烧伤合并吸入性损伤机械通气第24小时的氧合指数对患者预后的影响

Effect of oxygenation index at the 24th hour of mechanical ventilation on prognosis of patients with burns combined with inhalation injury

目的探讨烧伤合并吸入性损伤患者行机械通气第24小时的氧合指数(OI)对患者预后的影响。方法142例烧伤合并吸入性损伤行机械通气患者,根据第24小时的OI值分为A组[OI≤200 mm Hg(1 mm Hg=0.133 kPa),36例]、B组(200 mm Hg<OI≤300 mm Hg,46例)、C组(OI>300 mm Hg,60例)。比较三组一般资料及预后情况;依据预后情况将患者分为预后不良组(86例)与预后良好组(56例)。采用单因素和多因素Logistic回归分析烧伤合并吸入性损伤机械通气患者预后不良的危险因素。结果三组年龄、烧伤总面积(TBSA)、机械通气前氧分压(PaO_(2))、二氧化碳分压(PaCO_(2))、血氧饱和度(SaO_(2))及预后情况比较,差异具有统计学意义(P<0.05)。C组年龄(40.07±21.20)岁小于A组的(54.64±17.83)岁和B组的(51.72±17.99)岁(P<0.05);B组TBSA(60.43±29.04)%和C组TBSA(62.89±24.85)%小于A组的(74.14±21.90)%,预后不良率54.3%、48.3%低于A组的88.9%(P<0.05)。机械通气前,A组和B组PaO_(2)水平显著低于C组,PaCO_(2)高于C组(P<0.05);B和C组SaO_(2)高于A组(P<0.05)。三组机械通气开始时间、三度烧伤面积及入院延迟复苏情况比较差异无统计学意义(P>0.05)。预后不良组与预后良好组患者的年龄、TBSA、机械通气后第24小时OI比较差异具有统计学意义(P<0.05);预后不良组与预后良好组患者的机械通气开始时间、机械通气时间及机械通气前PaO_(2)、PaCO_(2)、SaO_(2)比较差异无统计学意义(P>0.05)。将筛选出P<0.05的因素纳入多元Logistic回归分析,排除混杂因素后,结果显示:机械通气后第24小时OI≤200 mm Hg、TBSA大、老年是烧伤合并吸入性损伤行机械通气患者预后不良的独立危险因素(OR=5.551、1.046、10.187,P<0.05)。结论机械通气第24小时OI≤200 mm Hg的烧伤合并吸入性损伤患者预后不良,TBSA越大,机械通气前PaO_(2)及SaO_(2)越低,通气后第24小时的OI可能越低。

Objective To investigate the effects of oxygenation index(OI)at 24th hour of mechanical ventilation on prognosis of patients with burns combined with inhalation injury.Methods A total of 142 patients with burns combined with inhalation injury who received mechanical ventilation were divided into group A[OI≤200 mm Hg(1 mm Hg=0.133 kPa),36 cases],group B(200 mm Hg<OI≤300 mm Hg,46 cases),and group C(OI>300 mm Hg,60 cases)according to their 24-h OI value.The general information and prognosis of the three groups were compared.According to the prognosis,the patients were divided into poor prognosis group(86 cases)and good prognosis group(56 cases).Univariate and multivariate Logistic regression were used to analyze the risk factors of poor prognosis in mechanical ventilation patients with burns and inhalation injury.Results There were significant differences in age,total body surface area(TBSA),arterial partial pressure of oxygen(PaO_(2)),arterial partial pressure of carbon dioxide(PaCO_(2)),blood oxygen saturation(SaO_(2))before mechanical ventilation and prognosis among the three groups(P<0.05).The age of(40.07±21.20)years in group C was lower than(54.64±17.83)years in group A and(51.72±17.99)years in group B(P<0.05).TBSA was(60.43±29.04)%in group B and(62.89±24.85)%in group C,which were lower than(74.14±21.90)%in group A;the poor prognosis rates of group B were 54.3%and 48.3%,which was lower than 88.9%in group A(P<0.05).Before mechanical ventilation, PaO_(2) level in group A and group B was significantly lower than that in group C, and PaCO_(2) was higher than that in group C (P<0.05). SaO_(2) in group B and group C was higher than that in group A (P<0.05). There was no statistically significant difference in the comparison of start time of mechanical ventilation, third-degree burn area and delayed resuscitation on admission among the three groups (P>0.05). There were significant differences in age, TBSA and OI at the 24th hour of mechanical ventilation between the poor prognosis group and the good prognosis group (P<0.05). There was no significant difference in the start time of mechanical ventilation, duration of mechanical ventilation and PaO_(2), PaCO_(2) and SaO_(2) before mechanical ventilation between the poor prognosis group and the good prognosis group (P>0.05). Factors with P<0.05 were selected into multiple Logistic regression analysis, and confounding factors were excluded. The results showed that OI≤200 mm Hg at 24th hours after mechanical ventilation, large TBSA and old age were independent risk factors for poor prognosis in patients with burns and inhalation injury receiving mechanical ventilation (OR=5.551, 1.046, 10.187;P<0.05). Conclusion Patients with burns combined with inhalation injury who have an OI ≤200 mm Hg at the 24th hour of mechanical ventilation have a poor prognosis. The larger the TBSA is, the lower the PaO_(2) and SaO_(2) before mechanical ventilation, and the lower the OI at the 24th hour of ventilation might be.