不同方法滴定呼气末正压对急性呼吸窘迫综合征患者循环动力学的影响

The hemodynamic influence of positive end expiratory pressures titrated by different methods on patients with acute respiratory distress syndrome

目的探讨不同方法滴定呼气末正压(PEEP)对急性呼吸窘迫综合征(ARDS)患者循环动力学的影响。方法采用单中心前瞻性自身对照观察性方法,选择早期中重度ARDS患者,先予以患者充分肺复张,然后在PEEP递减过程中分别使用最佳氧合法、最佳顺应性法和最小死腔分数法为患者滴定最佳PEEP,分别观察不同的PEEP对患者呼吸力学、血气分析结果和循环动力学的影响。结果共纳入符合标准的患者19例,其中男13例,女6例,年龄(49±11)岁。急性生理学与慢性健康状况评分系统Ⅱ评分为(20.8±6.41)分,中度ARDS 12例、重度ARDS 7例。最佳氧合法所滴定的PEEP水平为(16.7±3.7)cm H_2O,显著高于患者的基线水平(5.0±0.0)cm H_2O、最佳顺应性法(10.9±2.9)cm H_2O和最小死腔分数法(11.5±3.8)cm H_2O的水平(P<0.05)。在各方法滴定的PEEP水平下,最佳氧合法得到的氧合指数即动脉血氧分压/吸氧浓度为(313.7±88.5)mm Hg,显著高于基线水平(151.7±49.2)mm Hg,最佳顺应性法(268.6±92.6)mm Hg和最小死腔分数法的(261.7±71.4)mm Hg(P<0.05);但对肺静态顺应性[(49.7±12.25)m L/cm H2O]和死腔分数即死腔潮气量/呼出潮气量[(58.9±15.87)%]的改善不如最佳顺应性法[(63.3±9.88)m L/cm H2O和(53.3±11.63)%]和最小死腔分数法[(62.5±14.73)m L/cm H_2O和(50.1±9.41)%](P<0.05);与最佳顺应性法和最小死腔分数法相比,最佳氧合法会导致明显升高的中心静脉压[(18.6±5.9)cm H_2O vs(14.8±3.8)cm H_2O vs(15.1±3.7)cm H_2O,P<0.05],明显下降的心输出量(CO)[(3.81±1.32)L/min vs(4.28±0.99)L/min vs(4.32±1.44)L/min,P<0.05]和氧输送(DO_2)[(472.1±133.78)mL/min vs(501.8±99.89)mL/min vs(509.4±103.47)mL/min,P<0.05],但心率[(95.3±9.5)次/min vs(91.9±8.6)次/min vs(90.7±12.7)次/min],平均动脉压[(64.9±14.4)mm Hg vs(73.4±12.6)mmHg vs(73.3±7.8)mmHg]和中心静脉血氧饱和度[(67.74±10.26)%vs(70.53±11.54)%vs(68.87±15.64)%]在3种方法之间比较差异无统计学意义(P>0.05)。结论最佳氧合法所滴定的PEEP水平最高,但显著降低CO和DO_2,而最佳肺顺应性法和最小死腔通气法滴定的PEEP水平较低,但对患者CO和DO_2无显著性影响,临床医师对ARDS患者进行PEEP滴定时需充分考虑其对循环动力学的影响。

Objective To investigate the hemodynamic influence of positive end expiratory pressures （PEEPs） titrated by different methods on patients with acute respiratory distress syndrome （ARDS）. Methods A prospective self- control observational study was conducted. Moderate to severe ARDS patients in the early stage were enrolled from June 2014 to June 2016, who received recruitment maneuver and followed by a decremented PEEP trail, so as the optimal PEEPs were titrated using optimal oxygenation, best static pulmonary compliance and the lowest dead space fraction meth- ods. The parameters of respiratory mechanics, blood gas analysis and hemodynamic were observed. Results Totally 19 patients were enrolled accoMing to the criteria （13 male） , with age of 49± llyears old, acute physiology and chronic health evaluation Ⅱ （APACHE Ⅱ ） score of 20. 8 ±6. 41. Among them, 12 patients were moderate ARDS and 9 were severe ARDS. The optimal PEEP titrated by optimal oxygenation （16. 7 ±3. 7 cmH20） was significantly higher than the baseline （5.0 ± 0.0 cmH20）, and the PEEPs titrated by best static pulmonary compliance （10. 9± 2. 9 cmH2O） and lowest dead space fraction （ 11.5 ±3.8 cmH2O） （P 〈0. 05）. The optimal PEEP titrated by best oxygenation resulted in significant higher PaO2/FiO2 （313.7 ± 88.5 mmHg） than the baseline （ 151.7± 49. 2 mmHg）, and those using PEEPs titrated by best static pulmonary compliance （268.6 292. 6 mmHg） and lowest dead space fraction （261.7 ±71.4 mmHg） （P 〈 0. 05 ） ; also significant lower pulmonary compliance （Cst） （49. 7± 12. 25 mL/cmH2 O） and higher dead space fraction （Vd/Vt） （58.9 ± 15.87% ） than those using best static pulmonary compliance method （63.3 ±9. 88 mL/cmH2O and 53.3 2 11.63% ） and lowest dead space fraction method （ 62. 5 ± 14. 73 mL/cmH2O and 50. 1 ± 9.41% ） （P 〈 0. 05 ）. Compared with using best static pulmonary compliance method and lowest dead space fraction method, using best oxygenation method could result in significant increased CVP （18.6 ±5.9 vs. 14. 8 23.8 and 15.1 23.7 cmH2O, P 〈 0. 05） , decreased cardiac output （CO） （3.81± 1.32 vs. 4. 28 20. 99 and 4. 32 ±1.44 L/rain, P 〈0. 05） and delivery oxygen （DO2 ） （472. 1 ± 133.78 vs. 501.8 ±99. 89 and 509.4± 103.47 mL/min, P 〈0. 05）. There was no significant difference in heart rate （HR） （95. 3 ±9. 5 vs. 91.9 28. 6 and 90. 7 2 12. 7 bpm）, mean artery pressure （MAP） （64. 9 ± 14.4 vs. 73.4 2 12. 6 and 73.3 2 7.8 mmHg） or central venous saturation （ ScvO2 ） （67.74± 10. 26 vs. 70.53 2 11.54 and 68.87 ± 15.64% ） among the 3 methods （ all P 〉 0. 05 ）. Conclusion The optimal PEEP titrated by best oxygena- tion method is the highest one, but significantly reduces the CO and DO2. The optimal PEEPs titrated by best static pul- monary compliance and the lowest dead space fraction are lower but do not influence the CO and DO2 in ARDS patients.