慢性阻塞性肺疾病急性加重机械通气治疗后酸碱平衡状态及电解质的变化

目的 研究机械通气后代谢性碱中毒及电解质紊乱的发生状况,探讨恰当的处理方法,旨在提高慢性阻塞性肺疾病急性加重(AECOPD)机械通气技术的临床应用水平,并提高AECOPD抢救的成功率和改善慢性阻塞性肺疾病(COPD)患者的预后.方法 回顾性分析伴Ⅱ型呼吸衰竭的AECOPD并使用机械通气的患者62例,并分为无创通气(35例)和有创通气(27例)二组,观察比较二组患者使用机械通气前、机械通气后1h、2h、3h、24 h、72 h及通气结束后的动脉血气及Na+、K+、Ca2+变化.结果 二组患者使用机械通气后呼吸性酸中毒明显改善.无创通气组通气3h时出现6例失代偿期碱中毒(17.14％),通气72 h后有22例(62.86％)患者出现代谢性碱中毒(包括代偿期和失代偿期),其中失代偿期碱中毒7例(25.93％),达碱中毒高峰.有创通气组在通气2h出现7例失代偿期碱中毒(25.93％),通气3h后即出现21例(77.77％)代谢性碱中毒,其中失代偿期碱中毒9例(33.33％).二组在通气前Na+低于正常,且K+高于正常值,通气结束后恢复正常.比较24h时碱中毒者与无酸碱平衡紊乱者的电解质,发现碱中毒者K+、Ca2+低于无酸碱紊乱者.结论 机械通气用于治疗伴Ⅱ型呼吸衰竭的AECOPD患者疗效肯定.机械通气后由于二氧化碳排出过快往往导致高碳酸血症呼出后代谢性碱中毒的发生,同时引起电解质钾、钙的降低.有创机械通气较无创机械通气代谢性碱中毒出现早.

Acid-base balance and electrolyte changes in patients with acute exacerbation of chronic obstructive pulmonary disease after mechanical ventilation

Objective To explore the acid-base balance and electrolyte changes caused by mechanical ventilation, to improve the level of application of mechanical ventilation technology. It was important to improve the survival rate of acute exacerbation of chronic obstructive pulmonary disease （AECOPD） and chronic obstructive pulmonary disease （COPD） prognosis. Methods A retrospective analysis of 62 patients with AECOPD associated with type Ⅱ respiratory failure which were treated using mechanical ventilation was carried out. 35 patients of AECOPD were treated with the non-invasive mechanical ventilation and 27 patients were treated with invasive mechanical ventilation. Observation and comparison of arterial blood gas and ion sodium, potassium, calcium were made before using mechanical ventilation and after using mechanical ventilation for 1 hour, 2 hours, 3 hours, 24 hours, 72 hours and end ventilation. The acid-base balance status and electrolyte changes were summarized in patients before and after using mechanical ventilation. Results There were significantly improved in the arterial blood pH, PaO2, PaCO2, PaO2/FiO2 and SaO2 in 2 groups of patients compared with before and after using mechanical ventilation （ P 〈 0.05 ）. After 3 h ventilation, there were 6 cases（ 17. 14% ） of decompensated metabolic alkalosis occurred and after 72 h ventilation, 22 cases （62.86%） metabolic alkalosis （including compensatory and decompensated） were occurred including 7 cases （25.93%） decompensated alkalosis which achieved the peak of alkalosis incidence in non-invasive ventilation group. After 2 h ventilation, there were 7 cases （25.93 % ） of decompensated metabolic alkalosis occurred, and 21 cases （77.77%） metabolic alkalosis occurred after 3 h ventilation which included decompensated alkalosis 9 cases （33.33%） in invasive ventilation group. There were lower Na^＋ and higher K^＋ before ventilated, however Na^＋ and K ^＋ were restored to normal after ventilation in both group. There were lower Na^＋ and lower K ＋ in alkalosis patients compared with no acid-base balance disorder patients. Conclusions Mechanical ventilation for the treatment of AECOPD associated with the type II respiratory failure that efficacy in patients is sure. Mechanical ventilation often led to metabolic alkalosis after hypercapnia exhaled, due to excessive discharge of carbon dioxide, also caused electrolyte potassium, calcium reduced. The metabolic alkalosis occurred earlier in invasive mechanical ventilation compared with noninvasive mechanical ventilation.