Yang Wan-Jie, Zhao Xue-Feng, Feng Qing-Guo, Wei Kai, Ren Wen-Bo, Cheng Xiu-Ling
Intensive Care Unit, the Fifth Central Hospital of Tianjin, Tianjin 300450, China.
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue. 2011 Apr;23(4):228-31.
To find an accurate and convenient method of measuring end expiratory pulmonary artery wedge pressure (eePAWP) by "expiration holding" function of ventilator and "pulmonary artery wedge pressure (PAWP) Review" software of monitor.
Twelve patients with introduction of pulmonary artery catheter and undergoing mechanical ventilation were selected. Fifty measurements were randomly selected for the comparison of the differences between automatic measurement and expiration holding method in each patient. There were 21 cases underwent single positive pressure ventilation and 29 cases with positive pressure ventilation mixed with spontaneous breathing. All measurements were first divided into <8 mm Hg (1 mm Hg=0.133 kPa) or ≥8 mm Hg groups according to respiratory variability (RV). They were then divided into automatic measurement group and expiration holding group according to PAWP measurement, and the difference in the results between two groups were recorded.
In 21 cases with single positive pressure ventilation, in 12 cases PAWP (mm Hg) of automatic measurement group was higher than that of expiration holding group (12-16 vs. 9-14) when RVP<8 mm Hg, but the difference between two groups was not obvious, and measurements were similar occasionally. In automatic measurement group PAWP (mm Hg) was higher than that of expiration holding group (13-20 vs. 9-15) in 9 cases when RV≥8 mm Hg, the difference was obvious. Neither RVP<8 mm Hg nor RV≥8 mm Hg, the statistical difference was significant (all P<0.01). In 29 cases, when positive pressure ventilation was mixed with spontaneous breathing, RVP<8 mm Hg (n=13), RV≥8 mm Hg (n=16), most of the results in automatic measurement group were higher than those of expiration holding group (11-18 vs. 10-17), and only 4 of them were lower than expiration holding group (11-20 vs. 14-23). There was no statistically significant difference between two groups (all P>0.05).
Expiration holding measurement is a better method that can identify the eePAWP, and it reflects the true hemodynamic status more accurately and quickly whether positive pressure ventilation only or positive pressure ventilation mixed with spontaneous breathing is given.
通过呼吸机的“呼气末屏气”功能及监护仪的“肺动脉楔压（PAWP）回顾”软件，寻找一种准确、便捷的测量呼气末肺动脉楔压（eePAWP）的方法。
选取12例置入肺动脉导管并行机械通气的患者。为比较每位患者自动测量法与呼气末屏气法的差异，随机选取50次测量值。其中21例行单纯正压通气，29例行正压通气联合自主呼吸。所有测量值首先根据呼吸变异性（RV）分为<8 mmHg（1 mmHg = 0.133 kPa）组或≥8 mmHg组。然后根据PAWP测量方法分为自动测量组和呼气末屏气组，记录两组结果的差异。
在21例单纯正压通气患者中，当RV<8 mmHg时，自动测量组12例患者的PAWP（mmHg）高于呼气末屏气组（12 - 16 vs. 9 - 14），但两组差异不明显，偶尔测量值相近。当RV≥8 mmHg时，自动测量组9例患者的PAWP（mmHg）高于呼气末屏气组（13 - 20 vs. 9 - 15），差异明显。无论RV<8 mmHg还是RV≥8 mmHg，差异均有统计学意义（均P<0.01）。在29例正压通气联合自主呼吸患者中，RV<8 mmHg（n = 13），RV≥8 mmHg（n = 16），自动测量组多数结果高于呼气末屏气组（11 - 18 vs. 10 - 17），仅4例低于呼气末屏气组（11 - 20 vs. 14 - 23）。两组间差异无统计学意义（均P>0.05）。
呼气末屏气测量是一种较好的识别eePAWP的方法，无论给予单纯正压通气还是正压通气联合自主呼吸，它都能更准确、快速地反映真实的血流动力学状态。
