TY - JOUR
AU - Qian,, Wei
AB - Abstract Explosions always lead to serious public health, social, and economic problems. We investigated the epidemiology, outcomes, and costs of burn patients caused by explosion accident in Southwest China to explore more effective prevention and treatment strategies. This retrospective study included 497 inpatients with burns during explosion accident admitted to the Institute of Burn Research of Army Medical University from 2002 to 2016. A total of 497 cases (77.78% males) were found, accounting for 2.37% of the total burn patients. The average age was 34.38 ± 15.02 years. The most common etiology was gas explosions (51.51%). Most of the cases were caused by work-related activities. The average TBSA was 31.30 ± 28.32%. The median length of stay (LOS) was 31 days. The LOS was correlated with TBSA, full-thickness burns, older age, number of operations and outcome. The major factors determining the cost were larger TBSA, full-thickness burns, and higher cure rate. The mortality was 6.44%. Larger TBSA and older age were the most important risk factors for the mortality. This study suggested that special attention should be paid to prevent burns during explosion accident in adult males with occupational exposure. In the future, more effective and practical strategies for preventing and treating burns during explosion accident based on related risk factors should be implemented. Burns caused by explosions account for 1.8 to 18.5% of all burn hospitalizations.1–3 Unlike conventional burns or traumas, burns during explosion accident is actually a complex clinical syndrome caused by the combination of burns and all other blast effects, including primary injuries (barotraumas of air-filled organs, eg, lungs, ears, eyes, brain, and gastrointestinal tract) caused by the blast wave moving through the body, secondary injuries (fractures, amputations, lacerations, dislocations, and any type of soft-tissue injury) caused by debris that is displaced by the blast wind, and penetrates or interacts with the body surface, tertiary injuries (blunt traumas, penetrating injuries, or crush injuries) resulting from the impacts of the body on another object, and quaternary injuries caused by exposure to factors that are not included in the above three injury categories (eg, radiation, biological agents, toxins, environmental exposure, and psychological impact).4,5 Therefore, burns during explosion accident frequently manifest in a form of multiple injuries, and the victim’s illness is often more severe and complicated, which lead to a high mortality. However, for now, there is no exact definition of burns during explosion accident. In terms of burns, burns during explosion accident can be categorized as flame or flash burn or other burns during explosion accidents.6,7 But, from the perspective of the body as a whole, it is more accurate to define burns during explosion accident as the burns with other blast injuries. Moreover, burns during explosion accident can also be divided into different types according to different etiologies (gas, gunpowder, fireworks, dust, chemicals, and others), injury causes (work-related, private-household, and recreation-related activities, assault, suicide, and others), injury sites (head, face, neck, trunk, perineum, and extremities), injury patterns (single burns and burns with other blast injuries), etc. As the process of the industrialized accelerating, the number of burns during explosion accident in China has been increasing continuously in the recent years. Thus, burns during explosion accident, as one of the tough public health problems, should deserve special attention. Specific and timely epidemiological investigation can be beneficial to develop effective preventive strategies, improve treatment effects, and reduce the economic burden. Previous epidemiological studies have been limited to specific types of causes in explosions, including gas,8 gunpowder,9 fireworks,10 dust,6 and tires.11 In fact, they share common characteristics, such as high incidence of associated injury, severe burns, and high mortality. However, to date, there has been no comprehensive epidemiological investigation of burns during explosion accident in China, the biggest developing country in the world. Our burn center, Institute of Burn Research, Southwest Hospital of Third Military Medical University (Army Medical University) (TMMU or AMU), is one of the earliest burn centers in China and one of the largest burn centers in the world, with 107 beds for common treatment and 18 beds for intensive care. Our center admits ~1300 burned patients annually from most of southwestern China, including Chongqing, Sichuan, and Guizhou provinces. The present study was aimed to investigate the epidemiology, costs, and outcomes of burns during explosion accident admitted to our center in Southwest China from 2002 to 2016, in order to provide guidance for the prevention and treatment of burns during explosion accident. METHODS Data Extraction The medical records of 497 patients with burns during explosion accident admitted to Institute of Burn Research between January 2002 and December 2016 were reviewed. The following data were extracted and collected: demographics, etiologies, burn sites, associated injuries, burn depth and area, number of operations, surgical method, length of stay (LOS), length of ICU stay, patient outcome, and total cost. The patients’ outcomes were classified as cured, improved, invalid or died, according to the healing conditions of wounds and the basic conditions of patients when discharged. If the patient’s wound had thoroughly healed without residue, the outcome was defined as “cured”; if the area of the burn wound was reduced, but not disappeared after treatment, the outcome was classified as “improved”; if the area of the burn wound did not decrease significantly or became worse after treatment, the outcome was classified as “invalid”; if the patient was dead before discharge, the outcome was defined as “died.” The response rate equaled the sum of the improve rate and the cure rate. The criteria for inhalation injury with different degrees are as follows12,13: (1) the lesions limited to the mouth, nasal cavity, and pharynx are defined as “mild inhalation injury.” The main symptoms are pain and dry in pharyngeal area. The main signs include burnt nasal hair and redness of the nasopharynx. The bronchoscopy shows slight mucosal congestion. (2) The lesions mainly involving pharynx, larynx, and trachea are considered as “moderate inhalation injury.” The main symptoms are hoarseness and upper respiratory obstruction. The main signs include irritable cough, stridor, and rhonchus. The bronchoscopy shows obviously congested of mucosa. (3) The lesions involving bronchi, bronchioles, and even deep alveoli are regarded as “severe inhalation injury.” The main symptom is hypoxia and the main signs include rhonchi and moist rale. The bronchoscopy shows that the mucous is pale, necrotic, and deciduous. The Abbreviated Burn Severity Index (ABSI),14 prognostic burn index (PBI),15 and Baux score16 were calculated as follows: ABSI = sex (female = 0; male = 1) + age (0–20 = 1; 21–40 = 2; 41–60 = 3; 61–80 = 4; 80–100 = 5) + inhalation injury (yes = 1; no = 0) + TBSA (1–10% = 1; 11–20% = 2; 21–30% = 3; 31–40% = 4; 41–50% = 5; 51–60% = 6; 61–70% = 7; 71–80% = 8; 81–90% = 9; 91–100% = 10) + full-thickness burns (yes = 1; no = 0); PBI = ½ × % TBSA of the second-degree burn + % TBSA of the full-thickness burns + age; and Baux score = percent of burn+ 17 × (inhalation injury, 1 = yes; 0 = no) + age. The present study was approved by the Ethics Review Committee of Southwest Hospital of Third Military Medical University (Army Medical University) (Chongqing, China). The patient records/information were anonymized and de-identified prior to analysis. The informed consent requirement was waived due to the retrospective nature of this study. Statistical Analysis After initial processing of clinical data by Microsoft Excel 2016 (Microsoft), statistical analysis was performed using SPSS 22.0 (IBM analytics) and GraphPad Prism 6 (GraphPad Software Inc.). Quantitative data were described as mean and standard deviation, or median and interquartile range. Qualitative data were summarized as counts and/or relative frequency. For qualitative variables or quantitative variables following non-normal distribution, the comparison of two or more groups was conducted by the chi-square test, Mann–Whitney U test or Kruskal–Wallis test, and Dunn’s test was performed as a post hoc test to compare two groups. For quantitative variables with normal distribution, the t test or one-way ANOVA was used to compare two or more groups, and Scheffe’s test was performed as a post hoc test in the comparison of two groups. The stepwise linear regression was performed with significance level for variable entry and removal from the model set at 0.05 and 0.1, respectively, to ascertain risk factors for LOS and total cost. The multiple logistic regression analysis was conducted with significance level for variable entry and removal from the model set at 0.05 and 0.1, respectively, to explore risk factors associated with mortality. Results were presented as odds ratios (OR) and their corresponding 95% confidence intervals (CIs). The Kaplan–Meier method was performed for survival analysis. P-value of <0.05 was considered statistically significant. RESULTS Demographic Characteristics The data from 497 patients with burns during explosion accident, admitted from January 2002 to December 2016, were reviewed. The patients with burns during explosion accident accounted for 2.37% (497/20,998) of the total burn patients. The number of explosion burn patients fluctuated over a 15-year period, with a peak of 58 cases in 2013, and a low of 18 cases in 2004 (Figure 1A). The average number of hospitalizations per year was 33 (Figure 1A). The male-to-female ratio was 3.5:1 (Table 1). The average age was 34.38 ± 15.02 (range: 1–71) years old. The two most common age groups were 30 to 39 years old and 40 to 49 years old, accounting for 28.97% (144/497) and 24.55% (122/497), respectively (Figure 1D). The number of explosion burn patients peaked in July, which was usually the hottest month of the year in Southwest China, and reached a nadir in October (Figure 1B). The proportions of various explosion causes fluctuated throughout the months, especially gas explosion, which peaked in July and reached a nadir in October. Gunpowder explosions peaked in January and November. Fireworks explosions peaked in February when hundreds of millions of Chinese people celebrated the Lunar New Year (Figure 1C). Table 1. Patient characteristics from 2002 to 2016 Years . Cases (%) . Male/female . Age median (IQR) . Inhalation N (%) . Operation N (%) . LOS median (IQR) . ICU stay median (IQR) . Response rate N (%) . Cure rate N (%) . Mortality N (%) . 2002 22 (4.4%) 10:1 36.5 (29.25–40.5) 3 (13.6) 10 (45.5) 28.5 (14–45.75) 4.5 (0–17.75) 19 (86.4) 13 (59.1) 2 (9.1) 2003 36 (7.2%) 2.3:1 34 (28–39) 15 (41.7) 18 (50.0) 22 (9.25–45.25) 4.5 (0–14.25) 28 (77.8) 18 (50.0) 8 (22.2) 2004 18 (3.6%) 8:1 28 (13.75–40) 5 (27.8) 10 (55.6) 36 (20.75–87) 4 (0–19.25) 18 (100) 11 (61.1) 0 (0) 2005 38 (7.6%) 2.5:1 37 (30.75–41) 5 (13.2) 25 (65.8) 49 (10–185.75) 0 (0–11.5) 33 (86.8) 26 (68.4) 5 (13.2) 2006 25 (5.0%) 4:1 35 (12–49) 4 (16.0) 9 (36.0) 22 (12.5–59.5) 0 (0–6.5) 25 (100) 18 (72.0) 0 (0) 2007 23 (4.6%) 22:1 37 (16–40) 1 (4.3) 10 (43.5) 44 (17–92) 0 (0–4) 23 (100) 19 (82.6) 0 (0) 2008 27 (5.4%) 5.8:1 34 (21–44) 2 (7.4) 8 (29.6) 22 (18–35) 0 (0–9) 27 (100) 20 (74.1) 0 (0) 2009 44 (8.9%) 6.3:1 36.5 (30–43) 10 (22.7) 17 (38.6) 37 (12.25–64) 6.5 (0–18.5) 39 (88.6) 31 (70.5) 4 (9.1) 2010 41 (8.2%) 2.7:1 41 (29–48) 9 (22.0) 19 (46.3) 41 (22.5–83) 2 (0–16.5) 38 (92.7) 31 (75.6) 3 (7.3) 2011 51 (10.3%) 2.9:1 36 (27–45) 9 (17.6) 23 (45.1) 30 (13–54) 0 (0–7) 48 (94.1) 34 (66.7) 7 (5.9) 2012 31 (6.2%) 3.4:1 34 (14–39) 0 (0) 11 (35.5) 20 (11–43) 0 (0–0) 30 (96.8) 25 (80.6) 1 (3.2) 2013 58 (11.7%) 3.5:1 43 (34.75–49) 15 (25.9) 34 (58.6) 36 (19.5–60) 3 (0–19) 53 (91.4) 46 (79.3) 5 (8.6) 2014 32 (6.4%) 3.6:1 39.5 (29.5–43) 6 (18.8) 19 (59.4) 29.5 (11.25–118.25) 0 (0–10.75) 31 (96.9) 23 (71.9) 1 (3.1) 2015 31 (6.2%) 1.4:1 28 (17–47) 2 (6.5) 15 (48.4) 48 (11–44) 0 (0–7) 31 (100) 28 (90.3) 0 (0) 2016 20 (4.0%) 3:1 34.5 (12–45.75) 3 (15.0) 11 (55.0) 24.5 (16.25–36.25) 0 (0–0) 20 (100) 14 (70.0) 0 (0) Total 497 (100%) 3.5:1 36 (26–45) 89 (17.9) 239 (48.1) 31 (13.5–58) 0 (0–10) 463 (93.2) 357 (71.8) 32 (6.4) Statistic P-value 20.784, .107 25.569, .029 34.147, .002 19.004, .165 25.378, .031 35.075, .001 31.029, .005 31.941, .080 30.068, .007 Years . Cases (%) . Male/female . Age median (IQR) . Inhalation N (%) . Operation N (%) . LOS median (IQR) . ICU stay median (IQR) . Response rate N (%) . Cure rate N (%) . Mortality N (%) . 2002 22 (4.4%) 10:1 36.5 (29.25–40.5) 3 (13.6) 10 (45.5) 28.5 (14–45.75) 4.5 (0–17.75) 19 (86.4) 13 (59.1) 2 (9.1) 2003 36 (7.2%) 2.3:1 34 (28–39) 15 (41.7) 18 (50.0) 22 (9.25–45.25) 4.5 (0–14.25) 28 (77.8) 18 (50.0) 8 (22.2) 2004 18 (3.6%) 8:1 28 (13.75–40) 5 (27.8) 10 (55.6) 36 (20.75–87) 4 (0–19.25) 18 (100) 11 (61.1) 0 (0) 2005 38 (7.6%) 2.5:1 37 (30.75–41) 5 (13.2) 25 (65.8) 49 (10–185.75) 0 (0–11.5) 33 (86.8) 26 (68.4) 5 (13.2) 2006 25 (5.0%) 4:1 35 (12–49) 4 (16.0) 9 (36.0) 22 (12.5–59.5) 0 (0–6.5) 25 (100) 18 (72.0) 0 (0) 2007 23 (4.6%) 22:1 37 (16–40) 1 (4.3) 10 (43.5) 44 (17–92) 0 (0–4) 23 (100) 19 (82.6) 0 (0) 2008 27 (5.4%) 5.8:1 34 (21–44) 2 (7.4) 8 (29.6) 22 (18–35) 0 (0–9) 27 (100) 20 (74.1) 0 (0) 2009 44 (8.9%) 6.3:1 36.5 (30–43) 10 (22.7) 17 (38.6) 37 (12.25–64) 6.5 (0–18.5) 39 (88.6) 31 (70.5) 4 (9.1) 2010 41 (8.2%) 2.7:1 41 (29–48) 9 (22.0) 19 (46.3) 41 (22.5–83) 2 (0–16.5) 38 (92.7) 31 (75.6) 3 (7.3) 2011 51 (10.3%) 2.9:1 36 (27–45) 9 (17.6) 23 (45.1) 30 (13–54) 0 (0–7) 48 (94.1) 34 (66.7) 7 (5.9) 2012 31 (6.2%) 3.4:1 34 (14–39) 0 (0) 11 (35.5) 20 (11–43) 0 (0–0) 30 (96.8) 25 (80.6) 1 (3.2) 2013 58 (11.7%) 3.5:1 43 (34.75–49) 15 (25.9) 34 (58.6) 36 (19.5–60) 3 (0–19) 53 (91.4) 46 (79.3) 5 (8.6) 2014 32 (6.4%) 3.6:1 39.5 (29.5–43) 6 (18.8) 19 (59.4) 29.5 (11.25–118.25) 0 (0–10.75) 31 (96.9) 23 (71.9) 1 (3.1) 2015 31 (6.2%) 1.4:1 28 (17–47) 2 (6.5) 15 (48.4) 48 (11–44) 0 (0–7) 31 (100) 28 (90.3) 0 (0) 2016 20 (4.0%) 3:1 34.5 (12–45.75) 3 (15.0) 11 (55.0) 24.5 (16.25–36.25) 0 (0–0) 20 (100) 14 (70.0) 0 (0) Total 497 (100%) 3.5:1 36 (26–45) 89 (17.9) 239 (48.1) 31 (13.5–58) 0 (0–10) 463 (93.2) 357 (71.8) 32 (6.4) Statistic P-value 20.784, .107 25.569, .029 34.147, .002 19.004, .165 25.378, .031 35.075, .001 31.029, .005 31.941, .080 30.068, .007 Open in new tab Table 1. Patient characteristics from 2002 to 2016 Years . Cases (%) . Male/female . Age median (IQR) . Inhalation N (%) . Operation N (%) . LOS median (IQR) . ICU stay median (IQR) . Response rate N (%) . Cure rate N (%) . Mortality N (%) . 2002 22 (4.4%) 10:1 36.5 (29.25–40.5) 3 (13.6) 10 (45.5) 28.5 (14–45.75) 4.5 (0–17.75) 19 (86.4) 13 (59.1) 2 (9.1) 2003 36 (7.2%) 2.3:1 34 (28–39) 15 (41.7) 18 (50.0) 22 (9.25–45.25) 4.5 (0–14.25) 28 (77.8) 18 (50.0) 8 (22.2) 2004 18 (3.6%) 8:1 28 (13.75–40) 5 (27.8) 10 (55.6) 36 (20.75–87) 4 (0–19.25) 18 (100) 11 (61.1) 0 (0) 2005 38 (7.6%) 2.5:1 37 (30.75–41) 5 (13.2) 25 (65.8) 49 (10–185.75) 0 (0–11.5) 33 (86.8) 26 (68.4) 5 (13.2) 2006 25 (5.0%) 4:1 35 (12–49) 4 (16.0) 9 (36.0) 22 (12.5–59.5) 0 (0–6.5) 25 (100) 18 (72.0) 0 (0) 2007 23 (4.6%) 22:1 37 (16–40) 1 (4.3) 10 (43.5) 44 (17–92) 0 (0–4) 23 (100) 19 (82.6) 0 (0) 2008 27 (5.4%) 5.8:1 34 (21–44) 2 (7.4) 8 (29.6) 22 (18–35) 0 (0–9) 27 (100) 20 (74.1) 0 (0) 2009 44 (8.9%) 6.3:1 36.5 (30–43) 10 (22.7) 17 (38.6) 37 (12.25–64) 6.5 (0–18.5) 39 (88.6) 31 (70.5) 4 (9.1) 2010 41 (8.2%) 2.7:1 41 (29–48) 9 (22.0) 19 (46.3) 41 (22.5–83) 2 (0–16.5) 38 (92.7) 31 (75.6) 3 (7.3) 2011 51 (10.3%) 2.9:1 36 (27–45) 9 (17.6) 23 (45.1) 30 (13–54) 0 (0–7) 48 (94.1) 34 (66.7) 7 (5.9) 2012 31 (6.2%) 3.4:1 34 (14–39) 0 (0) 11 (35.5) 20 (11–43) 0 (0–0) 30 (96.8) 25 (80.6) 1 (3.2) 2013 58 (11.7%) 3.5:1 43 (34.75–49) 15 (25.9) 34 (58.6) 36 (19.5–60) 3 (0–19) 53 (91.4) 46 (79.3) 5 (8.6) 2014 32 (6.4%) 3.6:1 39.5 (29.5–43) 6 (18.8) 19 (59.4) 29.5 (11.25–118.25) 0 (0–10.75) 31 (96.9) 23 (71.9) 1 (3.1) 2015 31 (6.2%) 1.4:1 28 (17–47) 2 (6.5) 15 (48.4) 48 (11–44) 0 (0–7) 31 (100) 28 (90.3) 0 (0) 2016 20 (4.0%) 3:1 34.5 (12–45.75) 3 (15.0) 11 (55.0) 24.5 (16.25–36.25) 0 (0–0) 20 (100) 14 (70.0) 0 (0) Total 497 (100%) 3.5:1 36 (26–45) 89 (17.9) 239 (48.1) 31 (13.5–58) 0 (0–10) 463 (93.2) 357 (71.8) 32 (6.4) Statistic P-value 20.784, .107 25.569, .029 34.147, .002 19.004, .165 25.378, .031 35.075, .001 31.029, .005 31.941, .080 30.068, .007 Years . Cases (%) . Male/female . Age median (IQR) . Inhalation N (%) . Operation N (%) . LOS median (IQR) . ICU stay median (IQR) . Response rate N (%) . Cure rate N (%) . Mortality N (%) . 2002 22 (4.4%) 10:1 36.5 (29.25–40.5) 3 (13.6) 10 (45.5) 28.5 (14–45.75) 4.5 (0–17.75) 19 (86.4) 13 (59.1) 2 (9.1) 2003 36 (7.2%) 2.3:1 34 (28–39) 15 (41.7) 18 (50.0) 22 (9.25–45.25) 4.5 (0–14.25) 28 (77.8) 18 (50.0) 8 (22.2) 2004 18 (3.6%) 8:1 28 (13.75–40) 5 (27.8) 10 (55.6) 36 (20.75–87) 4 (0–19.25) 18 (100) 11 (61.1) 0 (0) 2005 38 (7.6%) 2.5:1 37 (30.75–41) 5 (13.2) 25 (65.8) 49 (10–185.75) 0 (0–11.5) 33 (86.8) 26 (68.4) 5 (13.2) 2006 25 (5.0%) 4:1 35 (12–49) 4 (16.0) 9 (36.0) 22 (12.5–59.5) 0 (0–6.5) 25 (100) 18 (72.0) 0 (0) 2007 23 (4.6%) 22:1 37 (16–40) 1 (4.3) 10 (43.5) 44 (17–92) 0 (0–4) 23 (100) 19 (82.6) 0 (0) 2008 27 (5.4%) 5.8:1 34 (21–44) 2 (7.4) 8 (29.6) 22 (18–35) 0 (0–9) 27 (100) 20 (74.1) 0 (0) 2009 44 (8.9%) 6.3:1 36.5 (30–43) 10 (22.7) 17 (38.6) 37 (12.25–64) 6.5 (0–18.5) 39 (88.6) 31 (70.5) 4 (9.1) 2010 41 (8.2%) 2.7:1 41 (29–48) 9 (22.0) 19 (46.3) 41 (22.5–83) 2 (0–16.5) 38 (92.7) 31 (75.6) 3 (7.3) 2011 51 (10.3%) 2.9:1 36 (27–45) 9 (17.6) 23 (45.1) 30 (13–54) 0 (0–7) 48 (94.1) 34 (66.7) 7 (5.9) 2012 31 (6.2%) 3.4:1 34 (14–39) 0 (0) 11 (35.5) 20 (11–43) 0 (0–0) 30 (96.8) 25 (80.6) 1 (3.2) 2013 58 (11.7%) 3.5:1 43 (34.75–49) 15 (25.9) 34 (58.6) 36 (19.5–60) 3 (0–19) 53 (91.4) 46 (79.3) 5 (8.6) 2014 32 (6.4%) 3.6:1 39.5 (29.5–43) 6 (18.8) 19 (59.4) 29.5 (11.25–118.25) 0 (0–10.75) 31 (96.9) 23 (71.9) 1 (3.1) 2015 31 (6.2%) 1.4:1 28 (17–47) 2 (6.5) 15 (48.4) 48 (11–44) 0 (0–7) 31 (100) 28 (90.3) 0 (0) 2016 20 (4.0%) 3:1 34.5 (12–45.75) 3 (15.0) 11 (55.0) 24.5 (16.25–36.25) 0 (0–0) 20 (100) 14 (70.0) 0 (0) Total 497 (100%) 3.5:1 36 (26–45) 89 (17.9) 239 (48.1) 31 (13.5–58) 0 (0–10) 463 (93.2) 357 (71.8) 32 (6.4) Statistic P-value 20.784, .107 25.569, .029 34.147, .002 19.004, .165 25.378, .031 35.075, .001 31.029, .005 31.941, .080 30.068, .007 Open in new tab Figure 1. Open in new tabDownload slide Distribution of patients with burns during explosion accident by year (A), month-sex (B), month-etiology (C) and age (D). Figure 1. Open in new tabDownload slide Distribution of patients with burns during explosion accident by year (A), month-sex (B), month-etiology (C) and age (D). Etiology The three most common reasons for explosions were gas, gunpowder, and fireworks. Of all patients with burns during explosion accident, 256 cases (51.51%) were caused by gas, 92 (18.51%) by gunpowder, and 30 (6.04%) by fireworks (Figure 2A). These were followed by boilers (5.03%), dust (2.82%), organic chemicals (2.82%), and oil drums (2.62%). In addition, six cases (1.21%) were caused by oxygen tanks, followed by hydrogen balloons (1.01%), and batteries (0.60%; Table 2). Gas and gunpowder explosions predominantly affected working-age populations, and fireworks explosion mainly affected children and juveniles (Figure 2B). The ratios of males to females were also very different depending on the causes. The ratio of gas explosion was the highest in all causes, with seasonal fluctuation (higher in the autumn and lower in the winter, Figure 2C). Furthermore, the ratios were significantly associated with different etiologies (χ2 = 293.052, P < 0.001). The highest male-to-female ratio (4.95:1) was observed for gas explosion, and the lowest ratio was obtained in gunpowder explosion (1.88:1; Figure 2D). Table 2. Categories of burns during explosion accident Types . Cases . . . N . Percentage . Gas explosion 256 51.51 Gunpowder explosion 92 18.51 Firework explosion 30 6.04 Boiler explosion 25 5.03 Dust explosion 14 2.82 Organic chemicals explosion 14 2.82 Oil drum explosion 13 2.62 Oxygen tank explosion 6 1.21 Hydrogen balloon explosion 5 1.01 Battery explosion 3 0.60 Other explosion 39 7.85 Types . Cases . . . N . Percentage . Gas explosion 256 51.51 Gunpowder explosion 92 18.51 Firework explosion 30 6.04 Boiler explosion 25 5.03 Dust explosion 14 2.82 Organic chemicals explosion 14 2.82 Oil drum explosion 13 2.62 Oxygen tank explosion 6 1.21 Hydrogen balloon explosion 5 1.01 Battery explosion 3 0.60 Other explosion 39 7.85 Open in new tab Table 2. Categories of burns during explosion accident Types . Cases . . . N . Percentage . Gas explosion 256 51.51 Gunpowder explosion 92 18.51 Firework explosion 30 6.04 Boiler explosion 25 5.03 Dust explosion 14 2.82 Organic chemicals explosion 14 2.82 Oil drum explosion 13 2.62 Oxygen tank explosion 6 1.21 Hydrogen balloon explosion 5 1.01 Battery explosion 3 0.60 Other explosion 39 7.85 Types . Cases . . . N . Percentage . Gas explosion 256 51.51 Gunpowder explosion 92 18.51 Firework explosion 30 6.04 Boiler explosion 25 5.03 Dust explosion 14 2.82 Organic chemicals explosion 14 2.82 Oil drum explosion 13 2.62 Oxygen tank explosion 6 1.21 Hydrogen balloon explosion 5 1.01 Battery explosion 3 0.60 Other explosion 39 7.85 Open in new tab Figure 2. Open in new tabDownload slide Etiological analysis. (A) Distribution of explosion type. (B) Distribution of etiology by age. (C). Distribution of etiology by season. (D). Distribution of etiology by sex. Figure 2. Open in new tabDownload slide Etiological analysis. (A) Distribution of explosion type. (B) Distribution of etiology by age. (C). Distribution of etiology by season. (D). Distribution of etiology by sex. Causes of Injury Workers in state-owned enterprises and private enterprises accounted for the majority (51.71%), followed by civilians (26.16%), farmers (8.25%), and children (8.05%; Figure 3A). Most burns during explosion accident were caused by work-related activities during producing processes (61.17%), followed by private-household (20.52%), and recreation-related activities (13.28%). There were three cases caused by assault (0.60%), and one resulting from a suicide attempt (0.20%; Figure 3B). Work-related injuries mainly occurred in working-age populations, and recreation-related injuries were frequently seen in children (Figure 3C). The proportion of hospitalized patients with burns during explosion accident from urban areas (50.50%) was roughly equal to that from rural areas (49.50%; Figure 3D). Of all gas explosions, most accidents occurred in coal mines (62.02%), followed by leakage of gas pipelines (18.22%), cooking-related gas explosions (8.91%), and gas tank explosions (3.10%; Figure 4A). The majority of gunpowder explosions were caused by improper operation (79.35%; Figure 4B). Of all fireworks explosions, most accidents were caused by misuse (60.00%; Figure 4C). Figure 3. Open in new tabDownload slide The condition of patients with burns during explosion accident. (A) Occupations. (B) Causes of explosions. (C) Explosion causes in different age groups. (D) Regions. Figure 3. Open in new tabDownload slide The condition of patients with burns during explosion accident. (A) Occupations. (B) Causes of explosions. (C) Explosion causes in different age groups. (D) Regions. Figure 4. Open in new tabDownload slide Causes of injury. (A) Causes of gas explosions. (B) Causes of gunpowder explosions. (C) Causes of firework explosions. Figure 4. Open in new tabDownload slide Causes of injury. (A) Causes of gas explosions. (B) Causes of gunpowder explosions. (C) Causes of firework explosions. Burn Severity The average TBSA was 31.30 ± 28.32% (median 20%). There were 166 patients (33.40%) with TBSAs of 0 to 10%, and 92 patients (18.51%) with TBSAs of 10 to 20%. One hundred twenty patients (24.14%) suffered burns covering ≥50% TBSAs (Figure 5A). The TBSA distribution of patients significantly differed among ages and etiologies (P < 0.001; Table 3). Most patients suffered deep partial-thickness burns (55.30%) and full-thickness burns (27.43%; Figure 5B). The average ABSI was 7.27 ± 3.44 (median: 6, range: 2–16). The majority of patients (88.93%) had ABSI >3 (Figure 5C). The mean PBI was 51.53 ± 26.86 (median: 49, range: 2–150; Figure 5D). The average Baux score was 74.89 ± 38.12 (median: 67, range: 8–173). Most patients (71.23%) had a Baux score >50 (Figure 5E). The burn severity scores significantly differed among etiologies (P < 0.001; Table 3). The ABSI, PBI, and Baux score of gas explosions were significantly higher than those of other explosions. In addition, the ABSI, PBI, and Baux score of the age group of 0 to 20 years were significantly lower than those of the other age groups (P < 0.001). The mortality was significantly higher when ABSI ≥ 12, PBI ≥ 80, or Baux score ≥ 120 (Figure 6). However, TBSA, ABSI, PBI, and Baux score significantly decreased from 2002 to 2016 (Table 3). Table 3. Burn severity analysis . TBSA median (IQR) . ABSI median (IQR) . Baux score median (IQR) . Prognostic burn Index median (IQR) . Etiology  Gas explosion 32 (14–60) 8 (5–11) 81 (56.25–111.75) 54.25 (40–73.125)  Gunpowder explosion 15 (5–59.5) 5 (4–9) 60 (36–110.25) 44 (16.125–75.625)  Firework explosion 5 (2.75–14) 4 (3–6) 37 (16.75–64.75) 20.5 (10.375–48.75)  Other explosion 12.5 (5–30) 5 (4–7) 59 (40–83) 44.5 (32–57) Statistic, P-value 55.561, <.001 47.294, <.001 43.682, <.001 37.976, <.001 Sex  Male 20 (8–51) 7 (5–10) 68 (47–106) 49.5 (35.75–69)  Female 19.5 (8.5–45) 5 (4–8) 63 (43–99) 44 (32–65.5) Statistic, P-value 0.232, .603 16.203, <.001 1.133, .287 1.074, .300 Age (years)  0–20 9 (4–19) 4 (3–5) 27 (16–46) 15 (10–23)  21–40 28.5 (10–58) 6 (5–10) 66 (48–105.75) 43.75 (35.625–64.125)  41–60 25 (10–55) 8 (6–11) 84 (63.75–118) 58 (50.5–78.125)  ≥61 18.5 (10.5–41.25) 7 (6.25–10.5) 84 (76.5–120.5) 70.75 (66.5–84.5) Statistic, P-value 40.448, <.001 115.46, <0.001 156.804, <.001 219.81, <.001 Years  2002–2006 32 (10–65) 7 (5–11) 75 (48–119) 50.5 (34.5–77.5)  2007–2011 20 (8–46) 6 (4.75–9) 67 (47.75–99.25) 50 (34–66.125)  2012–2016 15 (8–35) 6 (5–8) 63.5 (44.25–92.25) 45 (32.5–61) Statistic, P-value 11.324, .003 8.857, .012 6.663, .036 6.357, .042 . TBSA median (IQR) . ABSI median (IQR) . Baux score median (IQR) . Prognostic burn Index median (IQR) . Etiology  Gas explosion 32 (14–60) 8 (5–11) 81 (56.25–111.75) 54.25 (40–73.125)  Gunpowder explosion 15 (5–59.5) 5 (4–9) 60 (36–110.25) 44 (16.125–75.625)  Firework explosion 5 (2.75–14) 4 (3–6) 37 (16.75–64.75) 20.5 (10.375–48.75)  Other explosion 12.5 (5–30) 5 (4–7) 59 (40–83) 44.5 (32–57) Statistic, P-value 55.561, <.001 47.294, <.001 43.682, <.001 37.976, <.001 Sex  Male 20 (8–51) 7 (5–10) 68 (47–106) 49.5 (35.75–69)  Female 19.5 (8.5–45) 5 (4–8) 63 (43–99) 44 (32–65.5) Statistic, P-value 0.232, .603 16.203, <.001 1.133, .287 1.074, .300 Age (years)  0–20 9 (4–19) 4 (3–5) 27 (16–46) 15 (10–23)  21–40 28.5 (10–58) 6 (5–10) 66 (48–105.75) 43.75 (35.625–64.125)  41–60 25 (10–55) 8 (6–11) 84 (63.75–118) 58 (50.5–78.125)  ≥61 18.5 (10.5–41.25) 7 (6.25–10.5) 84 (76.5–120.5) 70.75 (66.5–84.5) Statistic, P-value 40.448, <.001 115.46, <0.001 156.804, <.001 219.81, <.001 Years  2002–2006 32 (10–65) 7 (5–11) 75 (48–119) 50.5 (34.5–77.5)  2007–2011 20 (8–46) 6 (4.75–9) 67 (47.75–99.25) 50 (34–66.125)  2012–2016 15 (8–35) 6 (5–8) 63.5 (44.25–92.25) 45 (32.5–61) Statistic, P-value 11.324, .003 8.857, .012 6.663, .036 6.357, .042 Open in new tab Table 3. Burn severity analysis . TBSA median (IQR) . ABSI median (IQR) . Baux score median (IQR) . Prognostic burn Index median (IQR) . Etiology  Gas explosion 32 (14–60) 8 (5–11) 81 (56.25–111.75) 54.25 (40–73.125)  Gunpowder explosion 15 (5–59.5) 5 (4–9) 60 (36–110.25) 44 (16.125–75.625)  Firework explosion 5 (2.75–14) 4 (3–6) 37 (16.75–64.75) 20.5 (10.375–48.75)  Other explosion 12.5 (5–30) 5 (4–7) 59 (40–83) 44.5 (32–57) Statistic, P-value 55.561, <.001 47.294, <.001 43.682, <.001 37.976, <.001 Sex  Male 20 (8–51) 7 (5–10) 68 (47–106) 49.5 (35.75–69)  Female 19.5 (8.5–45) 5 (4–8) 63 (43–99) 44 (32–65.5) Statistic, P-value 0.232, .603 16.203, <.001 1.133, .287 1.074, .300 Age (years)  0–20 9 (4–19) 4 (3–5) 27 (16–46) 15 (10–23)  21–40 28.5 (10–58) 6 (5–10) 66 (48–105.75) 43.75 (35.625–64.125)  41–60 25 (10–55) 8 (6–11) 84 (63.75–118) 58 (50.5–78.125)  ≥61 18.5 (10.5–41.25) 7 (6.25–10.5) 84 (76.5–120.5) 70.75 (66.5–84.5) Statistic, P-value 40.448, <.001 115.46, <0.001 156.804, <.001 219.81, <.001 Years  2002–2006 32 (10–65) 7 (5–11) 75 (48–119) 50.5 (34.5–77.5)  2007–2011 20 (8–46) 6 (4.75–9) 67 (47.75–99.25) 50 (34–66.125)  2012–2016 15 (8–35) 6 (5–8) 63.5 (44.25–92.25) 45 (32.5–61) Statistic, P-value 11.324, .003 8.857, .012 6.663, .036 6.357, .042 . TBSA median (IQR) . ABSI median (IQR) . Baux score median (IQR) . Prognostic burn Index median (IQR) . Etiology  Gas explosion 32 (14–60) 8 (5–11) 81 (56.25–111.75) 54.25 (40–73.125)  Gunpowder explosion 15 (5–59.5) 5 (4–9) 60 (36–110.25) 44 (16.125–75.625)  Firework explosion 5 (2.75–14) 4 (3–6) 37 (16.75–64.75) 20.5 (10.375–48.75)  Other explosion 12.5 (5–30) 5 (4–7) 59 (40–83) 44.5 (32–57) Statistic, P-value 55.561, <.001 47.294, <.001 43.682, <.001 37.976, <.001 Sex  Male 20 (8–51) 7 (5–10) 68 (47–106) 49.5 (35.75–69)  Female 19.5 (8.5–45) 5 (4–8) 63 (43–99) 44 (32–65.5) Statistic, P-value 0.232, .603 16.203, <.001 1.133, .287 1.074, .300 Age (years)  0–20 9 (4–19) 4 (3–5) 27 (16–46) 15 (10–23)  21–40 28.5 (10–58) 6 (5–10) 66 (48–105.75) 43.75 (35.625–64.125)  41–60 25 (10–55) 8 (6–11) 84 (63.75–118) 58 (50.5–78.125)  ≥61 18.5 (10.5–41.25) 7 (6.25–10.5) 84 (76.5–120.5) 70.75 (66.5–84.5) Statistic, P-value 40.448, <.001 115.46, <0.001 156.804, <.001 219.81, <.001 Years  2002–2006 32 (10–65) 7 (5–11) 75 (48–119) 50.5 (34.5–77.5)  2007–2011 20 (8–46) 6 (4.75–9) 67 (47.75–99.25) 50 (34–66.125)  2012–2016 15 (8–35) 6 (5–8) 63.5 (44.25–92.25) 45 (32.5–61) Statistic, P-value 11.324, .003 8.857, .012 6.663, .036 6.357, .042 Open in new tab Figure 5. Open in new tabDownload slide Burn severity. (A) Distribution TBSA. (B) Maximum burn depth. 2a: superficial partial thickness burns, 2b: deep partial-thickness burns, 3: full-thickness burns. (C) Distribution of ABSI. (D) Distribution of PBI. (E) Distribution of Baux score. Figure 5. Open in new tabDownload slide Burn severity. (A) Distribution TBSA. (B) Maximum burn depth. 2a: superficial partial thickness burns, 2b: deep partial-thickness burns, 3: full-thickness burns. (C) Distribution of ABSI. (D) Distribution of PBI. (E) Distribution of Baux score. Figure 6. Open in new tabDownload slide The distribution of treatment outcome by ABSI (A), PBI (B), and Baux score (C). Figure 6. Open in new tabDownload slide The distribution of treatment outcome by ABSI (A), PBI (B), and Baux score (C). Full-Thickness Burns There were 272 patients with full-thickness burns, accounting for 54.73% (Table 4). The most common etiology of full-thickness burns was gas explosions (52.21%), followed by gunpowder explosions (21.32%) and fireworks explosions (4.78%). The percentages of full-thickness burns were highest in gunpowder explosions (63.04%) and lowest in firework explosions (43.33%). Most full-thickness burn areas (73.90%) were <20% TBSA. The length of stay (LOS) and cost of full-thickness burns differed significantly among etiologies (P < 0.001; Table 4). Gas explosions had the longest LOS (39.5 days), and highest costs (62,920 CNY). Firework explosions had the shortest LOS (20 days) and lowest costs (17,541 CNY; Table 4). Table 4. Analysis of full-thickness burns by area, LOS, and outcome Etiology . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total . Statistic . P-value . Cases, n (% of III° burns) 142 (52.2) 58 (21.3) 13 (4.8) 59 (21.7) 272 170.253 <.001 Fraction of every cause 55.5 63.0 43.3 49.6 54.7 5.469 .140 III° burn area % 29.210 <.001  1–5 15 22 11 39 123  6–20 53 14 1 10 78  ≥21 38 22 1 10 71 Mortality, n (%) 16 (11.3) 9 (15.5) 0 (0) 7 (11.9) 32 (11.8) 2.554 .466 LOS (days) 35.072 <.001 Median 39.5 21 20 22 31  IQR 19.25–76.5 9.25–50.75 8.75–35.75 11–41 13.5–58 Cost (CNY) 44.145 <.001  Median 62,920.75 27,144.635 17,541.5 27,547.4 42,329.255  IQR 27,090.015–179,341.9 10,248.815–88,711.7925 6030.92–34,752.55 9709.11–89,498.415 15,480.65–131,807.025 Etiology . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total . Statistic . P-value . Cases, n (% of III° burns) 142 (52.2) 58 (21.3) 13 (4.8) 59 (21.7) 272 170.253 <.001 Fraction of every cause 55.5 63.0 43.3 49.6 54.7 5.469 .140 III° burn area % 29.210 <.001  1–5 15 22 11 39 123  6–20 53 14 1 10 78  ≥21 38 22 1 10 71 Mortality, n (%) 16 (11.3) 9 (15.5) 0 (0) 7 (11.9) 32 (11.8) 2.554 .466 LOS (days) 35.072 <.001 Median 39.5 21 20 22 31  IQR 19.25–76.5 9.25–50.75 8.75–35.75 11–41 13.5–58 Cost (CNY) 44.145 <.001  Median 62,920.75 27,144.635 17,541.5 27,547.4 42,329.255  IQR 27,090.015–179,341.9 10,248.815–88,711.7925 6030.92–34,752.55 9709.11–89,498.415 15,480.65–131,807.025 Open in new tab Table 4. Analysis of full-thickness burns by area, LOS, and outcome Etiology . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total . Statistic . P-value . Cases, n (% of III° burns) 142 (52.2) 58 (21.3) 13 (4.8) 59 (21.7) 272 170.253 <.001 Fraction of every cause 55.5 63.0 43.3 49.6 54.7 5.469 .140 III° burn area % 29.210 <.001  1–5 15 22 11 39 123  6–20 53 14 1 10 78  ≥21 38 22 1 10 71 Mortality, n (%) 16 (11.3) 9 (15.5) 0 (0) 7 (11.9) 32 (11.8) 2.554 .466 LOS (days) 35.072 <.001 Median 39.5 21 20 22 31  IQR 19.25–76.5 9.25–50.75 8.75–35.75 11–41 13.5–58 Cost (CNY) 44.145 <.001  Median 62,920.75 27,144.635 17,541.5 27,547.4 42,329.255  IQR 27,090.015–179,341.9 10,248.815–88,711.7925 6030.92–34,752.55 9709.11–89,498.415 15,480.65–131,807.025 Etiology . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total . Statistic . P-value . Cases, n (% of III° burns) 142 (52.2) 58 (21.3) 13 (4.8) 59 (21.7) 272 170.253 <.001 Fraction of every cause 55.5 63.0 43.3 49.6 54.7 5.469 .140 III° burn area % 29.210 <.001  1–5 15 22 11 39 123  6–20 53 14 1 10 78  ≥21 38 22 1 10 71 Mortality, n (%) 16 (11.3) 9 (15.5) 0 (0) 7 (11.9) 32 (11.8) 2.554 .466 LOS (days) 35.072 <.001 Median 39.5 21 20 22 31  IQR 19.25–76.5 9.25–50.75 8.75–35.75 11–41 13.5–58 Cost (CNY) 44.145 <.001  Median 62,920.75 27,144.635 17,541.5 27,547.4 42,329.255  IQR 27,090.015–179,341.9 10,248.815–88,711.7925 6030.92–34,752.55 9709.11–89,498.415 15,480.65–131,807.025 Open in new tab Burn Sites and Associated Injuries The most common burn sites were limbs, accounting for 73.44%, followed by head, face, and neck region (65.79%), trunk (46.48%), and hand (42.86%) (Table 5). Associated injuries were very common in the explosion burn patients. Eighty-nine patients (17.91%) accompanied with inhalation injury. In addition, 21 cases (4.23%) suffered ocular burns, followed by fracture (3.82%), soft-tissue injury (2.62%), pulmonary contusion (2.41%), shock (1.81%), and brain damage (0.80%) (Table 6). Table 5. Etiology distribution by sex and age Etiology . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total, n (%) . χ 2 . P-value . Patients, n (%) 256 (51.5%) 92 (18.5%) 30 (6.0%) 119 (23.95) 497 (100%) 293.052 <.001 Etiology 32.696 .018  Head/face/neck 159 67 21 80 327 (65.8%)  Hands 118 44 13 38 213 (42.9%)  Limbs 210 60 15 80 365 (73.4%)  Trunk 146 38 4 43 231 (46.5%)  Perineum 18 11 0 6 35 (7.0%)  Hip 38 20 0 11 69 (13.9%)  Feet 53 19 4 22 98 (19.7%) Sex 11.634 .009  Male 213 62 24 87 386 (77.7%)  Female 43 30 6 32 111 (22.3%) Age (years) 63.167 <.001  0–20 27 33 17 18 95 (19.1%)  21–40 118 31 4 55 208 (41.9%)  41–60 105 24 7 42 178 (35.8%)  ≥61 6 4 2 4 16 (3.2%) Etiology . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total, n (%) . χ 2 . P-value . Patients, n (%) 256 (51.5%) 92 (18.5%) 30 (6.0%) 119 (23.95) 497 (100%) 293.052 <.001 Etiology 32.696 .018  Head/face/neck 159 67 21 80 327 (65.8%)  Hands 118 44 13 38 213 (42.9%)  Limbs 210 60 15 80 365 (73.4%)  Trunk 146 38 4 43 231 (46.5%)  Perineum 18 11 0 6 35 (7.0%)  Hip 38 20 0 11 69 (13.9%)  Feet 53 19 4 22 98 (19.7%) Sex 11.634 .009  Male 213 62 24 87 386 (77.7%)  Female 43 30 6 32 111 (22.3%) Age (years) 63.167 <.001  0–20 27 33 17 18 95 (19.1%)  21–40 118 31 4 55 208 (41.9%)  41–60 105 24 7 42 178 (35.8%)  ≥61 6 4 2 4 16 (3.2%) Open in new tab Table 5. Etiology distribution by sex and age Etiology . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total, n (%) . χ 2 . P-value . Patients, n (%) 256 (51.5%) 92 (18.5%) 30 (6.0%) 119 (23.95) 497 (100%) 293.052 <.001 Etiology 32.696 .018  Head/face/neck 159 67 21 80 327 (65.8%)  Hands 118 44 13 38 213 (42.9%)  Limbs 210 60 15 80 365 (73.4%)  Trunk 146 38 4 43 231 (46.5%)  Perineum 18 11 0 6 35 (7.0%)  Hip 38 20 0 11 69 (13.9%)  Feet 53 19 4 22 98 (19.7%) Sex 11.634 .009  Male 213 62 24 87 386 (77.7%)  Female 43 30 6 32 111 (22.3%) Age (years) 63.167 <.001  0–20 27 33 17 18 95 (19.1%)  21–40 118 31 4 55 208 (41.9%)  41–60 105 24 7 42 178 (35.8%)  ≥61 6 4 2 4 16 (3.2%) Etiology . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total, n (%) . χ 2 . P-value . Patients, n (%) 256 (51.5%) 92 (18.5%) 30 (6.0%) 119 (23.95) 497 (100%) 293.052 <.001 Etiology 32.696 .018  Head/face/neck 159 67 21 80 327 (65.8%)  Hands 118 44 13 38 213 (42.9%)  Limbs 210 60 15 80 365 (73.4%)  Trunk 146 38 4 43 231 (46.5%)  Perineum 18 11 0 6 35 (7.0%)  Hip 38 20 0 11 69 (13.9%)  Feet 53 19 4 22 98 (19.7%) Sex 11.634 .009  Male 213 62 24 87 386 (77.7%)  Female 43 30 6 32 111 (22.3%) Age (years) 63.167 <.001  0–20 27 33 17 18 95 (19.1%)  21–40 118 31 4 55 208 (41.9%)  41–60 105 24 7 42 178 (35.8%)  ≥61 6 4 2 4 16 (3.2%) Open in new tab Table 6. The number and types of associated injury Types . Cases . . . N . Percentage . Inhalation injury  Slight 42 8.45  Moderate 38 7.65  Severe 9 1.81  Total 89 17.91 Ocular injury 21 4.23 Fracture 19 3.82 Soft-tissue injury 13 2.62 Lung contusion 12 2.41 Brain damage 4 0.80 Shock 9 1.81 Types . Cases . . . N . Percentage . Inhalation injury  Slight 42 8.45  Moderate 38 7.65  Severe 9 1.81  Total 89 17.91 Ocular injury 21 4.23 Fracture 19 3.82 Soft-tissue injury 13 2.62 Lung contusion 12 2.41 Brain damage 4 0.80 Shock 9 1.81 Open in new tab Table 6. The number and types of associated injury Types . Cases . . . N . Percentage . Inhalation injury  Slight 42 8.45  Moderate 38 7.65  Severe 9 1.81  Total 89 17.91 Ocular injury 21 4.23 Fracture 19 3.82 Soft-tissue injury 13 2.62 Lung contusion 12 2.41 Brain damage 4 0.80 Shock 9 1.81 Types . Cases . . . N . Percentage . Inhalation injury  Slight 42 8.45  Moderate 38 7.65  Severe 9 1.81  Total 89 17.91 Ocular injury 21 4.23 Fracture 19 3.82 Soft-tissue injury 13 2.62 Lung contusion 12 2.41 Brain damage 4 0.80 Shock 9 1.81 Open in new tab Inhalation Injury Among 89 inhalation-injured patients, slight, moderate, and severe inhalation injury accounted for 47.19, 42.70, and 10.11%, respectively, (Table 6). As shown in Table 7, the mean TBSA of the patients with inhalation injury (53.81 ± 29.77%) was significantly larger than that of those without inhalation injury (26.44 ± 25.51%). The percentage of full-thickness burns in the patients with inhalation injury (75.28%) was significantly higher than that of those without inhalation injury (50.25%). The percentage of the inhalation-injured patients significantly differed among etiologies. The surgical rate of the patients with inhalation injury (66.29%) was higher than that of those without inhalation injury (58.09%). The mean length of stay (LOS) of the patients with and without inhalation injury was 114.96 ± 171.93 and 55.96 ± 132.52 days, respectively. The average ICU stay of the patients with and without inhalation injury was 23.15 ± 27.66 and 6.41 ± 14.01 days, respectively. The mortality of the patients with inhalation injury (15.73%) was significantly higher than that of those without inhalation injury (4.42%) (P < .001). In addition, the total cost of the patients with inhalation injury (313,049 ± 437,266) was significantly higher than that of those without inhalation injury (89,988 ± 158,862; Table 7). However, no significant differences were found in ages and genders between the two groups. Table 7. Comparison between patients with and without inhalation injury Inhalation injury . With . Without . P-value . No. of patients (%) 89 (17.91%) 408 (82.09%) Age (SD) 36.25 (13.65) 33.96 (15.28) .150 Male (%) 71 (79.78%) 315 (77.21%) .675 Etiology .002 Gas explosion 62 (69.66%) 194 (47.55%) Gunpowder explosion 13 (14.61%) 79 (19.36%) Firework explosion 3 (3.37%) 27 (6.62%) Other explosion 11 (12.36%) 108 (26.47%) Mean TBSA (SD) 53.81 (29.77) 26.44 (25.51) <.001 % of III° burns 67 (75.28%) 205 (50.25%) <.001 Tracheostomy (%) 76 (85.39%) 151 (37.01%) <.001 Mechanical ventilation (%) 40 (44.94%) 46 (11.27%) <.001 Operation rate 59 (66.29%) 237 (58.09%) <.001 LOS (SD) 114.96 (171.93) 55.96 (132.52) <.001 ICU stay (SD) 23.15 (27.66) 6.41 (14.01) <.001 Mortality rate 14 (15.73%) 18 (4.42%) <.001 Total cost (SD) 313,049 (437,266) 89,988 (158,862) <.001 Inhalation injury . With . Without . P-value . No. of patients (%) 89 (17.91%) 408 (82.09%) Age (SD) 36.25 (13.65) 33.96 (15.28) .150 Male (%) 71 (79.78%) 315 (77.21%) .675 Etiology .002 Gas explosion 62 (69.66%) 194 (47.55%) Gunpowder explosion 13 (14.61%) 79 (19.36%) Firework explosion 3 (3.37%) 27 (6.62%) Other explosion 11 (12.36%) 108 (26.47%) Mean TBSA (SD) 53.81 (29.77) 26.44 (25.51) <.001 % of III° burns 67 (75.28%) 205 (50.25%) <.001 Tracheostomy (%) 76 (85.39%) 151 (37.01%) <.001 Mechanical ventilation (%) 40 (44.94%) 46 (11.27%) <.001 Operation rate 59 (66.29%) 237 (58.09%) <.001 LOS (SD) 114.96 (171.93) 55.96 (132.52) <.001 ICU stay (SD) 23.15 (27.66) 6.41 (14.01) <.001 Mortality rate 14 (15.73%) 18 (4.42%) <.001 Total cost (SD) 313,049 (437,266) 89,988 (158,862) <.001 Open in new tab Table 7. Comparison between patients with and without inhalation injury Inhalation injury . With . Without . P-value . No. of patients (%) 89 (17.91%) 408 (82.09%) Age (SD) 36.25 (13.65) 33.96 (15.28) .150 Male (%) 71 (79.78%) 315 (77.21%) .675 Etiology .002 Gas explosion 62 (69.66%) 194 (47.55%) Gunpowder explosion 13 (14.61%) 79 (19.36%) Firework explosion 3 (3.37%) 27 (6.62%) Other explosion 11 (12.36%) 108 (26.47%) Mean TBSA (SD) 53.81 (29.77) 26.44 (25.51) <.001 % of III° burns 67 (75.28%) 205 (50.25%) <.001 Tracheostomy (%) 76 (85.39%) 151 (37.01%) <.001 Mechanical ventilation (%) 40 (44.94%) 46 (11.27%) <.001 Operation rate 59 (66.29%) 237 (58.09%) <.001 LOS (SD) 114.96 (171.93) 55.96 (132.52) <.001 ICU stay (SD) 23.15 (27.66) 6.41 (14.01) <.001 Mortality rate 14 (15.73%) 18 (4.42%) <.001 Total cost (SD) 313,049 (437,266) 89,988 (158,862) <.001 Inhalation injury . With . Without . P-value . No. of patients (%) 89 (17.91%) 408 (82.09%) Age (SD) 36.25 (13.65) 33.96 (15.28) .150 Male (%) 71 (79.78%) 315 (77.21%) .675 Etiology .002 Gas explosion 62 (69.66%) 194 (47.55%) Gunpowder explosion 13 (14.61%) 79 (19.36%) Firework explosion 3 (3.37%) 27 (6.62%) Other explosion 11 (12.36%) 108 (26.47%) Mean TBSA (SD) 53.81 (29.77) 26.44 (25.51) <.001 % of III° burns 67 (75.28%) 205 (50.25%) <.001 Tracheostomy (%) 76 (85.39%) 151 (37.01%) <.001 Mechanical ventilation (%) 40 (44.94%) 46 (11.27%) <.001 Operation rate 59 (66.29%) 237 (58.09%) <.001 LOS (SD) 114.96 (171.93) 55.96 (132.52) <.001 ICU stay (SD) 23.15 (27.66) 6.41 (14.01) <.001 Mortality rate 14 (15.73%) 18 (4.42%) <.001 Total cost (SD) 313,049 (437,266) 89,988 (158,862) <.001 Open in new tab Tracheostomy and Mechanical Ventilation Of the inhalation-injured patients, 85.39% underwent a tracheostomy procedure, which was significantly higher than the proportion of patients without inhalation injury (37.01%, P < .001). Among all inhalation-injured patients, 44.94% were supported by mechanical ventilation, which was also significantly higher than the proportion for patients without inhalation injury (11.27%, P < .001; Table 7). Blood Transfusion There were 241 cases (48.49%) treated with blood transfusion. Of these patients, there were 50 patients (10.06%) who were transfused <1000 ml, and 89 patients (17.91%) who were transfused >5000 ml (Figure 7). Furthermore, the volume of transfused blood was 138.0 ml per 1% TBSA. Figure 7. Open in new tabDownload slide The volume of blood transfusions. Figure 7. Open in new tabDownload slide The volume of blood transfusions. Wound Operations A total of 239 patients (48.09%) underwent surgery (Table 1). The wounds of the other 258 patients healed after dressing changes and anti-infective treatment. Of the operated patients, 206 (86.19%) underwent skin autograft. The most common type of skin autograft was split-thickness skin graft (72.33%), followed by thin skin graft (32.52%), full-thickness skin graft (19.90%), and flap graft (7.77%). A minority underwent skin allograft (5.44%) and skin xenograft (0.84%, Table 8), in order to prepare good wound beds for subsequent skin autograft. Table 8. The number and type of operations on patients with burns during explosion accident . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total . No. of operation  1 98 (79.67%) 42 (87.50%) 11 (78.57%) 49 (90.74%) 200 (83.68%)  2 9 (7.32%) 2 (4.17%) 2 (14.29%) 1 (1.85%) 14 (5.86%)  3 8 (6.50%) 2 (4.17%) 1 (7.14%) 4 (7.41%) 15 (6.28%)  ≥4 8 (6.50%) 2 (4.17%) 0 0 10 (4.18%)  Total 123 (100%) 48 (100%) 14 (100%) 54 (100%) 239 (48.09%) Skin autograft 107 (86.99%) 42 (87.50%) 14 (100.00%) 43 (79.63%) 206 (86.19%)  Thin skin graft 39 (36.45%) 11 (26.19%) 5 (35.71%) 12 (27.91%) 67 (32.52%)  Split-thickness skin graft 77 (71.96%) 31 (73.81%) 9 (64.29%) 32 (74.42%) 149 (72.33%)  Full-thickness skin graft 21 (19.63%) 9 (21.43%) 3 (21.43%) 8 (18.60) 41 (19.90%)  Flap graft 2 (2.00%) 3 (7.69%) 4 (28.57%) 6 (15.00%) 15 (7.77%) Skin allograft 6 (4.88%) 4 (8.33%) 0 3 (5.56%) 13 (5.44%) Skin xenograft 1 (0.81%) 1 (2.08%) 0 0 2 (0.84%) Amputation 1 (0.81%) 2 (4.17%) 0 0 3 (1.26%) Others 15 (12.20%) 5 (10.42%) 1 (7.14%) 8 (14.81%) 29 (12.13%) . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total . No. of operation  1 98 (79.67%) 42 (87.50%) 11 (78.57%) 49 (90.74%) 200 (83.68%)  2 9 (7.32%) 2 (4.17%) 2 (14.29%) 1 (1.85%) 14 (5.86%)  3 8 (6.50%) 2 (4.17%) 1 (7.14%) 4 (7.41%) 15 (6.28%)  ≥4 8 (6.50%) 2 (4.17%) 0 0 10 (4.18%)  Total 123 (100%) 48 (100%) 14 (100%) 54 (100%) 239 (48.09%) Skin autograft 107 (86.99%) 42 (87.50%) 14 (100.00%) 43 (79.63%) 206 (86.19%)  Thin skin graft 39 (36.45%) 11 (26.19%) 5 (35.71%) 12 (27.91%) 67 (32.52%)  Split-thickness skin graft 77 (71.96%) 31 (73.81%) 9 (64.29%) 32 (74.42%) 149 (72.33%)  Full-thickness skin graft 21 (19.63%) 9 (21.43%) 3 (21.43%) 8 (18.60) 41 (19.90%)  Flap graft 2 (2.00%) 3 (7.69%) 4 (28.57%) 6 (15.00%) 15 (7.77%) Skin allograft 6 (4.88%) 4 (8.33%) 0 3 (5.56%) 13 (5.44%) Skin xenograft 1 (0.81%) 1 (2.08%) 0 0 2 (0.84%) Amputation 1 (0.81%) 2 (4.17%) 0 0 3 (1.26%) Others 15 (12.20%) 5 (10.42%) 1 (7.14%) 8 (14.81%) 29 (12.13%) Open in new tab Table 8. The number and type of operations on patients with burns during explosion accident . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total . No. of operation  1 98 (79.67%) 42 (87.50%) 11 (78.57%) 49 (90.74%) 200 (83.68%)  2 9 (7.32%) 2 (4.17%) 2 (14.29%) 1 (1.85%) 14 (5.86%)  3 8 (6.50%) 2 (4.17%) 1 (7.14%) 4 (7.41%) 15 (6.28%)  ≥4 8 (6.50%) 2 (4.17%) 0 0 10 (4.18%)  Total 123 (100%) 48 (100%) 14 (100%) 54 (100%) 239 (48.09%) Skin autograft 107 (86.99%) 42 (87.50%) 14 (100.00%) 43 (79.63%) 206 (86.19%)  Thin skin graft 39 (36.45%) 11 (26.19%) 5 (35.71%) 12 (27.91%) 67 (32.52%)  Split-thickness skin graft 77 (71.96%) 31 (73.81%) 9 (64.29%) 32 (74.42%) 149 (72.33%)  Full-thickness skin graft 21 (19.63%) 9 (21.43%) 3 (21.43%) 8 (18.60) 41 (19.90%)  Flap graft 2 (2.00%) 3 (7.69%) 4 (28.57%) 6 (15.00%) 15 (7.77%) Skin allograft 6 (4.88%) 4 (8.33%) 0 3 (5.56%) 13 (5.44%) Skin xenograft 1 (0.81%) 1 (2.08%) 0 0 2 (0.84%) Amputation 1 (0.81%) 2 (4.17%) 0 0 3 (1.26%) Others 15 (12.20%) 5 (10.42%) 1 (7.14%) 8 (14.81%) 29 (12.13%) . Gas explosion . Gunpowder explosion . Firework explosion . Other explosion . Total . No. of operation  1 98 (79.67%) 42 (87.50%) 11 (78.57%) 49 (90.74%) 200 (83.68%)  2 9 (7.32%) 2 (4.17%) 2 (14.29%) 1 (1.85%) 14 (5.86%)  3 8 (6.50%) 2 (4.17%) 1 (7.14%) 4 (7.41%) 15 (6.28%)  ≥4 8 (6.50%) 2 (4.17%) 0 0 10 (4.18%)  Total 123 (100%) 48 (100%) 14 (100%) 54 (100%) 239 (48.09%) Skin autograft 107 (86.99%) 42 (87.50%) 14 (100.00%) 43 (79.63%) 206 (86.19%)  Thin skin graft 39 (36.45%) 11 (26.19%) 5 (35.71%) 12 (27.91%) 67 (32.52%)  Split-thickness skin graft 77 (71.96%) 31 (73.81%) 9 (64.29%) 32 (74.42%) 149 (72.33%)  Full-thickness skin graft 21 (19.63%) 9 (21.43%) 3 (21.43%) 8 (18.60) 41 (19.90%)  Flap graft 2 (2.00%) 3 (7.69%) 4 (28.57%) 6 (15.00%) 15 (7.77%) Skin allograft 6 (4.88%) 4 (8.33%) 0 3 (5.56%) 13 (5.44%) Skin xenograft 1 (0.81%) 1 (2.08%) 0 0 2 (0.84%) Amputation 1 (0.81%) 2 (4.17%) 0 0 3 (1.26%) Others 15 (12.20%) 5 (10.42%) 1 (7.14%) 8 (14.81%) 29 (12.13%) Open in new tab Affecting Factors for LOS and Cost The average LOS and ICU stay was 66.53 ± 142.00 days (median: 31 days) and 9.40 ± 18.38 days (median: 0 days), respectively. The distributions of the LOS and LOS/TBSA were illustrated in Supplementary Table 1. A multiple linear regression was performed to screen risks factors for LOS, including age, number of operations, TBSA, full-thickness burns, cure rate, inhalation injury, mortality, and etiologies. Among these factors, larger TBSA had the largest impact on LOS (standardized coefficient = 0.528, P < .001), followed by greater number of operations (standardized coefficient = 0.282, P < .001), higher cure rate (standardized coefficient = 0.208, P < .001), full-thickness burns (standardized coefficient = 0.194, P < .001), and older age (standardized coefficient = 0.141, P < .001). Moreover, inhalation injury was also a risk factor affecting LOS (standardized coefficient = 0.085, P = .003; Table 9). Table 9. Multiple linear regression analysis of factors associated with length of stay . Unstandardized β coefficients . Standardized β coefficients . t . P–value . Age 0.014 0.141 5.1 <.001 Operations No. 0.402 0.282 9.794 <.001 TBSA 0.028 0.528 14.146 <.001 Cured 0.702 0.208 6.851 <.001 Died −0.544 −0.089 −2.634 .009 Inhalation injury 0.335 0.085 2.942 .003 Full-thickness burns 0.589 0.194 6.363 <.001 Etiology Gunpowder explosion −0.404 −0.104 −3.566 <.001 Firework explosion −0.37 −0.058 −2.039 .042 . Unstandardized β coefficients . Standardized β coefficients . t . P–value . Age 0.014 0.141 5.1 <.001 Operations No. 0.402 0.282 9.794 <.001 TBSA 0.028 0.528 14.146 <.001 Cured 0.702 0.208 6.851 <.001 Died −0.544 −0.089 −2.634 .009 Inhalation injury 0.335 0.085 2.942 .003 Full-thickness burns 0.589 0.194 6.363 <.001 Etiology Gunpowder explosion −0.404 −0.104 −3.566 <.001 Firework explosion −0.37 −0.058 −2.039 .042 Open in new tab Table 9. Multiple linear regression analysis of factors associated with length of stay . Unstandardized β coefficients . Standardized β coefficients . t . P–value . Age 0.014 0.141 5.1 <.001 Operations No. 0.402 0.282 9.794 <.001 TBSA 0.028 0.528 14.146 <.001 Cured 0.702 0.208 6.851 <.001 Died −0.544 −0.089 −2.634 .009 Inhalation injury 0.335 0.085 2.942 .003 Full-thickness burns 0.589 0.194 6.363 <.001 Etiology Gunpowder explosion −0.404 −0.104 −3.566 <.001 Firework explosion −0.37 −0.058 −2.039 .042 . Unstandardized β coefficients . Standardized β coefficients . t . P–value . Age 0.014 0.141 5.1 <.001 Operations No. 0.402 0.282 9.794 <.001 TBSA 0.028 0.528 14.146 <.001 Cured 0.702 0.208 6.851 <.001 Died −0.544 −0.089 −2.634 .009 Inhalation injury 0.335 0.085 2.942 .003 Full-thickness burns 0.589 0.194 6.363 <.001 Etiology Gunpowder explosion −0.404 −0.104 −3.566 <.001 Firework explosion −0.37 −0.058 −2.039 .042 Open in new tab The mean total cost was 130,489 ± 249,565 CNY (median: 42,329 CNY). The distributions of the cost and cost/TBSA were illustrated in Supplementary Table 1. A multiple linear regression was performed to screen risks factors for total cost, including number of operations, TBSA, full-thickness burns, cure rate, inhalation injury, mortality, and etiologies. Among these factors, a higher cure rate increased total cost to the greatest extent (standardized coefficient = 0.358, P < .001), followed by greater number of operations (standardized coefficient = 0.357, P < .001), larger TBSA (standardized coefficient = 0.244, P < .001), full-thickness burns (standardized coefficient = 0.183, P < .001), and inhalation injury (standardized coefficient = 0.068, P = .047; Table 10). Table 10. Multiple linear regression analysis of factors related to total cost . Unstandardized β coefficients . Standardized β coefficients . t . P-value . Operations No. 0.388 0.357 10.405 <.001 TBSA 0.01 0.244 5.514 <.001 Cured 0.917 0.358 9.902 <.001 Died −1.211 −0.258 −6.463 <.001 Inhalation injury 0.205 0.068 1.991 .047 Full-thickness burns 0.423 0.183 5.035 <.001 Etiology Gunpowder explosion −0.228 −0.077 −2.237 .026 Firework explosion −0.502 −0.104 −3.123 .002 . Unstandardized β coefficients . Standardized β coefficients . t . P-value . Operations No. 0.388 0.357 10.405 <.001 TBSA 0.01 0.244 5.514 <.001 Cured 0.917 0.358 9.902 <.001 Died −1.211 −0.258 −6.463 <.001 Inhalation injury 0.205 0.068 1.991 .047 Full-thickness burns 0.423 0.183 5.035 <.001 Etiology Gunpowder explosion −0.228 −0.077 −2.237 .026 Firework explosion −0.502 −0.104 −3.123 .002 Open in new tab Table 10. Multiple linear regression analysis of factors related to total cost . Unstandardized β coefficients . Standardized β coefficients . t . P-value . Operations No. 0.388 0.357 10.405 <.001 TBSA 0.01 0.244 5.514 <.001 Cured 0.917 0.358 9.902 <.001 Died −1.211 −0.258 −6.463 <.001 Inhalation injury 0.205 0.068 1.991 .047 Full-thickness burns 0.423 0.183 5.035 <.001 Etiology Gunpowder explosion −0.228 −0.077 −2.237 .026 Firework explosion −0.502 −0.104 −3.123 .002 . Unstandardized β coefficients . Standardized β coefficients . t . P-value . Operations No. 0.388 0.357 10.405 <.001 TBSA 0.01 0.244 5.514 <.001 Cured 0.917 0.358 9.902 <.001 Died −1.211 −0.258 −6.463 <.001 Inhalation injury 0.205 0.068 1.991 .047 Full-thickness burns 0.423 0.183 5.035 <.001 Etiology Gunpowder explosion −0.228 −0.077 −2.237 .026 Firework explosion −0.502 −0.104 −3.123 .002 Open in new tab Deaths There were 32 deaths in our study. The mortality of burns during explosion accident was 6.44%, which was higher than that of total burn population (1.16%). Risk factors for mortality were screened by logistic regression analysis. Larger TBSA had the greatest influence on mortality (OR = 1.211, P < .001), followed by older age (OR = 1.090, P < .008; Table 11). The majority of deaths occurred within 20 days after the injury. Three patients died within 2 days due to shock and sepsis. Fifteen patients died between 3 and 7 days, caused by shock (n = 4), multiple organ dysfunction syndrome (MODS) (n = 4), sepsis (n = 2), pulmonary infection (n = 2), heart failure (n = 1), and acute respiratory distress syndrome (ARDS) (n = 2). The causes of the other 13 deaths from 8 to 20 days were shock in two patients, MODS in eight patients and sepsis in three patients. Eleven patients died more than 21 days after injury (Table 12). A multivariate survival analysis (Kaplan–Meier method) was used to estimate survival rates. The survival in the inhalation-injured patients was significantly lower than that in the patients without inhalation injury (Figure 8). Table 11. Logistic regression analysis of risk factors related to mortality Variables . B . SE . OR . 95% CI . Wald . P-value . Older age 0.086 0.033 1.090 1.023–1.163 6.964 .008 Larger TBSA 0.191 0.037 1.211 1.126–1.303 26.363 <.001 Variables . B . SE . OR . 95% CI . Wald . P-value . Older age 0.086 0.033 1.090 1.023–1.163 6.964 .008 Larger TBSA 0.191 0.037 1.211 1.126–1.303 26.363 <.001 Constant = −19.874, chi-square = 25.787, P < 0.001; Cox and Snell R2 = 0.278, Nagelkerke R2 = 0.729. Open in new tab Table 11. Logistic regression analysis of risk factors related to mortality Variables . B . SE . OR . 95% CI . Wald . P-value . Older age 0.086 0.033 1.090 1.023–1.163 6.964 .008 Larger TBSA 0.191 0.037 1.211 1.126–1.303 26.363 <.001 Variables . B . SE . OR . 95% CI . Wald . P-value . Older age 0.086 0.033 1.090 1.023–1.163 6.964 .008 Larger TBSA 0.191 0.037 1.211 1.126–1.303 26.363 <.001 Constant = −19.874, chi-square = 25.787, P < 0.001; Cox and Snell R2 = 0.278, Nagelkerke R2 = 0.729. Open in new tab Table 12. Time and causes of death Types . Time postburn . . . . . <2 days . 3–7 days . 8–20 days . >20 day . Shock 2 4 2 2 MODS dysfunction syndromeMODS 4 8 3 Sepsis 1 2 3 5 Pulmonary infection 2 1 Heart failure 1 ARDS 2 Types . Time postburn . . . . . <2 days . 3–7 days . 8–20 days . >20 day . Shock 2 4 2 2 MODS dysfunction syndromeMODS 4 8 3 Sepsis 1 2 3 5 Pulmonary infection 2 1 Heart failure 1 ARDS 2 Open in new tab Table 12. Time and causes of death Types . Time postburn . . . . . <2 days . 3–7 days . 8–20 days . >20 day . Shock 2 4 2 2 MODS dysfunction syndromeMODS 4 8 3 Sepsis 1 2 3 5 Pulmonary infection 2 1 Heart failure 1 ARDS 2 Types . Time postburn . . . . . <2 days . 3–7 days . 8–20 days . >20 day . Shock 2 4 2 2 MODS dysfunction syndromeMODS 4 8 3 Sepsis 1 2 3 5 Pulmonary infection 2 1 Heart failure 1 ARDS 2 Open in new tab Figure 8. Open in new tabDownload slide Survival analysis. Patients without inhalation injury (blue line) always give higher chance of survival when compared with inhalation-injured patients (green line). Figure 8. Open in new tabDownload slide Survival analysis. Patients without inhalation injury (blue line) always give higher chance of survival when compared with inhalation-injured patients (green line). Discussion The prevalence of burns during explosion accident varies throughout the world. In this study, burns during explosion accident accounted for 2.37% of all burn inpatients. Our data showed that the number of burn inpatients increased initially and then decreased over the 15-year period. Mortality was lower in 2015 and 2016 than those in previous years. However, burn severity and LOS did not substantially decrease and cure rate did not substantially increase. These results suggest that more effective preventive measures and clinical treatment programs for burns during explosion accident are still needed. In addition, our data showed that working-age populations and males and were at the highest risk of burns during explosion accident during the study period. Further analysis showed that gas explosions had the highest male-to-female ratio (4.95:1), and gunpowder explosions had the lowest ratio (1.88:1). It might be that men are more likely to engage in dangerous jobs, such as coal mining, with poor safety protection. The incidence of fireworks explosion injury was high in children and youths. This could be due to the fact that children and youths are more prone to take risky behavior. Therefore, preventive measures focusing on working-age populations, children and youths should be considered. The results also indicated that the highest incidence of burns during explosion accident occurred in July (the hottest month of the year in southwest China), probably due to the high risk of explosions induced by high-temperature environments. Consistent with the findings of the previous study,1 gas explosions were the most common cause of burns during explosion accident (51.51%) in our study, followed by gunpowder (18.51%) explosions and fireworks (6.04%) explosions. The distribution of etiology significantly correlated with occupation, age, and season. Gas explosions mainly occurred in working-age populations who worked for coal mines, especially in private enterprises, and in people who cooked with gas. There are a couple of reasons for this: First, some local governments paid less attention to production safety, and some private enterprises did not construct safe facilities for the sake of reducing production cost, which often easily resulted in heavy casualties. Second, safety awareness of employees was poor in some locations. Third, mine local ventilation failure and ignition sources were the two major causes for gas explosions. Therefore, reinforcing industrial safety education, improving ventilation condition, and identifying ignition sources are the most effective methods to prevent gas explosions. Most cases of gunpowder explosions were work-related and mainly caused by improper operation. Our data also showed that fireworks explosions were predominant among the 0 to 20 years age group due to misuse in the Spring Festival. This may be due to the fact that Chinese people set off fireworks to celebrate both the Spring and Lantern Festivals. Among all eye traumas, the incidence of eye injuries caused by fireworks was highest. Fireworks-related eye injuries lead to severe visual damage or even blindness.10,17 Therefore, the government should enhance public awareness, strengthen safety education, and properly legislate for safe fireworks use to reduce such serious traumas. Twenty-five patients were burned by hot steam caused by boiler explosions. Fourteen cases were injured by dust explosions which occurred when combustible powders reached the explosive limit and were ignited.18 Dust explosions pose a tremendous hazard to public health. In June 2015, a mass casualty disaster occurred in Taiwan due to a color-dust explosion, injuring 499 people.6,19 Moreover, burns during explosion accident could also be caused by organic chemicals explosions,20 oil drum explosions,21 oxygen tank explosions, hydrogen balloon explosions, and battery explosions.22 In this study, 51.91% of burn areas were <20% of TBSA (0–10% TBSA burns comprised 33.40%, and 11–20% TBSA burns comprised 18.51%). However, 120 patients (24.14%) sustained burns covering ≥50% TBSAs. The number of extensively burned patients was much higher than that of conventional scald burns. Due to the high environmental temperature from explosions, burn injuries are always severe. In this study, 54.73% of the patients suffered from full-thickness burns. Full-thickness burns were most commonly caused by gas explosions, followed by gunpowder explosions, and fireworks explosions. The burn severity scores significantly differed among etiologies and ages. Gas explosions had significantly higher ABSI, PBI, and Baux score than those in other explosion types. In addition, patients in younger age groups had significantly lower ABSI, PBI, and Baux score than those in older age groups. Although the most full-thickness burn areas were <20%, the TBSA ABSI, PBI, and Baux score of full-thickness burn patients were significantly higher than those of patients without full-thickness burns. This inevitably leads to longer hospital stays, higher medical costs, and increased mortalities among full-thickness burn patients. Furthermore, full-thickness burns are more likely to cause scar contracture deformities. Therefore, early active surgery and postoperative rehabilitation therapy are needed for full-thickness burn patients.23 In our study, the incidence of burns during explosion accident in exposed parts of the body was high, including extremities (73.44%) and head, face, and neck (65.79%). Patients frequently suffered from associated injuries due to the high-energy explosion mechanisms, such as blast waves and subsequent collapse of building or mine. In this study, 17.91% had inhalation injury, and 4.23% accompanied by ocular burns. In addition, some patients sustained fractures (3.82%), soft-tissue injuries (2.62%), pulmonary contusions (2.41%), shock (1.81%), and brain damage (0.80%). The incidence of inhalation injury in conventional burn patients varies from different regions, ranging from 1.5% to 19.5%.24,25 The percentage of inhalation-injured patients in this study was higher than that of the previous study (8.01%) in Southwest China from 1986 to 2005.26 This difference might be due to the fact that victims of explosions often undergo the effect of high temperature and inhale toxic gases and powders of incomplete combustion. Furthermore, in our study, burns during explosion accident included single burns (330 cases) and burns with other blast injuries (167 cases). There are at least two possible reasons. First, due to the increasing improvement of safety protection, the burns during explosion accident admitted to our center were indeed relatively mild, and the main injury was burns. Second, some patients with explosion injuries were hospitalized in other clinical departments, eg, emergency departments, or might have died at the scene, on the way to our center, and in basic hospitals, or never sought medical care for social, economic or other reasons, which were excluded from our present study. Our results also showed that inhalation-injured patients had significantly higher LOS, ICU stays and costs, compared with patients without inhalation injury. Proper and timely airway management of inhalation-injured patients can have a significant influence on their outcome.27 Tracheostomy is considered as a vital intervention for severely burned patients with inhalation injury.28,29 In our study, 85.39% of inhalation-injured patients underwent tracheostomy, which was higher than that of a previous study.26 Mechanical ventilation is a significant therapeutic tool for severe inhalation injury, which can prevent upper airway obstruction and improve ventilation function.26,30 Among all inhalation-injured patients, 44.94% were treated by mechanical ventilation. The rate of mechanical ventilation was also higher than that of the previous study from our center.26 These results suggested that tracheotomy and mechanical ventilation were more widely used for the inhalation-injured patients. Both interventions were found to be helpful to decrease the mortality of inhalation-injured patients.28,31 Best supportive treatment practices, wound management, and prevention of complications associated with mechanical ventilation (respiratory infections and laryngeal injury) also improved the survival.32,33 However, the patients suffering from burns during explosion accident without inhalation injury also had high rates of tracheostomy and mechanical ventilation. There could be several reasons for this: First, early percutaneous dilational tracheostomy is advocated in our burn center after rigorous clinical evaluation if burn patients had a high risk of airway obstruction. Percutaneous dilational tracheostomy is a fast and minimally invasive procedure with less trauma and few complications. Moreover, compared to oral and nasal intubations, percutaneous dilational tracheostomy does not require intravenous anesthesia, which can avoid further aggravating the cardiovascular status by anesthesia. Second, due to the high environmental temperature resulting from explosions, burn injuries are always severe. Many of severe burns patient need trachea incision and mechanical ventilation for airway management, which can prepare a better condition for further surgery. Third, patients suffering from burns during explosion accident may combine with lung contusions, which are also the important causes of respiratory dysfunction. However, only 12 patients were diagnosed with lung contusion in our study, some of which might easily go undiagnosed due to the lack of knowledge about lung contusion and other chest injuries among doctors in our burn center. The surgical rate in our study was 48.09%. The majority of operated patients (86.19%) underwent skin autografting. 62.34% of operated patients underwent split-thickness skin graft. The percentage of flap graft (6.28%) and amputation (1.26%) in our study was lower than that of electrical burns.34 This may be because that electrical currents flow more easily into deeper tissues and damage them. In addition, 48.49% patients were treated with blood transfusion, which was higher than that of thermal burns.35 Patients with extensive full-thickness burns had high incidence of shock, for which blood transfusion was the most important treatment. The average LOS was 66.53 ± 142.00 days (median: 31 days), which was longer than those reported in previous studies.1,36 This was mainly because the burn severity of burns during explosion accident was highest among all type of burns.2 In addition, our burn center often received severe burn patients, who were transferred from other hospitals, and required long-term hospitalization for treatment and rehabilitation. The average ICU stay was 9.40 ± 18.38 days (median: 0 days). Furthermore, LOS was correlated with larger TBSA, the number of operations, full-thickness burns, older age, and outcome. In addition, inhalation injury also extended the time of hospitalization. Extensively burned patients with large area of full-thickness burns required more surgeries. All invasive surgeries require a recovery period, which prolongs hospitalization. Older patients also tended to stay in hospital longer due to poor regeneration, repair activity, and geriatric diseases. In this study, the average cost of patients with burns during explosion accident was 130,489 ± 249,565 CNY (median: 42,329 CNY). Our data also suggested that higher cure rate had the largest impact on costs, followed by greater number of operations, larger TBSA, and full-thickness burns. Moreover, inhalation injury was also a risk factor for higher hospital costs. In our study, the mortality among patients with burns during explosion accident was 6.44%, which was significantly higher than that of the overall population of burn patients.37–39 The mortality was correlated closely with the severity of the burn patients and the treatment level. Larger TBSA was the largest risk factor for mortality, followed by older age. High incidence of associated injuries in burns during explosion accident also increases the risk of mortality.9 In fact, we have enrolled many factors (eg, age, sex, inhalation injury, full-thickness burns, TBSA, etiologies, and number of operations) into the logistic regression model. However, only TBSA and age showed statistically significant differences. No association was found between inhalation injury, full-thickness burns, etiology, and mortality in our present study. The possible reason is that only 32 deaths (a mortality of 6.4%) may be quite insufficient to analyze the risk factors for mortality. The statistical errors may occur due to the small size of deaths, and some risk factors are screened out. The mortality for burns during explosion accident in our study could have been underestimated. On the one hand, our study did not contain patients who might have died at the scene of burns, on the way to our center, and in basic hospitals, those who received treatment as outpatients, and those who never sought medical care for social, economic, or other reasons; hence, we could not estimate the exact mortality. On the other hand, according to the Chinese tradition, many patients with severe burns during explosion accident chose to give up treatment and died at home; thus, we could not include them in the present study based on the medical records. Therefore, how to define the exact mortality and all potential risk factors for burns during explosion accident is still a challenge that we face. It is strongly recommended to further perform large multi-center studies to improve this limitation of our current study. Previous studies reported that the mortality rate of patients with thermal burns significantly increased when combined with inhalation injury.40,41 Our results also showed that inhalation-injured patients had significantly higher mortality compared with patients without inhalation injury. This finding was supported by multivariate survival analysis, which suggested that the survival in inhalation-injured patients was significantly lower than that of patients without inhalation injury. The most common cause of death was MODS, followed by sepsis. Three patients died within 2 days due to shock and sepsis. Patients with extensively deep burns were prone to shock, which not only leads directly to death, but also markedly increases the incidence of sepsis and MODS. The findings of this study should be interpreted cautiously because of the following limitations: First, explosions may lead to serious visceral injuries, which can be life-threatening if not diagnosed and treated promptly. Therefore, some patients with explosion injuries were hospitalized in other clinical departments, which might affect the morbidity reported in this study; second, patients involved in this study included only inpatients, whose burns were more severe than those of outpatients. Moreover, our burn center admits severely burned patients transferred from other hospitals. Hence, the severity of burns during explosion accident was higher than that of total burn population; third, only 32 deaths were recorded in this study. Therefore, the analysis results may be influenced by statistical error; fourth, the patients in our burn center mainly originated from Chongqing, Guizhou Province, and Sichuan Province. Hence, our findings merely reflect the epidemiology of burns during explosion accident in Southwest China. Conclusions To the best of our knowledge, this is the first study focusing on the epidemiological characteristics and outcomes of burn patients cause by explosion accident. who were admitted in Southwest Hospital of TMMU from 2002 to 2016. Our results strongly suggested that males and working-age population were the main victims of burns during explosion accident. Production safety should become a key target for preventing burns during explosion accident. Fireworks caused injuries in children and youths, as well as in users and bystanders. Fireworks explosions should receive more attention. The incidence of inhalation-injury in patients with burns during explosion accident was higher than that of the total burn population. Proper and timely airway management of inhalation-injured patients should be taken to improve outcomes. The LOS was correlated with TBSA, full-thickness burns, older age, number of operations, and outcome. The major factors determining cost were larger TBSA, full-thickness burns, higher cure rate, and greater number of operations. Moreover, larger TBSA and older age were found to be the most important risk factors for mortality. Explosions cause both severe public health security and economic problems, which affect health and workforce quality. More effective practical strategies for prevention and treatment are still needed to reduce the morbidity of explosion accident, improve therapeutic outcomes, and relieve the suffering and economic burden of patients. ACKNOWLEDGEMENTS We sincerely thank Dr Gaoming Li (a professional statistician from the Army Medical University) for providing helpful advice, and the medical staff at our center for their effective treatment of patients with burns during explosion accident and for preservation of medical records. Funding This work was supported by the National Natural Science Foundation of China (grant no. 81801915, 81630055, and 81920108022), the Talent Programme of Third Military Medical University (Army Medical University) (grant no. XZ-2019-505-065 and 2018XLC1001), the Science and Technology Innovation Plan of Southwest Hospital (grant no. SWH2016ZDCX2014 and SWH2017ZDCX1001), and the Key Laboratory of Emergency and Trauma (Hainan Medical University), Ministry of Education (grant no. KLET-201909). Conflict of interest statement. None. REFERENCES 1. Hosseini SN , Rashtchi V, Kamali K, Moghimi MH. Epidemiology and outcome of 2,590 burned patients in Northwest Iran . Ann Burns Fire Disasters 2017 ; 30 : 85 – 90 . Google Scholar PubMed OpenURL Placeholder Text WorldCat 2. Li H , Yao Z, Tan J, et al. Epidemiology and outcome analysis of 6325 burn patients: a five-year retrospective study in a major burn center in Southwest China . Sci Rep 2017 ; 7 : 46066 . 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TI - Epidemiology and Outcome Analysis of Burns During Explosion Accident at a Major Center in Southwestern China From 2002 to 2016
JF - Journal of Burn Care & Research
DO - 10.1093/jbcr/iraa103
DA - 2021-02-03
UR - https://www.deepdyve.com/lp/oxford-university-press/epidemiology-and-outcome-analysis-of-burns-during-explosion-accident-fMHqDqcLmd
SP - 49
EP - 62
VL - 42
IS - 1
DP - DeepDyve
ER -