New aspects of delirium in elderly patients with critical limb ischemia

Figures & data

Table 1 Characteristics of all included patients with critical limb ischemia receiving surgery

Characteristic	Rutherford classification score 4–6, n=92 (%)
Sex, male	53 (58)
Age, years, median (IQR)	76 (71–82)
Age 65–70 years	20 (22)
Age 70–79 years	37 (40)
Age ≥80 years	35 (38)
Living status
Nursing home	21 (23)
Daily care at home	18 (20)
Home without care	53 (57)
Comorbidity
Cardiac disease	55 (60)
Pulmonary disease	18 (20)
Renal impairment	10 (11)
Neurological disease	26 (28)
Diabetes mellitus	44 (48)
Operation
Necrosectomy	11 (12)
Minor amputation	14 (15)
Major amputation	18 (19)
Femoral endarterectomy	10 (11)
Femoropopliteal bypass	24 (26)
Femorocrural bypass	9 (10)
Aortofemoral bypass	6 (7)

Note: Data are presented as n and (%), unless otherwise specified.

Abbreviation: IQR, interquartile range.

Table 2 Onset and length of the delirium

	Rutherford classification score 4–6, n=92 (%)
Delirium	29 (32)
Preoperative delirium	17 (59)
Postoperative delirium	12 (41)
Onset of postoperative delirium (n=12)
Day 1 postoperation	7 (67)
Day 2 postoperation	3 (25)
Day 3 postoperation	–
Day 4 or more	2 (8)
Median length of delirium in days (IQR)	3 (1–6)

Note: Data are presented as n and (%).

Abbreviation: IQR, interquartile range.

Table 3 Univariate analysis of possible risk factors in patients with critical limb ischemia in relation to the onset of delirium

	No delirium, n=63 (%)	Delirium, n=29 (%)	P-value
Sex
Male	36 (57)	17 (59)	0.894
Age
Median age (years) (IQR)a	75 (69–80)	81 (76–86)	0.001b
Age 65–70 years	17 (27)	3 (10)
Age 70–79 years	30 (48)	7 (24)
Age ≥80 years	16 (25)	19 (66)	0.003
Fontaine classification
Fontaine 3	24 (38)	4 (13)
Fontaine 4	39 (62)	25 (87)	0.019
Comorbidity
Cardiac disease	32 (51)	23 (79)	0.010
Pulmonary disease	12 (19)	6 (21)	0.854
Renal impairment	5 (8)	5 (17)	0.278c
Neurological disease	16 (25)	10 (34)	0.369
Diabetes mellitus	27 (43)	17 (59)	0.160
Hypertension	38 (60)	12 (41)	0.090
Hypercholesterolemia	28 (44)	6 (21)	0.028
Other predisposing factors
Delirium in medical history	3 (5)	7 (24)	0.010c
Daily use of alcohol	18 (29)	2 (7)	0.017
Visual impairment	18 (29)	15 (52)	0.031
Hearing impairment	22 (35)	11 (38)	0.780
Frailty factors
Physical impairmentd	29 (46)	22 (76)	0.007
Undernourishmente	13/61 (21)	10/24 (42)	0.057
Daily nurse visits at home	11/55 (20)	7/16 (44)	0.093c
Living in nursing home	8 (13)	13 (45)	<0.001

Notes: Values in parentheses are percentages unless indicated otherwise;

a values are median (interquartile range). P-value is calculated with chi-squared test.

b Mann–Whitney U-test;

c Fisher’s exact test.

d Physical impairment is defined as a Katz-ADL score <6.²¹

e Undernourishment is defined as a SNAQ-RC-score ≥3.²²

Abbreviations: IQR, interquartile range; Katz-ADL, Katz Index of Independence in Activities of Daily Living; SNAQ-RC, Short Nutritional Assessment Questionnaire for Residential Care.

Table 4 Perioperative variables in relation to onset of postoperative delirium in patients with critical limb ischemia having surgery

	No delirium, n=63 (%)	Delirium, n=29 (%)	P-value
ASA score ≥3	43 (68)	26 (90)	0.028
Duration of anesthesia, median (IQR)	142 (27–211)	52 (26–100)	0.035b
Type of anesthesia
General anesthesia	56 (89)	28 (96)
Regional anesthesia	7 (11)	1 (4)	0.226
Operation type
Minor amputation	16 (25)	9 (31)	0.572
Major amputation	7 (11)	11 (38)	0.003
Bypassc	32 (51)	7 (24)	0.016
Femoral endarterectomy	8 (13)	2 (7)	0.714a
Hb and transfusion
Preoperative anemiad	35/59 (60)	22/27 (81)	0.044
Preoperative Hb, median (IQR)	7.7 (6.4–8.0)	6.8 (6.3–7.4)	0.075b
Postoperative anemiad	31/32 (97)	20/22 (91)	0.560a
Postoperative Hb, median (IQR)	6.45 (5.7–6.9)	6.2 (5.7–6.9)	0.832b
Packed cells transfusion	18 (29)	5 (17)	0.244
≥3 Packed cells transfused	9 (14)	2 (7)	0.492a

Notes: Data are presented as n and (%), unless otherwise specified. P-value is calculated with chi-squared test.

a Fisher’s exact test.

b Mann–Whitney U-test.

c Femoropopliteal, femorocrural, iliofemoral, and aortofemoral bypass.

d Anemia is defined as a Hb <7.6 mmol/L for women and <8.2 mmol/L for men.²³

Abbreviations: ASA, American Society of Anesthesiologists; IQR, interquartile range; Hb, hemoglobulin in mmol/L.

Table 5 Results of an exact conditional logistic regression analysis of delirium, where the conditioning is on operation type (four strata)

Variables	OR (95% CI)	P-value
Diabetes mellitus	6.23 (1.11–52.2)	0.035
SNAQ-RC ≥3	5.55 (1.07–42.0)	0.039
General anesthesia	13.3 (0.96–∞)	0.054
Visual impairment	3.72 (0.98–15.6)	0.055
Daily alcohol use	0.15 (0.01–1.07)	0.062
Hypercholesterolemia	0.30 (0.06–1.22)	0.10
Packed cells transfusion	0.68 (0.31–1.23)	0.27

Notes: Data presented as ORs and their 95% CI. Confidence limits and P-values are exact.

Abbreviations: OR, odds ratio; CI, confidence interval; SNAQ-RC, Short Nutritional Assessment Questionnaire for Residential Care.

Table 6 Length of hospital stay, ICU stay, and mortality in relation to onset of postoperative delirium in patients with critical ischemia

Medical adverse events	No delirium, n=63 (%)	Delirium, n=29 (%)	P-value
Cardiac	2 (3)	–	1.0a
Pulmonary	2 (3)	2 (7)	0.588a
Neurological renal/urinary	2 (3)	–5 (17)	0.030a
Surgical adverse events
Wound infection	4 (6)	3 (10)	0.674a
Re-bleeding requiring intervention	1 (2)	–	1.0a
Wound dehiscence	1 (2)	1 (3)	0.533a
Length of stay
Total hospital stay in days, median (IQR)	8 (6–13)	14 (9–20)	0.001b
Admission to ICU	5 (8)	3 (10)	0.704a
ICU stay in days ≥2	–	1 (3)	0.315a
Discharge destination
New nursing home client after discharge	10 (16)	5 (17)	0.761a

Notes: Data are presented as n and (%), unless otherwise specified. P-value is calculated with chi-squared test.

a Fisher’s exact test.

b Mann–Whitney U-test.

Abbreviations: ICU, intensive care unit; IQR, interquartile range.

Figure 1 Survival in relation to the onset of delirium in patients with critical limb ischemia.

Abbreviation: DOSS, Delirium Observation Screening Scale.

Table

DOSS (Delirium Observation Screening Scale)
1	Dozes during conversation or activities
2	Easily gets distracted by stimuli from the environment
3	Maintains attention to conversation or answer
4	Does not finish question answer
5	Gives answers which do not fit the question
6	Reacts slowly to instructions
7	Thinks to be somewhere else
8	Knows which part of the day it is
9	Remembers recent event
10	Is picking, disorderly, restless
11	Pulls intravenous tubes, feeding tubes, catheter
12	Is easy or sudden emotional
13	Additive or visual hallucinations

Notes: If present, 1 point. Rate three times per day.

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