1. Basic demographic characteristics and clinical outcomes of the 199 HFEPs according to timeline
The 132 (66.3%) male and 67 (33.7%) female HFEPs had a mean (SD) age of 41.6 (14.4) years (Table 1). There was no difference on age and sex according to timeline respectively (p=0.3625), (p=0.1983). In terms of mechanism of patient, proportion of inhalation injury were higher than complex (more than two) injury in all subgroups of timeline (p<0.0001), (Table 1). In terms of occupation, worker group as 5 (62.5%) in acute phase, unknown group both as 93 (55.69%) in subacute phase and as 16 (66.67%) in chronic phase were the most (p=0.0021), (Table 1). In terms of distance between patient location and incident spot, both 8 (100%) in acute phase and 86 (51.50%) in subacute phase were reported being within 100 m from the incident location and were more than away from 100 m group but vice versa on 15 (62.5%) in chronic phase (p=0.0062), (Table 1). According to injury severity, frequencies of the NMBG were the most in subacute phase and chronic phase both as 122 (73.05%) and 22 (91.67%) but vice versa in acute phase as 8 (100%) of the MBG (p=0.0001), (Table 1). Frequencies of chemical intoxication group among diagnosis were the most in all phases as 5 (62.5%) in acute phase, 163 (97.6%) in subacute phase, and 22 (91.67%) in chronic phase (p=0.0012), (Table 1). The single site group in extent of damage were the most in all phases as 5 (62.5%) in acute phase, 167 (100%) in subacute phase, and 20 (83.33%) in chronic phase (p<0.0001), (Table 1). The respiratory tract group in damaged site were the most in all phases as 5 (62.5%) in acute phase, 163 (97.6%) in subacute phase, and 22 (91.67%) in chronic phase (p=0.0001), (Table 1). In terms of ED disposition, the DAMA group in acute phase as 5 (62.5%), the discharge group both in subacute and chronic phase as 167 (100%) and 23 (95.83%) were the most (p<0.0001), (Table 1). One patient in chronic phase was admitted to the hospital after visiting ED with chief complaint of vomiting on 6, October, 2012 after hydrogen fluoride exposure and diagnosed as gastric ulcer. However, there was no definite data in terms of criteria for admission on the chart review (Table 1). Five patients of DAMA were comprised of three factory workers on the scene and two news reporters on the scene. They got medical treatment of calcium gluconate nebulizer for their dyspnea symptom and were recommended to admit the hospital but they refused. Only one worker among them visited ophthalmological outpatient department later (Table 1). Two patients died [one was dead on arrival at the ED and the other was alive on ED arrival but had severe hypocalcemia (blood calcium level, 3 mg/dL; normal adult range, 8.6–10.2 mg/dL) and recurrent refractory ventricular dysrhythmia. The patient died despite >1 h advanced cardiovascular life support, including calcium gluconate administration] (Table 1).
Table 1. Basic demographic characteristics and clinical outcomes of the 199 HFEPs according to timeline
Variable
|
Total
(N=199)
|
Acute phase
(N=8)
|
Subacute phase
(N=167)
|
Chronic phase
(N=24)
|
p-value
|
Age (years)
|
41.6 ± 14.4
|
36.63 ± 11.06
|
41.52 ± 14.22
|
44.08 ± 16.54
|
*0.3625
|
Sex
|
|
|
|
|
†0.1983
|
Male
|
132 (66.3%)
|
7 (87.50%)
|
112 (67.07%)
|
13 (54.17%)
|
|
Female
|
67 (33.7%)
|
1 (12.50%)
|
55 (32.93%)
|
11 (45.83%)
|
|
Injury mechanism of patient
|
|
|
|
|
‡<0.0001
|
Inhalation
|
195 (97.99%)
|
5 (62.50%)
|
167 (100%)
|
23 (95.83%)
|
|
Complex (more than two)
|
4 (2.01%)
|
3 (37.50%)
|
0 (0%)
|
1 (4.17%)
|
|
Occupation
|
|
|
|
|
‡0.0021
|
Worker
|
48 (24.12%)
|
5 (62.50%)
|
39 (23.35%)
|
4 (16.67%)
|
|
Resident
|
14 (7.04%)
|
0 (0%)
|
10 (5.99%)
|
4 (16.67%)
|
|
Fire fighter
|
17 (8.54%)
|
0 (0%)
|
17 (10.08%)
|
0 (0%)
|
|
EMS
person
|
3 (1.51%)
|
0 (0%)
|
3 (1.80%)
|
0 (0%)
|
|
Police
|
5 (2.51%)
|
0 (0%)
|
5 (2.99%)
|
0 (0%)
|
|
Reporter
|
2 (1.01%)
|
2 (25.00%)
|
0 (0%)
|
0 (0%)
|
|
Unknown
|
110 (55.28%)
|
1 (12.50%)
|
93 (55.69%)
|
16 (66.67%)
|
|
Distance between patient location and incident spot
|
|
|
|
|
‡0.0062
|
>100 m
|
96 (48.24%)
|
0 (0%)
|
81 (48.50%)
|
15 (62.50%)
|
|
≤100 m
|
103 (51.76%)
|
8 (100%)
|
86 (51.50%)
|
9 (37.50%)
|
|
Injury severity
|
|
|
|
|
‡0.0001
|
MBG
|
55 (27.6%)
|
8 (100%)
|
45 (26.95%)
|
2 (8.33%)
|
|
NMBG
|
144 (72.4%)
|
0 (0%)
|
122 (73.05%)
|
22 (91.67%)
|
|
Diagnosis
|
|
|
|
|
‡0.0012
|
Chemical intoxication
|
190 (95.48%)
|
5 (62.50%)
|
163 (97.60%)
|
22 (91.67%)
|
|
Complex
(more than two)
|
9 (4.52%)
|
3 (37.50%)
|
4 (2.40%)
|
2 (8.33%)
|
|
Extent of damage
|
|
|
|
|
‡<0.0001
|
Single site
|
192 (97.0%)
|
5 (62.50%)
|
167 (100%)
|
20 (83.33%)
|
|
Multiple sites
|
7 (3.0%)
|
3 (37.50%)
|
0 (0%)
|
4 (16.67%)
|
|
Damaged site
|
|
|
|
|
‡0.0001
|
Respiratory tract
|
188 (94.47%)
|
5 (62.50%)
|
163 (97.60%)
|
20 (83.33%)
|
|
Complex (more than two)
|
11 (5.53%)
|
3 (37.50%)
|
4 (2.40%)
|
4 (16.67%)
|
|
ED disposition
|
|
|
|
|
‡<0.0001
|
Discharge
|
191 (96.0%)
|
1 (12.50%)
|
167 (100%)
|
23 (95.83%)
|
|
DAMA
|
5 (2.5%)
|
5 (62.50%)
|
0 (0%)
|
0 (0%)
|
|
Death
|
2 (1.01%)
|
2 (25%)
|
0 (0%)
|
0 (0%)
|
|
ADM
|
1 (0.5%)
|
0 (0%)
|
0 (0%)
|
§1 (4.17%)
|
|
ADM, admission; Chronic phase, time period from 00:00 am on September 29 to 00:00 am on October 21, 2012; DAMA, discharge against medical advice; ED, emergency department; EMS, emergency medical service; HFEPs, hydrogen fluoride-exposed patients; MBG, major burn group; NMBG, non–major burn group; Subacute phase, time period from 00:00 am on September 28 to 00:00 am on September 29, 2012 (the 24-h period after the acute phase); *, One-way ANOVA test was performed; †, chi-square test with Yates' continuity correction was performed; ‡, Fisher’s Exact Test with two-sided was performed; §, one patient was admitted to the hospital after visiting ED with chief complaint of vomiting on 6, October, 2012 after hydrogen fluoride exposure and diagnosed as gastric ulcer. However there was no definite data in terms of criteria for admission on the chart review; Subgroups of timeline were composed of acute phase, subacute phase, and chronic phase.; Acute phase, time period from 16:00 pm on September 27 to 00:00 am on September 28, 2012 (the first 8 h after the HF leak); Five patients of DAMA on acute phase were comprised of three factory workers on the scene and two news reporters on the scene. They got medical treatment of calcium gluconate nebulizer for their dyspnea symptom and were recommended to admit the hospital but they refused. Only one worker among them visited ophthalmological outpatient department later.; Two patients confirmed as death on acute phase classified as categorized diagnosis of complex (more than two) combined of chemical intoxication and burn [one was dead on arrival at the ED and the other was alive on ED arrival but had severe hypocalcemia (blood calcium level, 3 mg/dL; normal adult range, 8.6–10.2 mg/dL) and recurrent refractory ventricular dysrhythmia. The patient died despite >1 h advanced cardiovascular life support, including calcium gluconate administration].
Data are reported as the mean ± standard deviation for continuous variables and number (%) for categorical variables. P-values were calculated by one-way ANOVA test for continuous variables and the chi-square test with Yates' continuity correction or Fisher's exact test with two-sided for categorical variables.
2. HFEPs and TPs in the ED by date
Among the 2628 TPs, including the 199 HFEPs, who visited the ED during the study period, 8 (4.02%) HFEPs and 83 (3.16%) TPs were seen during the acute phase. Thus, HFEPs accounted for 9.64% of the acute-phase TPs (Table 2, Figure 1). During the subacute phase, 167 (83.92%) HFEPs and 262 (9.97%) TPs visited the ED, with HFEPs accounting for 63.74% of the TPs (Table 2, Figure 1). During the chronic phase, 24 (12.06%) HFEPs and 2283 (86.87%) TPs were seen in the ED, with HFEPs making up 20.35% of the TPs (Table 2, Figure 1).
Table 2. Frequencies of hydrogen fluoride–exposed patients (HFEPs) and total patients (TPs) in the emergency department by date
Date
|
HFEP
n (%)
|
TP
n (%)
|
(HFEPs / TPs) * 100 (%)
|
2012-Sept. 27 (acute phase)
|
8 (4.020100503)
|
83 (3.158295282)
|
9.638554217
|
2012-Sept. 28 (subacute phase)
|
167 (83.91959799)
|
262 (9.9695586)
|
63.74045802
|
2012-Sept. 29 (chronic phase)
|
10 (5.025125628)
|
214 (8.143074581)
|
4.672897196
|
2012-Sept. 30 (chronic phase)
|
1 (0.502512563)
|
189 (7.191780822)
|
0.529100529
|
2012-Oct. 01 (chronic phase)
|
1 (0.502512563)
|
194 (7.382039574)
|
0.515463918
|
2012-Oct. 02 (chronic phase)
|
0 (0)
|
95 (3.614916286)
|
0
|
2012-Oct. 03 (chronic phase)
|
1 (0.502512563)
|
128 (4.870624049)
|
0.78125
|
2012-Oct. 04 (chronic phase)
|
2 (1.005025126)
|
80 (3.04414003)
|
2.5
|
2012-Oct. 05 (chronic phase)
|
2 (1.005025126)
|
68 (2.587519026)
|
2.941176471
|
2012-Oct. 06 (chronic phase)
|
2 (1.005025126)
|
111 (4.223744292)
|
1.801801802
|
2012-Oct. 07 (chronic phase)
|
0 (0)
|
146 (5.555555556)
|
0
|
2012-Oct. 08 (chronic phase)
|
1 (0.502512563)
|
78 (2.96803653)
|
1.282051282
|
2012-Oct. 09 (chronic phase)
|
1 (0.502512563)
|
87 (3.310502283)
|
1.149425287
|
2012-Oct. 10 (chronic phase)
|
1 (0.502512563)
|
62 (2.359208524)
|
1.612903226
|
2012-Oct. 11 (chronic phase)
|
0 (0)
|
64 (2.435312024)
|
0
|
2012-Oct. 12 (chronic phase)
|
1 (0.502512563)
|
61 (2.321156773)
|
1.639344262
|
2012-Oct. 13 (chronic phase)
|
0 (0)
|
114 (4.337899543)
|
0
|
2012-Oct. 14 (chronic phase)
|
0 (0)
|
125 (4.756468798)
|
0
|
2012-Oct. 15 (chronic phase)
|
0 (0)
|
72 (2.739726027)
|
0
|
2012-Oct. 16 (chronic phase)
|
0 (0)
|
76 (2.891933029)
|
0
|
2012-Oct. 17 (chronic phase)
|
0 (0)
|
61 (2.321156773)
|
0
|
2012-Oct. 18 (chronic phase)
|
0 (0)
|
74 (2.815829528)
|
0
|
2012-Oct. 19 (chronic phase)
|
0 (0)
|
76 (2.891933029)
|
0
|
2012-Oct. 20 (chronic phase)
|
1 (0.502512563)
|
108 (4.109589041)
|
0.925925926
|
2012-Sept. 29–Oct. 20
(TP during the chronic phase)
|
24 (12.06030151)
|
2283 (86.87214612)
|
1.051248357
|
Total
|
199 (100)
|
2628 (100)
|
(100)
|
(HFEPs / TPs) * 100 (%), percentage of hydrogen fluoride–exposed patients (HFEPs) among the total patients (TPs) in the emergency department; acute phase, first 8 h after the onset of the HF leak; subacute phase, the 24 h after the acute phase; chronic phase, the month after the acute and subacute phases.
3. Distribution of HFEPs by major burn criteria and ED manpower according to the timeline
During the acute phase, eight patients in the MBG and no patient in the NMBG were seen in the ED, which was staffed at that time by three doctors and three nurses (Table 3). During the subacute phase, 45 patients in the MBG and 122 patients in the NMBG were seen in the ED, which was staffed at that time by 6 doctors and 10 nurses (Table 3). During the chronic phase, 2 patients in the MBG and 22 patients in the NMBG were seen in the ED. No data were available regarding the number of doctors and nurses on duty in the ED during that time (Table 3). It was confirmed by interview with ED specialist staff physician on duty at Soonchunhyang University Gumi Hospital during the study period that there was no special ED triage for HFEPs was done on every phase (Table 3).
Table 3. Distribution of the 199 HFEPs by major burn criteria and ED manpower during the disaster timeline
Timeline
|
MBG + NMBG (n)
|
MBG (n)
|
NMBG (n)
|
Doctors (n)
|
Nurses (n)
|
Acute phase
(16:00 Sept. 27–00:00 Sept. 28)
|
8
|
8
|
0
|
3
|
3
|
Subacute phase
(00:00 Sept. 28–00:00 Sept. 29)
|
167
|
45
|
122
|
6
(3 on day shift, 3 on night shift)
|
10
(3 on day shift, 4 on evening shift, 3 on night shift)
|
Chronic phase
(00:00 Sept. 29–00:00 Oct. 21)
|
24
|
2
|
22
|
NA
|
NA
|
ED, emergency department; HF, hydrogen fluoride; HFEPs, hydrogen fluoride–exposed patients; MBG, major burn group; NMBG, non–major burn group; NA, not available or not accountable; acute phase, first 8 h after the onset of the HF leak; subacute phase, the 24 h after the acute phase; chronic phase, the month after the acute and subacute phases. It was confirmed that there was no special ED triage for HFEPs was done on every phase by interview with ED specialist staff physician on duty at Soonchunhyang University Gumi Hospital during the study period.
4. ED treatment orders implemented for HFEPs
Treatment of the HFEPs, as determined from the ED treatment orders, was classified according to the targets (respiratory tract, skin burns, and systemic intoxication; Table 4).
Table 4. Emergency department treatment orders implemented for HFEPs in the 2012 Gumi City HF leak disaster
Target site
|
Emergency department treatment order for HFEPs
|
Respiratory tract
|
Applying nebulizer with 2 ml mixed calcium gluconate solution comprising 1 ampoule calcium gluconate (2.084 g/20 ml) dissolved in 100 ml normal saline (0.9 g sodium chloride)
|
Skin burn
|
Applying gauze soaked with 1 ampoule calcium gluconate (2.084 g/20 ml) dissolved in 100 ml normal saline
|
Systemic intoxication
|
Administering calcium gluconate (2.084 g/20 ml) intravenously
|
HFEPs, hydrogen fluoride–exposed patients; HF, hydrogen fluoride. According to target sites of HFEPs, treatments based on calcium gluconate were done in ED. These results were confirmed by medical chart reviews and by interview with ED specialist staff physician on duty during the study period.
5. Checklist results of hospital disaster response according to staff, space, stuff, and system
In the staff category, there was no reinforcement of hospital disaster response personnel or duty time adjustments or duty relocation for ED working personnel (Table 5). In the space category, there was no expansion of ED space to inside or outside of ED or securing disaster reserve beds (Table 5). In the stuff category, there were no reinforcement of medicines including antidote such as calcium gluconate or supplying of PPE as well as other logistics required for hospital's disaster response (Table 5). In the system category, there were no operations of hospital's disaster command system or disaster related measures of administration department or disaster triage such as START or SALT or decontamination zone setup or decontamination or disaster related diagnostic testing measures or unification and management of the entrances and exits of hospitals (Table 5).
Table 5. Checklist results of hospital disaster response according to staff, space, stuff, and system
Category
|
Question
|
Yes or No
|
Staff
|
Were there any reinforcement of hospital disaster response persons such as doctors or nurses or administration persons or security persons?
|
*No
|
Were there any duty time adjustments or duty relocation of ED working personnel?
|
*No
|
Space
|
Was there any expansion of ED space to accommodate surging patients inside ED?
|
*No
|
Was there any expansion of ED space to accommodate surging patients outside ED?
|
*No
|
Were there any disaster reserve beds secured in the hospital?
|
*No
|
Stuff
|
Were there any reinforcement of medicines including antidote such as calcium gluconate?
|
*No
|
Was there any personal protective equipment provided for hospital disaster response personnel to respond to the CBRNE disaster?
|
*No
|
Were there any reinforcement of logistics other than those mentioned above for the hospital's disaster response?
|
*No
|
System
|
Were there any hospital's disaster command systems in operation?
|
*No
|
Did the administration department implement disaster related measures to accept a large number of patients different from usual?
|
*No
|
Has disaster triage such as START or SALT in preparation for multiple casualty accidents or disasters been implemented apart from usual ED patient triage?
|
*No
|
Was there any decontamination zone setup in the hospital?
|
*No
|
Did the hospital perform decontamination of the patients?
|
*No
|
Were there any different diagnostic testing measures implemented to address the rapidly surging ED patient testing needs different from usual?
|
*No
|
Were there any unification and management of the entrances and exits of hospitals that should be operated in case of disaster?
|
*No
|
CBRNE, chemical, biological, radiological, nuclear, and explosives; ED, emergency department. *, the authors checked and confirmed these results by medical chart review and by interview with ED specialist staff physician on duty during the study period. The authors developed these checklist questions by review of literatures concerning hospital’s disaster response [1-3, 5-17].