Table 1 Respiratory and sleep variables by polysomnography in active sleep: sleeping supine in a cot compared with sleeping supine in a car seat
VariableCotCar seatp ValueChange and 95% CI
Total sleep time (min)*81.9 (19.1)53.8 (20.3)0.0002–28.1 (–40.6 to –15.7)
Central apnoea (events/h)†53.6 (29.5 to 102.5)45.1 (12.6 to 76.6)0.0470.63 (0.40 to 0.99)
Mixed apnoea (events/h)†5.9 (3.8 to 11.6)5.2 (3.2 to 10.9)0.851.06 (0.58 to 1.94)
Obstructive apnoea (events/h)†4.9 (2.5 to 8.2)5.1 (3.2 to 12.2)0.121.61 (0.88 to 2.94)
Mixed + obstructive apnoea10.6 (8.8 to 14.0)12.9 (6.4 to 18.9)0.381.23 (0.76 to 1.98)
(events/h)†
Mean apnoea length (s)†6.9 (6.7 to 7.3)6.6 (6.5 to 7.2)0.600.98 (0.93 to 1.05)
Longest apnoea (s)†11.6 (10.5 to 13.2)11.2 (9.0 to 14.0)0.490.94 (0.79 to 1.13)
Mean Sao2 (%)*98.0 (1.7)97.4 (2.2)0.30–0.6 (–1.8 to 0.6)
Minimum average Sao2 (%)94.6 (2.1)94.2 (2.6)0.60–0.3 (–1.6 to 1.0)
after apnoea*
Mean of lowest Sao2 (%)85.2 (5.5)85.7 (4.5)0.660.6 (–2.0 to 3.1)
after apnoea*
Arousal (events/h)†20.4 (17.9 to 23.1)17.4 (10.7 to 23.1)0.0240.79 (0.64 to 0.97)
Reflux index (%)†9.2 (1.3 to 27.1)3.4 (0.0 to 19.1)0.360.67 (0.28 to 1.65)
  • *Data are mean (SD) and change and 95% CI.

  • †Log-transformed data expressed as median and interquartile range and ratio and 95% CI.