Table 1.

Studies investigating NIV in COPD patients after an acute exacerbation with AHRF.

Study	Design	Ventilator settings	Primary outcome	Primary outcome	Survival	Important other outcomes
Tuggey et al. [2003] N = 13	Retrospective audit 1 year	Not shown	Cost analysis	Cost saving of £8254 per patient	Year after NIV: median 29 months	Admissions year before: 5 year after NIV: 2
Galli et al. [2014] N = 166	Retrospective: NIV post-discharge versus no NIV 6 months	IPAP 22 EPAP 6 BF unknown	Event-free survival (time without rehospitalization or death)	Adjusted HR# 3.29 (95% CI 2.05-5.27) Event at 6 months: NIV: 40% No NIV: 75%	6 months: NIV: 10% No NIV: 19%	–
Cheung et al. [2010] N = 49	RCT BiPAP versus CPAP 5 cm H2O 1 year	IPAP 15 EPAP 5 BF 14/min	Recurrent exacerbation with AHRF (pH <7.35 and PaCO2 >6 kPa) resulting in repeat NIV, intubation or death)	NIV: 38.5% CPAP: 60.2% (all AHRF)	Unclear Not significant	High drop out NIV: 8 CPAP: 4
Funk et al. [2011] N = 26	RCT Continuation versus withdrawal of NIV after 6 months 1 year	IPAP 10–20 EPAP 5 Patient-triggered	Time to clinical worsening: (1) ICU admission (2) NIV with severe dyspnoea (2a) or ↑PaCO2 ⩾ 10% (2b)	NIV: 391 days (n = 2, 15%, 2 ICU) Withdrawal: 162 days (n = 10, 77%, 3 ICU)	No deaths	6MWD after 3 months NIV: 56 m Withdrawal: –17 m SGRQ, blood gases, FEV1, steroid and antibiotic use not different
Struik et al. [2014b] N = 201	RCT NIV versus Standard care 1 year	IPAP 19 EPAP 5 BF 15/min	Time to event (readmission for respiratory cause or death)	NIV: 192 days (65% had an event) Standard: 198 days (64% had an event)	NIV: 30% Standard: 30%	Daytime PaCO2 NIV: 7.7>6.4 kPa Standard: 7.4>6.6 kPa (Treatment effect: –0.5 kPa)

NIV, noninvasive ventilation; IPAP, inspiratory positive airway pressure (cmH₂O); EPAP, expiratory airway pressure (cmH₂O); BF, backup breathing frequency set by the ventilator; BiPAP, bilevel positive airway pressure; CPAP, continuous positive airway pressure; AHRF, acute hypercapnic respiratory failure; PaCO₂, arterial carbon dioxide tension; ICU, intensive care unit; 6MWD, 6-minute walking distance; SGRQ, St. George Respiratory Questionnaire; FEV₁, forced expiratory volume in 1 second.

#HR: hazard ratio, subjects who did not use NIV post-discharge had inferior event-free survival through 180 days compared with patients who used NIV post-discharge after matching the groups for age, FEV₁, the existence of obstructive sleep apnoea/obesity hypoventilation (OSA/OHS), home oxygen therapy, and admission date, and additionally adjusting for OSA/OHS and PaCO₂ at discharge.