背景:呼气末正压(PEEP)是机械通气改善呼吸衰竭危重患者氧合的重要组成部分。腹部和胸腔压力之间的相互作用是众所周知的。尤其是在腹内高压中,较低的PEEP可通过反复打开和关闭肺泡而引起肺静脉损伤。
目的:在本研究中,本研究旨在研究根据腹内压(IAP)调整PEEP对氧合的影响,并阐明可能的危害.
方法:18岁以上的患者因低氧性呼吸衰竭而机械通气,IAP正常(<15mmHg)纳入研究。排除严重心血管功能障碍患者。应用以下PEEP水平:PEEPzero为0cmH2O,PEEPIAP/2=IAP的50%,PEEPIAP=IAP的100%。经过30分钟的平衡期,测量动脉血气和平均动脉压。
结果:本研究招募了138名患者(平均年龄66.5±15.9,56.5%为男性)。平均IAP为9.8±3.4。79%的患者PaO2/FiO2比值低于300mmHg。图1显示了PaO2/FiO2比率的变化,PaCO2,PPlato,根据PEEP水平和患者的MAP。在PaO2/FiO2比值(P<0.001)和Pplato(P<0.001)中检测到总体增加,而PaCO2和MAP在逐渐增加PEEP后没有变化。配对分析显示PEEPzero(186.4[85.7-265.8])和PEEPIAP/2(207.7[101.7-292.9])之间的PaO2/FiO2差异(t=-0.77,P<0.001),基线和PEEPIAP(236.1[121.4-351.0])之间(t=-1.7,P<0.001),在PEEPIAP/2和PEEPIAP之间(t=-1.0,P<0.001)。柏拉图压力在所有三个PEEP水平(PEEPzero=12[10-15],PEEPIAP/2=15[13-18],PEEPIAP=17[14-22])。
结论:在急性低氧性呼吸衰竭和机械通气的患者中,根据IAB进行PEEP调整可改善氧合,特别是在缺乏其他PEEP滴定方法的有限来源的环境中。
BACKGROUND: Positive end-expiratory pressure (PEEP) is a crucial component of mechanical ventilation to improve oxygenation in critically ill patients with respiratory failure. The interaction between abdominal and thoracic compartment pressures is known well. Especially in intra-abdominal hypertension, lower PEEP may cause atelectotrauma by repetitive opening and closing of alveoli.
OBJECTIVE: In this study, it was aimed to investigate the effect of PEEP adjustment according to the intra-abdominal pressure (IAP) on oxygenation and clarify possible harms.
METHODS: Patients older than 18 were mechanically ventilated due to hypoxemic respiratory failure and had normal IAP (<15 mmHg) included in the study. Patients with severe cardiovascular dysfunction were excluded. The following PEEP levels were applied: PEEPzero of 0 cmH2O, PEEPIAP/2 = 50% of IAP, and PEEPIAP = 100% of IAP. After a 30-minute equilibration period, arterial blood gases and mean arterial pressures were measured.
RESULTS: One hundred thirty-eight patients (mean age 66.5 ± 15.9, 56.5% male) enrolled on the study. The mean IAP was 9.8 ± 3.4. Seventy-nine percent of the patients\' PaO2/FiO2 ratio was under 300 mmHg. Figure 1 shows the change in PaO2/FiO2 ratio, PaCO2, PPlato, and MAP of the patients according to the PEEP levels. Overall increases were detected in the PaO2/FiO2 ratio (P < 0.001) and Pplato (P < 0.001), while PaCO2 and MAP did not change after increasing PEEP gradually. Pairwise analyses revealed differences in PaO2/FiO2 between PEEPzero (186.4 [85.7-265.8]) and PEEPIAP/2 (207.7 [101.7-292.9]) (t = -0.77, P < 0.001), between baseline and PEEPIAP (236.1 [121.4-351.0]) (t = -1.7, P < 0.001), and between PEEPIAP/2 and PEEPIAP (t = -1.0, P < 0.001). Plato pressures were in the safe range (<30 cmH2O) at all three PEEP levels (PEEPzero = 12 [10-15], PEEPIAP/2 = 15 [13-18], PEEPIAP = 17 [14-22]).
CONCLUSIONS: In patients with acute hypoxemic respiratory failure and mechanically ventilated, PEEP adjustment according to the IAB improves oxygenation, especially in the settings of the limited source where other PEEP titration methods are absent.