Baseline characteristics of the three treatment groups
| Treatment arm | |||
|---|---|---|---|
| Control (n = 20) | CPAP (n = 20) | Bilevel (n = 20) | |
| *Mean (SD). | |||
| Demography | |||
| Age (y)* | 74.6 (11.1) | 74.9 (12.2) | 76.0 (8.4) |
| Male sex (%) | 9 (45) | 8 (40) | 6 (30) |
| Physiology on arrival | |||
| Heart rate (bpm)* | 110 (23) | 113 (18) | 110 (23) |
| Respiratory rate (bpm)* | 36 (7) | 35 (6) | 35 (8) |
| Systolic blood pressure (mm Hg)* | 165 (42) | 166 (42) | 166 (34) |
| Diastolic blood pressure (mm Hg)* | 92 (21) | 93 (25) | 92 (16) |
| Arterial blood H+ ion concentration (nmol/l)* | 63.47 (11.33) | 68.76 (17.86) | 62.16 (11.20) |
| Arterial blood pH* | 7.204 (0.078) | 7.175 (0.105) | 7.212 (0.074) |
| Arterial blood po2 (kPA)* | 13.45 (7.23) | 13.75 (9.19) | 12.49 (5.75) |
| Arterial blood pco2 (kPA)* | 7.44 (2.33) | 9.21 (2.56) | 8.01 (2.28) |
| Arterial blood oxygen saturation (%)* | 91 (8) | 89 (11) | 90 (12) |
| Past history (number (%) of patients) | |||
| Heart failure | 7 (35) | 5 (25) | 12 (60) |
| Ischaemic heart disease | 12 (60) | 9 (45) | 11 (55) |
| Diabetes mellitus | 5 (25) | 4 (20) | 6 (30) |
| Hypertension | 5 (25) | 6 (30) | 11 (55) |
| Chronic obstructive pulmonary disease | 6 (30) | 3 (15) | 7 (35) |