Table 2.

Respiratory parameters and blood gas analysis at normal breathing and rebreathing

Respiratory and blood gas parameters	35 s system	50 s system
Respiratory rate (breaths/min)
Normal breathing	16 (15–18)	17 (15–17)
Rebreathing	18* (16–22)	19* (16–22)
Minute ventilation (l/min)
Normal breathing	6.6 (5.9–7.4)	6.3 (6.2–7.3)
Rebreathing	8.8* (8.0–11.6)	9.5* (8.2–12.4)
Arterial carbon dioxide tension (mmHg)
Normal breathing	42.1 (41.0–46.9)	42.2 (39.6–48.6)
Rebreathing	46.5* (43.5–52.5)	47.2* (45.9–55.0)
Mixed venous carbon dioxide tension (mmHg)
Normal breathing	46.2 (44.4–52.2)	48.0 (43.9–52.2)
Rebreathing	47.6* (46.1–52.9)	49.0* (47.0–54.4)

Values are expressed as median (interquartile range). *P < 0.05 versus normal breathing.