Cyanide poisoning in Thailand before and after establishment of the National Antidote Project^*

Figures & data

Table 1. Characteristics of cyanide ingestion cases reported to the Ramathibodi Poison Center.

	Number of cases; n (%)
Characteristics	Before group (130 cases)	Project group (213 cases)	Total (343 cases)	p Value
Age (median, IQR)	5 (2.5, 13)	5 (3, 32)	5 (3, 29)	NS
Sex				NS
Male	69 (53.1)	108 (50.7)	177 (51.6)
Female	61 (46.9)	105 (49.3)	166 (48.4)
Source of exposure				NS
Cyanogenic glycoside	93 (71.5)	152 (71.4)	245 (71.4)
Cyanide chemical source	37 (28.5)	61 (28.6)	98 (28.6)
Intent of exposure				.038
Intentional self-harm	5 (3.9)	22 (10.3)	27 (7.9)
Unintentional	125 (96.1)	191 (89.7)	316 (92.1)

IQR: Interquartile range; NS: non-significant, p value ≥.05.

Table 2. Initial severity of cyanide ingestion cases reported to the Ramathibodi Poison Center.

	Number of cases; n (%)
Initial severity	Before group (130 cases)	Project group (213 cases)	Total (343 cases)	Adjusted OR (95% CI)^a	Adjusted p Value^a
No effect	4 (3.1)	1 (0.5)	5 (1.5)	0.136 (0.014–1.320)	NS
Minor	68 (52.3)	108 (50.7)	176 (51.3)	Reference	Reference
Moderate	35 (26.9)	47 (22.1)	82 (23.9)	1.025 (0.588–1.789)	NS
Severe	23 (17.7)	57 (26.8)	80 (23.3)	1.883 (0.986–3.595)	NS

Minor symptoms group, which is majority of the cases, is used as reference.

CI: confidence interval; OR: odds ratio; NS: non-significant, p value ≥.05.

^a Adjusted for age, sex, source of exposure, and intent of exposure.

Figure 1. Cyanide and cyanogenic glycoside ingestions reported to Ramathibodi Poison Center by year.

Figure 2. Cyanide and cyanogenic glycoside ingestions reported to Ramathibodi Poison Center by month of the year.

Figure 3. Cyanide and cyanogenic glycoside ingestions reported to Ramathibodi Poison Center by region.

Table 3. Common clinical effects of cyanide ingestion cases reported to the Ramathibodi Poison Center.

	Number of cases; n (%)
Clinical effects	Before group (130 cases)	Project group (213 cases)	Total (343 cases)	Adjusted OR (95% CI)^a	Adjusted p Value^a
Vomiting	82 (63.1)	136 (63.9)	218 (63.6)	0.983 (0.588–1.636)	NS
CNS depression	65 (50.0)	122 (57.3)	187 (54.5)	1.785 (1.104–2.886)	.018
Nausea	68 (52.3)	73 (37.3)	141 (41.1)	0.380 (0.232–0.621)	<.001
Acidosis	50 (38.5)	79 (37.1)	129 (37.6)	1.113 (0.694–1.786)	NS
Respiratory failure	38 (29.2)	56 (26.3)	94 (27.4)	0.884 (0.531–1.472)	NS
Dyspnea	34 (26.2)	58 (27.2)	92 (26.8)	1.144 (0.688–1.904)	NS
Tachycardia	15 (11.5)	70 (32.9)	85 (24.8)	4.217 (2.244–7.924)	<.001
Hypotension	25 (19.2)	43 (20.2)	68 (19.8)	1.046 (0.588–1.860)	NS
Seizure (all)	15 (11.5)	41 (19.3)	56 (16.3)	2.859 (1.423–5.742)	.003
Seizure (single)	11 (8.5)	29 (13.6)	40 (11.7)	2.438 (1.122–5.301)	.024
Seizure (multiple)	4 (3.1)	12 (5.6)	16 (4.7)	2.650 (0.811–8.658)	NS
Abdominal pain	13 (10.0)	29 (13.6)	42 (12.2)	1.116 (0.538–2.317)	NS
Cardiac arrest	13 (10.0)	22 (10.3)	35 (10.2)	0.876 (0.388–1.976)	NS
Dizziness	10 (7.7)	20 (9.4)	30 (8.7)	0.960 (0.412–2.234)	NS
Fever/hyperthermia	8 (6.2)	19 (8.9)	27 (7.9)	1.645 (0.685–3.950)	NS
Hypertension	3 (2.31)	17 (8.0)	20 (5.8)	2.690 (0.730–9.911)	NS
Hyperglycemia	8 (6.15)	12 (5.6)	20 (5.8)	0.888 (0.341–2.309)	NS
Agitated	7 (5.4)	12 (5.6)	19 (5.5)	1.042 (0.391–2.779)	NS

CI, confidence interval; CNS, central nervous system; OR, odds ratio; NS, non-significant, p value ≥.05.

^a Adjusted for age, sex, source of exposure, and intent of exposure.

Table 4. Common treatments of cyanide ingestion cases reported to the Ramathibodi Poison Center.

	Number of cases; n (%)
Treatments	Before group (130 cases)	Project group (213 cases)	Total (343 cases)	Adjusted OR (95% CI)^a	Adjusted p Value^a
Intravenous fluids	97 (74.6)	166 (77.9)	263 (76.7)	1.303 (0.768–2.212)	NS
Oxygen supplementation	52 (40.0)	91 (42.7)	143 (41.7)	1.270 (0.786–2.051)	NS
Cyanide antidote	32 (24.6)	85 (39.9)	117 (34.1)	2.382 (1.422–3.991)	.001
Sodium nitrite	16 (12.3)	38 (17.8)	54 (15.7)	1.681 (0.827–3.414)	NS
Sodium thiosulfate	32 (24.6)	82 (38.5)	114 (33.2)	2.242 (1.337–3.757)	.002
Intubation and ventilatory support	40 (30.8)	71 (33.3)	111 (32.4)	1.218 (0.733–2.024)	NS
Sodium bicarbonate	41 (31.5)	56 (26.3)	97 (28.3)	0.796 (0.475–1.333)	NS
Gastric lavage	23 (17.7)	33 (15.5)	56 (16.3)	0.833 (0.457–1.518)	NS
Activated charcoal	24 (18.5)	31 (14.6)	55 (16.0)	0.763 (0.416–1.398)	NS
Vasopressors	18 (13.9)	32 (15.0)	50 (14.6)	1.045 (0.529–2.062)	NS
Benzodiazepines	11 (8.46)	26 (12.2)	37 (10.8)	1.806 (0.826–3.950)	NS
Antiemetic	12 (9.2)	16 (7.5)	28 (8.2)	0.788 (0.354–1.752)	NS
Cardiopulmonary resuscitation	7 (5.38)	14 (6.57)	21 (6.1)	1.097 (0.410–2.935)	NS

CI: confidence interval; OR, odds ratio; NS: non-significant, p value ≥.05.

^a Adjusted for age, sex, source of exposure, and intent of exposure.

Table 5. Appropriateness of antidote use in cyanide poisoning from ingestion cases reported to the Ramathibodi Poison Center.

	Number of cases received antidote; n (%)
Antidote uses	Before group (32 cases)	Project group (85 cases)	Total (117 cases)	Adjusted OR (95% CI)^a	Adjusted p Value^a
Appropriate antidote uses	16 (50.0)	63 (74.1)	79 (67.5)	3.600 (1.395–9.289)	.008
Correct indication	28 (87.5)	85 (100)	113 (96.6)	NA^b	NA^b
Proper dosing regimen	30 (93.8)	82 (96.5)	112 (95.7)	1.911 (0.246–14.847)	NS
Timely administration	17 (53.1)	65 (76.5)	82 (70.1)	3.605 (1.347–9.647)	.011

CI: confidence interval; OR: odds ratio; NS: non-significant, p value ≥.05.

^a Adjusted for age, sex, source of exposure, and intent of exposure.

^b NA not available, all antidote uses in the Project group were with correct indication.

Table 6. Medical outcome of cyanide ingestion cases reported to the Ramathibodi Poison Center.

	Number of cases; n (%)
Medical outcome	Before group (130 cases)	Project group (213 cases)	Total (343 cases)	Adjusted OR(95% CI)^a	Adjusted p Value^a
Minor	68 (52.3)	101 (47.4)	169 (49.3)	Reference	Reference
Moderate	37 (28.5)	52 (24.4)	89 (26.0)	1.612 (0.671–2.009)	NS
Severe	12 (9.2)	43 (20.2)	55 (16.3)	3.436 (1.576–7.490)	.002
Death	13 (10.0)	17 (8.0)	30 (8.8)	0.883 (0.351–2.222)	NS

CI: confidence interval; OR: odds ratio; NS: non-significant, p value ≥.05.

^a Adjusted for age, sex, source of exposure, and intent of exposure.

Table 7. Characteristics of deaths and surviving cases related to cyanide ingestion reported to the Ramathibodi Poison Center.

	Number of cases; n (%)
Characteristics or intervention	Death (30 cases)	Survive (313 cases)	Total (343 cases)	p Value
Age (median, IQR)	23 (3, 31)	5 (3, 24)	5 (3, 29)	NS
Sex				NS
Male	16 (53.3)	161 (51.4)	177 (51.6)
Female	14 (46.7)	152 (48.6)	166 (48.4)
Source of exposure				<.001
Cyanogenic glycoside	6 (20.0)	239 (76.3)	245 (71.4)
Cyanide chemical source	24 (80.0)	74 (23.7)	98 (28.6)
Intent of exposure				<.001
Intentional self-harm	11 (36.7)	16 (5.1)	27 (7.9)
Unintentional	19 (63.3)	297 (94.9)	316 (92.1)
Initial severity				<.001
No clinical effect	0	5 (1.60)	5 (1.46)
Minor	0	176 (56.2)	176 (51.3)
Moderate	0	82 (26.2)	82 (23.9)
Severe	30 (100)	50 (16.0)	80 (23.3)
Intervention
National Antidote Project (NAP)				NS
Before the NAP	13 (43.3)	117 (37.4)	130 (37.9)
Period with the NAP	17 (56.7)	196 (62.6)	213 (62.1)
Overall antidote use	24 (80.0)	93 (29.7)	117 (34.1)	<.001
Appropriate antidote uses (% of cases with antidote use)^a	3 (12.5)	76 (81.7)	79 (67.5)	<.001

IQR: interquartile range; NS: non-significant; p value ≥.05.

^a Percent of cases with antidote use.

Table 8. Univariate subgroup analysis of the 80 initial severe cases determining association between presence of the National Antidote Project (NAP), overall antidote use, appropriate antidote use, and death.

	Number of cases; n (%)
Intervention	Death (30 cases)	Survive (50 cases)	OR (95% CI)	p Value
Presence of the NAP	17 (56.7)	40 (80.0)	0.327 (0.106–0.997)	.026
Overall antidote use	24 (80.0)	42 (84.0)	0.762 (0.204–3.014)	NS
Appropriate antidote uses^a	3 (12.5)	36 (85.7)	0.024 (0.004–0.122)	<.001

CI: confidence interval; OR: odds ratio; NS: non-significant, p value ≥.05.

^a Percent of cases with antidote use.

Table 9. Multivariate subgroup analysis of the 80 initial severe cases determining association between presence of the National Antidote Project (NAP), appropriate antidote use, age, sex, intent of exposure, cyanide source, and death.

Parameters	Odd ratio	95% CI	p Value
Presence of the NAP	0.122	0.023–0.633	.012
Appropriate antidote use	0.034	0.007–0.167	<.001
Self-harm intent	33.931	2.559–449.857	.008
Cyanide chemical source	1.669	0.343–8.122	NS
Male sex	0.855	0.214–3.410	NS
Age	0.966	0.92–1.01	NS

CI: confidence interval; NS: non-significant, p value ≥.05.