The effect of insufflation leaks in long-term ventilation. Waking and sleeping transcutaneous gas tensions in ventilator-dependent patients with an uncuffed tracheostomy tube.

Transcutaneous blood gases were recorded for 60 min when awake and asleep in 10 ventilator-dependent patients with high tetraplegia who used a pressure-limited ventilator and uncuffed tracheostomy tube. The mean arterial oxygen tension awake was 16.0 kPa compared with 15.2 kPa when asleep; the mean arterial carbon dioxide tension awake was 3.2 kPa, compared with 3.9 kPa when asleep. The oxygen tensions in each patient during the awake and sleep states were not significantly different between the two states, but during sleep the carbon dioxide tension was significantly greater.