Table 1

Baseline values: the effects of age, sleep position, and sleep state on Sao 2, heart rate, and respiratory rate

Constant1-150 Factor1-150 Δ1-151 (95% CI) p value
Sao 2(%)98.0(97.5, 98.4)
Age0.7(0.3, 1.2)<0.0001
Sleep state−0.3(−0.4, −0.06)0.017
Position at newborn−0.8(−1.2, −0.3)0.001
Position at 3 mth−0.05(−0.4, 0.3)NS
Heart rate (bpm)132.7(130.2, 135.1)
Age−10.3(−13.3, −7.4)<0.0001
Sleep state1.5(0.2, 2.8)0.029
Position at newborn2.2(0.1, 4.2)0.037
Position at 3 mth6.7(4.6, 8.8)0.001
Respiratory rate (breaths/min)48.8(46.0, 51.5)
Age−14.5(−17.3, −11.7)<0.0001
Sleep state7.1(5.5, 8.7)<0.0001
Position at newborn−5.4(−7.9, −3.0)0.006
Position at 3 mth−0.8(−2.4, 0.7)NS
  • 1-150 Each factor has a nominated default value; for age this is newborn, for sleep state, QS, and for sleep position, supine. The value for each variable when all the default factors operate is the “constant” and the switching of each factor alters the nominated variable by the difference (Δ) indicated. For example, the constant for respiratory rate is 48.8 breaths/min and there is a fall of 14.5 breaths/min attributable to taking 3 month data rather than newborn. It does not necessarily follow that the mean respiratory rate was 34.3 breaths/min (48.8–14.5), as other factors may be different in the two age groups, for example, more data obtained in QS. In one case the change associated with altering sleep position is different in the two age groups so these are presented separately.

  • 1-151 Δ values represent the differences in the direction indicated for:

  • Age; newborn → 3 months

  • Sleep state; QS → AS

  • Position; supine → prone.