重型颅脑损伤患者机械通气呼气末与动脉血二氧化碳分压关系的对照研究

The correlation between PaCO_2 and PetCO_2 in severe traumatic brain injury patients with mechanical venitilation therapy:a contrast study

目的探讨重型颅脑损伤患者机械通气时呼气末二氧化碳分压(PaCO2)与动脉血二氧化碳分压(PaCO2)的相关性和不同呼气末正压(PEEP)条件下PaCO2与PetCO2差值(ADco2)的变化。方法20例需机械通气的重型颅脑损伤患者,在血流动力学和通气参数稳定后,于机械通气后1、12、24、48、72 h调节PEEP分别为0、5、10、15 cmH2O时同时测定PaCO2。和PetCO2。结果机械通气1 h、PEEP分别为0、5、10、15 cmH2O时PaCO2与PetCO2间均显著相关(分别是r=0.69,P<0.05;r=0.48,P<0.05;r=0.54,P<0.05;r=0.59,P<0.05);机械通气12 h、PEEP为5 cmH2O时,PaCO2与PetCO2间显著相关(r=0.69,P<0.05);PEEP为5cmH2O时PaCO2-PetCO2值最小(除12 h外)。结论PetCO2只能作为机械通气开始时的参考;5 cmH2O可能是此类患者机械通气的最佳PEEP。

Objective To investigate the correlation between end-tidal carbon dioxide tension（ PaCO2 ） and arterial pressure of carbon dioxide（ PaCO2 ） and to evaluate the clinical value of ADco2 （ PaCO2 - PetCO2 ） at various level of positive end expiratory pressure（PEEP） in severe traumatic brain injury（STBI） patients with mechanical ventilation therapy. Methods Twenty patients with STBI received mechanical ventilation. PoCO2 and PetCO2were measured at 1,12,24,48 and 72 hours affter applying mechanical ventilation meanwhile the pressure of PEEP was separately rgeulated 0,5,10,15 cmH2O when the ventilator parameters and the hemodynamic were stable. Results Pa CO2 were significantly correlated with PaCO2 at the PEEP of 0,5,10,15 cmH2O when 1 hour（r=0. 69,P〈0.05;r=0. 48,P〈0.05;r=0. 54,P〈0.05;r=0. 59,P 〈 0.05 respeclivcly） , Pet CO2 were significantly correlated with PaCO2 at the PEEP of 5 cmH2O when 12 hours （ r =0. 58, P 〈 0. 05 ）. ADco2 was the minimum at PEEP of5 cm2O. Condusions PetCO2 could be used as a reference at the beginning in the STBI patients with mechanical ventilaton. 5 cmH2O could be regarded as the most practicable PEEP.