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A population-based study of inpatients admitted due to suffocation in Taiwan during 2005–2007
Accident Analysis and Prevention 50 (2013) 523–529
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A population-based study of inpatients admitted due to suffocation in Taiwan during 2005–2007 Chi-Hsiang Chung a , Ching-Huang Lai b , Wu-Chien Chien b,∗ , Chia-Hsin Lin b , Chien-Hua Cheng b a b
Graduate Institute of Life Sciences, National Defense Medical Center, Taiwan, Republic of China School of Public Health, National Defense Medical Center, Taiwan, Republic of China
a r t i c l e
i n f o
Article history: Received 21 December 2011 Received in revised form 23 May 2012 Accepted 28 May 2012 Keywords: Suffocation Hospitalized National Health Insurance Research Database
a b s t r a c t The objective of this study was to analyze the epidemiology and factors associated with prognoses (inpatient fatality) of patients hospitalized due to suffocation. Data from 2005 to 2007 were sourced from the Taiwanese National Health Insurance Research Database. Suffocation was defined as E911–E915 according to the ICD-9-CM classification. In total, 4062 hospitalizations occurred in Taiwan due to suffocation from 2005 to 2007, with an inpatient fatality rate of 6.5%. Among hospitalizations due to suffocation, “foreign body unintentionally entering other orifice”, “food causing obstruction”, and “other object causing obstruction” accounted for 58.4%, 17.9%, and 11.0%, respectively. There were more cases of male inpatients than female patients; in terms of age, infants under 1 year old and the elderly aged 65 and over had the highest rates of hospitalization. Factors associated with inpatient fatality included “age”, “cardiac arrest”, “received surgery or procedure”, “acute respiratory failure”, “anoxic brain damage”, and “foreign body in larynx”. Infants and the elderly were high-risk groups for hospitalization as a result of suffocation; the dominant cause among inpatient fatality was “food causing obstruction”, which accounted for 22.2% of cases. Medical institutions should focus on the factors associated with inpatient fatality to improve prognoses and decrease the fatality rates of inpatients. Crown Copyright © 2012 Published by Elsevier Ltd. All rights reserved.
1. Introduction In Taiwan, a total of 7130 people died of unintentional injuries in 2007, among which 277 cases were attributed to suffocation, accounting for 3.9% of all unintentional injuries. The mortality rate was 1.2 per 100,000, making suffocation the fifth most common cause of death among unintentional injuries (Department of Health Executive Yuan, Taiwan, 2012). According to the national mortality database in England and Wales, of the 11,053 cases of deaths due to unintentional injuries in 2005, suffocation was the number four cause of death, accounting for 4.2% of all causes of death (Stistic, 2007). A Nicaraguan case study on non-lethal injuries leading to ER visits showed that of the 5991 patients suffering unintentional injuries, approximately 5.2% were hospitalized due to “other object causing obstruction”, making it the fifth most common cause of injury (Espitia-Hardeman et al., 2007).
Although suffocation is not the primary cause of injury among unintentional injuries, multidimensional efforts to improve safety and reduce injury are needed to reduce the overall injury-related morbidity and mortality. Moreover, because of limited human and material resources, an injury practitioner often needs to decide which sector of the population, area and specific causes of injury should be targeted for prevention. Past literature on suffocation focused mainly on individual cases, with little attention being paid to the epidemiology of hospitalized patients and no attention paid to the factors of inpatient fatality. We hoped that a better understanding of suffocation inpatients might serve as a reference for the improvement of medical care and the design of future prevention programs. Therefore, the objective of this study was to analyze the epidemiology and factors associated with inpatient fatalities of inpatients admitted due to suffocation.
2. Methods ∗ Corresponding author at: School of Public Health 4210R, No. 161, Section 6, MinChuan East Road, Neihu District, Taipei City, 11490, Taiwan, Republic of China. Tel.: +886 2 8792 3100x18441; fax: +886 2 8792 3147. E-mail addresses: [email protected] (C.-H. Chung), [email protected] (C.-H. Lai), [email protected] (W.-C. Chien), [email protected] (C.-H. Lin), [email protected] (C.-H. Cheng).
2.1. Data sources This study was conducted utilizing information sourced from the National Health Insurance Research Database. The Professional Peer Reviewer Committee approved the application for data retrieval, and all of the patients whose data were employed in this
0001-4575/$ – see front matter. Crown Copyright © 2012 Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.aap.2012.05.033
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report are non-identifiable; thus, this study was in complete compliance with the Declaration of Helsinki, in which patient privacy is listed as an item of protection. The information retrieved from the National Health Insurance Research Database in Taiwan was fully representative of all population groups, as over 99% of the population of Taiwan is included in the government-run health insurance program (National Health Research Institutes, ROC, 2011). This study employed whole population inpatient data as “inpatient expenditures by admissions” and “registry for contracted medical facilities” between 2005 and 2007 from the National Health Insurance Research Database to analyze the epidemiology of patients hospitalized due to suffocation. The total Taiwanese population in 2006 was 22,823,455. 2.2. Variable definitions and statistical methods Research variables in this study included types of suffocation (suffocation was classified in accordance with the ICD-9-CM ECode into five groups: E911 food causing obstruction, E912 other object causing obstruction, E913 unintentional mechanical suffocation, E914 foreign body unintentionally entering eye and adnexa, and E915 foreign body unintentionally entering other orifice), gender (male and female), age (six groups: <1 year, 1–14 years, 15–24 years, 25–44 years, 45–64 years, and 65 years), catastrophic illness (two groups consisting of patients with/without catastrophic illness, such as cancer, injury severity score 16, and rare diseases), surgical operation (two groups consisting of patients who received a surgical operation or not in accordance with the ICD-9-CM OPCode OP01-OP86), diagnostic procedure (two groups consisting of patients who received diagnostic procedure or not in accordance with the ICD-9-CM OP-Code OP87-OP99), Charlson comorbidity index (CCI) (four groups: 0, 1, 2, and 3), length of stay (three groups: 1 day, 2–5 days, and >5 days), cardiac arrest (two groups consisting of patients with/without cardiac arrest in accordance with the ICD-9-CM N-Code 427.50), acute respiratory failure (two groups consisting of patients with/without acute respiratory failure in accordance with the ICD-9-CM N-Code 518.81), anoxic brain damage (two groups consisting of patients with/without anoxic brain damage in accordance with the ICD-9-CM N-Code 348.1), foreign body in larynx (two groups consisting of patients with/without foreign body in larynx in accordance with the ICD-9-CM N-Code 933.10), area of hospitalization (four groups: northern, central, southern, and eastern Taiwan), type of hospital (private and public), level of hospital (local hospital, regional hospital, and medical center), department of care (five groups: department of pediatrics, internal medicine, surgery, otorhinolaryngology, and other), and inpatient fatality (two groups consisting of patients who died during hospitalization or immediately after leaving a hospital in a critical condition and patients who survived). To calculate the CCI, the first five diagnostic codes (N-Code) of each patient were each multiplied by the scores assigned to 19 different diseases put forth by Charlson et al. (1987), and the five resulting figures were then totaled to obtain a final index. A higher index was representative of more or more serious accompanying diseases. This study calculated the hospitalization rate and inpatient fatality by types of suffocation with 95% confidence intervals (95% CIs); moreover, the hospitalization rate was further stratified by gender and age groups. We also calculated age-gender-adjusted total hospitalization rates using the standard Taiwanese population in 2006. We stratified inpatients admitted due to suffocation by types of suffocation to analyze the risk factors (gender, age, catastrophic illness, surgical operation, diagnostic procedure, CCI, length of stay, cardiac arrest, acute respiratory failure, anoxic brain damage, foreign body in larynx, area of hospitalization, types of hospital, levels
of hospital, and departments of care). Multiple logistic regressions were used to examine the above determinants associated with inpatient fatality (setting p < 0.05 as the threshold of significance). All of these analyses were performed with SPSS 18.0 software. 3. Results 3.1. Characteristics of inpatients In Taiwan, a total of 4062 people were hospitalized due to suffocation between 2005 and 2007, with a hospitalization rate at 5.93 per 100,000. In terms of gender, 2527 of the 4062 patients were male, accounting for 62.2%, with a hospitalization rate of 7.28 per 100,000, while 1535 were female, accounting for 37.8%, with a hospitalization rate of 4.55 per 100,000. The average hospitalization rate for males was 1.6 times greater than for females (with “food causing obstruction” being the lowest, at 1.3 times greater, and “foreign body unintentionally entering eye and adnexa” being the highest, at 5.4 times greater). Among the causes of hospitalization due to suffocation, “foreign body unintentionally entering other orifice” was the main type of injury, followed by “food causing obstruction”, “other object causing obstruction”, “foreign object entering eye and adnexa”, and finally “unintentional mechanical suffocation”. In terms of inpatient fatality, a total of 263 people died over the three-year period, accounting for 6.5% of all inpatients. “Food causing obstruction” was the primary cause of death in cases of suffocation, with 161 people dying of this cause, accounting for 61.2% of inpatient fatalities. Furthermore, this type of suffocation also had the highest inpatient fatality rate (Table 1). In terms of age, the elderly aged 65 and over and infants under 1 year old had higher rates of hospitalization from three types of suffocation: “food causing obstruction”, “other object causing obstruction”, and “foreign body unintentionally entering other orifice”. Infants under 1 year old had the highest hospitalization rate from “unintentional mechanical suffocation”, at 1.02 per 100,000, which was 6.8 times greater than the average hospitalization rate of 0.15 per 100,000. Persons aged 45–64 had the highest hospitalization rate from “foreign object entering eye and adnexa”, at 0.96 per 100,000, which was 1.6 times greater than the average hospitalization rate of 0.61 per 100,000 (Table 2). 3.2. Medical resource utilization Regionally, “unintentional mechanical suffocation” was most widely documented in hospitals located in southern Taiwan (58.8%). The remaining four types of suffocation were more commonly observed in central Taiwan, with percentages ranging from approximately 35.5% to 40.9%. With regard to types of hospitals, private hospitals had a visibly higher rate in treating all types of injuries. In terms of levels of hospitals, local hospitals had the highest rate in “unintentional mechanical suffocation”, and medical centers documented more cases of “foreign object entering eye and adnexa”, while the remaining three types of suffocation were mostly found in regional hospitals (Table 3). With regard to departments of care, most of the patients suffering from “food causing obstruction” and “other object causing obstruction” sought medical assistance from internal medicine, the majority of patients with a “foreign body unintentionally entering other orifice” turned to otorhinolaryngology, and patients suffering from the remaining two types of suffocation tended to seek help from other departments. A further investigation showed that most patients with “unintentional mechanical suffocation” sought help from the department of orthopedics, and most patients with “foreign object entering eye and adnexa” preferred visiting an ophthalmology department (Table 3).
Table 1 Number of patients hospitalized due to suffocation, hospitalization rate with 95% CI, and inpatient fatality in Taiwan, 2005–2007. Types of suffocation
E911–E915 E911 E912 E913 E914 E915
Hospitalization cases: n (%)
Hospitalization rate (per 100,000) with 95% CI
Male
Female
Total
Male
Female
Total
2527 (62.2) 416 (57.3) 300 (67.1) 70 (68.6) 353 (84.9) 1388 (58.5)
1535 (37.8) 310 (42.7) 147 (32.9) 32 (31.4) 63 (15.1) 983 (41.5)
4062 (100) 726 (100) 447 (100) 102 (100) 416 (100) 2371 (100)
7.28 (7.27–7.29) 1.20 (1.19–1.21) 0.86 (0.85–0.87) 0.20 (0.20–0.21) 1.02 (1.01–1.03) 4.00 (3.99–4.01)
4.55 (4.54–4.56) 0.92 (0.91–0.93) 0.44 (0.43–0.44) 0.09 (0.09–0.10) 0.19 (0.18–0.19) 2.91 (2.90–2.92)
5.93 (5.92–5.94) 1.06 (1.05–1.07) 0.65 (0.65–0.66) 0.15 (0.14–0.16) 0.61 (0.60–0.61) 3.46 (3.45–3.47)
Inpatient death cases n (%)
Inpatient fatality rate (%)
263 (100) 161 (61.2) 60 (22.8) 11 (4.2) 0 (0) 31 (11.8)
6.5 22.2 13.4 10.8 0 1.3
Table 2 Gender and age hospitalization rates due to suffocation (per 100,000) with 95% CI in Taiwan, 2005–2007. 1–14 years
15–24 years
25–44 years
45–64 years
65 years
Total
6.17 (6.14–6.20) 4.36 (4.33–4.39) 5.31 (5.29–5.33)
2.23 (2.21–2.25) 1.03 (1.01–1.05) 1.65 (1.64–1.66)
4.10 (4.08–4.12) 2.00 (1.99–2.01) 3.06 (3.05–3.07)
7.72 (7.69–7.75) 4.55 (4.53–4.57) 6.03 (6.01–6.05)
26.60 (26.52–26.68) 17.82 (17.75–17.89) 22.18 (22.13–22.23)
7.28 (7.27–7.29) 4.55 (4.54–4.56) 5.93 (5.92–5.94)
5.21 (5.07–5.53) 4.64 (4.51–4.77) 4.93 (4.83–5.03)
0.49 (0.48–0.50) 0.36 (0.35–0.37) 0.43 (0.42–0.44)
0.09 (0.09–0.10) 0.08 (0.08–0.09) 0.09 (0.09–0.10)
0.24 (0.23–0.24) 0.21 (0.20–0.21) 0.23 (0.22–0.24)
0.90 (0.89–0.91) 0.56 (0.55–0.57) 0.71 (0.70–0.72)
7.88 (7.83–7.93) 5.97 (5.93–6.01) 6.92 (6.89–6.95)
1.20 (1.19–1.21) 0.92 (0.91–0.93) 1.06 (1.05–1.07)
Male Female Total
1.63 (1.55–1.71) 1.43 (1.35–1.51) 1.53 (1.48–1.58)
0.81 (0.80–0.82) 0.35 (0.34–0.36) 0.59 (0.58–0.60)
0.11 (0.10–0.11) 0.08 (0.07–0.08 0.10 (0.10–0.11)
0.23 (0.22–0.23) 0.09 (0.09–0.10) 0.16 (0.15–0.16)
0.51 (0.50–0.52) 0.27 (0.26–0.28) 0.38 (0.37–0.39)
5.07 (5.03–5.11) 2.56 (2.53–2.59) 3.81 (3.78–3.84)
0.86 (0.85–0.87) 0.44 (0.43–0.44) 0.65 (0.65–0.66)
E913
Male Female Total
0.98 (0.92–1.04) 1.07 (1.00–1.14) 1.02 (0.98–1.06)
0.10 (0.09–0.10) 0.09 (0.09–0.10) 0.09 (0.09–0.10)
0.11 (0.10–0.11) 0.04 (0.03–0.04) 0.08 (0.08–0.09)
0.18 (0.17–0.18) 0.06 (0.06–0.07) 0.12 (0.12–0.13)
0.22 (0.21–0.23) 0.07 (0.07–0.08) 0.15 (0.15–0.15)
0.47 (0.46–0.48) 0.26 (0.25–0.27) 0.37 (0.36–0.38)
0.20 (0.20–0.21) 0.09 (0.09–0.10) 0.15 (0.14–0.16)
E914
Male Female Total
0 0 0
0.40 (0.39–0.41) 0.16 (0.15–0.17) 0.28 (0.27–0.29)
0.81 (0.80–0.82) 0.02 (0.02–0.03) 0.43 (0.42–0.44)
1.11 (1.10–1.12) 0.13 (0.13–0.14) 0.63 (0.62–0.64)
1.61 (1.59–1.63) 0.31 (0.30–0.32) 0.96 (0.95–0.97)
0.84 (0.82–0.86) 0.38 (0.37–0.39) 0.61 (0.60–0.62)
1.02 (1.01–1.03) 0.19 (0.18–0.19) 0.61 (0.60–0.61)
E915
Male Female Total
5.53 (5.39–5.67) 4.99 (4.85–5.13) 5.27 (5.17–5.37)
4.47 (4.44–4.50) 3.41 (3.38–3.44) 3.99 (3.97–4.01)
1.10 (1.08–1.12) 0.81 (0.80–0.82) 0.96 (0.95–0.97)
2.33 (2.31–2.35) 1.50 (1.49–1.51) 1.92 (1.91–1.93)
4.47 (4.45–4.49) 3.34 (3.32–3.36) 3.90 (3.88–3.92)
Types of suffocation
<1 years
E911–E915
Male Female Total
E911
Male Female Total
E912
13.34 (13.13–13.55) 12.12 (11.91–12.33) 12.76 (12.61–12.91)
12.33 (12.27–12.39) 8.65 (8.60–8.71) 10.47 (10.43–10.51)
C.-H. Chung et al. / Accident Analysis and Prevention 50 (2013) 523–529
E911: Food causing obstruction; E912: other object causing obstruction; E913: unintentional mechanical suffocation; E914: foreign body unintentionally entering eye and adnexa; E915: foreign body unintentionally entering other orifice. Hospitalization rate (per 100,000) = (number of hospitalization cases)/(population) × 100,000. Inpatient fatality rate (%) = (number of inpatient death cases)/(number of hospitalization cases) × 100%.
4.00 (3.99–4.01) 2.91 (2.90–2.92) 3.46 (3.45–3.47)
525
E911: Food causing obstruction; E912: other object causing obstruction; E913: unintentional mechanical suffocation; E914: foreign body unintentionally entering eye and adnexa; E915: foreign body unintentionally entering other orifice. Hospitalization rate (per 100,000) = (number of hospitalization cases)/(population) × 100,000.
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3.3. Factors of inpatient fatalities This study employed multivariate logistic regression to analyze the inpatient fatality factors of patients hospitalized in Taiwan due to suffocation from 2005 to 2007, and we excluded “foreign body unintentionally entering eye and adnexa”, which had no inpatient death cases. There were nine variables in the model, with Nagelkerke R2 of 0.378. In terms of age, infants under 1 year old and the elderly aged 65 and over had a higher inpatient fatality
rate. In terms of surgeries and procedures, the inpatient fatality rate for patients with surgeries was lower, with an adjusted OR of 0.87 (95% CI, 0.51–1.00), while it was higher for patients with procedures, with an adjusted OR of 2.78 (95% CI, 2.01–3.99). The CCI also provided insight into inpatient fatality rates. An increase of one score corresponded to an increase of 39% in the inpatient fatality rate (adjusted OR = 1.39, 95% CI, 1.25–1.44). Diagnostically, patients diagnosed with cardiac arrest, acute respiratory failure, anoxic brain damage, and foreign body in larynx had significantly
Table 3 Epidemiology of patients hospitalized due to suffocation in Taiwan, 2005–2007. Variables
Gender Male Female Age groups <1 year 1–14 years 15–24 years 25–44 years 45–64 years 65 years Catastrophic illness No Yes Surgical operation No Yes Diagnostic procedure No Yes Charlson comorbidity index, CCI 0 1 2 3 Length of stay 1 day 2–5 days >5 days Cardiac arrest No Yes Acute respiratory failure No Yes Anoxic brain damage No Yes Foreign body in larynx No Yes Area of hospitalization Northern Taiwan Central Taiwan Southern Taiwan Eastern Taiwan Type of hospital Private Public Level of hospital Local hospital Regional hospital Medical center Department of care Pediatric Internal medicine Surgery Otorhinolaryngology Other department
E911 N = 726 n (%)
E912 N = 447 n (%)
416 (57.3) 310 (42.7)
300 (62.7) 147 (32.9)
29 (4.0) 52 (7.2) 9 (1.2) 52 (7.2) 117 (16.1) 467 (64.3)
E913 N = 102 n (%)
E914 N = 416 n (%)
E915 N = 2371 n (%)
E911–E915 N = 4062 n (%)
70 (68.6) 32 (31.4)
353 (84.9) 63 (15.1)
1388 (58.5) 983 (41.5)
2527 (62.2) 1535 (37.8)
9 (2.0) 71 (15.9) 10 (2.2) 37 (8.3) 63 (14.1) 257 (57.5)
6 (5.9) 11 (10.8) 8 (7.8) 28 (27.5) 24 (23.5) 25 (24.5)
0 (0) 34 (8.2) 44 (10.6) 143 (34.4) 154 (37.0) 41 (9.9)
31 (1.3) 470 (19.8) 98 (4.1) 437 (18.4) 628 (26.5) 707 (29.8)
75 (1.8) 638 (15.7) 169 (4.2) 637 (17.2) 986 (24.3) 1497 (36.9)
620 (85.4) 106 (14.6)
339 (75.8) 108 (24.2)
98 (96.1) 4 (3.9)
414 (99.5) 2 (0.5)
2191 (92.4) 180 (7.6)
3662 (90.2) 400 (9.8)
461 (63.5) 265 (36.5)
250 (55.9) 197 (44.1)
40 (39.2) 62 (60.8)
81 (19.5) 335 (80.5)
800 (33.7) 1571 (66.3)
1632 (40.2) 2430 (59.8)
212 (29.2) 514 (70.8)
163 (36.5) 284 (63.5)
32 (31.4) 70 (68.6)
334 (80.3) 82 (19.7)
998 (42.1) 1373 (57.9)
1739 (42.8) 2323 (57.2)
460 (63.4) 160 (22.0) 59 (8.1) 47 (6.5)
275 (61.5) 70 (15.7) 47 (10.5) 55 (12.3)
82 (80.4) 15 (14.7) 3 (2.9) 2 (2.0)
406 (97.6) 3 (0.7) 5 (1.2) 2 (0.5)
1963 (82.8) 222 (9.4) 80 (3.4) 106 (4.5)
3186 (78.4) 470 (11.6) 194 (4.8) 212 (5.2)
152 (20.9) 242 (33.3) 332 (45.7)
76 (17.0) 140 (31.3) 231 (51.7)
17 (16.7) 58 (56.9) 27 (26.5)
36 (8.7) 203 (48.8) 177 (42.5)
702 (30.3) 950 (40.1) 719 (29.6)
983 (24.2) 1593 (39.2) 1486 (36.6)
677 (93.3) 49 (6.7)
432 (96.6) 15 (3.4)
97 (95.1) 5 (4.9)
416 (100) 0 (0)
2368 (99.9) 3 (0.1)
3990 (98.2) 72 (1.8)
465 (64.0) 261 (36.0)
314 (70.2) 133 (29.8)
98 (96.1) 4 (3.9)
415 (99.8) 1 (0.2)
2268 (95.7) 103 (4.3)
3560 (87.6) 502 (12.4)
612 (84.3) 114 (15.7)
420 (94.0) 27 (6.0)
86 (84.3) 16 (15.7)
416 (100) 0 (0)
2346 (98.9) 25 (1.1)
3880 (95.5) 182 (4.5)
336 (46.3) 390 (53.7)
349 (78.1) 98 (21.9)
100 (98.0) 2 (2.0)
0 (0) 416 (100)
2253 (95.0) 118 (5.0)
3534 (85.0) 608 (15.0)
261 (36.0) 274 (37.7) 148 (20.4) 43 (5.9)
123 (27.5) 181 (40.5) 117 (26.2) 26 (5.8)
17 (16.7) 22 (21.6) 60 (58.8) 3 (2.9)
119 (28.6) 170 (40.9) 106 (25.5) 21 (5.0)
715 (30.2) 841 (35.5) 643 (27.1) 172 (7.3)
1235 (30.4) 1488 (36.6) 1074 (26.4) 265 (6.5)
514 (70.8) 212 (29.2)
305 (68.2) 142 (31.8)
88 (86.3) 14 (13.7)
228 (54.8) 188 (45.2)
1575 (66.4) 796 (33.6)
2710 (66.7) 1352 (33.3)
214 (29.5) 338 (46.6) 174 (24.0)
72 (16.1) 188 (42.1) 187 (41.8)
69 (67.6) 20 (19.6) 13 (12.7)
6 (1.4) 105 (25.2) 305 (73.3)
210 (8.9) 1293 (54.5) 868 (36.6)
571 (14.1) 1944 (47.9) 1547 (38.1)
76 (10.5) 498 (68.6) 35 (4.8) 54 (7.4) 63 (8.7)
53 (11.9) 286 (64.0) 31 (6.9) 36 (8.1) 41 (9.2)
9 (8.8) 12 (11.8) 30 (29.4) 0 (0) 51 (50.0)
0 (0) 9 (2.2) 6 (1.4) 2 (0.5) 399 (95.9)
302 (12.7) 525 (22.1) 537 (32.6) 775 (32.7) 232 (9.8)
440 (10.8) 1330 (32.7) 639 (15.7) 867 (21.3) 786 (19.4)
E911: Food causing obstruction; E912: other object causing obstruction; E913: unintentional mechanical suffocation; E914: foreign body unintentionally entering eye and adnexa; E915: foreign body unintentionally entering other orifice.
C.-H. Chung et al. / Accident Analysis and Prevention 50 (2013) 523–529 Table 4 Factors associated with inpatient fatality of patients hospitalized due to suffocation in Taiwan, 2005–2007.
Age groups <1 year 1–14 years 15–24 years 25–44 years 45–64 years 65 years Surgical operation No Yes Diagnostic procedure No Yes Charlson comorbidity index, CCI Cardiac arrest No Yes Acute respiratory failure No Yes Anoxic brain damage No Yes Foreign body in larynx No Yes Area of hospitalization Northern Taiwan Central Taiwan Southern Taiwan Eastern Taiwan
Adjusted odds ratios (95% CI)
p-Value
9.42 (7.47–13.21) Reference 1.38 (0.69–1.89) 2.77 (2.48–3.65) 2.59 (2.01–4.75) 4.64 (2.99–6.67)
<0.001 0.694 0.032 0.026 <0.001
Reference 0.87 (0.51–1.00)
0.050
Reference 2.78 (2.01–3.99) 1.39 (1.25–1.44)
0.001 <0.001
Reference 4.97 (3.82–5.92)
<0.001
Reference 2.43 (1.92–3.21)
<0.001
Reference 2.75 (2.26–4.13)
<0.001
Reference 2.89 (2.01–3.54)
<0.001
Reference 0.42 (0.38–0.50) 0.61 (0.51–0.68) 0.49 (0.39–0.87)
0.001 0.005 0.024
a The model excluded “foreign body unintentionally entering eye and adnexa”, which had no inpatient death cases. b Nagelkerke R2 = 0.378. c All of the variables were significant (p < 0.05) in univariate analysis. The model was adjusted with gender, catastrophic illness, length of stay, type of hospital, level of hospital, and department of care. The interaction between variables was not significant.
higher inpatient fatality rates. Regionally, hospitals in northern Taiwan showed a higher inpatient fatality rate in comparison with other parts of Taiwan (Table 4). 4. Discussion 4.1. Gender distribution In terms of gender, the study found that the hospitalization rate of males suffering from suffocation was 1.6 times higher than that of females, and the inpatient fatality rate for males was also higher than that of females (crude OR = 1.68, 95% CI, 1.19–2.19) (data not presented). There were several studies conducted overseas that showed similar results. A Canadian study on death due to suffocation showed that 77.1% of the dead patients were male (Boghossian et al., 2010); A French study on death due to suffocation on food and other objects causing obstruction indicated that males accounted for approximately 60.0% of cases (Berzlanovich et al., 1999). This phenomenon could be a possible result of the relatively higher intake of alcohol by men. Many studies had noted that the use of alcohol was much more common in men than in women (Grant et al., 2001; Danielson et al., 2009), and past research has supported the correlation between adult suffocation injuries and the consumption of alcohol (Berzlanovich et al., 1999; Boghossian et al., 2010). Moreover, other studies also suggested that the more energetic and adventurous nature of boys might be responsible for their higher risk in many types of unintentional injuries compared with
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girls (Li and Huang, 1999). This was another possible reason that explained the different inpatient fatality rate in terms of gender. 4.2. Age distribution of all suffocation injuries The age distribution of suffocation injuries showed that hospitalization rates were the highest among infants under 1 year old and the elderly aged 65 and over. Many studies conducted outside of Taiwan also showed corresponding results, in which infants and the elderly appeared to be the high-risk groups for food and other objects causing obstruction (Berzlanovich et al., 1999; Tomashek et al., 2003; Dolkas et al., 2007; Pearson and Stone, 2009). Risk factors and causes of suffocation, however, varied among these age groups. Infants under 1 year old were more susceptible to food causing obstruction and other object causing obstruction because they were in the process of going through the oral stage of development, in which infants obtain joy and pleasure via sucking, chewing, and biting (Paterson et al., 2006), which serves to increase their sense of security and relieve pressure. Moreover, the upper airways of infants are narrower, which might also explain the higher infant suffocation hospitalization rate and inpatient fatality rate due to “food or other object causing obstruction”. The objects responsible for infant suffocation were mostly food or small foreign objects that could be placed into the mouth, such as candy, nuts, pacifiers, small balls, coins, and small toys (Baker and Fisher, 1980; Rimell et al., 1995). Parents with infants should pay close to attention to these objects and try to keep them out of reach of infants to avoid suffocation. The study found that the loss or impairment of teeth (affecting their chewing function), accompanying diseases (e.g., Parkinson’s disease) and the use of sleeping pills and tranquilizers maybe be risk factors for elderly suffocation. Soft and smooth food was found to be the main type of food responsible for “food causing obstruction”, while unintentional swallowing of loosened dentures was most common in “other object causing obstruction”, and these factors should be closely observed (Roca et al., 1982; Dolkas et al., 2007). This study also found that the rate of hospitalization due to mechanical suffocation for infants under 1 year old was higher than other age groups, almost 6.8 times greater than average. Moreover, this age group exhibited a higher inpatient fatality (crude OR = 7.43, 95% CI, 5.13–8.75) (data not presented). Studies from outside of Taiwan have shown similar findings (Drago and Dannenberg, 1999; Tomashek et al., 2003). A US study on infant mortality showed that unintentional mechanical injury was the number two cause of death (21.7%) in unintentional infant injuries. The significance of unintentional mechanical suffocation was thus self-evident. With regard to “foreign object entering eye and adnexa”, this study found that the highest hospitalization rate appeared in the 25–44 and 45–64 age groups. A further investigation into the background offered some insight into the cause. A high percentage of the injuries were reported as occupational injuries within these two age groups (28.3% and 18.2%, respectively). Because people in these age groups are the major population of the labor force, it was our conjecture that “foreign object entering eye and adnexa” exhibited high correlation with occupational factors. The specific types and causes were not discussed and therefore should be investigated in future studies. In terms of “foreign body unintentionally entering other orifice”, the elderly aged 65 and over had the highest hospitalization rate. A further investigation into the diagnoses indicated that foreign bodies in the esophagus (27%) and the digestive tract (18.1%) were the primary types of suffocation. The digestive tract included the stomach, small intestines, colon, anus, and rectum. Past literature showed that unintentionally swallowing dentures was the major cause of “other object causing obstruction” in the elderly (Roca et al., 1982; Dolkas et al., 2007). It was thus our conjecture
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that the higher risk of denture swallowing might be due to the loosening of dentures; this issue might be discussed further in future studies. 4.3. Factors of inpatient fatalities This study found that the inpatient fatality rate of infants under 1 year and the elderly aged 65 and over were 9.42 and 4.64 times higher than the 1–14 age group. Physical limitations of infants, including physical functions, such as the respiratory system and behavioral competency, and organs, such as the brain, heart, and lungs, not yet being fully developed, might contribute to the higher inpatient fatality rate of infants. Thus, when suffocation injuries occurred under circumstances in which no immediate help could be offered, it was likely for infants to suffer major physical damage or even death. US researchers working on a study about sudden infant death syndrome (SIDS) examined infant stem cells and found that the abnormal or delayed development of the function to detect oxygen concentration at the brainstem was an important factor in SIDS. Normally, adults in a status of sleep would instinctively wake up, turn around, and increase the rate of breathing when the brainstem detects a high level of carbon dioxide in the body. However, some infants might have abnormal brainstem cells, causing the loss of the ability to alert the body when the level of oxygen is low. This loss might result in a higher percentage of infant suffocation cases (Paterson et al., 2006). This study found that developing accompanying diseases, such as heart disease and diabetes, was one of the factors in suffocationrelated deaths in adults (Berzlanovich et al., 1999). The CCI for patients hospitalized due to suffocation in all age groups showed that the elderly aged 65 and over had a higher percentage of developing 1, 2, and 3 accompanying diseases (68.7%, 73.7% and 61.3%, respectively) (data not presented). This result showed that in comparison with other age groups, the elderly aged 65 and over had a markedly higher chance of developing one or more accompanying diseases. It was thus our conjecture that the higher inpatient fatality rate among the elderly might be a result of their existing accompanying diseases. This study found that the inpatient fatality rate of suffocation patients who died of cardiac arrest was 4.97 times higher than in other patients. Past literature also indicated that patients who developed cardiac arrest had not only a lower chance of survival but also a much less promising prognosis (Engdahl et al., 2000; Herlitz et al., 2003; Langhelle et al., 2003). A further analysis of the percentages of all types of suffocation injuries that accompanied cardiac arrest showed that “food causing obstruction”, “unintentional mechanic suffocation”, and “other object causing obstruction” accounted for 6.7%, 4.9%, and 3.4%, respectively. The inpatient fatality rate of suffocation patients who developed acute respiratory failure was 2.43 times greater than other patients. Among the various types of suffocation injuries, “food causing obstruction” and “other object causing obstruction” accounted for 36.0% and 29.8%, respectively. The inpatient fatality rate of suffocation patients who developed anoxic brain damage was 2.75 times greater than other patients. Among the various types of suffocation injuries, “food causing obstruction” and “unintentional mechanic suffocation” accounted for 15.7% and 6.0%, respectively, of cases of anoxic brain damage. It is important that medical care staff remain aware of these factors to provide better medical care and reduce fatalities caused by such reasons. 4.4. Implications for prevention Our study showed that infants and the elderly appeared to be the high-risk groups for food and other object causing obstruction. In term of infants, caregivers should pay close to attention
to make food sizes smaller for infants; moreover, manufacturers should develop safe toys suitable for infants, inspection agencies should perform safety inspections of these items, and subsidies could be provided to low-income families for the purchase of safe toys. In term of the elderly, we should remind them to be alert when eating soft and smooth food; in addition, unintentional swallowing of loosened dentures was most common in “other object causing obstruction” and should also be carefully. Our study also found that the rate of hospitalization due to mechanical suffocation for infants was higher than other age groups. When infants sleep together with their caregivers, the caregivers might unintentionally roll onto the infants and cause mechanical suffocation (Moon and Omron, 2002); therefore, caregivers should let infants sleep in a crib to prevent mechanical suffocation. Our study noted that the highest hospitalization rate of “foreign object entering eye and adnexa” appeared in the 25–44 and 45–64 age groups, which are the major population of the labor force. Therefore, we should improve occupational safety; for example, workers should use protective equipment, such as masks or industrial goggles.
4.5. Limitations Data for this study were sourced from the National Health Insurance Research Database, which was limited in its “scope of data collection”, in which deaths on the spot and patients dying on the way to a hospital were not included in the database. Moreover, factors such as level of education, marriage status, occupation, and injury locations were not available for analysis. This study used inpatient data exclusively and could not obtain any information on suffocation cases that were mild enough to not require care or the patient only received outpatient/emergency care. In addition, although the National Health Insurance Research Database had data on outpatient/emergency care, these data only provided the diagnosis of disease or injury (in accordance with the ICD-9-CM N-Code) but did not record the cause of injury (in accordance with the ICD-9-CM E-Code) (National Health Research Institutes, ROC, 2011). Therefore, our study could not provide incidence rates of suffocation in Taiwanese people.
5. Conclusions Infants under 1 year old and the elderly aged 65 and over were high-risk groups of suffocation. “Foreign body unintentionally entering other orifice” was the primary type of suffocation, while “food causing obstruction” had the highest inpatient fatality rate (22.2%). Inpatient fatality prognostic factors included cardiac arrest, acute respiratory failure, anoxic brain damage, and foreign body in larynx. It is vital that hospital medical care staff pay more attention to these factors to provide higher quality medical care and to reduce deaths related to such causes.
Authors’ contribution Chi-Hsiang Chung and Chien-Hua Cheng contributed to interpretation of the data and drafted the paper. Chia-Hsin Lin contributed to interpretation of the data. Ching-Huang Lai provided suggestions for revision of the manuscript. Wu-Chien Chien contributed to the study design, obtained the data and commented on the interpretation. All of the authors have read and approved the final manuscript.
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Conflicts of interest The authors declare that they have no competing interests. Funding This study was not supported by any funding. Acknowledgments This study was based in part on data from the National Health Insurance Research Database provided by the Bureau of National Health Insurance, Department of Health, and managed by the National Health Research Institutes. The interpretation and conclusions contained in this paper do not represent those of the Bureau of National Health Insurance, Department of Health, or National Health Research Institutes. References Baker, S.P., Fisher, R.S., 1980. Childhood asphyxiation by choking or suffocation. JAMA 244 (12), 1343–1346. Berzlanovich, A.M., Muhm, M., Sim, E., Bauer, G., 1999. Foreign body asphyxiation – an autopsy study. American Journal of Medicine 107 (4), 351–355. Boghossian, E., Tambuscio, S., Sauvageau, A., 2010. Nonchemical suffocation deaths in forensic setting: a 6-year retrospective study of environmental suffocation, smothering, choking, and traumatic/positional asphyxia. Journal of Forensic Sciences 55 (3), 646–651. Charlson, M.E., Pompei, P., Ales, K.L., MacKenzie, C.R., 1987. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. Journal of Chronic Diseases 40 (5), 373–383. Danielson, C.K., Amstadter, A.B., Dangelmaier, R.E., Resnick, H.S., Saunders, B.E., Kilpatrick, D.G., 2009. Trauma-related risk factors for substance abuse among male versus female young adults. Addictive Behaviors 34 (4), 395–399. Department of Health Executive Yuan, Taiwan (ROC), 2012. Statistics of Causes of Death – Number of Deaths Classified According to the Basic Tabulation List by Gender and Age. (accessed 15.03.12).
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Dolkas, L., Stanley, C., Smith, A.M., Vilke, G.M., 2007. Deaths associated with choking in San Diego County. Journal of Forensic Sciences 52 (1), 176–179. Drago, D.A., Dannenberg, A.L., 1999. Infant mechanical suffocation deaths in the United States, 1980–1997. Pediatrics 103 (5), e59. Engdahl, J., Abrahamsson, P., Bång, A., Lindqvist, J., Karlsson, T., Herlitz, J., 2000. Is hospital care of major importance for outcome after out-of-hospital cardiac arrest? Experience acquired from patients with out-of-hospital cardiac arrest resuscitated by the same Emergency Medical Service and admitted to one of two hospitals over a 16-year period in the municipality of Göteborg. Resuscitation 43 (3), 201–211. Espitia-Hardeman, V., Rocha, J., Clavel-Arcas, C., Dahlberg, L., Mercy, J.A., ConchaEastman, A., 2007. Characteristics of non-fatal injuries in Leon, Nicaragua – 2004. International Journal of Injury Control and Safety Promotion 14 (2), 69–75. Grant, B.F., Stinson, F.S., Harford, T., 2001. The 5-year course of alcohol abuse among young adults. Journal of Substance Abuse 13 (3), 229–238. Herlitz, J., Bång, A., Gunnarsson, J., Engdahl, J., Karlson, B.W., Lindqvist, J., et al., 2003. Factors associated with survival to hospital discharge among patients hospitalised alive after out of hospital cardiac arrest: change in outcome over 20 years in the community of Göteborg Sweden. Heart 89 (1), 25–30. Langhelle, A., Tyvold, S.S., Lexow, K., Hapnes, S.A., Sunde, K., Steen, P.A., 2003. Inhospital factors associated with improved outcome after out-of-hospital cardiac arrest. A comparison between four regions in Norway. Resuscitation 56 (3), 247–263. Li, L.P., Huang, G., 1999. Childhood unintentional injury: personal characteristics of parents of the victims. Journal of Disease Control 3, 256–257. Moon, R.Y., Omron, R., 2002. Determinants of infant sleep position in an urban population. Clinical Pediatrics 41 (8), 569–573. National Health Research Institutes, ROC (Taiwan), 2011. National Health Insurance Research Database – Introduction of Service. (accessed 09.02.11). Paterson, D.S., Trachtenberg, F.L., Thompson, E.G., Belliveau, R.A., Beggs, A.H., Darnall, R., et al., 2006. Multiple serotonergic brainstem abnormalities in sudden infant death syndrome. JAMA 296 (17), 2124–2132. Pearson, J., Stone, D.H., 2009. Pattern of injury mortality by age-group in children aged 0–14 years in Scotland, 2002–2006, and its implications for prevention. BMC Pediatric 9, 26. Rimell, F.L., Thome Jr., A., Stool, S., Reilly, J.S., Rider, G., Stool, D., 1995. Characteristics of objects that cause choking in children. JAMA 274 (22), 1763–1766. ˜ na, ˜ A., Rodriguez-Roisin, R., Alvarez, P., Agusti-Vidal, A., Rozman, C., Roca, J., Grane 1982. Fatal airway disease in an adult with chronic graft-versus-host disease. Thorax 37 (1), 77–78. Stistic, OfN., 2007. Mortality statistics 2005: injury and poisoning. Health Statistics Quarterly 35, 72–77. Tomashek, K.M., Hsia, J., Iyasu, S., 2003. Trends in postneonatal mortality attributable to injury, United States, 1988–1998. Pediatrics 111 (5 Part 2), 1219–1225.
Contents lists available at SciVerse ScienceDirect
Accident Analysis and Prevention journal homepage: www.elsevier.com/locate/aap
A population-based study of inpatients admitted due to suffocation in Taiwan during 2005–2007 Chi-Hsiang Chung a , Ching-Huang Lai b , Wu-Chien Chien b,∗ , Chia-Hsin Lin b , Chien-Hua Cheng b a b
Graduate Institute of Life Sciences, National Defense Medical Center, Taiwan, Republic of China School of Public Health, National Defense Medical Center, Taiwan, Republic of China
a r t i c l e
i n f o
Article history: Received 21 December 2011 Received in revised form 23 May 2012 Accepted 28 May 2012 Keywords: Suffocation Hospitalized National Health Insurance Research Database
a b s t r a c t The objective of this study was to analyze the epidemiology and factors associated with prognoses (inpatient fatality) of patients hospitalized due to suffocation. Data from 2005 to 2007 were sourced from the Taiwanese National Health Insurance Research Database. Suffocation was defined as E911–E915 according to the ICD-9-CM classification. In total, 4062 hospitalizations occurred in Taiwan due to suffocation from 2005 to 2007, with an inpatient fatality rate of 6.5%. Among hospitalizations due to suffocation, “foreign body unintentionally entering other orifice”, “food causing obstruction”, and “other object causing obstruction” accounted for 58.4%, 17.9%, and 11.0%, respectively. There were more cases of male inpatients than female patients; in terms of age, infants under 1 year old and the elderly aged 65 and over had the highest rates of hospitalization. Factors associated with inpatient fatality included “age”, “cardiac arrest”, “received surgery or procedure”, “acute respiratory failure”, “anoxic brain damage”, and “foreign body in larynx”. Infants and the elderly were high-risk groups for hospitalization as a result of suffocation; the dominant cause among inpatient fatality was “food causing obstruction”, which accounted for 22.2% of cases. Medical institutions should focus on the factors associated with inpatient fatality to improve prognoses and decrease the fatality rates of inpatients. Crown Copyright © 2012 Published by Elsevier Ltd. All rights reserved.
1. Introduction In Taiwan, a total of 7130 people died of unintentional injuries in 2007, among which 277 cases were attributed to suffocation, accounting for 3.9% of all unintentional injuries. The mortality rate was 1.2 per 100,000, making suffocation the fifth most common cause of death among unintentional injuries (Department of Health Executive Yuan, Taiwan, 2012). According to the national mortality database in England and Wales, of the 11,053 cases of deaths due to unintentional injuries in 2005, suffocation was the number four cause of death, accounting for 4.2% of all causes of death (Stistic, 2007). A Nicaraguan case study on non-lethal injuries leading to ER visits showed that of the 5991 patients suffering unintentional injuries, approximately 5.2% were hospitalized due to “other object causing obstruction”, making it the fifth most common cause of injury (Espitia-Hardeman et al., 2007).
Although suffocation is not the primary cause of injury among unintentional injuries, multidimensional efforts to improve safety and reduce injury are needed to reduce the overall injury-related morbidity and mortality. Moreover, because of limited human and material resources, an injury practitioner often needs to decide which sector of the population, area and specific causes of injury should be targeted for prevention. Past literature on suffocation focused mainly on individual cases, with little attention being paid to the epidemiology of hospitalized patients and no attention paid to the factors of inpatient fatality. We hoped that a better understanding of suffocation inpatients might serve as a reference for the improvement of medical care and the design of future prevention programs. Therefore, the objective of this study was to analyze the epidemiology and factors associated with inpatient fatalities of inpatients admitted due to suffocation.
2. Methods ∗ Corresponding author at: School of Public Health 4210R, No. 161, Section 6, MinChuan East Road, Neihu District, Taipei City, 11490, Taiwan, Republic of China. Tel.: +886 2 8792 3100x18441; fax: +886 2 8792 3147. E-mail addresses: [email protected] (C.-H. Chung), [email protected] (C.-H. Lai), [email protected] (W.-C. Chien), [email protected] (C.-H. Lin), [email protected] (C.-H. Cheng).
2.1. Data sources This study was conducted utilizing information sourced from the National Health Insurance Research Database. The Professional Peer Reviewer Committee approved the application for data retrieval, and all of the patients whose data were employed in this
0001-4575/$ – see front matter. Crown Copyright © 2012 Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.aap.2012.05.033
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report are non-identifiable; thus, this study was in complete compliance with the Declaration of Helsinki, in which patient privacy is listed as an item of protection. The information retrieved from the National Health Insurance Research Database in Taiwan was fully representative of all population groups, as over 99% of the population of Taiwan is included in the government-run health insurance program (National Health Research Institutes, ROC, 2011). This study employed whole population inpatient data as “inpatient expenditures by admissions” and “registry for contracted medical facilities” between 2005 and 2007 from the National Health Insurance Research Database to analyze the epidemiology of patients hospitalized due to suffocation. The total Taiwanese population in 2006 was 22,823,455. 2.2. Variable definitions and statistical methods Research variables in this study included types of suffocation (suffocation was classified in accordance with the ICD-9-CM ECode into five groups: E911 food causing obstruction, E912 other object causing obstruction, E913 unintentional mechanical suffocation, E914 foreign body unintentionally entering eye and adnexa, and E915 foreign body unintentionally entering other orifice), gender (male and female), age (six groups: <1 year, 1–14 years, 15–24 years, 25–44 years, 45–64 years, and 65 years), catastrophic illness (two groups consisting of patients with/without catastrophic illness, such as cancer, injury severity score 16, and rare diseases), surgical operation (two groups consisting of patients who received a surgical operation or not in accordance with the ICD-9-CM OPCode OP01-OP86), diagnostic procedure (two groups consisting of patients who received diagnostic procedure or not in accordance with the ICD-9-CM OP-Code OP87-OP99), Charlson comorbidity index (CCI) (four groups: 0, 1, 2, and 3), length of stay (three groups: 1 day, 2–5 days, and >5 days), cardiac arrest (two groups consisting of patients with/without cardiac arrest in accordance with the ICD-9-CM N-Code 427.50), acute respiratory failure (two groups consisting of patients with/without acute respiratory failure in accordance with the ICD-9-CM N-Code 518.81), anoxic brain damage (two groups consisting of patients with/without anoxic brain damage in accordance with the ICD-9-CM N-Code 348.1), foreign body in larynx (two groups consisting of patients with/without foreign body in larynx in accordance with the ICD-9-CM N-Code 933.10), area of hospitalization (four groups: northern, central, southern, and eastern Taiwan), type of hospital (private and public), level of hospital (local hospital, regional hospital, and medical center), department of care (five groups: department of pediatrics, internal medicine, surgery, otorhinolaryngology, and other), and inpatient fatality (two groups consisting of patients who died during hospitalization or immediately after leaving a hospital in a critical condition and patients who survived). To calculate the CCI, the first five diagnostic codes (N-Code) of each patient were each multiplied by the scores assigned to 19 different diseases put forth by Charlson et al. (1987), and the five resulting figures were then totaled to obtain a final index. A higher index was representative of more or more serious accompanying diseases. This study calculated the hospitalization rate and inpatient fatality by types of suffocation with 95% confidence intervals (95% CIs); moreover, the hospitalization rate was further stratified by gender and age groups. We also calculated age-gender-adjusted total hospitalization rates using the standard Taiwanese population in 2006. We stratified inpatients admitted due to suffocation by types of suffocation to analyze the risk factors (gender, age, catastrophic illness, surgical operation, diagnostic procedure, CCI, length of stay, cardiac arrest, acute respiratory failure, anoxic brain damage, foreign body in larynx, area of hospitalization, types of hospital, levels
of hospital, and departments of care). Multiple logistic regressions were used to examine the above determinants associated with inpatient fatality (setting p < 0.05 as the threshold of significance). All of these analyses were performed with SPSS 18.0 software. 3. Results 3.1. Characteristics of inpatients In Taiwan, a total of 4062 people were hospitalized due to suffocation between 2005 and 2007, with a hospitalization rate at 5.93 per 100,000. In terms of gender, 2527 of the 4062 patients were male, accounting for 62.2%, with a hospitalization rate of 7.28 per 100,000, while 1535 were female, accounting for 37.8%, with a hospitalization rate of 4.55 per 100,000. The average hospitalization rate for males was 1.6 times greater than for females (with “food causing obstruction” being the lowest, at 1.3 times greater, and “foreign body unintentionally entering eye and adnexa” being the highest, at 5.4 times greater). Among the causes of hospitalization due to suffocation, “foreign body unintentionally entering other orifice” was the main type of injury, followed by “food causing obstruction”, “other object causing obstruction”, “foreign object entering eye and adnexa”, and finally “unintentional mechanical suffocation”. In terms of inpatient fatality, a total of 263 people died over the three-year period, accounting for 6.5% of all inpatients. “Food causing obstruction” was the primary cause of death in cases of suffocation, with 161 people dying of this cause, accounting for 61.2% of inpatient fatalities. Furthermore, this type of suffocation also had the highest inpatient fatality rate (Table 1). In terms of age, the elderly aged 65 and over and infants under 1 year old had higher rates of hospitalization from three types of suffocation: “food causing obstruction”, “other object causing obstruction”, and “foreign body unintentionally entering other orifice”. Infants under 1 year old had the highest hospitalization rate from “unintentional mechanical suffocation”, at 1.02 per 100,000, which was 6.8 times greater than the average hospitalization rate of 0.15 per 100,000. Persons aged 45–64 had the highest hospitalization rate from “foreign object entering eye and adnexa”, at 0.96 per 100,000, which was 1.6 times greater than the average hospitalization rate of 0.61 per 100,000 (Table 2). 3.2. Medical resource utilization Regionally, “unintentional mechanical suffocation” was most widely documented in hospitals located in southern Taiwan (58.8%). The remaining four types of suffocation were more commonly observed in central Taiwan, with percentages ranging from approximately 35.5% to 40.9%. With regard to types of hospitals, private hospitals had a visibly higher rate in treating all types of injuries. In terms of levels of hospitals, local hospitals had the highest rate in “unintentional mechanical suffocation”, and medical centers documented more cases of “foreign object entering eye and adnexa”, while the remaining three types of suffocation were mostly found in regional hospitals (Table 3). With regard to departments of care, most of the patients suffering from “food causing obstruction” and “other object causing obstruction” sought medical assistance from internal medicine, the majority of patients with a “foreign body unintentionally entering other orifice” turned to otorhinolaryngology, and patients suffering from the remaining two types of suffocation tended to seek help from other departments. A further investigation showed that most patients with “unintentional mechanical suffocation” sought help from the department of orthopedics, and most patients with “foreign object entering eye and adnexa” preferred visiting an ophthalmology department (Table 3).
Table 1 Number of patients hospitalized due to suffocation, hospitalization rate with 95% CI, and inpatient fatality in Taiwan, 2005–2007. Types of suffocation
E911–E915 E911 E912 E913 E914 E915
Hospitalization cases: n (%)
Hospitalization rate (per 100,000) with 95% CI
Male
Female
Total
Male
Female
Total
2527 (62.2) 416 (57.3) 300 (67.1) 70 (68.6) 353 (84.9) 1388 (58.5)
1535 (37.8) 310 (42.7) 147 (32.9) 32 (31.4) 63 (15.1) 983 (41.5)
4062 (100) 726 (100) 447 (100) 102 (100) 416 (100) 2371 (100)
7.28 (7.27–7.29) 1.20 (1.19–1.21) 0.86 (0.85–0.87) 0.20 (0.20–0.21) 1.02 (1.01–1.03) 4.00 (3.99–4.01)
4.55 (4.54–4.56) 0.92 (0.91–0.93) 0.44 (0.43–0.44) 0.09 (0.09–0.10) 0.19 (0.18–0.19) 2.91 (2.90–2.92)
5.93 (5.92–5.94) 1.06 (1.05–1.07) 0.65 (0.65–0.66) 0.15 (0.14–0.16) 0.61 (0.60–0.61) 3.46 (3.45–3.47)
Inpatient death cases n (%)
Inpatient fatality rate (%)
263 (100) 161 (61.2) 60 (22.8) 11 (4.2) 0 (0) 31 (11.8)
6.5 22.2 13.4 10.8 0 1.3
Table 2 Gender and age hospitalization rates due to suffocation (per 100,000) with 95% CI in Taiwan, 2005–2007. 1–14 years
15–24 years
25–44 years
45–64 years
65 years
Total
6.17 (6.14–6.20) 4.36 (4.33–4.39) 5.31 (5.29–5.33)
2.23 (2.21–2.25) 1.03 (1.01–1.05) 1.65 (1.64–1.66)
4.10 (4.08–4.12) 2.00 (1.99–2.01) 3.06 (3.05–3.07)
7.72 (7.69–7.75) 4.55 (4.53–4.57) 6.03 (6.01–6.05)
26.60 (26.52–26.68) 17.82 (17.75–17.89) 22.18 (22.13–22.23)
7.28 (7.27–7.29) 4.55 (4.54–4.56) 5.93 (5.92–5.94)
5.21 (5.07–5.53) 4.64 (4.51–4.77) 4.93 (4.83–5.03)
0.49 (0.48–0.50) 0.36 (0.35–0.37) 0.43 (0.42–0.44)
0.09 (0.09–0.10) 0.08 (0.08–0.09) 0.09 (0.09–0.10)
0.24 (0.23–0.24) 0.21 (0.20–0.21) 0.23 (0.22–0.24)
0.90 (0.89–0.91) 0.56 (0.55–0.57) 0.71 (0.70–0.72)
7.88 (7.83–7.93) 5.97 (5.93–6.01) 6.92 (6.89–6.95)
1.20 (1.19–1.21) 0.92 (0.91–0.93) 1.06 (1.05–1.07)
Male Female Total
1.63 (1.55–1.71) 1.43 (1.35–1.51) 1.53 (1.48–1.58)
0.81 (0.80–0.82) 0.35 (0.34–0.36) 0.59 (0.58–0.60)
0.11 (0.10–0.11) 0.08 (0.07–0.08 0.10 (0.10–0.11)
0.23 (0.22–0.23) 0.09 (0.09–0.10) 0.16 (0.15–0.16)
0.51 (0.50–0.52) 0.27 (0.26–0.28) 0.38 (0.37–0.39)
5.07 (5.03–5.11) 2.56 (2.53–2.59) 3.81 (3.78–3.84)
0.86 (0.85–0.87) 0.44 (0.43–0.44) 0.65 (0.65–0.66)
E913
Male Female Total
0.98 (0.92–1.04) 1.07 (1.00–1.14) 1.02 (0.98–1.06)
0.10 (0.09–0.10) 0.09 (0.09–0.10) 0.09 (0.09–0.10)
0.11 (0.10–0.11) 0.04 (0.03–0.04) 0.08 (0.08–0.09)
0.18 (0.17–0.18) 0.06 (0.06–0.07) 0.12 (0.12–0.13)
0.22 (0.21–0.23) 0.07 (0.07–0.08) 0.15 (0.15–0.15)
0.47 (0.46–0.48) 0.26 (0.25–0.27) 0.37 (0.36–0.38)
0.20 (0.20–0.21) 0.09 (0.09–0.10) 0.15 (0.14–0.16)
E914
Male Female Total
0 0 0
0.40 (0.39–0.41) 0.16 (0.15–0.17) 0.28 (0.27–0.29)
0.81 (0.80–0.82) 0.02 (0.02–0.03) 0.43 (0.42–0.44)
1.11 (1.10–1.12) 0.13 (0.13–0.14) 0.63 (0.62–0.64)
1.61 (1.59–1.63) 0.31 (0.30–0.32) 0.96 (0.95–0.97)
0.84 (0.82–0.86) 0.38 (0.37–0.39) 0.61 (0.60–0.62)
1.02 (1.01–1.03) 0.19 (0.18–0.19) 0.61 (0.60–0.61)
E915
Male Female Total
5.53 (5.39–5.67) 4.99 (4.85–5.13) 5.27 (5.17–5.37)
4.47 (4.44–4.50) 3.41 (3.38–3.44) 3.99 (3.97–4.01)
1.10 (1.08–1.12) 0.81 (0.80–0.82) 0.96 (0.95–0.97)
2.33 (2.31–2.35) 1.50 (1.49–1.51) 1.92 (1.91–1.93)
4.47 (4.45–4.49) 3.34 (3.32–3.36) 3.90 (3.88–3.92)
Types of suffocation
<1 years
E911–E915
Male Female Total
E911
Male Female Total
E912
13.34 (13.13–13.55) 12.12 (11.91–12.33) 12.76 (12.61–12.91)
12.33 (12.27–12.39) 8.65 (8.60–8.71) 10.47 (10.43–10.51)
C.-H. Chung et al. / Accident Analysis and Prevention 50 (2013) 523–529
E911: Food causing obstruction; E912: other object causing obstruction; E913: unintentional mechanical suffocation; E914: foreign body unintentionally entering eye and adnexa; E915: foreign body unintentionally entering other orifice. Hospitalization rate (per 100,000) = (number of hospitalization cases)/(population) × 100,000. Inpatient fatality rate (%) = (number of inpatient death cases)/(number of hospitalization cases) × 100%.
4.00 (3.99–4.01) 2.91 (2.90–2.92) 3.46 (3.45–3.47)
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E911: Food causing obstruction; E912: other object causing obstruction; E913: unintentional mechanical suffocation; E914: foreign body unintentionally entering eye and adnexa; E915: foreign body unintentionally entering other orifice. Hospitalization rate (per 100,000) = (number of hospitalization cases)/(population) × 100,000.
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3.3. Factors of inpatient fatalities This study employed multivariate logistic regression to analyze the inpatient fatality factors of patients hospitalized in Taiwan due to suffocation from 2005 to 2007, and we excluded “foreign body unintentionally entering eye and adnexa”, which had no inpatient death cases. There were nine variables in the model, with Nagelkerke R2 of 0.378. In terms of age, infants under 1 year old and the elderly aged 65 and over had a higher inpatient fatality
rate. In terms of surgeries and procedures, the inpatient fatality rate for patients with surgeries was lower, with an adjusted OR of 0.87 (95% CI, 0.51–1.00), while it was higher for patients with procedures, with an adjusted OR of 2.78 (95% CI, 2.01–3.99). The CCI also provided insight into inpatient fatality rates. An increase of one score corresponded to an increase of 39% in the inpatient fatality rate (adjusted OR = 1.39, 95% CI, 1.25–1.44). Diagnostically, patients diagnosed with cardiac arrest, acute respiratory failure, anoxic brain damage, and foreign body in larynx had significantly
Table 3 Epidemiology of patients hospitalized due to suffocation in Taiwan, 2005–2007. Variables
Gender Male Female Age groups <1 year 1–14 years 15–24 years 25–44 years 45–64 years 65 years Catastrophic illness No Yes Surgical operation No Yes Diagnostic procedure No Yes Charlson comorbidity index, CCI 0 1 2 3 Length of stay 1 day 2–5 days >5 days Cardiac arrest No Yes Acute respiratory failure No Yes Anoxic brain damage No Yes Foreign body in larynx No Yes Area of hospitalization Northern Taiwan Central Taiwan Southern Taiwan Eastern Taiwan Type of hospital Private Public Level of hospital Local hospital Regional hospital Medical center Department of care Pediatric Internal medicine Surgery Otorhinolaryngology Other department
E911 N = 726 n (%)
E912 N = 447 n (%)
416 (57.3) 310 (42.7)
300 (62.7) 147 (32.9)
29 (4.0) 52 (7.2) 9 (1.2) 52 (7.2) 117 (16.1) 467 (64.3)
E913 N = 102 n (%)
E914 N = 416 n (%)
E915 N = 2371 n (%)
E911–E915 N = 4062 n (%)
70 (68.6) 32 (31.4)
353 (84.9) 63 (15.1)
1388 (58.5) 983 (41.5)
2527 (62.2) 1535 (37.8)
9 (2.0) 71 (15.9) 10 (2.2) 37 (8.3) 63 (14.1) 257 (57.5)
6 (5.9) 11 (10.8) 8 (7.8) 28 (27.5) 24 (23.5) 25 (24.5)
0 (0) 34 (8.2) 44 (10.6) 143 (34.4) 154 (37.0) 41 (9.9)
31 (1.3) 470 (19.8) 98 (4.1) 437 (18.4) 628 (26.5) 707 (29.8)
75 (1.8) 638 (15.7) 169 (4.2) 637 (17.2) 986 (24.3) 1497 (36.9)
620 (85.4) 106 (14.6)
339 (75.8) 108 (24.2)
98 (96.1) 4 (3.9)
414 (99.5) 2 (0.5)
2191 (92.4) 180 (7.6)
3662 (90.2) 400 (9.8)
461 (63.5) 265 (36.5)
250 (55.9) 197 (44.1)
40 (39.2) 62 (60.8)
81 (19.5) 335 (80.5)
800 (33.7) 1571 (66.3)
1632 (40.2) 2430 (59.8)
212 (29.2) 514 (70.8)
163 (36.5) 284 (63.5)
32 (31.4) 70 (68.6)
334 (80.3) 82 (19.7)
998 (42.1) 1373 (57.9)
1739 (42.8) 2323 (57.2)
460 (63.4) 160 (22.0) 59 (8.1) 47 (6.5)
275 (61.5) 70 (15.7) 47 (10.5) 55 (12.3)
82 (80.4) 15 (14.7) 3 (2.9) 2 (2.0)
406 (97.6) 3 (0.7) 5 (1.2) 2 (0.5)
1963 (82.8) 222 (9.4) 80 (3.4) 106 (4.5)
3186 (78.4) 470 (11.6) 194 (4.8) 212 (5.2)
152 (20.9) 242 (33.3) 332 (45.7)
76 (17.0) 140 (31.3) 231 (51.7)
17 (16.7) 58 (56.9) 27 (26.5)
36 (8.7) 203 (48.8) 177 (42.5)
702 (30.3) 950 (40.1) 719 (29.6)
983 (24.2) 1593 (39.2) 1486 (36.6)
677 (93.3) 49 (6.7)
432 (96.6) 15 (3.4)
97 (95.1) 5 (4.9)
416 (100) 0 (0)
2368 (99.9) 3 (0.1)
3990 (98.2) 72 (1.8)
465 (64.0) 261 (36.0)
314 (70.2) 133 (29.8)
98 (96.1) 4 (3.9)
415 (99.8) 1 (0.2)
2268 (95.7) 103 (4.3)
3560 (87.6) 502 (12.4)
612 (84.3) 114 (15.7)
420 (94.0) 27 (6.0)
86 (84.3) 16 (15.7)
416 (100) 0 (0)
2346 (98.9) 25 (1.1)
3880 (95.5) 182 (4.5)
336 (46.3) 390 (53.7)
349 (78.1) 98 (21.9)
100 (98.0) 2 (2.0)
0 (0) 416 (100)
2253 (95.0) 118 (5.0)
3534 (85.0) 608 (15.0)
261 (36.0) 274 (37.7) 148 (20.4) 43 (5.9)
123 (27.5) 181 (40.5) 117 (26.2) 26 (5.8)
17 (16.7) 22 (21.6) 60 (58.8) 3 (2.9)
119 (28.6) 170 (40.9) 106 (25.5) 21 (5.0)
715 (30.2) 841 (35.5) 643 (27.1) 172 (7.3)
1235 (30.4) 1488 (36.6) 1074 (26.4) 265 (6.5)
514 (70.8) 212 (29.2)
305 (68.2) 142 (31.8)
88 (86.3) 14 (13.7)
228 (54.8) 188 (45.2)
1575 (66.4) 796 (33.6)
2710 (66.7) 1352 (33.3)
214 (29.5) 338 (46.6) 174 (24.0)
72 (16.1) 188 (42.1) 187 (41.8)
69 (67.6) 20 (19.6) 13 (12.7)
6 (1.4) 105 (25.2) 305 (73.3)
210 (8.9) 1293 (54.5) 868 (36.6)
571 (14.1) 1944 (47.9) 1547 (38.1)
76 (10.5) 498 (68.6) 35 (4.8) 54 (7.4) 63 (8.7)
53 (11.9) 286 (64.0) 31 (6.9) 36 (8.1) 41 (9.2)
9 (8.8) 12 (11.8) 30 (29.4) 0 (0) 51 (50.0)
0 (0) 9 (2.2) 6 (1.4) 2 (0.5) 399 (95.9)
302 (12.7) 525 (22.1) 537 (32.6) 775 (32.7) 232 (9.8)
440 (10.8) 1330 (32.7) 639 (15.7) 867 (21.3) 786 (19.4)
E911: Food causing obstruction; E912: other object causing obstruction; E913: unintentional mechanical suffocation; E914: foreign body unintentionally entering eye and adnexa; E915: foreign body unintentionally entering other orifice.
C.-H. Chung et al. / Accident Analysis and Prevention 50 (2013) 523–529 Table 4 Factors associated with inpatient fatality of patients hospitalized due to suffocation in Taiwan, 2005–2007.
Age groups <1 year 1–14 years 15–24 years 25–44 years 45–64 years 65 years Surgical operation No Yes Diagnostic procedure No Yes Charlson comorbidity index, CCI Cardiac arrest No Yes Acute respiratory failure No Yes Anoxic brain damage No Yes Foreign body in larynx No Yes Area of hospitalization Northern Taiwan Central Taiwan Southern Taiwan Eastern Taiwan
Adjusted odds ratios (95% CI)
p-Value
9.42 (7.47–13.21) Reference 1.38 (0.69–1.89) 2.77 (2.48–3.65) 2.59 (2.01–4.75) 4.64 (2.99–6.67)
<0.001 0.694 0.032 0.026 <0.001
Reference 0.87 (0.51–1.00)
0.050
Reference 2.78 (2.01–3.99) 1.39 (1.25–1.44)
0.001 <0.001
Reference 4.97 (3.82–5.92)
<0.001
Reference 2.43 (1.92–3.21)
<0.001
Reference 2.75 (2.26–4.13)
<0.001
Reference 2.89 (2.01–3.54)
<0.001
Reference 0.42 (0.38–0.50) 0.61 (0.51–0.68) 0.49 (0.39–0.87)
0.001 0.005 0.024
a The model excluded “foreign body unintentionally entering eye and adnexa”, which had no inpatient death cases. b Nagelkerke R2 = 0.378. c All of the variables were significant (p < 0.05) in univariate analysis. The model was adjusted with gender, catastrophic illness, length of stay, type of hospital, level of hospital, and department of care. The interaction between variables was not significant.
higher inpatient fatality rates. Regionally, hospitals in northern Taiwan showed a higher inpatient fatality rate in comparison with other parts of Taiwan (Table 4). 4. Discussion 4.1. Gender distribution In terms of gender, the study found that the hospitalization rate of males suffering from suffocation was 1.6 times higher than that of females, and the inpatient fatality rate for males was also higher than that of females (crude OR = 1.68, 95% CI, 1.19–2.19) (data not presented). There were several studies conducted overseas that showed similar results. A Canadian study on death due to suffocation showed that 77.1% of the dead patients were male (Boghossian et al., 2010); A French study on death due to suffocation on food and other objects causing obstruction indicated that males accounted for approximately 60.0% of cases (Berzlanovich et al., 1999). This phenomenon could be a possible result of the relatively higher intake of alcohol by men. Many studies had noted that the use of alcohol was much more common in men than in women (Grant et al., 2001; Danielson et al., 2009), and past research has supported the correlation between adult suffocation injuries and the consumption of alcohol (Berzlanovich et al., 1999; Boghossian et al., 2010). Moreover, other studies also suggested that the more energetic and adventurous nature of boys might be responsible for their higher risk in many types of unintentional injuries compared with
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girls (Li and Huang, 1999). This was another possible reason that explained the different inpatient fatality rate in terms of gender. 4.2. Age distribution of all suffocation injuries The age distribution of suffocation injuries showed that hospitalization rates were the highest among infants under 1 year old and the elderly aged 65 and over. Many studies conducted outside of Taiwan also showed corresponding results, in which infants and the elderly appeared to be the high-risk groups for food and other objects causing obstruction (Berzlanovich et al., 1999; Tomashek et al., 2003; Dolkas et al., 2007; Pearson and Stone, 2009). Risk factors and causes of suffocation, however, varied among these age groups. Infants under 1 year old were more susceptible to food causing obstruction and other object causing obstruction because they were in the process of going through the oral stage of development, in which infants obtain joy and pleasure via sucking, chewing, and biting (Paterson et al., 2006), which serves to increase their sense of security and relieve pressure. Moreover, the upper airways of infants are narrower, which might also explain the higher infant suffocation hospitalization rate and inpatient fatality rate due to “food or other object causing obstruction”. The objects responsible for infant suffocation were mostly food or small foreign objects that could be placed into the mouth, such as candy, nuts, pacifiers, small balls, coins, and small toys (Baker and Fisher, 1980; Rimell et al., 1995). Parents with infants should pay close to attention to these objects and try to keep them out of reach of infants to avoid suffocation. The study found that the loss or impairment of teeth (affecting their chewing function), accompanying diseases (e.g., Parkinson’s disease) and the use of sleeping pills and tranquilizers maybe be risk factors for elderly suffocation. Soft and smooth food was found to be the main type of food responsible for “food causing obstruction”, while unintentional swallowing of loosened dentures was most common in “other object causing obstruction”, and these factors should be closely observed (Roca et al., 1982; Dolkas et al., 2007). This study also found that the rate of hospitalization due to mechanical suffocation for infants under 1 year old was higher than other age groups, almost 6.8 times greater than average. Moreover, this age group exhibited a higher inpatient fatality (crude OR = 7.43, 95% CI, 5.13–8.75) (data not presented). Studies from outside of Taiwan have shown similar findings (Drago and Dannenberg, 1999; Tomashek et al., 2003). A US study on infant mortality showed that unintentional mechanical injury was the number two cause of death (21.7%) in unintentional infant injuries. The significance of unintentional mechanical suffocation was thus self-evident. With regard to “foreign object entering eye and adnexa”, this study found that the highest hospitalization rate appeared in the 25–44 and 45–64 age groups. A further investigation into the background offered some insight into the cause. A high percentage of the injuries were reported as occupational injuries within these two age groups (28.3% and 18.2%, respectively). Because people in these age groups are the major population of the labor force, it was our conjecture that “foreign object entering eye and adnexa” exhibited high correlation with occupational factors. The specific types and causes were not discussed and therefore should be investigated in future studies. In terms of “foreign body unintentionally entering other orifice”, the elderly aged 65 and over had the highest hospitalization rate. A further investigation into the diagnoses indicated that foreign bodies in the esophagus (27%) and the digestive tract (18.1%) were the primary types of suffocation. The digestive tract included the stomach, small intestines, colon, anus, and rectum. Past literature showed that unintentionally swallowing dentures was the major cause of “other object causing obstruction” in the elderly (Roca et al., 1982; Dolkas et al., 2007). It was thus our conjecture
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that the higher risk of denture swallowing might be due to the loosening of dentures; this issue might be discussed further in future studies. 4.3. Factors of inpatient fatalities This study found that the inpatient fatality rate of infants under 1 year and the elderly aged 65 and over were 9.42 and 4.64 times higher than the 1–14 age group. Physical limitations of infants, including physical functions, such as the respiratory system and behavioral competency, and organs, such as the brain, heart, and lungs, not yet being fully developed, might contribute to the higher inpatient fatality rate of infants. Thus, when suffocation injuries occurred under circumstances in which no immediate help could be offered, it was likely for infants to suffer major physical damage or even death. US researchers working on a study about sudden infant death syndrome (SIDS) examined infant stem cells and found that the abnormal or delayed development of the function to detect oxygen concentration at the brainstem was an important factor in SIDS. Normally, adults in a status of sleep would instinctively wake up, turn around, and increase the rate of breathing when the brainstem detects a high level of carbon dioxide in the body. However, some infants might have abnormal brainstem cells, causing the loss of the ability to alert the body when the level of oxygen is low. This loss might result in a higher percentage of infant suffocation cases (Paterson et al., 2006). This study found that developing accompanying diseases, such as heart disease and diabetes, was one of the factors in suffocationrelated deaths in adults (Berzlanovich et al., 1999). The CCI for patients hospitalized due to suffocation in all age groups showed that the elderly aged 65 and over had a higher percentage of developing 1, 2, and 3 accompanying diseases (68.7%, 73.7% and 61.3%, respectively) (data not presented). This result showed that in comparison with other age groups, the elderly aged 65 and over had a markedly higher chance of developing one or more accompanying diseases. It was thus our conjecture that the higher inpatient fatality rate among the elderly might be a result of their existing accompanying diseases. This study found that the inpatient fatality rate of suffocation patients who died of cardiac arrest was 4.97 times higher than in other patients. Past literature also indicated that patients who developed cardiac arrest had not only a lower chance of survival but also a much less promising prognosis (Engdahl et al., 2000; Herlitz et al., 2003; Langhelle et al., 2003). A further analysis of the percentages of all types of suffocation injuries that accompanied cardiac arrest showed that “food causing obstruction”, “unintentional mechanic suffocation”, and “other object causing obstruction” accounted for 6.7%, 4.9%, and 3.4%, respectively. The inpatient fatality rate of suffocation patients who developed acute respiratory failure was 2.43 times greater than other patients. Among the various types of suffocation injuries, “food causing obstruction” and “other object causing obstruction” accounted for 36.0% and 29.8%, respectively. The inpatient fatality rate of suffocation patients who developed anoxic brain damage was 2.75 times greater than other patients. Among the various types of suffocation injuries, “food causing obstruction” and “unintentional mechanic suffocation” accounted for 15.7% and 6.0%, respectively, of cases of anoxic brain damage. It is important that medical care staff remain aware of these factors to provide better medical care and reduce fatalities caused by such reasons. 4.4. Implications for prevention Our study showed that infants and the elderly appeared to be the high-risk groups for food and other object causing obstruction. In term of infants, caregivers should pay close to attention
to make food sizes smaller for infants; moreover, manufacturers should develop safe toys suitable for infants, inspection agencies should perform safety inspections of these items, and subsidies could be provided to low-income families for the purchase of safe toys. In term of the elderly, we should remind them to be alert when eating soft and smooth food; in addition, unintentional swallowing of loosened dentures was most common in “other object causing obstruction” and should also be carefully. Our study also found that the rate of hospitalization due to mechanical suffocation for infants was higher than other age groups. When infants sleep together with their caregivers, the caregivers might unintentionally roll onto the infants and cause mechanical suffocation (Moon and Omron, 2002); therefore, caregivers should let infants sleep in a crib to prevent mechanical suffocation. Our study noted that the highest hospitalization rate of “foreign object entering eye and adnexa” appeared in the 25–44 and 45–64 age groups, which are the major population of the labor force. Therefore, we should improve occupational safety; for example, workers should use protective equipment, such as masks or industrial goggles.
4.5. Limitations Data for this study were sourced from the National Health Insurance Research Database, which was limited in its “scope of data collection”, in which deaths on the spot and patients dying on the way to a hospital were not included in the database. Moreover, factors such as level of education, marriage status, occupation, and injury locations were not available for analysis. This study used inpatient data exclusively and could not obtain any information on suffocation cases that were mild enough to not require care or the patient only received outpatient/emergency care. In addition, although the National Health Insurance Research Database had data on outpatient/emergency care, these data only provided the diagnosis of disease or injury (in accordance with the ICD-9-CM N-Code) but did not record the cause of injury (in accordance with the ICD-9-CM E-Code) (National Health Research Institutes, ROC, 2011). Therefore, our study could not provide incidence rates of suffocation in Taiwanese people.
5. Conclusions Infants under 1 year old and the elderly aged 65 and over were high-risk groups of suffocation. “Foreign body unintentionally entering other orifice” was the primary type of suffocation, while “food causing obstruction” had the highest inpatient fatality rate (22.2%). Inpatient fatality prognostic factors included cardiac arrest, acute respiratory failure, anoxic brain damage, and foreign body in larynx. It is vital that hospital medical care staff pay more attention to these factors to provide higher quality medical care and to reduce deaths related to such causes.
Authors’ contribution Chi-Hsiang Chung and Chien-Hua Cheng contributed to interpretation of the data and drafted the paper. Chia-Hsin Lin contributed to interpretation of the data. Ching-Huang Lai provided suggestions for revision of the manuscript. Wu-Chien Chien contributed to the study design, obtained the data and commented on the interpretation. All of the authors have read and approved the final manuscript.
C.-H. Chung et al. / Accident Analysis and Prevention 50 (2013) 523–529
Conflicts of interest The authors declare that they have no competing interests. Funding This study was not supported by any funding. Acknowledgments This study was based in part on data from the National Health Insurance Research Database provided by the Bureau of National Health Insurance, Department of Health, and managed by the National Health Research Institutes. The interpretation and conclusions contained in this paper do not represent those of the Bureau of National Health Insurance, Department of Health, or National Health Research Institutes. References Baker, S.P., Fisher, R.S., 1980. Childhood asphyxiation by choking or suffocation. JAMA 244 (12), 1343–1346. Berzlanovich, A.M., Muhm, M., Sim, E., Bauer, G., 1999. Foreign body asphyxiation – an autopsy study. American Journal of Medicine 107 (4), 351–355. Boghossian, E., Tambuscio, S., Sauvageau, A., 2010. Nonchemical suffocation deaths in forensic setting: a 6-year retrospective study of environmental suffocation, smothering, choking, and traumatic/positional asphyxia. Journal of Forensic Sciences 55 (3), 646–651. Charlson, M.E., Pompei, P., Ales, K.L., MacKenzie, C.R., 1987. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. Journal of Chronic Diseases 40 (5), 373–383. Danielson, C.K., Amstadter, A.B., Dangelmaier, R.E., Resnick, H.S., Saunders, B.E., Kilpatrick, D.G., 2009. Trauma-related risk factors for substance abuse among male versus female young adults. Addictive Behaviors 34 (4), 395–399. Department of Health Executive Yuan, Taiwan (ROC), 2012. Statistics of Causes of Death – Number of Deaths Classified According to the Basic Tabulation List by Gender and Age.
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