比例辅助通气和同步间歇指令通气治疗幼兔重度胎粪吸入综合征的相关参数水平

Changes of Relevant Parameters of Proportional Assist Ventilation and Synchronized Intermittent Mandatory Ventilation in Young Rabbits with Severe Meconium Aspiration Syndrome

目的观察比例辅助通气(PAV)和同步间歇指令通气(SIMV)治疗幼兔重症胎粪吸入综合征(MAS)时相关参数的变化。方法将30只20～30 d日龄健康日本大耳兔随机分为4组:(1)PAV组(n=8),灌入胎粪混悬液后予PAV通气;(2)SIMV组(n=8),灌入胎粪后实施SIMV通气;(3)MAS组(n=8),胎粪灌入后不予通气但予持续氧气(500 mL·L-1)吸入;(4)对照组(n=6),灌入9 g·L-1盐水后予持续氧气(500 mL·L-1)吸入。分别于灌注前、灌注后0.5 h及通气1 h、2 h、3 h、4 h、5 h、6 h、7 h、8 h记录各组循环参数及呼吸力学参数,包括心率、呼吸频率、潮气量、呼吸道峰压(PIP)、平均呼吸道压(MAP)。灌注前(0点)和灌注后0.5 h(0'点)、通气4 h及通气8 h检测动脉血气,并计算动脉/肺泡氧分压比值(a/APO2)。结果 PAV组和SIMV组4 h、8 h动脉血二氧化碳分压在正常范围;PAV组和SIMV组4 h、8 h a/APO2值均较0'点升高(Pa<0.05);PAV组与SIMV组在各时间点a/APO2值差异均无统计学意义(Pa>0.05);在通气过程中,SIMV组PIP及MAP较PAV组高,差异均有统计学意义(Pa<0.05)。PAV组和SIMV组心率相近,各时间点变化不大,差异无统计学意义(P>0.05)。结论 PAV能在较短时间内有效改善幼兔重度胎粪吸入时肺部氧合状态;在取得同样的血气值和氧饱和度情况下,与SIMV相比,PAV治疗幼兔MAS时PIP及MAP较低;PAV对幼兔重度胎粪吸入时的心率影响较小。

Objective To observe the changes in relevant parameters of proportional assist ventilation （PAV） and synchronized intermit- tent mandatory ventilation （SIMV） in young rabbits with severe meconium aspiration syndrome （MAS）. Methods Thirty newborn Japanese big ear young rabbits （20 - 30 days old） were randomly divided into 4 groups ： （ 1 ） PAV group （ n = 8 ）, supported by PAV after meconium as- piration ; （2） SIMV group （ n = 8 ）, supported by SIMV after meconium aspiration ; （ 3 ） MAS group （ n =8 ） ,without ventilation but received continuous oxygen （500 mL . L- 1 ） inhalation after meconium aspiration ; （4） Control group （ n = 6）, receiving continuous oxygen （500 mL . L-1 ） inhalation was received after saline aspiration. Related parameters recorded before （point 0） and 0.5 h after inhaled （point 0 ′）, and at 1 h,2 h,3 h,4 h,5 h,6 h,7 h,8 hours of ventilation,including heart rate,breathing rate,tidal volume,peak airway pressure and mean airway pressure were investigated. The arterial blood gas was detected before and after 0.5 h irrigation ,4 h and 8 h after ventilation,t,nd the arterial/ alveolar oxygen ratio （ a/APO2 ） was calculated. Results Partial pressure of arterial carbon dioxide in PAV group and SIMV group at 4 h,8 h time points were in the normal range. The a/APO2 values in PAV group and SIMV group at 4 h, 8 h were higher than those in point 0′（ Pa 〈 0.05 ） ; There was no statistically significant difference in a/APO2 values at each point of time between the PAV group and SIMV group（ Pa〉 0.05 ）. During the ventilation, peak airway pressure and mean airway pressure in SIMV group were higher than those in PAV group, the diffe- rences at each time point were statistically significant （P 〈 0.05 ）. HR in SIMV group and MAS group were similar,the differences were not statistically significant at each time point （ Pa 〉 0.05 ）. Conclusions PAV can improve oxygenation state of lung in young rabbits with severe MAS effectively in a short term. Compared with SIMV, PAV has lower peak airway pressure and mean airway pressure when treated in young rabbits with severe MAS. PAV has little influence on heart rate of the young rabbits with severe MAS.