n | 2012–13 cohort* n=101 | 2017–18 cohort† n=80 | P value | |
Baseline characteristics | ||||
Age (years) | 181 | 78 (68–83) | 78 (70–84) | 0.472 |
Male, n (%) | 181 | 27 (27) | 25 (31) | 0.573 |
BMI (kg/m2) | 133 | 23 (19–27) | 25 (21–29) | 0.055 |
FEV1 % of predicted | 153 | 33 (26–43) | 38 (24–52) | 0.246 |
MRC score | 124 | 4 (3–5) | 4 (3–5) | 0.984 |
LTOT, n (%) | 181 | 19 (18.8) | 14 (17.5) | 0.837 |
Smoker, n (%) | 179 | |||
Never | 8 (7.9) | 1 (1.2) | 0.0460 | |
Previous | 50 (49.5) | 51 (63.8) | 0.198 | |
Current | 42 (41.6) | 27 (33.8) | 0.403 | |
Pack-years | 164 | 40 (30–50) | 50 (40–60) | 0.033 |
COPD admission prior to enrolment, n (%) | 181 | |||
Within 1 month | 21 (20.8) | 12 (15.0) | 0.365 | |
Within1 year | 40 (39.6) | 27 (33.8) | 0.520 | |
Index admission data | ||||
Duration of admission (days) | 181 | 6 (3–9) | 6 (4–8) | 0.928 |
Fever (>38°C), n (%) | 179 | 9 (8.9) | 13 (16.2) | 0.158 |
Maximum CRP | 179 | 55 (19–135) | 32 (14–117) | 0.124 |
Antibiotics (oral or intravenous), n (%) | 180 | 90 (90) | 67 (84) | 0.655 |
RR at NIV initiation | 154 | 28 (24–32) | 24 (20–28) | 0.001 |
Arterial gasses at NIV initiation | ||||
pH | 181 | 7.28 (7.23–7.31) | 7.29 (7.25–7.32) | 0.552 |
PaCO2 (kPa) | 181 | 8.8 (7.7–11.0) | 8.9 (7.8–9.9) | 0.638 |
PaO2 (kPa) | 176 | 9.5 (7.9–11.0) | 9.2 (8.3–10.4) | 0.638 |
HCO3− (mmol/L) | 174 | 26.0 (23.0–31.0) | 26.2 (23.2–28.8) | 0.472 |
Base excess (mmol/L) | 175 | 4.0 (−0.2 to 9.7) | 4.0 (0.2–7.6) | 0.596 |
Lactate (mmol/L) | 170 | 1.1 (0.7–1.9) | 1.2 (0.8–2.1) | 0.395 |
Late-onset acidaemia (>12 hours after admission), n (%) | 181 | 2 (2) | 15 (18,8) | <0.001 |
Hyperoxia (Pa02 >16 kPa) on admission, n (%) | 180 | 6 (6) | 4 (4,9) | 0.776 |
Max IPAP (cm H2O) | 180 | 12 (10–14) | 20(18-24) | <0.001 |
Max EPAP (cm H2O | 180 | 5 (5–5) | 5 (5–5) | 0.119 |
Initially treated in ICU, n (%) | 181 | 4 (4.0) | 3 (3.8) | 0.943 |
DNI/DNR-order, n (%) | 179 | 61 (60) | 33 (42) | 0.098 |
Late, >2 hours of admission (% of all DNI/DNR orders) | 14 (23) | 9 (27) | ||
NIV failure, n (%) | 181 | 8 (8.0) | 2 (2.5) | 0.123 |
Data is presented as median (IQR) unless stated otherwise. Comparison of groups using Mann-Whitney U test or χ2 test.
*Low IPAP regime.
†High IPAP regime.
BMI, body mass index; COPD, chronic obstructive pulmonary disease; CRP, C reactive protein; DNI/DNR, do not intubate/do not resuscitate; EPAP, expiratory positive airway pressure ; FEV1, forced expiratory volume in 1 s; ICU, intensive care unit; IPAP, inspiratory positive airway pressure; LTOT, long-term oxygen treatment; MRC, Medical Research Council Dyspnoea Scale; NIV, non-invasive ventilation; RF, respiratory frequency.