Hachey W E, Eyal F G, Curtet-Eyal N L, Kellum F E
Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD, USA.
Crit Care Med. 1998 Mar;26(3):556-61. doi: 10.1097/00003246-199803000-00031.
To compare the cardiopulmonary effects of high-frequency oscillatory ventilation (HFO) and conventional ventilation (CV) in a piglet model of meconium aspiration syndrome.
Prospective, randomized control study.
Piglets 1 to 2 wks of age.
Meconium aspiration was induced in 30 piglets. They were then randomized to CV, HFO at 10 Hz, or HFO at 15 Hz.
Arterial blood gas, and systemic and pulmonary hemodynamics were measured serially. Airway opening pressure (P-Flex), static lung compliance (Crs), and trapped gas volume (TGV) were derived. Meconium instillation produced similar stable decreases in Crs (6.7 +/- 0.7 [SEM] to 4.7 +/- 0.4 mL/cm) and increases in pulmonary vascular resistance (68 +/- 6.4 vs. 91.9 +/- 8.5 mm Hg/mL/kg/min). A greater proportion of animals (40%, p< .007) remained hypercarbic during HFO at 15 Hz. Oxygenation indices were similar for all groups. In regards to high-frequency support, both power and deltaP were higher in the HFO at 15 Hz group (p< .001). When compared with both CV and HFO at 10 Hz, the TGV in the HFO at 15 Hz group was significantly higher following randomization to ventilator type. P-Flex was also greatest in the 15 Hz group, followed by the 10 Hz group and the CV group. Higher airway opening pressures, given identical compliance, suggest that HFO at 15 Hz resulted in greater large airway obstruction. With HFO's inherent low tidal volumes, progression of meconium to the distal airways may be delayed.
Early institution of HFO at 15 Hz in meconium aspiration may exacerbate air trapping. HFO at lower rates may be the optimal method of respiratory support in meconium aspiration syndrome. HFO may extend the window of time available for removal of meconium.
在胎粪吸入综合征仔猪模型中比较高频振荡通气（HFO）和传统通气（CV）对心肺的影响。
前瞻性随机对照研究。
1至2周龄的仔猪。
对30只仔猪诱导胎粪吸入。然后将它们随机分为接受CV、10Hz的HFO或15Hz的HFO。
连续测量动脉血气、全身和肺血流动力学。得出气道开口压力（P-Flex）、静态肺顺应性（Crs）和潴留气体量（TGV）。胎粪注入使Crs出现类似的稳定下降（从6.7±0.7[标准误]降至4.7±0.4mL/cm），肺血管阻力增加（从68±6.4增至91.9±8.5mmHg/mL/kg/min）。在15Hz的HFO期间，更高比例的动物（40%，p <.007）保持高碳酸血症。所有组的氧合指数相似。关于高频支持，15Hz的HFO组的功率和压差均更高（p <.001）。与CV组和10Hz的HFO组相比，随机分配到通气类型后，15Hz的HFO组的TGV显著更高。P-Flex在15Hz组中也最高，其次是10Hz组和CV组。在相同顺应性情况下，更高的气道开口压力表明15Hz的HFO导致更大的大气道阻塞。由于HFO固有的低潮气量，胎粪向远端气道的进展可能会延迟。
在胎粪吸入时早期采用15Hz的HFO可能会加剧气体潴留。较低频率的HFO可能是胎粪吸入综合征呼吸支持的最佳方法。HFO可能会延长清除胎粪的时间窗。
