TABLE 17.
Grading of OSAS Severity
| Mild | Moderate | Severe | |
| Guilleminault309 | |||
| Apnea + hypopnea | 1–5 events/hr | 5–24 events/hr | >24 events/hr |
| Sheldon448 | |||
| AHI | 1–4 | 5–10 | >10 |
| Desaturation | 86–91 | 76–85 | ≤75 |
| Peak end tidal CO2 | >53 | >60 | >65 |
| End tidal CO2 %TST | 10–24 | 25–49 | ≥50 |
| Arousals per hour with EEG | >11 | >11 | >11 |
| Galland449 | |||
| Apnea index or | 1–4 events/hr | 5–9 events/hr | >10 events/hr |
| Desaturation in association with obstruction | Nadir of 87%–91% | Nadir of 76%–85% | Nadir of <75% |
| Hypoventilation | 10%–24% total sleep time | 25%–49% total sleep time | >50% total sleep time |
| Goroza450 | |||
| AHI | 5–15 events/hr | 16–30 events/hr | >30 events/hr |
| Desaturations | 81%–90% | 71%–80% | <71% |
AHI, apnea-hypopnea index; EEG, electroencephalogram; TST, total sleep time.