Socio-demographic characteristics
A total of 384 patients were included in the study making for a 100% response rate. Greater than half (57.8%) of the study participants were males and the rest, 162 (42.2%) were females. Regarding the age of the participants, 170 (44.3%) was aged between 65 and 74 years. The majority, 312 (81.3%) of the participants were married. With respect to educational status, greater than one-third (37.2%) of the study participants had no formal education.
Pre-operative Factors
As the distribution of pre-operative factors showed, ASA II held nearly three fourths (74.2%), of the ASA status of old-age patients, while ASA - I and ASA - III, were 84(21.9%) and 15(3.9%), respectively. Those patients who had a history of co-morbid disease were 76 (19.8%). Opioids were the most frequently given premedication, 120 (31.3%), followed by anti-cholinergic, 105 (27.3%) and other premedication like diazepam and steroids, 95 (24.7%). Regarding pre-operative hemoglobin levels, more than three-fourths (81.0%) of the old-age patients had normal hemoglobin levels, and the rest, 19.0% had low hemoglobin levels (anemic) (Table - 1).
Table - 1. A cross-tabulation of the pre-operative factors in old-age patients who underwent elective surgery in the Teaching Hospitals of Ethiopia, Ethiopia (n=384)
Variables
|
Categories
|
Frequency (%)
|
Emergence delirium, frequency (%)
|
Yes(n=106)
|
No(n=278)
|
106(27.6)
|
278(72.4)
|
Patient ASA status
|
ASA-1
|
84(21.9)
|
25(29.8)
|
59(70.2)
|
ASA-2
|
285(74.2)
|
73(25.6)
|
112(74.4)
|
ASA-3
|
15(3.9)
|
8(53.3)
|
7(46.7)
|
Comorbidity
|
Yes
|
76(19.8)
|
35(46.1)
|
41(53.9)
|
No
|
308(80.2)
|
71(23.1)
|
237(76.9)
|
Premedication
|
Anticholinergics
|
Yes
|
105 (24.7)
|
57(60)
|
48(40)
|
No
|
289(75.3)
|
49(17.0)
|
240(83.0)
|
Opioids
|
Yes
|
120(31.3)
|
65(54.2)
|
55(45.8)
|
No
|
264(68.8)
|
41(15.5)
|
223(84.5)
|
Others (steroids, diazepam)
|
Yes
|
95(27.3)
|
37(35.2)
|
58(64.8)
|
No
|
279(72.7)
|
69(24.7)
|
210(75.3)
|
Pre-operative Hgb levels
|
Anemic
|
73(19.0)
|
61(83.6)
|
12(16.4)
|
Not-anemic
|
311(81.0)
|
45(14.5)
|
266(85.5)
|
Intra-operative and post-operative factors
General anesthesia was provided to nearly more than half of the old-age participants (54.2%). 85 (39.9%) of the participants were induced with ketofol, and the majority (86.4%) of the participants were maintained with inhalation anesthetics, with isoflurane accounting for nearly two-thirds (67.9%) of the participants. The majority of surgeries took longer than two hours, with 314 (81.8%) taking longer than that (Table - 2).
Table - 2. A cross-tabulation of the intra-operative and post- operative factors in old-age patients who underwent elective surgery at Teaching Hospitals of Ethiopia, Ethiopia (n=384)
Variables
|
Categories
|
Frequency (%)
|
Emergence delirium, frequency (%)
|
Yes(n=106)
|
No(n=278)
|
106(27.6)
|
278(72.4)
|
Types of anesthesia
|
Regional Anesthesia
|
176(45.8)
|
34(19.3)
|
142(80.7)
|
General Anesthesia
|
208(54.2)
|
72(34.6)
|
136(65.4)
|
Induction agent
|
Ketamine
|
28(13.1)
|
10(35.7)
|
18(64.3)
|
Propofol
|
62(29.1)
|
25(40.3)
|
37(59.7)
|
Thiopental
|
38(17.9)
|
14(36.8)
|
24(63.2)
|
Ketofol
|
85(39.9)
|
29(34.1)
|
56(65.9)
|
Maintenance agent(s)
|
Inhalational
|
184(86.4)
|
73(39.7)
|
111(60.3)
|
Propofol
|
3(1.4)
|
1(33.3)
|
2(66.7)
|
Others
|
26(12.2)
|
4(15.4)
|
22(84.6)
|
Inhalational agent for maintenance
|
Halothane
|
68(32.1)
|
34(50)
|
34(50)
|
Isoflurane
|
144(67.9)
|
44(30.6)
|
100(69.4)
|
Duration of surgery
|
Short duration (<2hours)
|
70(18.2)
|
16(22.9)
|
54(77.1)
|
Longer duration (>2hours)
|
314(81.8)
|
90(28.7)
|
224(71.3)
|
Post-operative pain
|
No – mild
|
362(94.3)
|
93(25.7)
|
269(74.3)
|
Moderate – severe
|
22(5.7)
|
13(59.1)
|
9(40.9)
|
General surgery operations were the most commonly performed procedures among old-age patients as compared to other specialties, accounting for 98 (25.5%) of the total, as shown in the bar chart (Figure 1).
Two-thirds (66.7) of old-age patients were calm and the rest were agitated, 36(9.4%), restless, 33(8.6%), combative, 32(8.3%) and very agitated, 27(7.0%) respectively according to the PACU sedation score, as shown in the (Figure-2)
Prevalence of emergence delirium
The prevalence of emergence delirium in old-age patients who underwent elective surgery at Teaching Hospitals of Ethiopia was 106 (27.6%).
Factors Associated with Emergence Delirium among old-age patients who underwent elective surgery at PACU
Bi-variable and multi-variable logistic regression of factors associated with emergence delirium in old-age patients who underwent elective surgery at Teaching Hospitals of Ethiopia
Bi-variable logistic regression was fitted to identify candidate variables for the multi-variable logistic regression. Accordingly, educational status, marital status, premedication with opioids and anti-cholinergic, comorbidity, pre-operative hemoglobin level, types of anesthesia, maintenance agent, post-operative pain, and post-operative sedation were associated with emergence delirium at p-value of < 0.25 (Table - 3)
Table - 3. Bivariable logistic regression of factors associated with emergence delirium in old-age patients who underwent elective surgery in the Teaching Hospitals of Ethiopia, Ethiopia (n=384)
Variables
|
Categories
|
Emergence delirium, frequency (%)
|
COR(95% CI)
|
p-value
|
Yes(n=106)
|
No(n=278)
|
106 (27.6)
|
278(72.4)
|
Educational status
|
High education
|
26(22.6)
|
89(77.4)
|
1
|
|
Low education
|
18(14.3)
|
108(85.7)
|
0.57(0.22 – 0.66)
|
0.22
|
No
|
62(43.4)
|
81(56.6)
|
2.62(0.90 – 3.40)
|
0.18
|
Marital status
|
Married
|
71(22.8)
|
241(77.2)
|
1
|
|
Single
|
23(46.9)
|
26(53.1)
|
3.0(0.46 – 3.33)
|
0.22
|
Divorced
|
12(52.2)
|
11(47.8)
|
4.16(1.57 – 8.75)
|
0.23
|
Comorbidity
|
No
|
71(23.1)
|
237(76.9)
|
1
|
|
Yes
|
35(46.1)
|
41(53.9)
|
2.85(2.11 – 10.0)
|
0.16
|
Pre-operative Hemoglobin level
|
Not-anemic
|
45(14.5)
|
266(85.5)
|
1
|
|
Anemic
|
61(83.6)
|
12(16.4)
|
30.1(3.10 – 26.0)
|
0.24
|
Types of anesthesia
|
Regional anesthesia
|
34(19.3)
|
142(80.7)
|
1
|
|
General Anesthesia
|
72(34.6)
|
136(65.4)
|
2.21 (1.82 – 9.2)
|
0.22
|
Premedication
|
Anti-cholinergic
|
No
|
49(17)
|
240(83)
|
1
|
|
Yes
|
57(60)
|
38(40)
|
7.35(5.5 – 11.3)
|
0.12
|
Opioids
|
No
|
41(15.5)
|
223(84.5)
|
1
|
|
Yes
|
65(54.2)
|
55(45.8)
|
6.43(20 – 55)
|
0.23
|
Types of surgery
|
Others(Plastics and EENT)
|
2(7.4)
|
23(92.6)
|
1
|
|
Urology
|
8(19.5)
|
33(80.5)
|
2.79(1.21 – 9.33)
|
0.44
|
Neurologic surgery
|
10(37.0)
|
17(63.0)
|
6.76(2.0 – 17.15)
|
0.23
|
Oral and maxillofacial
|
10(19.6)
|
41(80.4)
|
2.80(0.42 – 8.55)
|
0.26
|
Gynecology
|
10(22.7)
|
34(77.3)
|
3.38(1.06 – 12.0)
|
0.54
|
Thoracic
|
13(41.9)
|
18(58.1)
|
8.31(4.44 – 21.1)
|
0.19
|
Orthopedics
|
18(27.7)
|
49(72.3)
|
4.22(0.65 – 3.88)
|
0.20
|
General surgery
|
35(35.7)
|
63(64.3)
|
6.39(1.46 – 17.2)
|
0.22
|
Post- operative pain
|
No-mild
|
93(25.7)
|
269(74.3)
|
1
|
|
Moderate- severe
|
13(59.1)
|
9(40.9)
|
4.18(7.3 –17.1)
|
0.23
|
Sedation levels
|
Calm or no answers
|
56(21.9)
|
200(78.1)
|
1
|
|
Restless
|
10(31.3)
|
22(68.7)
|
1.62(22 – 38)
|
0.22
|
Agitated
|
9(33.3)
|
18(66.7)
|
1.78(2.4 – 3.1)
|
0.24
|
Very agitated
|
17(47.2)
|
19(52.8)
|
3.19(1.5 – 6.4)
|
0.19
|
Combative
|
14(42.4)
|
19(57.6)
|
2.63(1.6 – 8.1)
|
0.21
|
N.B: Bold p-value = significant association on bivariable logistic regression at p-value < 0.25. 1- Reference group
Factors independently associated with emergence of delirium in old-age patients who underwent elective surgery at Teaching Hospitals of Ethiopia
Multi-variable logistic regression was fitted to identify factors independently associated with emergence delirium. Accordingly, pre-operative low hemoglobin levels, premedication of opioids and anti-cholinergic, and moderate to severe post-operative pain at PACU were significantly associated with emergence delirium in multi-variable logistic regression at a p-value of <0.05.
When compared to participants who did not receive opioids premedication, those who received opioids premedication were 8 times (AOR: 8.0, 95%CI: 3.22 – 27.8), more likely to suffer emergence delirium. Anti-cholinergic premedication increased the risk of emergence delirium in old-age patients by 8.5 times (AOR: 8.5, 95%CI: 8.5(6.85 – 17.35) as compared to those who had not.
When compared to those with normal pre-operative hemoglobin, old-age patients with low pre-operative hemoglobin were 2 times (AOR; 2.0, 95% CI, 1.77 – 3.46) more likely suffer emergence delirium. When compared to old-age patients experiencing mild pain in the PACU, those experiencing moderate to severe pain were 3.10 times (AOR; 3.10, 95% CI, 2.07 – 9.84) more likely to develop emergence delirium (Table- 4)
Table - 4. Results of multivariable logistic regression of factors independently associated with emergence delirium in old-age patients who underwent elective surgery at Teaching Hospitals of Ethiopia, Ethiopia (n=384)
Variables
|
Categories
|
AOR(95% CI)
|
Educational status
|
High education
|
1
|
Low education
|
1.33(0.11 – 1.14)
|
No
|
1.21(0.03 – 2.58)
|
Marital status
|
Married
|
1
|
Single
|
0.88(0.19 – 2.33)
|
Divorced
|
1.11(0.37 – 1.66)
|
Comorbidity
|
No
|
1
|
Yes
|
9.45(0.83 – 22.99)
|
Pre-operative Hemoglobin levels
|
Not-anemic
|
1
|
Anemic
|
1.98(1.77 – 3.46)
|
Types of anesthesia
|
Regional anesthesia
|
1
|
General Anesthesia
|
4.33(0.5 – 11.66)
|
Premedication
|
Anticholinergic
|
No
|
1
|
Yes
|
8.5(6.85 – 17.35)
|
Opioids
|
No
|
1
|
Yes
|
7.89(3.22 – 27.8)
|
Post- operative pain
|
No-mild
|
1
|
Moderate- severe
|
3.10(2.07 – 9.84)
|
Sedation level
|
Calm or no answers
|
1
|
Restless
|
3.11(0.29 – 1.88)
|
Agitated
|
0.80(0.33 – 1.66)
|
Very agitated
|
1.11(0.04 – 18.06)
|
Combative
|
2.75(0.36 – 22.5)
|
N.B: Bold: Significant association on multivariable logistic regression