Table 2 Studies reporting oxygen desaturation

Rosenberg-Adamsen et al. [30] (1997) Denmark

13 patients scheduled for gastro-intestinal surgery

Descriptive sleep study of

• Mean average SpO2 (%): Supine: 95, lateral: 95

?

We have used preoperative values only (postoperative values may be confounded).

• Mean average SpO₂ supine vs. lateral sleeping during preoperative night.

• Mean number of desaturation episodes/h: Supine: 13, lateral: 3

+

Reports p = 0.04.

• Mean number of desaturations pr. hour, defined as sudden desaturation of more than 5% below the patient’s baseline value.

No difference in mean SpO2, but in number of desaturation episodes.

Cao et al. [31] (2005) China

225 adults with known obstructive sleep apnea (OSA)

Descriptive sleep study of nadir (lowest) SpO₂ in lateral vs. supine sleeping position. Reports separately on positional patients (with a known position dependent OSA) and non-positional patients.

Nadir SpO₂ (mean; %),

?

p-values not given.

• Positional patients: Supine: 78.9, lateral: 79.5

Very low values for both groups in both positions.

• Non-positional patients: Supine: 71.5, lateral: 75.1

+

Shao et al. [32] (2011) China

110 elderly patients with OSA

Descriptive sleep study of oxygen saturation in supine left and right sleeping positions, reporting time intervals between desaturation episodes (the latter not defined).

Time between desaturation episodes (median; min): Supine: 2.36, left side: 11.54, right side: 12.45

+

Conference abstract only.

p < 0.01 for both left and right vs. supine.

Oksenberg et al. [33] (2000) Israel

30 adults with OSA

Descriptive sleep study, reporting

• Mean apnea duration + (sec): Supine: 26.6, lateral: 22.8

+

p < 0.0001

• apnea duration

• Mean minimum SpO₂ (%): Supine: 82.0, lateral: 86.2

+

Clinically relatively small differences.

• minimum oxygen desaturation

• Mean ∆ SpO2 (%): Supine: 12.6, lateral: 8.3

+

• difference between max. and min. oxygen desaturation

Sasai et al. [34] (2011)

30 adults with OSA

Descriptive study of average SaO₂ in supine vs. all sleeping positions. Reports data sorted by severity of OSA (moderate and severe).

Mean average SaO₂ (%), supine vs. all:

?

p < 0.01 and < 0.05, respectively, but at least in the severe OSA group the differences are not clinically important.

• Moderate OSA: Supine: 93.9, all positions: 95.1

• Severe OSA: Supine: 88.0, all positions: 88.4

?

Browaldh et al. [35] (2013) Sweden

64 OSA patients

Two groups, one treated surgically for OSA (1), the other just observed (2). Reports data on oxygen desaturation index (ODI; events/h) before treatment.

ODI (events/h):

+

p-values not given. Clinically important difference, may have been even larger if supine was not included in all positions.

• 1: Supine: 62.7, all positions: 44.6

• 2: Supine: 54.5, all positions: 41.1

+