Mazurok Vadim, Kasherininov Igor, Bautin Andrey, Kulemina Olga, Rzheutskaya Ryta
Almazov National Medical Research Centre, Akkuratova St, 2, Saint Petersburg 197341, Russia.
Crit Care Res Pract. 2021 Mar 23;2021:6617809. doi: 10.1155/2021/6617809. eCollection 2021.
This study compared the hemodynamic effects and gas exchange under several different ventilator settings-with regard to tidal volume, respiratory rate, and end-expiratory pressure-in patients after coronary artery bypass grafting (CABG).
Prospective interventional cohort study with a controlled group in a single cardiosurgical ICU involving 119 patients following on-pump CABG surgery. During the 1st postoperative hour, the intervention group patients were ventilated with Vt 10 ml × kg, RR 14/min, PEEP 5 cmHO ("conventional ventilation"). During the 2nd hour, RR was reduced to 8/min ("reduced RR ventilation"). At 3 hrs, Vt was decreased to 6 ml × kg, RR returned to 14/min, and PEEP increased to 10 cmHO ("low Vt-high PEEP ventilation").
Patients in the "low Vt-high PEEP" ventilation period showed significantly lower alveolar ventilation and thoraco-pulmonary compliance than during "reduced RR" ventilation. Mean airway pressure and Vds/Vt peaked during low Vt-high PEEP ventilation; however, driving pressure was lower. Vt decrease and PEEP increase did not lead to oxygenation improvement and worsened CO elimination. Hemodynamically, the study revealed significant cardiac output decrease during low Vt-high PEEP ventilation. In 23.2% of patients, catecholamine therapy was initiated.
In postoperative cardiosurgical patients, MV with Vt 6 ml × kg and PEEP 10 cm HO is characterized by worsened oxygenation and elimination of CO and a less favorable hemodynamic profile than ventilation with Vt 10 ml × kg and PEEP 5 cmHO. . (i) Patients after CABG may be especially sensitive to low tidal volume and increased PEEP as it negatively affects hemodynamic profile by means of the right heart preload decrease and afterload increase. (ii) Mechanical ventilation settings aiming to minimize mean airway pressure reduce the negative effects of positive inspiratory pressure and are favorable for hemodynamics.
本研究比较了冠状动脉搭桥术（CABG）后患者在几种不同通气设置下（潮气量、呼吸频率和呼气末压力）的血流动力学效应和气体交换情况。
在一家心脏外科重症监护病房进行的前瞻性干预队列研究，设有对照组，纳入119例体外循环冠状动脉搭桥术患者。术后第1小时，干预组患者采用潮气量10 ml×kg、呼吸频率14次/分钟、呼气末正压5 cmH₂O进行通气（“传统通气”）。第2小时，呼吸频率降至8次/分钟（“降低呼吸频率通气”）。3小时时，潮气量降至6 ml×kg，呼吸频率恢复至14次/分钟，呼气末正压增至10 cmH₂O（“低潮气量-高呼气末正压通气”）。
“低潮气量-高呼气末正压”通气期患者的肺泡通气和胸肺顺应性显著低于“降低呼吸频率”通气期。平均气道压力和无效腔量/潮气量在低潮气量-高呼气末正压通气时达到峰值；然而，驱动压力较低。潮气量降低和呼气末正压增加并未改善氧合，反而使二氧化碳清除恶化。在血流动力学方面，研究显示低潮气量-高呼气末正压通气期间心输出量显著降低。23.2%的患者开始使用儿茶酚胺治疗。
在心脏外科术后患者中，与潮气量10 ml×kg、呼气末正压5 cmH₂O通气相比，潮气量6 ml×kg、呼气末正压10 cmH₂O的机械通气表现为氧合和二氧化碳清除恶化，血流动力学状况较差。（i）冠状动脉搭桥术后患者可能对低潮气量和呼气末正压增加特别敏感，因为这会通过降低右心前负荷和增加后负荷对血流动力学状况产生负面影响。（ii）旨在使平均气道压力最小化的机械通气设置可降低吸气正压的负面影响，有利于血流动力学。
