儿童膈肌疲劳的诊断研究

Diagnostic study on children′s diaphragmatic fatigue

目的 分析胸腹非同步呼吸运动 ,诊断膈肌疲劳。方法 采用电阻抗呼吸图仪 ,观察53例有非同步呼吸运动的患儿胸腹运动曲线是否同步、主波方向是否一致 ,并计算胸腹运动曲线峰值错位时间与呼吸周期的比值 (M值 )。再以腹部阻抗值为X轴 ,胸部阻抗值为Y轴 ,描绘胸腹呼吸运动曲线二维图和最大X值到最小X值连线与X轴的夹角α值。并检测动脉血气及监测呼吸和心率的变化。结果 (1 )一维图M值和二维图α值之间存在十分显著的正相关关系 (r =0 956 ,P <0 0 0 1 ) ,非同步呼吸运动可分为三型 :①膈肌疲劳Ⅰ型 :一维图呈胸腹部矛盾呼吸运动曲线 ,M值为(48 1± 4 4) % ,二维图顺时针方向运行 ,α值为 (1 38 3± 1 5 0 )°;②膈肌疲劳Ⅱ型 :一维图呈现胸腹呼吸运动曲线峰值错位 ,M值为 (1 6 5± 4 7) % ,二维图为逆时针方向运行 ,α值为 (55 3± 1 0 8)° ;③膈肌疲劳Ⅲ型 :一维图呈腹部双峰型曲线 ,M值为 0 ,二维图呈“8”字型双环 ,α值为 (41 3± 3 8)°。 (2 )动脉血pH、PCO2 在Ⅰ型、Ⅱ型与Ⅲ型或对照组组间相比差异均有非常显著性 (P分别 <0 0 0 1 ) ,而Ⅲ型与对照组相比差异无显著性 (P >0 0 5)。 (3)呼吸频率和心率无论在Ⅰ型、Ⅱ型或Ⅲ型均高于对照组 (P分别 <0 0 0 1 ) 。

Objective In the recent twenty years, the diaphragmatic contraction, relaxation functions and electric activity have been explored through electromyography (EMG) and transdiaphragmatic pressure (Pdi) determination But these techniques required some complex and expensive instruments, so the diagnosis and treatment of children′s diaphragmatic fatigue have not been well evaluated The present study explored the diagnosis of children′s diaphragmatic fatigue through measuring ribcage abdomen motion and analyzed its asynchrony Methods Fifty three children (male 37, female 16, and age rage from 1 months to 9 years) with respiratory rate>30 breaths/min, heart rate >110 beats/min, and respiratory dysfunction had asynchronized ribcage abdomen motion showed by impedance respirograph (IRG) The authors observed whether ribcage abdomen motion was synchronic and calculated M levels (staggered peak time /total duration of the breathing cycle) The ribcage and abdomen outputs were displayed on vertical (for rib cage) and horizontal (for abdomen) axes of X Y instrument In addition, the change of respiratory frequency and heart rate was observed and arterial blood gas analysis was also performed Results (1) M levels in one dimensional IRG were positively correlated with alpha angle in two dimensional IRG ( r =0 956, P <0 001 ) Asynchronized respiratory motions could be divided into three types type Ⅰ showed completely contra directional movements of respiration, M levels for (48 1 ±4 4)%, an irregularly clockwise loop in the two dimensional IRG, and alpha angle for (138 3±15 0) degrees In type Ⅱ, one dimensional IRG showed displaced peak of the chest and abdomen motion curves, M levels were(16 5±4 7)%, two dimensional IRG was displaced in a counterclockwise direction, and alpha angle was (55 3±10 8) degrees In type Ⅲ, abdominal motion curve of one dimensional IRG had double peaks, M levels were 0, two dimensional IRG was presented as 8 shaped double circles, alpha angle was (41 3±3 8)degrees; (2) pH levels in the patients with type Ⅰand type Ⅱ diaphragmatic fatigue were significantly lower, and PCO 2 levels were significantly higher than those with type Ⅲ or in the normal subjects ( P <0 001 for all), but there was no statistically significant difference between type Ⅲ and the normal subjects ( P >0 05); (3) Both of respiratory rate and heart rate in type Ⅰ, type Ⅱ and type Ⅲ were higher than those in the normal subjects (all P <0 001), and the differences among the three types were significant ( P <0 001 for all); (4) Both M levels and alpha angle were negatively correlated with pH levels ( r =-0 514, P <0 001 and r =-0 497, P <0 001 ), while positively correlated with PCO 2 levels ( r =0 672, P <0 001 and r =0 625, P =0 01).Conclusions (1) IRG can be reliably used to diagnose children′s diaphragmatic fatigue This technique is simple and easy to perform and non invasive It is therefore worthy of recommending for further clinical investigations (2) According to the characteristics of IRG, diaphragmatic fatigue can be divided into three types (3) The development of children′s diaphragmatic fatigue has a series of characteristic changes (4) To avoid the patients suffering from respiratory failure, it is the key time to adopt the policies of prevention and treatment when IRG shows signs of type Ⅲdiaphragmatic fatigue