Objective: To explore the epidemiological characteristics and treatment outcomes of patients with inhalation injuries combined with total burn area less than 30% total body surface area (TBSA). Methods: A retrospective observational study was performed on medical records of 266 patients with inhalation injuries combined with total burn area less than 30%TBSA who were admitted to the First Affiliated Hospital of Naval Medical University from January 2008 to December 2016 and met the inclusion criteria. The following statistical data of the patients were collected, including gender, age, injury site, injurious factors of inhalation injury, degree of inhalation injury, combined total burn area, tracheotomy, time of tracheotomy, mechanical ventilation, whether stayed in intensive care unit (ICU) or not, microbial culture results of bronchoalveolar lavage fluid, length of hospital stay, length of ICU stay, mechanical ventilation days, and respiratory tract infections. Single factor and multivariate linear regression analysis were used to screen out the risk factors impacting the length of hospital stay, length of ICU stay, and mechanical ventilation days of patients. Single factor and multivariate logistic regression analysis were used to screen out the risk factors impacting respiratory tract infections of patients. Results: The 266 patients included 190 males and 76 females, with the majority age of above or equal to 21 years and below 65 years (217 patients). The major injury site was confined space. The major factor causing inhalation injury was hot air. Mild and moderate inhalation injuries were more common in patients. The combined total burn area was 9.00% (3.25%, 18.00%) TBSA. In 111 patients who had tracheotomy, most of them received the procedures before being admitted to the First Affiliated Hospital of Naval Medical University. The length of hospital stay of patients was 27 (10, 55) days. The length of ICU stay of 160 patients who were hospitalized in ICU was 15.5 (6.0, 40.0) days. The mechanical ventilation days of 109 patients who were conducted with mechanical ventilation were 6.0 (1.3, 11.5) days. A total of 119 patients were diagnosed with respiratory tract infections, with 548 strains including 35 types of pathogens isolated, mainly Gram-negative bacteria. Single factor linear regression analysis showed that age, injurious factors of inhalation injury, combined total burn area, degree of inhalation injury (moderate and severe), tracheotomy, mechanical ventilation, and respiratory tract infections were the factors impacting the length of hospital stay of patients (β=-0.198, -0.224, 0.021, 0.127, 0.164, -0.298, 0.357, 0.447, 95% confidence interval (CI)=-0.397--0.001, -0.395--0.053, 0.015-0.028, 0.009-0.263, 0.008-0.319, -0.419--0.176, 0.242-0.471, 0.340-0.555, P<0.1). Multivariate linear regression analysis showed that with mechanical ventilation and respiratory tract infections were the independent risk factors impacting the length of hospital stay of patients (β=0.146, 0.383, 95% CI=0.022-0.271, 0.261-0.506, P<0.05 or P<0.01). Single factor linear regression analysis showed that injurious factors of inhalation injury, combined total burn area, degree of inhalation injury (moderate and severe), tracheotomy (no tracheotomy and prophylactic tracheotomy), mechanical ventilation, and respiratory tract infections were the factors impacting the length of ICU stay of patients (β=0.225, 0.008, 0.237, 0.203, -0.408, -0.334, 0.309, 0.523, 95% CI=0.053-0.502, 0.006-0.010, -0.018-0.457, -0.022-0.428, -0.575--0.241, -0.687--0.018, 0.132-0.486, 0.369-0.678, P<0.1). Multivariate linear regression analysis showed that with respiratory tract infections was the independent risk factor impacting the length of ICU stay of patients (β=0.440, 95% CI=0.278-0.601, P<0.01). Single factor linear regression analysis showed that injury site, injurious factors of inhalation injury (smoke and chemical gas), combined total burn area, degree of inhalation injury (moderate and severe), tracheotomy (no tracheotomy and prophylactic tracheotomy), and respiratory tract infections were the factors impacting mechanical ventilation days of patients (β=-0.300, 0.545, 0.163, 0.005, 0.487, 0.799, -0.791, -0.736, 0.300, 95% CI=-0.565--0.034, 0.145-0.946, 0.051-1.188, 0.001-0.009, 0.127-0.847, 0.436-1.162, -1.075--0.508, -1.243--0.229, 0.005-0.605, P<0.1). Multivariate linear regression analysis showed that smoke inhalation, severe inhalation injury, and respiratory tract infections were the independent risk factors impacting mechanical ventilation days of patients (β=0.210, 0.495, 0.263, 95% CI=0.138-0.560, 0.143-0.848, 0.007-0.519, P<0.05 or P<0.01). Single factor logistic regression analysis showed that age, injury site, combined total burn area (10%-19%TBSA and 20%-29%TBSA), degree of inhalation injury (moderate and severe), tracheotomy (prophylactic tracheotomy and no tracheotomy), and mechanical ventilation were the factors impacting respiratory tract infections of patients (odds ratio=1.079, 0.815, 1.400, 1.331, 1.803, 1.958, 0.990, 0.320, 3.094, 95% CI=0.840-1.362, 0.641-1.044, 1.122-1.526, 1.028-1.661, 1.344-2.405, 1.460-2.612, 0.744-1.320, 0.241-0.424, 2.331-4.090, P<0.1). Multivariate logistic regression analysis showed that with mechanical ventilation was the independent risk factor impacting respiratory tract infections of patients (odds ratio=4.300, 95% CI=2.152-8.624, P<0.01). Conclusions: The patients with inhalation injuries combined with total burn area less than 30%TBSA are mainly young and middle-aged males. Smoke inhalation, degree of inhalation injury, with mechanical ventilation and respiratory tract infections are the factors that affect the outcomes of patients with inhalation injuries combined with total burn area less than 30%TBSA. Additionally, prophylactic tracheotomy shows its potential value in reducing respiratory tract infections in patients with moderate or severe inhalation injuries.
目的： 探讨合并烧伤总面积<30%体表总面积（TBSA）的吸入性损伤患者的流行病学特征及治疗结局。 方法： 对2008年1月—2016年12月海军军医大学第一附属医院收治的符合入选标准的266例合并烧伤总面积<30%TBSA的吸入性损伤患者的病历资料进行回顾性观察性研究。统计患者的性别、年龄、受伤地点、吸入性损伤致伤因素、吸入性损伤严重程度、合并烧伤总面积、气管切开情况、气管切开时间、机械通气情况、是否入住重症监护病房（ICU）、支气管肺泡灌洗液微生物培养结果、总住院天数、住ICU天数、机械通气天数、呼吸道感染情况。采用单因素和多因素线性回归分析筛选影响患者住ICU天数、总住院天数、机械通气天数的危险因素。采用单因素和多因素logistic回归分析筛选影响患者呼吸道感染的危险因素。 结果： 266例患者中男190例、女76例，年龄主要集中在≥21岁且<65岁（217例），常见的受伤地点是密闭空间，吸入性损伤最常见致伤因素是热空气，轻度和中度吸入性损伤较为常见，合并烧伤总面积为9.00%（3.25%，18.00%）TBSA。在111例接受气管切开术的患者中，大部分患者在被送至海军军医大学第一附属医院前接受了气管切开术。本组患者总住院天数为27（10，55）d，160例入住ICU患者住ICU天数为15.5（6.0，40.0）d，109例行机械通气患者机械通气天数为6.0（1.3，11.5）d。119例患者在住院期间发生过呼吸道感染，检出了548株共35种病原体，以革兰阴性菌为主。单因素线性回归分析显示，年龄、吸入性损伤致伤因素、合并烧伤总面积、吸入性损伤严重程度（中度和重度）、气管切开情况、机械通气情况和呼吸道感染情况是患者总住院天数的影响因素（β=-0.198、-0.224、0.021、0.127、0.164、-0.298、0.357、0.447，95%置信区间=-0.397~-0.001、-0.395~-0.053、0.015~0.028、0.009~0.263、0.008~0.319、-0.419~-0.176、0.242~0.471、0.340~0.555，P<0.1）。多因素线性回归分析显示，行机械通气、有呼吸道感染是影响患者总住院天数的独立危险因素（β=0.146、0.383，95%置信区间=0.022~0.271、0.261~0.506，P<0.05或P<0.01）。单因素线性回归分析显示，吸入性损伤致伤因素、合并烧伤总面积、吸入性损伤严重程度（中度和重度）、气管切开情况（未行气管切开术、预防性气管切开术）、机械通气情况、呼吸道感染情况是患者住ICU天数的影响因素（β=0.225、0.008、0.237、0.203、-0.408、-0.334、0.309、0.523，95%置信区间=0.053~0.502、0.006~0.010、-0.018~0.457、-0.022~0.428、-0.575~-0.241、-0.687~-0.018、0.132~0.486、0.369~0.678，P<0.1）。多因素线性回归分析显示，有呼吸道感染是影响患者住ICU天数的独立危险因素（β=0.440，95%置信区间=0.278~0.601，P<0.01）。单因素线性回归分析显示，受伤地点、吸入性损伤致伤因素（烟雾、化学气体）、合并烧伤总面积、吸入性损伤严重程度（中度和重度）、气管切开情况（未行气管切开术、预防性气管切开术）、呼吸道感染情况是患者机械通气天数的影响因素（β=-0.300、0.545、0.163、0.005、0.487、0.799、-0.791、-0.736、0.300，95%置信区间=-0.565~-0.034、0.145~0.946、0.051~1.188、0.001~0.009、0.127~0.847、0.436~1.162、-1.075~-0.508、-1.243~-0.229、0.005~0.605，P<0.1）。多因素线性回归分析显示，吸入烟雾、重度吸入性损伤、有呼吸道感染是影响患者机械通气天数的独立危险因素（β=0.210、0.495、0.263，95%置信区间=0.138~0.560、0.143~0.848、0.007~0.519，P<0.05或P<0.01）。单因素logistic回归分析显示，年龄、受伤地点、合并烧伤总面积（10%~19%TBSA、20%~29%TBSA）、吸入性损伤严重程度（中度和重度）、气管切开情况（预防性气管切开术、未行气管切开术）、机械通气情况是患者呼吸道感染的影响因素（比值比=1.079、0.815、1.400、1.331、1.803、1.958、0.990、0.320、3.094，95%置信区间=0.840~1.362、0.641~1.044、1.122~1.526、1.028~1.661、1.344~2.405、1.460~2.612、0.744~1.320、0.241~0.424、2.331~4.090，P<0.1）。多因素logistic回归分析显示，行机械通气是影响患者呼吸道感染的独立危险因素（比值比=4.300，95%置信区间=2.152~8.624，P<0.01）。 结论： 合并<30%TBSA烧伤总面积的吸入性损伤人群以中青年男性为主。影响合并烧伤总面积<30%TBSA的吸入性损伤患者院内结局的因素包括吸入烟雾、吸入性损伤严重程度、行机械通气、有呼吸道感染。此外，预防性气管切开术在降低中度或重度吸入性损伤患者呼吸道感染中有潜在价值。.