compared with UC (5/25 vs 12/25) RC-Cornet had the same effect as UC on hospital stays (17 vs 18 days). |
| McCarroll (2005)31 | Stable COPD with hypersecretion RCT | Acapella plus PR n=12 | 10 mins, 2 x per week, for 8 weeks | Every 4 weeks |
Control 1: UC n=11 Control 2: PR n=12 (2 sessions per week, for 8 weeks) | Acapella had the same effect as UC and PR on lung function (Δ FEV1 and PEFR; +0.28 L/min and +16 L/min) Improvement in exercise capacity did not differ significantly between UC and PR (Δ6MWD; +44 m vs +54 m). |
| Nicolini (2018)26 | Stable COPD FEV1=31%±10% RCT | Lung Flute plus UC n=40 | 30 mins, 2 x per day, for 12 days and then 26 weeks follow-up | Every 4 weeks |
Control 1: Flutter n=40 (30 mins, 2 x per day, for 12 days and then 26 weeks follow-up) Control 2: UC n=40 | Lung Flute and Flutter reduced exacerbations compared with UC (7/40 vs 9/40 vs 11/40) Lung Flute and Flutter improved exercise capacity vs UC (Δ6MWD; +18.4 m/+11.5 m / −4.8 m) Lung Flute, Flutter, and UC; no difference in cough or sputum clearance (Δ BCSS score; −3/−3.1/−3.5) Lung Flute and Flutter improved HRQoL compared with UC (Δ CAT score; –7.5/–6.4/−1.6) Lung Flute and Flutter reduced dyspnoea compared with UC (ΔMMRC score; –0.6/–0.4/+0.1). |
| Sethi (2015)27 | Stable COPD with sputum production, FEV1 50%±3% RCT | Lung Flute plus UC n=33 | 5 mins, 2 x per day for 26 weeks | Every 8 weeks | UC n=36 | Lung Flute reduced symptoms compared with UC (Δ CCQ score; −0.23 vs +0.01) Lung Flute improved HRQoL compared with UC (ΔSGRQ score; −3.23 vs −1.85, p=0.03) Lung Flute reduced exacerbations compared with UC (6/33 vs 14/36, p=0.03) Lung Flute improved exercise capacity compared with UC (Δ6MWD;+7 m vs −42 m). |
| Svenningsen (2016)28 | Stable COPD- sputum producer vs non-sputum producer FEV1 60%±18% RXT | Aerobika plus UC n=27 | 20 mins, 4 x per day, for 3 weeks (1 week intervention, 1 week washout, and 1 week UC) | Not reported | UC | Aerobika improved lung function compared with UC (Δ FVC% predicted;+6%, p=0.005) Aerobika improved HRQoL compared with UC (ΔSGRQ score; −9, p=0.01). Aerobika improved sputum clearance compared with UC (ΔPEQ- ease-bringing-up-sputum; −1.2, p=0.005) Aerobika improved exercise capacity compared with UC (Δ 6MWD;+19 m, p=0.04) Aerobika improved regional ventilation compared with UC (Δ 3He MRI ventilation deficit percent; −1%). |
| Weiner, (1996)29 | Stable COPD FEV1 35%±8.5% predicted RCT | Flutter n=10 | 10 mins, 4–8 x per day for 3 months. | Not reported | Sham Flutter 10 mins, 4–8 times/day for 3 months. n=10 | Flutter and Sham Flutter no effect on lung function (ΔFVC% predicted +2% vs +2%) Flutter improved exercise capacity vs Sham Flutter (Δ12-minute walk distance; +649 m vs +538 m). |
| Wolkove, (2004)30 | Stable COPD with sputum production and smoking history FEV1 50%±15% RXT | Flutter plus UC n=15 | 10 mins, 4x per day, for 1 week | Every week | Sham Flutter 10 mins, 4x per day, for 1 week | Flutter improved lung function vs Sham Flutter (Δ FVC%; +24%, p=0.05) Flutter improved exercise capacity vs Sham Flutter (Δ 6MWD; +10 m, p=0.05) Flutter reduced dyspnoea vs Sham Flutter (Δ Borg scale; +1, p=0.05). |
Δ, data presented as mean difference in absolute values between groups; ACBT, active cycle of breathing technique; AECOPD, acute exacerbations of COPD; BCSS, Breathlessness, Cough and Sputum Scale; C, control; CAT, COPD assessment test; CCQ, Clinical COPD Questionnaire; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; 3He, hyperpolarised 3 helium; HRQoL, health-related quality of life; I, intervention; MMRC, Modified Medical Research Council; 6MWD, Six-minutes Walking Distance; OPEP, oscillatory positive expiratory pressure; PEFR, peak expiratory flow rate; PEQ, Patient Evaluation Questionnaire; PR, pulmonary rehabilitation; RCT, randomised controlled trial; RXT, randomised cross-over trial; SGRQ, St. George’s Respiratory Questionnaire; UC, usual care.