Respiratory events during sleep in both nights at altitude
| Placebo | Acetazolamide | Theophylline | |
| First night | |||
| Desaturation index n·h−1 | 41.5 (6–114) | 6.5 (3–28)** | 8.5 (3–32)** |
| AHI n·h−1 | 16.2 (3–92) | 2.5 (0–11) | 4.2 (0–19)** |
| Basal oxyhaemoglobin saturation % | 78.9 (71–84) | 86.8 (83–88)** | 80.3 (77–86) |
| Second night | |||
| Desaturation index n·h−1 | 24.0 (6–89) | 5.0 (4–8)** | 8.0 (2–31)** |
| AHI second night n·h−1 | 6.9 (1–77) | 1 (0–6)** | 3.5 (1–6)** |
| Basal oxyhaemoglobin saturation % | 81.7 (67–86) | 86.5 (83–88)# | 82.5 (76–88) |
Data are presented as median (range)
AHI: apnoea/hypopnoea index
**: p<0.01 versus corresponding values in the placebo group
#: p<0.05 versus corresponding values in the placebo group