Intensive Care Unit, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, 37786University of Thessaly, Larissa, Greece.
Laboratory of Physiology, Faculty of Medicine, School of Health Sciences, 37786University of Thessaly, Larissa, Greece.
Sci Prog. 2022 Apr-Jun;105(2):368504221094161. doi: 10.1177/00368504221094161.
Permissive hypercapnia is commonly used in mechanically ventilated patients to avoid lung injury but its effect on pulmonary artery pressure (PAP) is still unclear, particularly in combination with tidal volume (Vt). Therefore, an study was performed on adult rabbits ventilated with low (9 ml/Kg, LVt group) or high (15 ml/Kg, HVt group) tidal volume (Vt) and alterations in PAP were estimated. Both groups of animals initially were ventilated with FiO 0.3 (Normocapnia-1) followed by inhalation of enriched CO gas mixture (FiCO 0.10) to develop hypercapnia (Hypercapnia-1). After 30 min of hypercapnia, animals were re-ventilated with FiO 0.3 to develop normocapnia (Normocapnia-2) again and then with FiCO 0.10 to develop hypercapnia (Hypercapnia-2). Systolic, diastolic and mean PAP were assessed with a catheter in the pulmonary artery. In HP-1 and HP-2, PaCO increased ( < 0.0001) in both LVt and HVt animals compared to baseline values. pH decreased to ≈7.2 in HP-1 and ≈7.1 in HP -2. In normocapnia, the rise in Vt from 9 to 15 ml/Kg induced an increase in static compliance (Cstat), plateau airway pressure (Pplat) and PAP. Hypercapnia increased PAP in either LVt or HVt animals without significant effect on Cstat or Pplat. A two-way ANOVA revealed that there was not a statistically significant interaction between the effects of hypercapnia and tidal volume on mPAP ( = 0.76). In conclusion, increased Vt induced an increase in Cstat, Pplat and PAP in normocapnia. Hypercapnia increased PAP in rabbits ventilated with low or high Vt but this effect was not long-lasting.
允许性高碳酸血症常用于机械通气患者以避免肺损伤，但它对肺动脉压（PAP）的影响仍不清楚，尤其是与潮气量（Vt）结合时。因此，对接受低（9ml/Kg，LVt 组）或高（15ml/Kg，HVt 组）潮气量（Vt）通气的成年兔进行了一项研究，并评估了 PAP 的变化。两组动物最初均用 FiO 0.3（常氧 1）通气，然后吸入富 CO 气体混合物（FiCO 0.10）以发展高碳酸血症（高碳酸血症 1）。高碳酸血症 1 30 分钟后，动物再次用 FiO 0.3 通气以再次发展为常氧（常氧 2），然后用 FiCO 0.10 发展为高碳酸血症（高碳酸血症 2）。肺动脉导管评估收缩压、舒张压和平均 PAP。在 HP-1 和 HP-2 中，与基础值相比，LVt 和 HVt 动物的 PaCO 升高（ < 0.0001）。在 HP-1 中 pH 降至约 7.2，在 HP-2 中降至约 7.1。在常氧时，Vt 从 9 升至 15ml/Kg 会引起静态顺应性（Cstat）、平台气道压（Pplat）和 PAP 升高。高碳酸血症增加了 LVt 或 HVt 动物的 PAP，但对 Cstat 或 Pplat 无显著影响。双因素方差分析显示，高碳酸血症和潮气量对 mPAP 的影响之间没有统计学显著的相互作用（ = 0.76）。结论：在常氧时，增加 Vt 会导致 Cstat、Pplat 和 PAP 升高。低或高 Vt 通气的兔高碳酸血症增加 PAP，但这种效应不持久。
