根据压力-容积曲线选择理想潮气量对呼吸机护理的指导

目的探讨使用呼吸机时，不同的潮气量对急性肺损伤患者血流动力学、肺通气和肺机械力学的影响及护理要点。方法对ICU急性肺损伤16例患者采取自身对照的方法，利用压力-容积（P．v）曲线下曲点＋0．196kPa确定呼气末正压（PEEP）后，再根据P—V曲线的上拐点（VUIP），分别取上拐点对应的潮气量100％Vt、85％Vt和70％Vt分为3组，以相同的分钟通气量和吸入氧浓度分别给予定容机械通气，监测肺机械力学、血流动力学、血气改变及P—V曲线的变化。结果85％Vt组在心率、中心静脉压、动脉血氧分压、气道峰值压、气道平均压及系统静态顺应性等对患者的综合影响优于100％Vt组和70％Vt组。结论以呼吸系统P-V曲线的下曲点（Pinf）确定PEEP值，以上拐点压力对应的潮气量的85％调节潮气量符合个体化保护性通气策略，对改善肺的顺应性、降低肺病理性损伤效果最好。护理时应注重P—V曲线的变化。

Selection of ideal tidal volume according to pressure- volume curve for instruction of mechanical ventilation nursing

Objective To study the influence of the different tidal volume on hemodynamics,pul- monary ventilation and pulmonary mechanics during mechanical ventilation in patients with acute lung in- jury. Methods To adopt contrast method, making use of the VIIP ＋0.196 kPa of P- V curve to decide PEEP, then according to the VUIP of P- V curve, obtaining the three different data of humidity 100%Vt, 85% Vt and 70 Vt . At the same time, monitoring the change of static compliance, the changing of hemody- namics and P-V curve. Results 85%Vt group was better than 100%Vt group and 70%Vt group in the heart rates, CVP, PaO2,the peak airway pressure（PIP）and mean pressure（Pm）,Cst.PaO/FiO2. Conclu- sions When insuring the PEEP data in low inflection point pressure （Pinf）of breathing system P- V curve, and 85% humidity in upper inflection point pressure, which is in accordance with individual protecting breathing strategy. The curative effect is the best for improving static compliance and decreasing the harm of lung injury. The change of pressure-volume curve should be paid attention to in nursing.