新生儿高频振荡通气时呼出气潮气量与动脉二氧化碳分压的研究

摘要

Objective To evaluate the relationship between expiratory tidal volume and PaCO2 during high frequency oscillatory ventilation (HFOV) in neonates. Methods The simultaneous measurement of PaCO2, expiratory tidal volume (VTe), frequency (F), mean airway pressure (MAP), amplitude (ΔP), fraction of inspired oxygen (FiO2) were performed in neonates with severe respiratory distress during HFOV and their correlations were analyzed sequentially. Results PaCO2 and respiratory parameters were measured in 46 patients. The mean gestational age was 36.37±13.53 weeks and mean birth weight was 2.76 ± 7.77 kg. Median VTe/kg in different PaCO2 groups ( ＜ 35 mmHg,35 - 45 mmHg, 46 - 55 mmHg, ＞ 55 mmHg) were 2.20 ml/kg, 1.96 ml/kg, 1.71 ml/kg and 1.21 ml/kg respectively (x2 = 85.74, P ＜ 0.05) and a negative linear correlation was found between VTe/kg and PaCO2 (r = -0.59, P ＜0.05). During normocapnia (PaCO2 35 - 45 mmHg), median VTe/kg in different MAP groups (8 - 10 cmH2O, 11 -13 cmH2O, 14 - 16 cmH2O, ＞ 16 cmH2O) were 1.73 ml/kg, 1.90 ml/kg, 2.19 ml/kg and 2.53 ml/kg, respectively (x2 = 18.96, P ＜ 0.05), and a positive linear correlation was found between VTe/kg and MAP (r = 0.43, P ＜ 0.05).The calculated regression equation for prediction of PaCO2 was: PaCO2 = -13 VTe/kg + 4.32 F + 0.13 FiO2 + 19.68 (r =0.68, r2 = 0.47, P ＜ 0.05). Conclusions There were significantly negative correlation between VTe/kg and PaCO2during HFOV, and positive correlation between VTe/kg and MAP during normocapnia.%目的 探讨新生儿高频振荡通气(HFOV)时呼出气潮气量与动脉二氧化碳分压(PaCO2)变化的关系.方法 对应用HFOV的重症呼吸衰竭新生儿,监测记录PaCO2、呼出气潮气量(VTe)、呼吸机频率(F)、平均气道压(MAP)、振幅(ΔP)及吸入氧浓度(FiO2)等指标,并进行相关性分析.结果 共46例患儿接受HFOV治疗,平均胎龄(36.37 ± 3.53)周,出生体质量(2.76 ± 7.77)kg.不同PaCO2组( ＜ 35 mmHg、35 ～ 45 mmHg、46 ～ 55 mmHg、＞ 55 mmHg)对应VTe/kg平均值分别为(2.20 ± 0.40)ml/kg、(1.96 ± 0.46)ml/kg、(1.71 ± 0.44)ml/kg、(1.21 ± 0.33)ml/kg,组间比较差异有统计学意义(χ2 ＝ 85.74,P ＜ 0.05),Vte/kg与PaCO2呈负相关(r ＝ -0.59,P ＜ 0.05).当PaCO2于正常范围(35 ～ 45 mmHg),MAP为8 ～ 10 cmH2O、11 ～ 13 cmH2O、14 ～ 16 cmH2O、＞ 16 cmH2O时,对应VTe/kg平均值分别为(1.73 ± 0.33)ml/kg、(1.90 ± 0.39)ml/kg、(2.19 ± 0.54)ml/kg、(2.53 ± 0.53)ml/kg,组间比较差异有统计学意义(χ2 ＝ 18.96,P ＜ 0.05),VTe/kg和MAP呈正相关(r ＝ 0.43,P ＜ 0.05).经多元线性回归分析逐步法建立回归方程:PaCO2 ＝ -13 VTe/kg + 4.32 F + 0.13 FiO2 + 19.68(r ＝ 0.68,r2 ＝ 0.47,P ＜ 0.05).结论 新生儿高频振荡通气时VTe/kg与PaCO2呈负相关,PaCO2正常范围时VTe/kg和MAP呈正相关;高频振荡通气时监测VTe可作为调控PaCO2的参考.