Table 1.
Characteristics of the overall cohort and in patients with hypercapnia and hypo‐normocapnia
| Overall cohort | Hypercapnia | Hypo‐normocapnia | ||
|---|---|---|---|---|
| Characteristics | n = 193 | n = 65 | n = 128 | P |
| Mean age, years | 73 (12) | 74 (9) | 73 (13) | 0.63 |
| Sex, male, % | 60.6 | 58.5 | 61.7 | 0.76 |
| Body mass index, kg/m2 | 23.7 (4.8) | 23.3 (4.6) | 23.9 (4.9) | 0.42 |
| Background | ||||
| Coronary artery disease, % | 60.1 | 64.6 | 57.8 | 0.44 |
| Hypertension, % | 75.1 | 80.0 | 72.7 | 0.29 |
| Valvular heart disease, % | 29.5 | 24.6 | 32.0 | 0.32 |
| Atrial fibrillation, % | 30.6 | 21.5 | 35.2 | 0.07 |
| Prior hospitalization for heart failure, % | 36.6 | 37.5 | 36.2 | 0.87 |
| Diabetes mellitus, % | 43.5 | 49.2 | 40.6 | 0.28 |
| Current smoker, % | 29.6 | 37.1 | 26.0 | 0.13 |
| Pack‐years of smoking | 30 (37) | 28 (29) | 31 (41) | 0.62 |
| Medications prior to admission | ||||
| Loop diuretic, % | 39.2 | 39.7 | 38.9 | >0.99 |
| Spironolactone, % | 17.5 | 19.0 | 16.7 | 0.69 |
| ACE inhibitor or ARB, % | 45.5 | 42.9 | 46.8 | 0.64 |
| Beta blocker, % | 34.0 | 37.1 | 32.5 | 0.62 |
| Digoxin, % | 10.5 | 4.7 | 13.5 | 0.08 |
| Night‐time admission (8 pm–9 am), % | 48.7 | 66.2 | 39.8 | <0.001 |
| Admission by ambulance, % | 70.2 | 89.2 | 60.3 | <0.001 |
| Acute onset within 6 h, % | 33.7 | 50.8 | 25.0 | <0.001 |
| Shock, % | 1.6 | 4.6 | 0.0 | 0.04 |
| NYHA Class IV, % | 85.0 | 96.9 | 78.9 | <0.001 |
| Disturbance of consciousness, % | 25.9 | 55.7 | 11.3 | <0.001 |
| Systolic blood pressure, mmHg | 167 (41) | 188 (43) | 156 (36) | <0.001 |
| Diastolic blood pressure, mmHg | 94 (29) | 105 (30) | 89 (27) | <0.001 |
| Heart rate, beats/min | 110 (27) | 116 (27) | 108 (27) | 0.03 |
| Respiratory rate, times/min (n = 130) | 27 (7) | 28 (8) | 26 (7) | 0.19 |
| Pulse oximeter saturation with oxygen, % | 94 (7) | 92 (10) | 95 (6) | 0.01 |
| Oxygen supplementation, % | 66.8 | 84.4 | 57.9 | <0.001 |
| Radiographic alveolar oedema, % | 66.8 | 84.6 | 57.8 | <0.001 |
| Echocardiography | ||||
| Left ventricular ejection fraction, (%) | 38 (16) | 40 (17) | 37 (16) | 0.28 |
| Moderate/severe mitral regurgitation, % | 53.9 | 46.2 | 57.8 | 0.13 |
| Laboratory findings | ||||
| Haemoglobin, g/dL | 12.4 (2.3) | 12.5 (2.2) | 12.4 (2.4) | 0.97 |
| Serum creatinine, mg/dL | 1.59 (1.74) | 1.55 (1.57) | 1.61 (1.82) | 0.81 |
| Estimated GFR, mL/min/1.72 m2 | 48 (23) | 49 (26) | 47 (22) | 0.54 |
| B‐type natriuretic peptide, pg/mL* | 849 (480–1495) | 913 (590–1604) | 745 (427–1429) | 0.12 |
| In‐hospital management | ||||
| NPPV or intubation, % | 34.7 | 78.5 | 12.5 | <0.001 |
| NPPV, % | 27.5 | 58.5 | 11.7 | <0.001 |
| Intubation, % | 8.8 | 24.6 | 0.8 | <0.001 |
| Pulmonary artery catheter, % | 4.7 | 6.2 | 3.9 | 0.49 |
| Coronary angiography, % | 35.2 | 36.9 | 34.4 | 0.75 |
| Percutaneous coronary intervention, % | 9.4 | 9.2 | 9.4 | >0.99 |
| Coronary artery bypass grafting, % | 5.7 | 6.2 | 5.5 | >0.99 |
| Intra‐aortic balloon pump, % | 1.0 | 1.5 | 0.8 | >0.99 |
| Length of hospital stay, days* | 17 (10–26) | 18 (12–28) | 17 (9–26) | 0.25 |
ACE, angiotensin converting enzymes; ARB, angiotensin 2 receptor blockers; NYHA, New York Heart Association; GFR, glomerular filtration rate; NPPV, non‐invasive positive pressure ventilation.
*
Median (inter‐quartile range).