Liu Ning, Gu Qin, Yu Jian-feng
Intensive Care Unit, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu, China.
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue. 2012 Jul;24(7):419-22.
To investigate the influence of positive end-expiratory pressure (PEEP) on hemodynamic and the ability of stroke volume variation (SVV) to predict cardiac preload.
Thirty healthy anesthetized pigs were given tracheal intubation and ventilated. With the envelope method, they were all randomly divided into control group(n = 10), hypovolemia group (n = 10) and hypervolemia group (n = 10). Hypovolemia group were exsanguinated 20% blood volume within 5 minutes, hypervolemia group: additional infusion of hydroxyethyl starch equal to 20% blood volume,and control group: no intervention. In each group, ventilator settings were changed in a randomized order by changing PEEP [0, 5, 10 and 15 cm H(2)O, PEEP0, PEEP5, PEEP10, PEEP15, 1 cm H(2)O = 0.098 kPa]. The changes in hemodynamic parameters, including heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), cardiac index (CI), stroke volume index (SVI), systemic vascular resistance index (SVRI), intrathoracic blood volume index (ITBVI) and SVV, were monitored with a pulse-indicated continuous cardiac output (PiCCO).
In the control group, HR, CVP, SVRI and SVV were evaluated accompanying with the increasing of PEEP, but CI, SVI and ITBVI submitted decreasing tendency. The value reached peaking or valley on the level of PEEP15, and there was significance compared with PEEP0 [HR (bpm): 124 ± 18 vs. 88 ± 12, CVP (mm Hg, 1 mm Hg = 0.133 kPa): 11 ± 1 vs. 8 ± 3, SVRI [kPa×s×L(-1)×m(-2)]: 289.6 ± 81.5 vs. 215.0 ± 79.1, SVV: (23 ± 6)% vs. (11 ± 2)%, CI [L×min(-1)×m(-2)]: 3.1 ± 0.8 vs. 4.3 ± 1.4, SVI [ml×min(-1)×m(-2)]: 26 ± 7 vs. 41 ± 4, ITBVI [ml/m(2)]: 440 ± 43 vs. 491 ± 47, all P < 0.05]. There was no change in MAP. In the hypovolemia group, HR, CVP and SVV were evaluated accompanying with the increasing of PEEP, but MAP, CI, SVI and ITBVI submitted decreasing tendency. The value reached peaking or valley on the level of PEEP15, and there was significance compared with PEEP0 [HR (bpm): 146 ± 31 vs. 115 ± 27, CVP (mm Hg): 11 ± 2 vs. 5 ± 1, SVV: (28 ± 4)% vs. (20 ± 5)%, MAP(mm Hg): 90 ± 26 vs. 115 ± 19, CI [L×min(-1)×m(-2)]: 2.3 ± 0.6 vs. 3.4 ± 1.1, SVI [ml×min(-1)×m(-2)]: 20 ± 6 vs. 31 ± 9, ITBVI [ml/m(2)]: 355 ± 34 vs. 396 ± 53, all P < 0.05]. There was no change in SVRI. In the hypervolemia group, SVV submitted increasing tendency with the increasing of PEEP, but CI, SVI and ITBVI were in the tendency of decreasing, the value reached peaking or valley on the level of PEEP15, and there was significance compared with PEEP0 [SVV: (18 ± 4)% vs. (6 ± 2)%, CI [L×min(-1)×m(-2)]: 4.5 ± 0.9 vs. 5.0 ± 1.2, SVI [ml×min(-1)×m(-2)]: 37 ± 9 vs. 49 ± 7, ITBVI [ml/m(2)]: 473 ± 71 vs. 565 ± 94, all P < 0.05]. There was no change in HR, MAP, CVP and SVRI. SVV was increased in the hypovolemia group compared with control group, and decreased in the hypervolemia group. In the control group, SVV was negatively related to CI on different level of PEEP [r(PEEP0) = -0.831, r(PEEP5) = -0.790, r(PEEP10) = -0.875, r(PEEP15) = -0.560, P < 0.05 or P < 0.01].
SVV was a precise indicator of cardiac preload, however high PEEP may influence hemodynamic and the accuracy of SVV.
探讨呼气末正压（PEEP）对血流动力学的影响以及每搏量变异度（SVV）预测心脏前负荷的能力。
30只健康麻醉猪行气管插管并机械通气。采用套囊法，将其随机分为对照组（n = 10）、低血容量组（n = 10）和高血容量组（n = 10）。低血容量组在5分钟内放血20%血容量，高血容量组：额外输注等于20%血容量的羟乙基淀粉，对照组：不干预。每组中，通过改变PEEP[0、5、10和15 cm H₂O，PEEP0、PEEP5、PEEP10、PEEP15，1 cm H₂O = 0.098 kPa]以随机顺序改变呼吸机设置。采用脉搏指示连续心输出量（PiCCO）监测血流动力学参数的变化，包括心率（HR）、平均动脉压（MAP）、中心静脉压（CVP）、心脏指数（CI）、每搏量指数（SVI）、全身血管阻力指数（SVRI）、胸腔内血容量指数（ITBVI）和SVV。
在对照组中，随着PEEP增加，HR、CVP、SVRI和SVV升高，但CI、SVI和ITBVI呈下降趋势。在PEEP15水平达到峰值或谷值，与PEEP0相比有显著性差异[HR（次/分钟）：124±18 vs. 88±12，CVP（mmHg，1 mmHg = 0.133 kPa）：11±1 vs. 8±3，SVRI[kPa×s×L⁻¹×m⁻²]：289.6±81.5 vs. 215.0±79.1，SVV：(23±6)% vs. (11±2)%，CI[L×min⁻¹×m⁻²]：3.1±0.8 vs. 4.3±1.4，SVI[ml×min⁻¹×m⁻²]：26±7 vs. 41±4，ITBVI[ml/m²]：440±43 vs. 491±47，均P < 0.05]。MAP无变化。在低血容量组中，随着PEEP增加，HR、CVP和SVV升高，但MAP、CI、SVI和ITBVI呈下降趋势。在PEEP15水平达到峰值或谷值，与PEEP0相比有显著性差异[HR（次/分钟）：146±31 vs. 115±27，CVP（mmHg）：11±2 vs. 5±1，SVV：(28±4)% vs. (20±5)%，MAP(mmHg)：90±26 vs. 115±19，CI[L×min⁻¹×m⁻²]：2.3±0.6 vs. 3.4±1. , SVI[ml×min⁻¹×m⁻²]：20±6 vs. 31±9，ITBVI[ml/m²]：355±34 vs. 396±53，均P < 0.05]。SVRI无变化。在高血容量组中，随着PEEP增加，SVV呈上升趋势，但CI、SVI和ITBVI呈下降趋势，在PEEP15水平达到峰值或谷值，与PEEP0相比有显著性差异[SVV：(18±4)% vs. (6±2)%，CI[L×min⁻¹×m⁻²]：4.5±0.9 vs. 5.0±1.2，SVI[ml×min⁻¹×m⁻²]：37±9 vs. 49±7，ITBVI[ml/m²]：473±71 vs. 565±94，均P < 0.05]。HR、MAP、CVP和SVRI无变化。低血容量组SVV高于对照组，高血容量组SVV低于对照组。在对照组中，不同PEEP水平下SVV与CI呈负相关[r(PEEP0) = -0.831，r(PEEP5) = -0.790，r(PEEP10) = -0.875，r(PEEP15) = -0.560，P < 0.05或P < 0.01]。
SVV是心脏前负荷的精确指标，然而高PEEP可能影响血流动力学及SVV的准确性。
