Table 1

	Total (n=69)		Delirium (n=20)		No Delirium (n=49)		p value
Gender	Male	50 (72.5%)	Male	17 (34.0%)	Male	33 (66.0%)	0.234 #
	Female	19 (27.5%)	Female	3 (15.8%)	Female	16 (84.2%)
Age (years)	66.65 (± 10.46)		65.60 (± 8.53)		65.67 (± 11.24)		0.979 §
ASA class	ASA 3	7 (10.1%)	ASA 3	1 (4.5%)	ASA 3	7 (10.1%)	0.664 #
	ASA 4	62 (89.9%)	ASA 4	19 (95.5)	ASA 4	62 (89.9%)
ADS (antichilinergic drud scale)	0	59 (85.5%)	0	17 (85.0%)	0	42 (85.7%)	all > 0.05
	1	8 (11.6%)	1	3 (15.0%)	1	5 (10.2%)
	2	1 (1.4%)	2	0	2	1 (2.0%)
	3	0	3	0	3	0
	4	1 (1.4%)	4	0	4	1 (2%)
Euroscore	1.61 (± 1.38)		1.99 (± 1.57)		1.45 (± 1.28)		0.123
Smoker	Yes	31 (44.9%)	Yes	11 (35.5%)	Yes	20 (64.5%)	0.301 #
	NO	38 (55.1%)	NO	9 (64.5%)	NO	28 (35.5%)
C2 intake (Regular)	Yes	33 (47.8%)	Yes	14 (70.0%)	Yes	19 (38.8%)	0.032*#
	NO	36 (52.2 %)	NO	6 (30.0%)	NO	30 (61.2%)

Table 1: Baseline characteristics (n = number of patients; p=level of significance [<0.05]; ASA = physical status classification system; ADS = anticholinergic drug scale [0= no anticholinergic drugs; 4= very high “load”]; C2 = ethanol [drinking]; § = independent sample t-test; # = exact fisher test; ^ = Mann-Whitney-U test; * = significant difference)

Table 2

AChE mean (SD)	Delirium, n = 20	No delirium, n = 49	Effect size	p-value
Baseline	46 (6)	48 (9)	0.28(cohen´s r)	0.6^W
Before anesthesia (induction)	47 (8)	46 (7)	0.23(cohen´s d)	0.4^T
Admission intensive care unit	43 (6)	45 (8)	0.18(cohen´s d)	0.5^T
1^st postoperative day	44 (5)	45 (8)	0.13(cohen´s d)	0.6^T
2^nd postoperative day	45 (5)	45 (5)	0.07(cohen´s d)	0.8^T
3^rd postoperative day	46 (5)	46 (6)	0.01(cohen´s d)	>0.9^T

Table 2: comparison of AChE values (acetylcholinesterase in U/g Hb [units per gram hemoglobin]). SD = standard deviation; w Mann-Whitney-U test (with median values without normal distribution); T independent sample t-test (with mean values with normal distribution); p-values (level of significance [<0.05]); f = effect size. Values of AChE baseline were not distributed equally.

Table 3

BChE mean (SD)	Delirium,n = 20	No delirium,n = 49	Effect size	p-value
Baseline	3,419 (668)	3,393 (799)	0.03(cohen´s d)	>0.9^T
Before anesthesia (induction)	3,338 (854)	3,355 (766)	0.02(cohen´s d)	>0.9^T
Admission intensive care unit	3,277 (918)	3,097 (608)	0.3(cohen´s d)	0.3^T
1^st postoperative day	3,105 (834)	2,906 (528)	0.15(cohen´s r)	0.2^W
2^nd postoperative day	2,639 (467)	2,561 (477)	0.16(cohen´s d)	0.5^T
3^rd postoperative day	2,529 (516)	2,614 (540)	0.16(cohen´s d)	0.5^T

Table 3: Comparison of BChE values (butyrylcholinesterase in U/l [units per liter]). SD = standard deviation; w Mann-Whitney-U test (with median values without normal distribution); T Two Sample t-test (with mean values with normal distribution); w Mann-Whitney-U test; T independent sample t-test; p-values (level of significance [<0.05]). Variances BChE 1st postop. day unequal.

Table 4

AChE (p/r(r*)/n)	Leukocytes Delirium	Leukocytes Non-Delirium	CRP Delirium	CRP Non-Delirium	Il-6 Delirium	Il-6 Non-Delirium
Baseline	p=0.855 r=0.05 (n=16)	p=0.684 -0.07 (n=38)	p=0.816 r=0.06 (n=16)	p=0.149 r=0.24 (n=39)	na (n=0)	na (n=1)
Induction	p=0.47 r=0.2 (n=15)	p=0.223 r=0.18 (n=46)	na (n=1)	p=0.582 r=0.19 (n=11)	na (n=0)	na (n=1)
Admission	p=0.749 r=0.14 (n=8)	p=0.084 r=0.43 (n=17)	na (n=1)	p=0.796 r=-0.2 (n=4)	na (n=2)	p=0.002 r=1 (n=4)
postOP1	p=0.125 r=0.35 (n=20)	p=0.284 r=0.16 (n=48)	p=0.554 r=0.14 (n=20)	p=0.088 r=-0.25 (n=47)	p=0.847 r=0.05 (n=18)	p=0.189 r=0.02 (n=38)
postOP2	p=0.44 r=0.18 (n=20)	p=0.942 r=0.01 (n=48)	p=0.081 r=0.4 (n=20)	p=0.612 r=-0.08 (n=45)	p=0.821 r=-0.07 (n=14)	p=0.368 r=-0.16 (n=32)
postOP3	p=0.518 r=-0.16 (n=19)	p=0.656 r=-0.07 (n=47)	p=0.689 r=-0.1 (n=19)	p=0.499 r=-0.1 (n=44)	p=0.489 r=0.25 (n=10)	p=0.766 r=0.06 (n=27)

Table 4: Correlations between acetylcholinesterase (AChE), occurrence of delirium and common inflammation parameters (Leukocytes; CRP [c”c-reactive protein”] and Il-6 [“interleukin six”]. All correlations with normal distribution of parameters were done with Pearson-correlation; except those without normal distribution:* =Spearman correlation. The number in the tabe are the correlation coefficients. Induction was start of anesthesia; admission was arrival on intensive care unit; postop 1-3 were postoperative days 1-3; r = cohen´s r (effect size for pearson correlation); r*=spearman correlation (without normal distribution)

Table 5

BChE (p/r(r*)/n)	Leukocytes Delirium	Leukocytes Non-Delirium	CRP Delirium	CRP Non-Delirium	Il-6 Delirium	Il-6 Non-Delirium
Baseline	p=0.894 r=-0.04 (n=16)	p=0.69 r=0.07 (n=38)	p=0.761 r=0.08 (n=16)	p=0.206 r=-0.21 (n=39)	na (n=0)	na (n=1)
Induction	p=0.134 r=-0.41 (n=15)	p=0.448 r=-0.11 (n=46)	na (n=1)	p=0.01 r=-071 (n=11) $	na (n=0)	na (n=1)
Admission	p=0.095 r=-0.63 (n=8)	p=0.194 r=-0.33 (n=17)	na (n=1)	p=0.626 r=0.37 (n=4)	na (n=2)	p=0.089 r=-0.91 (n=4)
postOP1	p=0.808 r=-0.06 (n=20)	p<0.001 r=-0.5 (n=48) $	p=0.632 r=0.11 (n=20)	p=0.723 r=-0.05 (n=47)	p=0.096 r=0.4 (n=18)	p=0.862 r=0.03 (n=38)
postOP2	p=0.992 r=0 (n=20)	p=0.024 r=-0.33 (n=48) $	p=0.943 r=-0.02 (n=20)	p=0.574 r=0.09 (n=45)	p=0.608 r=-0.15 (n=14)	p=0.871 r=-0.03 (n=32)
postOP3	p=0.848 r=0.05 (n=19)	p=0.005 r=-0.41 (n=47) $	p=0.689 r=-0.1 (n=19)	p=0.904 r=0.02 (n=44)	p=0.437 r=0.28 (n=10)	p=0.761 r=-0.06 (n=27)

Table 5: Correlations between butyrylcholinesterase (BChE), occurrence of delirium and common inflammation parameters (Leukocytes; CRP [c”c-reactive protein”] and Il-6 [“interleukin six”]. All correlations with normal distribution of parameters were done with Pearson-correlation; except those without normal distribution:* =Spearman correlation. The number in the tabe are the correlation coefficients. $ = indicates significant correlation. Induction was start of anesthesia; admission was arrival on intensive care unit; postop 1-3 were postoperative days 1-3; r = cohen´s r (effect size for pearson correlation); r*=spearman correlation (without normal distribution)

Tables at a glance

Table 1

Table 2

Table 3

Table 4

Table 5

Figures at a glance

Figure 1

Figure 2

Figure 3

Figure 4

FIGURE 1

Figure 1: Screening/allocation procedure. N=number of patients in each group

FIGURE 2

Figure 2: Overview of the perioperative measures carried out (Nu-DESC = Nursing Delirium Screening Scale; CAM-ICU = confusion assessment method for the intensive care unit; AChE = acetylcholinesterase; BChE = butyrylcholinesterase; CRP = c-reactive protein; Il-6 = interleukin 6; 1-6: perioperative time points

FIGURE 3

Figure 3: Boxplots of perioperative course of AChE (acetylcholinesterase in U/g Hb [units per gram hemoglobin]) in delirious (left diagram) and non-delirious (right diagram) patients. postop 1-3 = postoperative days 1-3; ICU = intensive care unit; induction = anesthesia induction). Displayed are mean differences (mean values; upper & lower quantile & extremes [dots]). Average differences between patients with and without delirium: hospital admission: -2/ before anesthesia: 1/ admission Intensive Care Unit: -2/ 1st postoperative day: -1/ 2nd postoperative day: 0.5/ 3rd postoperative day: 0

FIGURE 4

Figure 4: Boxplots of perioperative course of BChE (butyrylcholinesterase in U/l [units per litre]) in delirious (left diagram) and non-delirious (right diagram) patients. postop 1-3 = postoperative days 1-3; ICU = intensive care unit; induction = anesthesia induction). Displayed are mean differences (mean values; upper & lower quantil & extremes [dots]). Average differences between patients with and without delirium: hospital admission: 26/ before anesthesia: 17/ admission Intensive Care Unit: 180/ 1st postoperative day: 199/ 2nd postoperative day: 78/ 3rd postoperative day: 85