Wiswell T E, Bley J A, Turner B S, Hunt R E, Fritz D L
Division of Medicine, Walter Reed Army Institute of Research, Washington, DC.
Pediatrics. 1990 Jan;85(1):70-8.
To assess the role of high-frequency ventilator strategy in the propagation of airway injury, we compared the tracheobronchial histologic alterations in 20 newborn piglets ventilated for 8 hours with high-frequency flow interruption (HFFI). Ten animals were assigned to HFFI with a strategy of continuous pulsations at a frequency of 10 Hz and a mean airway pressure of 16 cm H2O. Ten piglets were treated at identical settings except for 10 one-second baseline pauses per minute to a positive end-expiratory pressure of 5 cm H2O. A semiquantitative scoring system was used to grade light microscopic tissue alterations in the trachea, carina, and mainstem bronchi. Ultrastructural changes were evaluated with scanning electron microscopy. The HFFI-continuous-treated piglets had significantly more damage in all areas than the HFFI-baseline pause group (P less than .001). The upper tracheas of animals in both groups were altered to a greater extent than the lower tracheas (P less than .007). In addition, numerous "skip" areas of injury were noted throughout the tracheas. High-frequency ventilator strategy is a determinant of the severity of airway histologic changes. Factors that adversely affect tissue oxygenation or cause direct mechanical trauma may also influence the degree of injury. Optimal operating characteristics and limitations of different high-frequency devices must be assessed before their use in human neonates.
为评估高频通气策略在气道损伤传播中的作用，我们比较了20只新生仔猪在高频气流阻断（HFFI）通气8小时后的气管支气管组织学改变。10只动物采用频率为10Hz、平均气道压力为16cmH₂O的持续脉动策略进行HFFI通气。另外10只仔猪除每分钟有10次1秒的基线暂停至呼气末正压为5cmH₂O外，其他设置相同。采用半定量评分系统对气管、隆突和主支气管的光镜下组织改变进行分级。通过扫描电子显微镜评估超微结构变化。与HFFI-基线暂停组相比，持续接受HFFI治疗的仔猪在所有区域的损伤明显更严重（P<0.001）。两组动物的上气管改变程度均大于下气管（P<0.007）。此外，在整个气管中发现了许多“跳跃”性损伤区域。高频通气策略是气道组织学改变严重程度的一个决定因素。对组织氧合产生不利影响或导致直接机械创伤的因素也可能影响损伤程度。在将不同的高频设备用于人类新生儿之前，必须评估其最佳操作特性和局限性。
