Mayers I, Long R, Breen P H, Wood L D
Anesthesiology. 1986 Jun;64(6):739-46. doi: 10.1097/00000542-198606000-00011.
The authors studied the abnormalities of gas exchange and lung mechanics in a canine model of bronchopleural fistula during intermittent positive pressure ventilation (IPPV) and high-frequency oscillatory ventilation (HFOV). The left lower lobe bronchus was opened to atmosphere and it was determined that end expired volume was best maintained at frequencies of 45-50 breaths/min. during IPPV. Comparing alternating periods of IPPV and HFOV in six dogs (Group I) at matched airway opening pressure (Pao), we found that Pao2 decreased significantly to 68 +/- 14 mmHg and 69 +/- 24 mmHg, respectively, on opening the fistula. In a second group of six dogs (Group 2), when Pao was increased by additional bias flow into the ventilatory circuit during both IPPV and HFOV, Pao2 increased significantly to 89 +/- 12 mmHg and 87 +/- 8 mmHg, respectively. Repeating Group 2 studies after induction of oleic acid low-pressure pulmonary edema demonstrated that conventional IPPV was associated with large intrapulmonary shunts. HFOV, however, maintained gas exchange at near baseline values. For both Group 1 and Group 2, the calculated gas flow through the fistula was significantly less at all levels of airway pressure during HFOV. The authors conclude that HFOV offers advantages over conventional IPPV in the maintenance of oxygenation and in the reduction of gas leak through the fistula.
作者研究了支气管胸膜瘘犬模型在间歇正压通气（IPPV）和高频振荡通气（HFOV）期间的气体交换和肺力学异常。左下叶支气管开放与大气相通，结果显示在IPPV期间，呼气末容积在45 - 50次/分钟的频率下维持最佳。在六只犬（第一组）中，在匹配的气道开口压力（Pao）下比较IPPV和HFOV的交替时段，我们发现瘘管开放时，Pao2分别显著降至68±14 mmHg和69±24 mmHg。在第二组六只犬（第二组）中，当在IPPV和HFOV期间通过向通气回路增加偏流来提高Pao时，Pao2分别显著升至89±12 mmHg和87±8 mmHg。在诱导油酸低压肺水肿后重复第二组研究表明，传统IPPV与大量肺内分流有关。然而，HFOV将气体交换维持在接近基线值。对于第一组和第二组，在HFOV期间，在所有气道压力水平下，通过瘘管的计算气体流量均显著减少。作者得出结论，在维持氧合和减少通过瘘管的气体泄漏方面，HFOV比传统IPPV具有优势。
