Table 2 Descriptive statistics of the measured physiological parameters in different sleeping positions

Supine (S)Supine with tilt (ST)Prone with tilt (PT)Prone (P)p valueap valueb
Arterial blood oxygen saturation (%); Median (IQR)97,0
(96,0-98,3)
97,0
(96,0-98,0)
96,0
(96,0-97,5)
96,0
(95,0-97,0)
p = 0,001S vs ST = 0,847
ST vs PT = 0,009*
PT vs P = 0,037*
S vs P = 0,004*
S vs PT = 0,014*
ST vs P = 0,001*
Heart rate (/min)
Median (IQR)
136,5
(122,3-145,0)
134,0
(128,0-143,0)
132,5
(124,0-141,3)
130,0
(120,0-138,0)
p = 0,238NS
Breathing frequency (bpm) Median (IQR)47 (44–50)47
(45–50)
45 (43–49)45
(42,0-47,5)
p = 0,001S vs ST = 0,039*
ST vs PT = 0,001*
PT vs P = 0,045*
S vs P = 0,001*
S vs PT = 0,025*
ST vs P = 0,001*
Systolic arterial pressure (mmHg) Median (IQR)71,0
(62,8-78,3)
73,0
(68,5-82,0)
72,0
(66,0-79,0)
72,0
(67,0-80,0)
p = 0,334NS
Diastolic arterial pressure (mmHg) Median (IQR)42,5
(37,5-46,0)
45,0
(40,0-50,0)
41,0
(37,0-46,5)
44,0
(40,0-50,0)
p = 0,637NS
Mean arterial pressure (mmHg) Median (IQR)51,0
(47,0-57,0)
54,0
(49,5-59,5)
52,0
(47,3-54,0)
54,0
(48,0-60,0)
p = 0,179NS
Temperature (°C) Mean (SD)36,6 ± 0,0436,6 ± 0,0436,6 ± 0,0436,6 ± 0,04 NS
1. aFriedman test
2. bWillcoxon signed rank test
3. *p values < 0,05 (False discovery rate – FDR; corr. Factor Benjamini and Hochberg)
4. NS: non- significant
5. Data are presented as median value and IQR (interquartile range), except for the temperature data which are means+/− SD. In the last collon, statistical differences between two positions are presented