Efficacy of prehospital amiodarone on survival in adult out-of-hospital cardiac arrest: a retrospective observational study

	Overall (n = 66)	No amiodarone (n = 45)	Amiodarone (n = 21)	SD
Age, median (IQR)	65 (52–76)	69 (52–77)	63 (53–71)	0.19
Male, n (%)	54 (81.8)	40 (88.9)	14 (66.7)	0.55
Clinical frailty scale^a, n (%)				−0.06
Very fit	3 (5.0)	2 (5.0)	1 (5.0)
Well	9 (15.0)	7 (17.5)	2 (10.0)
Managing well	29 (48.3)	19 (47.5)	10 (50.0)
Vulnerable	10 (16.7)	6 (15.0)	4 (20.0)
Mildly frail	4 (6.7)	2 (5.0)	2 (10.0)
Moderately frail	2 (3.3)	2 (5.0)	0 (0)
Severely frail	3 (5.0)	2 (5.0)	1 (5.0)
Very severely frail	0 (0)	0 (0)	0 (0)
Terminally ill	0 (0)	0 (0)	0 (0)
Charlson comorbidity index^b, median (IQR)	0 (0–1)	0 (0–1)	0 (0–1)	0.38
Time of emergency call, n (%)				0.42
7:00–14:59	32 (48.5)	21 (46.7)	11 (52.4)
15:00–22:59	25 (37.9)	16 (35.6)	9 (42.9)
23:00–6:59	9 (13.6)	8 (17.8)	1 (4.8)
Witness status, n (%)				0.25
None	8 (12.1)	6 (13.3)	2 (9.5)
EMS personnel	1 (1.5)	1 (2.2)	0 (0)
Others	57 (86.4)	38 (84.4)	19 (90.5)
Bystander CPR, n (%)				0.47
Presence	43 (65.2)	29 (64.4)	14 (66.7)
Absence	23 (34.8)	16 (35.6)	7 (33.3)
Initial monitored cardiac rhythm, n (%)				0.38
VF	63 (95.5)	42 (93.3)	21 (100)
Pulseless VT	3 (4.5)	3 (6.7)	0 (0)
Cause of cardiac arrest, n (%)				0.16
Cardiogenic	61 (92.4)	41 (91.1)	20 (95.2)
Other intrinsic disease	5 (7.6)	4 (8.9)	1 (4.8)
Time from scene to initiation of CPR^c, min, median (IQR)	11 (9–13)	11 (10–14)	10 (9–12)	0.17
Adrenaline administration by EMS before physician contact^d, n (%)	34 (68.0)	21 (70.0)	13 (65.0)	0.31
AAM by EMS before physician contact, n (%)	39 (59.0)	25 (55.5)	14 (66.6)	0.39
Type of AAM by EMS, n (%)				0.39
Supraglottic airway device	36 (54.5)	24 (53.3)	12 (57.1)
Endotracheal tube	3 (4.5)	1 (2.2)	2 (9.5)
Shock delivery by EMS before physician contact, n (%)	60 (90.9)	41 (91.1)	19 (90.5)	0.16
Adrenaline administration before amiodarone administration, n (%)	24 (36.4)	16 (35.6)	8 (38.1)	0.05
Time from physician contact to adrenaline administration before amiodarone administration^e, min, median (IQR)	3 (1.8–4.3)	3.5 (1.8–5.3)	2.5 (1.8–3)	0.39
AAM before amiodarone administration, n (%)	24 (36.4)	16 (35.6)	8 (38.1)	0.05
Time from physician contact to AAM before amiodarone administration^f, min, median (IQR)	3 (3–5)	4.5 (3–5)	3 (2.8–3)	0.84
Time from scene to amiodarone administration, min, median (IQR)	27 (22–32)	-	27 (22–32)	-
Time from physician contact to amiodarone administration, min, median (IQR)	4 (2–7)	-	4 (2–7)	-
Time from physician contact to hospital arrival, min, median (IQR)	13 (9–16)	14 (8–16)	11 (10–15)	−0.18
Time from scene to ROSC^g, min, median (IQR)	27 (21–38)	26 (21–37)	28 (23–49)	−0.34

Missing data:

a n = 6 (9.1%);

b n = 2 (3.0%);

c n = 8 (12.1%);

d n = 17 (25.8%);

e n = 42 (63.6%);

f n = 42 (63.6%);

g n = 23 (34.8%)

Abbreviations: AAM, advanced airway management; CPR, cardiopulmonary resuscitation; IQR, interquartile range; EMS, emergency medicine service; OHCA, out-of-hospital cardiac arrest; ROSC, return of spontaneous circulation; SD, standardized difference; VF, ventricular fibrillation; VT, ventricular tachycardia.

Table 2.

Outcomes in original cohort

	Overall (n = 66)	No amiodarone (n = 45)	Amiodarone (n = 21)	SD
30-day neurological outcome
CPC 1	10 (15.2)	9 (20.0)	1 (4.8)	0.67
CPC 2	5 (7.6)	3 (6.7)	2 (9.5)
CPC 3	3 (4.5)	1 (2.2)	2 (9.5)
CPC 4	7 (10.6)	6 (13.3)	1 (4.8)
CPC 5	41 (62.1)	26 (57.8)	15 (71.4)
30-day favorable neurological outcome	15 (22.7)	12 (26.7)	3 (14.3)	0.31
30-day survival	25 (37.9)	19 (42.2)	6 (28.6)	0.29

[i] Abbreviations: CPC, cerebral performance category; SD, standardized difference.

Table 3.

Characteristics of adults with OHCA with and without amiodarone after time-dependent propensity score matching

	Overall (n = 76)	No amiodarone yet at the same index time point (n = 57)	Received amiodarone at the index time point (n = 19)	SD
Age, median (IQR)	63 (52–76)	59 (52–80)	65 (57–73)	−0.01
Male, n (%)	53 (69.7)	41 (71.9)	12 (63.2)	0.19
Clinical frailty scale^a, n (%)				−0.13
Very fit	2 (2.8)	1 (1.9)	1 (5.6)
Well	16 (22.5)	15 (28.3)	1 (5.6)
Managing well	30 (42.3)	21 (39.6)	9 (50.0)
Vulnerable	14 (19.7)	10 (18.9)	4 (22.2)
Mildly frail	2 (2.8)	0 (0)	2 (11.1)
Moderately frail	7 (9.9)	6 (11.3)	1 (5.6)
Severely frail	2 (2.8)	1 (1.9)	1 (5.6)
Very severely frail	0 (0)	0 (0)	0 (0)
Terminally ill	0 (0)	0 (0)	0 (0)
Charlson comorbidity index, median (IQR)	0 (0–1)	0 (0–0)	0 (0–1)	0.05
Time of emergency call, n (%)				0.10
7:00–14:59	39 (51.3)	29 (50.9)	10 (52.6)
15:00–22:59	34 (44.7)	26 (45.6)	8 (42.1)
23:00–6:59	3 (3.9)	2 (3.5)	1 (5.3)
Witness status, n (%)				0
None	0 (0)	0 (0)	0 (0)
EMS personnel	0 (0)	0 (0)	0 (0)
Others	76 (100)	57 (100)	19 (100)
Bystander CPR, n (%)				0.16
Presence	56 (73.7)	43 (75.4)	13 (68.4)
Absence	20 (26.3)	14 (24.6)	6 (31.6)
Initial monitored cardiac rhythm, n (%)				0
VF	76 (100)	57 (100)	19 (100)
Pulseless VT	0 (0)	0 (0)	0 (0)
Cause of cardiac arrest, n (%)				0.09
Cardiogenic	73 (96.1)	55 (96.5)	18 (94.7)
Other intrinsic disease	3 (3.9)	2 (3.5)	1 (5.3)
Time from scene to initiation of CPR, min, median (IQR)	11 (10–12)	11 (10–13)	10 (9–12)	0.10
Adrenaline administration by EMS before physician contact^b, n (%)	44 (74.6)	32 (78.0)	12 (66.7)	0.26
AAM by EMS before physician contact, n (%)	49 (64.5)	36 (63.1)	13 (68.5)	0.22
Type of AAM by EMS, n (%)				0.22
Supraglottic airway device	44 (57.9)	32 (56.1)	12 (63.2)
Endotracheal tube	5 (6.6)	4 (7.0)	1 (5.3)
Shock delivery by EMS before physician contact, n (%)	71 (93.4)	54 (94.7)	17 (89.5)	0.33
Adrenaline administration before amiodarone administration, n (%)	21 (27.6)	14 (24.6)	7 (36.8)	0.27
Time from physician contact to adrenaline administration before amiodarone administration^c, min, median (IQR)^*	3 (2–3)	3 (2.3–3)	2 (1.5–3)	0.67
AAM before amiodarone administration, n (%)	21 (27.6)	14 (24.6)	7 (36.8)	0.27
Time from physician contact to AAM before amiodarone administration^d, min, median (IQR)^*	3 (2–3)	3 (2.3–3.8)	3 (2.5–3)	0.24
Time from physician contact to hospital arrival, min, median (IQR)	14 (11–17)	14 (11–17)	11 (10–15)	0.28
Time from scene to ROSC^e, min, median (IQR)	25 (17–35)	25 (17–28)	28 (23–49)	−0.51

Missing data:

a n = 5 (6.6%);

b n = 17 (22.4%);

c n = 55 (72.4%);

d n = 55 (72.4%);

e n = 18 (23.7%).

* Matching does not necessarily improve the balance, since the variable is only for patients who received that treatment.

Table 4.

Outcomes in time-dependent propensity score matched cohort

Outcomes	Number of patients with outcome/total number of patients (%)		Risk ratio (95% CI)
Outcomes	No amiodarone yet at the same index time point	Received amiodarone at the index time point	Risk ratio (95% CI)
30-day neurological outcome
CPC 1	12 (21.1)	1 (5.3)
CPC 2	6 (10.5)	2 (10.5)
CPC 3	1 (1.8)	2 (10.5)
CPC 4	1 (3.5)	1 (5.3)
CPC 5	36 (63.2)	13 (68.4)
30-day favorable neurological outcome	18/57 (31.6)	3/19 (15.8)	0.45 (0.14–1.47)
30-day survival	21/57 (36.8)	6/19 (31.6)	0.74 (0.31–1.73)

[i] Abbreviations: CI, confidence interval.

Table 5.

Results of sensitivity analysis

Outcomes (RR [95%CI])	GEE results including covariates with SD > 0.25 in time-dependent PSM	1:1 time-dependent PSM
30-day favorable neurological outcome	0.92 (0.29–2.89)	1 (0.26–3.83)
30-day survival	-^*	1.6 (0.53–4.86)

Abbreviations: CI, confidence interval; GEE, generalised estimating equation; PSM, propensity score matching; RR, risk ratio; SD, standardised difference.

* The model did not converge when performing the GEE analysis, and results for 30-day survival could not be obtained.

Articles in this issue

DOI: https://doi.org/10.62838/jccm-2026-0024 | Journal eISSN: 2393-1817 | Journal ISSN: 2393-1809

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Language: English

Page range: 426 - 437

Submitted on: Oct 11, 2025

Accepted on: Mar 19, 2026

Published on: Jul 27, 2026

Published by: University of Medicine, Pharmacy, Science and Technology of Targu Mures

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

amiodarone,

cardiopulmonary resuscitation,

emergency medical services,

out-of-hospital cardiac arrest

Related subjects:

Medicine,

Clinical medicine,

Internal medicine,

Internal medicine, other,

Surgery,

Surgery, other,

Anaesthesiology,

Emergency medicine and intensive-care medicine

© 2026 Yuki Kishihara, Shunsuke Amagasa, Yosuke Homma, Takashi Tagami, Hideto Yasuda, Masahiro Kashiura, Yutaro Shinzato, Takashi Moriya, published by University of Medicine, Pharmacy, Science and Technology of Targu Mures
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 12 (2026): Issue 3 (July 2026)

Efficacy of prehospital amiodarone on survival in adult out-of-hospital cardiac arrest: a retrospective observational study

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