Table 2: Univariate associations between level of sleep interruption during the night of POD1 and patient and surgery characteristics.

 

Least interrupted

WASO

15%

(N  =  94)

Somewhat interrupted WASO

15-25%

(N  =  37)

Moderately/highly interrupted

WASO

> 25%

(N  =  25)

p-value

Patient Characteristics

Age, % 75+ years

66%

62%

80%

0.31

Gender, % male

51%

62%

52%

0.51

Race, % White

73%

81%

76%

0.65

Surgery Characteristics

Surgery type, %

General

54%

41%

40%

 

Major joint

15%

19%

12%

0.42*

Spine

31%

41%

48%

 

Surgery End Time, % 19:00 and later

11%

4%

2%

0.94*

Surgery Duration, % 6 hours or more

30%

27%

48%

0.17

Postoperative Events

Postoperative pain, % ≤ 5

33%

28%

25%

0.68

ICU, % admitted

5%

3%

0%

0.72*

Sleep Characteristics

Preoperative WASO

 

 

 

0.65*

≤ 15%

54%

62%

44%

 

15 to 25%

28%

27%

36%

 

> 25%

18%

11%

20%

 

Preoperative daytime sleep

 

 

 

0.64

≤ 20%

24%

 

22%

 

16%

 

 

20 to 40%

53%

62%

68%

 

> 40%

24%

16%

16%

 

*Results from Fisher’s exact test

WASO: Wake After Sleep Onset; ICU: Intensive Care Unit; POD1: Post-Operative Day 1

WASO groupings are based on previously defined categories [10].